Mobile House.

2010-05-27T22:56:00.000-07:00

Mobile House Glossary

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ADC - Analog to Digital Converter.
Adjacent channel interference - Refers to interference caused by the energy from a transmitting channel spilling over into an adjacent channel. This interference can be minimized by applying filters to the transmitting and receiving ends or by simply using non-adjacent frequency channels within a cell. Cellular systems typically transmit on non-adjacent frequencies within a cell in order to prevent adjacent channel interference.
Airtime - Actual time spent talking on the cellular telephone. Most carriers bill customers based on how many minutes of airtime they use each month.
AJ - Anti-Jam. A communication signal that is designed to resist interference or jamming.
Alert - Constant 10 KHz signaling tone sent on the reverse voice channel (by the mobile), in an analog conversation, while the mobile phone is ringing.
Alphanumeric - A message or other type of readout containing both letters ("alphas") and numbers ("numerics"). In cellular, "alphanumeric memory dial" is a special type of dial-from- memory option that displays both the name of the individual and that individual's phone number on the cellular phone handset.
AM - Amplitude Modulation. The simplest carrier modulation technique where the RF carrier's amplitude envelope is modulated.
AMPS - Advanced Mobile Phone System. The current analog cellular FM system in North America. It uses 30 KHz channels and signaling is done superaudio.
Analog - The traditional method of modulating radio signals so that they can carry information. AM (amplitude modulation) and FM (frequency modulation) are the two most common methods of analog modulation. Analog modulation techniques have been around for more than 50 years and offer a proven, known method of using analog, but the switch to digital is already underway.
ANSI - American National Standards Institute. The ultimate accolade for any standard is ANSI certification. This does not mean that ANSI has reviewed the standard, but that it has been circulated widely throughout the industry and that it conforms to their document design and publication guidelines.
ARDIS - A wireless two-way data network jointly owned and operated by Motorola and IBM.
Attenuation - Weakening of the RF signal due to being partially blocked or absorbed. Attenuation is heavily dependent on the frequency of the RF transmission and on the physical characteristics of the material that the transmission interacts with. For example, high frequency microwave transmissions are severely attenuated by rain, but lower frequency cellular transmissions are not.
Auto-correlation - A measure of the similarity between a signal and a time-shifted replica of itself; a special case of cross-correlation. The auto-correlation function is the theoretical basis of direct sequence spread spectrum.
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Bandit Mobile - A mobile subscriber that is revealed in the toll-ticketing records as having an invalid ESN, invalid telephone number, or other problem that warrants denial of service to that mobile.
Bandwidth - The amount of frequency allocated for an RF transmission. For example, a cellular channel typically has a bandwidth of 30 KHz, I.E. a cellular system requires 30 KHz of frequency per channel to transmit it's signal.
Base station - The base station is a multicircuit transceiver located at the center of a cell whose primary purpose is to handle all incoming & outgoing calls within the cell. The base station relays the mobile's signal to the MTSO via wireline.
BER - Bit Error Rate.
Broadband - A communications channel that has a bandwidth greater than 64 kilobits per second and that can provide higher speed data communications than a standard telephone circuit (also called wide band).
BT - Bandwidth data rate product, filter bandwidth times bit period, for various modulations including GMSK. Also referred as modulation depth. For example, GSM uses GMSK with BT=0.3.
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Call Forwarding - A feature allowing the subscriber to forward a call to another telephone number.
Call Processing - The complete process of routing, originating, terminating cellular telephone calls, along with the necessary billing and statistical collection processes.
Call Record - A record stored on DAS tape containing mobile number, dialed digits, time stamp information, and other data needed to bill or 'ticket' a cellular telephone call.
Call Setup - The call processing events that occur during the time a call is being established, but not yet connected.
Call Waiting - A feature allowing the subscriber to be alerted of another call during a current conversation. User can answer the call waiting, but cannot connect all parties (connecting all parties is considered a conference call).
Carrier - The operating frequency of a wireless system. A fixed frequency radio signal which is shifted up and down (modulated) in either frequency (FM) or level (AM) by the audio signal.
CDMA - Code Division Multiple Access. In a CDMA system, each voice circuit is labeled with a unique code and transmitted on a single channel simultaneously along with many other coded voice circuits. The receiver uses the same code to recover the signal from the noise. The only distinctions between the multiple voice circuits are the assigned codes. The channel is typically very wide with each voice circuit occupying the entire channel bandwidth. This system used 1.23 MHz wide channel sets. The full vocoder rate is 8.55 Kbits/sec, but voice activity detection and variable rate coding can cut the data rate to 1200 bits/sec. A very robust and secure channel can be established, even for an extremely low-power signal-theoretically, the signal can be weaker than the noise floor.
Example:
CDMA channel

           -----------------------------------

1.25MHz     |   64 different voice circuits   |

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64 different voice circuits can be simultaneously transmitted on the same channel. More impressively, by using different codes, a number of different channels can simultaneously share the same spectrum, without interfering with each other. The voice circuits are identified by their assigned codes.

CDPD - Cellular Digital Packet Data - sending digital data over the existing AMPS system, by transmitting dense packets on vacant analog channels
CDPD Forum - Cellular Digital Packet Data Forum. A trade association to promote the development of the cellular data industry and, in particular, to the standardization and effective use of cellular digital packet data (CDPD technology). This group maintains the CDPD protocol specification that allows the transmission of packet data over analog cellular channels.
Cell - The RF coverage area in the cellular system resulting from operation of a single multiple-channel set of base station frequencies. Cell can also refer to the base site equipment servicing this area. A city or county is divided into smaller "cells", each of which is equipped with a low-powered radio transmitter/receiver. The cells can vary in size depending upon terrain, capacity demands, etc. By controlling the transmission power, the radio frequencies assigned to one cell can be limited to the boundaries of that cell.
Cell splitting - A means of increasing the capacity of a cellular system by subdividing or splitting cells into two or more smaller cells.
CELP - Code Excited Linear Predictive compression algorithm.
Central Office (CO) - The switching office that connects the MTSO (Mobile Telephone Switching Office) to the PSTN (Public Switched Telephone Network). The CO is also known as a Class 5, or 'end' office.
CGSA - Cellular Geographic Service Area. The actual area in which a cellular company provides cellular service.
Channel - A unique RF frequency that is used for communication between subscriber unit and cell site base station. Must be assigned by the FCC (Federal Communications Commission).
Chip - The time it takes to transmit a bit or single symbol of a PN code.
Click Tone - A particular progress tone injected onto the forward voice channel (mobile unit receive, base station transmit) to indicate to the subscriber that the call has not been abandoned by the system.
Cochannel interference - Cochannel interference refers to the interference caused between two cells transmitting on the same frequency within a network. Since cochannel interference is caused by another cell transmitting the same frequency, you can't simply filter out the interference. You can only minimize the cochannel interference through proper cellular network design. A cellular network must be designed to maximize the C/I ratio. The C/I ratio is the carrier-to-cochannel interference ratio. One of the ways to maximize the C/I ratio is to increase the frequency re-use distance, I.E. increase the distance between cells using the same set of transmission frequencies. The C/I ratio in part determines the frequency re-use distance of a cellular network.
Compandor - A combination of a compressor at the transmitter to reduce the dynamic range of the transmitted signal and an expander at the receiver to recover this signal to the original dynamic range. The transmitter encodes (compresses) the dynamics of the audio signal and the receiver decodes (expands) the dynamics of the audio signal. Used in communications systems to improve signal-to-noise as a result of reduced transmitted dynamic range. In analog cellular, 2:1 syllabic compression is used to limit the maximum peak voice deviation to +/- 2.9 KHz.
Constructive interference - Interference that occurs when waves occupying the same space combine to form a single stronger wave. The strength of the composite wave depends on the how close in phase the two component waves are. For example if you transmitted two waves of the same phase, each with an amplitude of 10, they would combine into a composite wave of amplitude 20, but two waves slightly out of phase would combine into a composite wave of amplitude less than 20.
Control Channel - A unique RF channel used by each base station dedicated for the transmission of digital control information from the base station to the mobile unit. Used to assign voice channels, control mobile power, authorize handoffs, etc.
Correlator - The receiver component that demodulates a spread spectrum signal; a device that measures the similarity of of an incoming signal and a stored reference code.
COTS - Commercial Off The Shelf.
Cross-correlation - A measure of the similarity of two different signals.
CT2 - Cordless Telephone 2.
CTIA - Cellular Telecommunications Industry Association.
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DAR - Digital Audio Radio.
DAS Tape - The magnetic tape that is used at the MTSO to record traffic statistics and call billing information. This tape is sent to a third-party 'billing-house' where the actual billing of the subscribers is done.
dB (decibel) - A unit stating the logarithmic ratio between two amounts of power. Typically used in receiver and transmitter measurements.
dBi - Decibel, Isotropic; decibel referenced to the gain of a theoretical isotropic radiator.
dBm - Decibel, Milliwatt; decibel referenced to one milliwatt into 50 ohms.
DBS - Direct Broadcast Satellite.
DCS - Digital Cellular System
DCS-1800 - Low power variant of GSM, with 1.8 GHz carrier, used in Europe (e.g., Mercury One-2-One)
DCS-1900 - Proposed use of GSM with 1.9 GHz carrier for PCS applications.
DCTU - Digital Cordless Telephone U.S. - a version of DECT proposed for the U.S. PCS market
DDS - Direct Digital Synthesis.
DECT - Digital European Cordless Telephone. A digital cordless telephone standard that incorporates some of the features of the cellular telephone systems. DECT telephones use picocells, and calls can be handed off from one cell to the next.
Detector (Demodulator) - The circuit in a receiver which is used to recover the intelligence (audio) from a signal.
De-Spreading - The process used by a correlator to recover narrowband information from a spread spectrum signal.
Destructive interference - Interference that occurs when waves occupying the same space combine to form a single weaker wave. This type of interference occurs when waves out of phase combine to form a composite wave which is weaker than any of it's component waves. For example if you transmitted two waves that were exactly 180 degrees out of phase, each with an amplitude of 10, they would completely cancel each other out.
DGPS - Differential GPS.
Digital modulation - A method of encoding information for transmission that will eventually replace analog transmission. Digital modulation reduces voice to binary code -- the zeros and ones of computer language. At the receiving end, the information is reconverted. Digital transmission offers stronger reception, less static, greater call handling capacity, fewer dropped calls, improved call privacy, and the potential for additional voice and data service such as fax and computer data transmission.
Direct Sequence - A pseudorandom (PN) code is added to the data signal which increases the modulation rate and signal bandwidth. This spreading of the energy over a wide bandwidth looks like a low level signal to other users in the band. The receiver must know the PN code transmitted and be synchronized to the code to assemble each data bit.
Diversity - Sharing a signal characteristic to allow more users in the same frequency band.
Diversity Receive - A method commonly employed by cellular manufactures to improve the signal strength of received signals. Uses two independent antennas that receive signals which differ in phase and amplitude resulting from the slight difference in antennas position. These two signals are either summed or the strongest is accepted by voting. The most popular methods include dual-antenna phase switching, dual-receiver audio switching and "ratio diversity" audio combining. The most effective method is ratio diversity combining.
Discontinuous Transmission (DTX) - A subscriber unit feature that allows the mobile to disable it's RF PA during conversation when the subscriber is not talking. Save on battery life to increase talk time. The cellular system must support this feature if the subscriber wants to use DTX.
DMR - Digital Mobile Radio.
DPSK - Differential Phase Shift Keying -- a simplified BPSK where only data transitions are transmitted.
Drop Out - A momentary loss of the carrier and sound, or a buildup of background noise when the transmitter is in a certain location in the room. Moving the transmitter (even a few inches) usually restores the sound to normal.
DSP - Digital Signal Processing.
DSRR - Digital Short Range Radio. The Commission of the European Community has designated 880 to 890 MHz and 933 to 935 MHz for unlicensed, business citizens band radio in Europe. For point-to-point communications over distances up to 6 km maximum, depending on antenna height.
DTMF - Dual Tone Multi Frequency. Commonly known as 'touch-tones', this in-band signaling is made up of two tones (out of a group of 8) and is used to translate dialed digits.
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EIA/TIA-553 - The ANSI version of the analog cellular standard. Generally one step behind IS-91, and without support for NAMPS.
Electronic Serial Number (ESN) - A 32 bit code that is unique to each mobile unit. Used to validate mobile. Not alterable by both cellular operator and end user. Each cellular phone is assigned an ESN, which is automatically transmitted to the base station every time a cellular call is placed. The Mobile Telephone Switching Office checks the ESN to make sure it is valid, that the phone has not been reported stolen, that the user's monthly bill has been paid, etc., before permitting the call to go through.
Erlang - A dimensionless quantity used in the traffic statistical measurements in the cellular system. One erlang is equivalent to the average number of simultaneous calls. One erlang equals 3600 call-seconds per hour or 36 CCS (call century seconds) per hour.
ESMR - Enhanced Specialized Mobile Radio. Digital mobile telephone services offered to the public over channels previously used only for analog two-way dispatch.
ETACS - Extended TDMA. This system uses the same 30 KHz channels as TDMA, but has six users per channel. The vocoder rate is cut to 4 Kbits/sec, and the channels are dynamically assigned based on voice activity detection.
ETSI - European Telecommunications Standards Institute. The mission of ETSI is "to produce the technical standards which are necessary to achieve a large unified European telecommunications market". This includes the specification of the GSM cellular and PCS standard.
Execute source - An order sent to the mobile on the Forward Voice Channel telling mobile to change channels. Order contains new channel number and new power level.
Execute target - An order sent to the cell a mobile is being handed off to, informing the cell of the pending arrival of a mobile.
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Fade - A drop in the received signal strength as a result of the RF transmission's interactions with the transmission environment.
FCC - Federal Communications Commission. The government agency responsible for regulating telecommunications in the United States, located in Washington, D.C. Their responsibilities for public radio communications, such as cellular, include allocation of frequencies, the development of regulations that govern their use and monitoring to ensure that regulations are followed.
FDMA - Frequency Division Multiple Access. FDMA systems transmit one voice circuit per channel. Each conversation gets its own, unique, radio channel. The channels are relatively narrow, usually 30 KHz or less and are defined as either transmit or receive channels. A full duplex conversation requires a transmit & receive channel pair. For example, if a FDMA system had 200 channels, the system could handle 100 simultaneously full duplex conversations. (100 channels for transmitting and 100 channels for receiving)
Example:
FDMA channel
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30KHz   | Single voice circuit - one way conversation only  |

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FEC - Forward Error Correction (coding / decoding technique). 
FER - Frame Error Rate.
FH - Frequency Hopping.
FHMA - Frequency Hopping Multiple Access.
Flash- Hook - 400ms of signaling tone sent on the reverse voice channel (by the mobile) to request a hook flash.
FM - Frequency Moduation; modulation of the RF carrier frequency.
Follow-Me Roaming - The ability for the cellular system to automatically forward calls to a roaming mobile that has left it's primary service area. Without this feature, the calling party must know the location of the roamer and place a call to that areas MTSO first (calling a 'port'), then calling the mobile.
Forced Disconnect - A call processing function that forces termination of a call, usually not at the mobile subscriber's request.
Forward Control Channel (FOCC) - A Control Channel used from the base station-to-subscriber direction, also known as the control channel downlink.
Forward Voice Channel (FVC) - A voice channel used in the base station-to-subscriber direction, also known as the voice channel downlink.
Four-Wire Line - A two-way transmission circuit using two pairs of conductors, to allow full duplex (simultaneous) conversation without multiplexing.
Free space loss - This is simply the power loss of the signal as a result of the signal spreading out as it travels through space. As a wave travels, it spreads out its power over space, I.E. as the wave front spreads, so does its power.
Frequency hopping - The transmitter hops to one of many channels, The receiver knows the sequence of the frequency hopper and follows each hop.
Frequency Reuse - The ability to use the same frequencies repeatedly within a single system, made possible by the basic design approach for cellular. Since each cell is designed to use radio frequencies only within its boundaries, the same frequencies can be reused in other cells not far away with little potential for interference. The reuse of frequencies is what allows a cellular system to handle a huge number of calls with a limited number of channels.
Frequency Shift Keying (FSK) - The form of frequency modulation that used two separate audio frequencies to transmit binary ones and zeros.
Front-End - The first stage of filtering in a receiver. The first circuit stage following the antenna input to the receiver.
FSK - Frequency Shift Keying; a digital binary modulation of the RF carrier frequency.
Full Duplex - Refers to a communications system that uses two separate transmit and receive paths to allow simultaneous conversation in two directions.
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GaAs - Gallium Arsenide.
GEO - Geosynchronous Earth Orbit satellite. Geosynchronous systems include Inmarsat and OmniTRACS. The Inmarsat system uses allocations in the 6 GHz band from the ground station to the satellite, 1.5 GHz for the satellite-to-terminal downlink, 1.6 GHz for the terminal-to-satellite uplink, and 1 GHz from the satellite to the ground station.
Glare Hold and Glare Release - A method of glare resolution. Glare occurs when both the local and distant end of a trunk are seized at the same instant; this usually results in deadlock of the trunk. To prevent this, one end of the trunk is assigned a glare hold status and the other a glare release status. In the event of glare, the glare hold end holds the trunk and the glare release end releases the trunk and attempts to seize another. Used between MTSO and connecting cell sites.
GLONASS - The Russian Global Navigation Satellite System is similar in operation and may prove complimentary to the NAVSTAR system. Launched in 1996, is a 24 satellite constellation 19,100 Km above the earth in three orbital planes.
GMSK - Gaussian Minimum Shift Keying. A form of frequency shift keying which shapes pulses to minimize spectral leakage. Used in GSM.
GNSS - Global Navigation Satellite Systems. Extended GPS systems, providing users with sufficient accuracy and integrity information to be useable for critical navigation applications.
GPS - Global Positioning Satellite. Satellite-based radio positioning systems that provide 24 hour three-dimensional position, velocity and time information to suitably equipped users anywhere on or near the surface of the Earth (and sometimes off the earth). GPS is a 24 satellite constellation, 20,000 Km above the earth in six orbital planes. The NAVSTAR system, operated by the U.S. Department of Defense, was the first GPS system widely available to civilian users.
Grade-of-Service - A measure of what percentage of calls placed through an exchange fail to be completed due to congestion of that exchange. In cellular, a 2% GOS is considered acceptable.
GSM - Global System for Mobiles. The most mature digital wireless standard is GSM, usually referred to as the 'European' digital standard. GSM is a TDMA standard, with 8 users per channel. The speech is taken in 20 ms windows, which are sampled (13-bit resolution at 8 ksps), processed and compressed. The vocoder rate of 13 kbits/s is used. A channel is 200 KHz wide, and contains data from eight users. Each user has a time slot of 0.577 mS, during which a burst of 156 bits is transmitted at a modulation frequency of approximately 270 KHz. GSM is transmitted on a 900 MHz carrier.
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Half-rate - A variant on GSM; doubles capacity by more efficient coding using speech compression.
Handoff (inter-cell) - The process by which subscribers traveling throughout the system coverage area are switched from cell-to-cell (and different channels) with better coverage for that particular area when poor quality conversation is detected.
Handoff (intra-cell) - The process by which subscribers traveling throughout the system coverage area are switched from cell sector-to-sector (and different channels) with better coverage for that particular area when poor quality conversation is detected.
Hands-free: - A feature that's included with most of today's car phones. It permits the driver to use his cellular car phone without lifting or holding the handset to his ear. An important safety feature.
HO Tone - Handoff Tone. 50ms of signaling tone sent by the mobile on the REVC to indicate leaving the source cell site during handoff.
Hand Off Measurement Request. (HOMR) - A digital message sent from the MTSO to a possible target cell site requesting the scanning receiver at that cell scan and report the RSSI of a particular mobile.
Handshaking - A set of signals that coordinate the transfer of data from one device to another.
Hard-Handoff - A hand off that occurs when the subscriber is already using the TPC (three-party-conference) card, and the TPC card cannot be used to aid in a smooth handoff.
Harmonic Filter - Used in the base-station and subscriber transmitter circuits to remove unwanted harmonics from being transmitted and radiated by the antenna.
High Side Injection - A superhet receiver design in which the oscillator frequency is above the carrier frequency.
HIPERLAN - An ETSI approved wireless WLAN, operating at 5.2 GHz with data rates up to 20 Mbps per channel (5 channels).
Hybrid - A circuit used in telephony to convert 2-wire to 4-wire operation and vice-versa. Every telephone contains a hybrid to separate ear piece and mouthpiece audio and couple both into a 2-wire circuit that connects to the Central Office. If the hybrid is not balanced properly, echo or 'loop-back' can result in the circuit when the transmitted signal is reflected back into the receive path.
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Idle Channel - A channel that is assigned to a base station use but is not currently in service (being used). All idle channels for each base station are kept in a 'idle-link-list' which is constantly updated at the MTSO.
IEEE802.11 - A WLAN standard (or set of standard), operating at 2.4 GHz and with data rates of up to 1 Mbps
IF - Intermediate Frequency. Refers to the resulting signal in a superhet receiver after the incoming carrier is mixed with the oscillator signal.
Image Rejection - A measure of the ability of the receiver to reject RF signals present on the image frequency of the receiver. Image rejection is one of the purposes of front-end filtering in a superhet receiver.
IM Rejection - A measure of the ability of the receiver to reject signals which are capable of producing IM products.
Infrastructure - All parts of the cellular system, excluding the subscriber. Includes the MTSO, Base Stations, Cell Sites, and all links between them.
In-Band Signaling - A process in which audio tones between 300 and 3400 Hz provide supervisory and/or address signaling.
Interface - A common boundary between two or more systems, integrated circuits, or pieces of equipment that ensures a proper connection between them.
Intermodulation - Also referred to as "IM." The mixing of two or more signals, producing sums, differences and harmonic multiples. IM generally occurs in the gain amplifier ahead of the mixer stage within a receiver, but also occurs in any non-linear device.
IS-3 - The original analog cellular standard, now replaced by ANSI standard EIA/TIA-553 and TIA interim standard IS-91.
IS-41 - The protocol for 'roaming' within the USA, describing how services should 'hand over' between operators
IS-54 - The TDMA standard for U.S. digital cellular. A digital cellular system that squeezes three conversations into one cellular channel.
IS-88 - Narrowband Analog Cellular system developed by Motorola that squeezes three conversations into one cellular channel using analog frequency division multiplexing. First standardized in TIA interim standard IS-88, and now incorporated in IS-91.
IS-91 - Analog Cellular and PCS. The TIA version of the analog cellular standard, incorporating the functionality of IS-88 (narrowband analog) and IS-94 as well as PCS band operation.
IS-94 - Inbuilding Cellular. A standard for inbuilding operation of analog cellular systems using extremely low power. Now incorporated in IS-91.
IS-95 - The CDMA (Qualcomm) standard for U.S. digital cellular. A digital cellular system that squeezes between 10 and 20 conversations into one cellular channel by combining 30 KHz cellular channels into a single 1.25 MHz channel and using code division multiplexing to combine and recover the individual conversations.
IS-136 - TIA standard that provides dual mode (analog and digital) cellular services using the TDMA technology. An enhancement to IS-54 TDMA, that includes a more advanced control channel (known as the digital control channel (DCCH), to distinguish it from the 'analog' control channel, which although less sophisticated, is still digital!).
IS-634 - TIA standard for 800 MHz cellular base-station to switch interface. Supports CDMA.
IS-651 - TIA standard for an open interface between the PCS switching center and the radio base-station subsystem in a PCS network. Supports both GSM and CDMA.
ISM Band - Industry, Scientific and Medical Band. Unlicensed 902 - 928 MHz, 2.4 - 2.4835 GHz and 5.725 - 5.850 GHz bands, RF power up to 1 watt. Frequency hopping or direct sequence transmission allowed.
Isotropic Radiator - A completely non-directional antenna (one which radiates equally well in all directions.) This antenna exists only as a mathematical concept and is used as a known reference to measure antenna gain.
ITS - Intelligent Transportation Systems.
IVHS - Intelligent Vehicle Highway Systems.
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JDC - Japanese Digital Cellular - now renamed PDC. Uses upper 900 MHz and 1.5 GHz bands.
J-TACS - Japan Total Access Communication System. Narrowband analog cellular FM system used in Japan. Channels are 12.5 KHz wide and signaling is subaudio.
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Late Target Channel Keyup - A condition when the target cell does not receive the execute target order in time for the arriving mobile, caused by link delays between MTSO and target cell site. After the mobile retunes to the target cell, noise will be heard on the downlink audio from the target cell, as the assigned voice channel is not on the air (yet). This results in noise during the handoff.
LEO - Low Earth Orbit satellite.
Little LEO - Relatively small and inexpensive satellites that provide low-cost, low-data rate, two-way digital communications, and location positioning to small handheld terminals. The frequency allocations are in the VHF band below 400 MHz. Systems include Leosat, Orbcomm, Starnet, and Vitasat. For example, the Orbcomm system requires 34 satellites for reliable full-world coverage.
LMR - Land Mobile Radio - wireless for specialized applications - e.g., taxi or emergency services
LMS - Local and Monitoring Service.
LNA - Low Noise Amplifier.
Low Side Injection - A superhet receiver design in which the oscillator frequency is below the carrier frequency.
LPC - Linear Predictive Coding compression algorithm.
LTP - Long Term Prediction compression algorithm.
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Microwave - A signal in the generic frequency range from above 1 GHz to an upper end of perhaps 30 or 40 GHz.
Microwave Hop - A microwave RF connection between MTSO and cell sites in remote locations.
Mixer - The circuit or component in a superhet receiver where the oscillator signal is combined with the incoming carrier signal.
MIN1 - The 24-bit number which corresponds to the 7-digit subscriber telephone number.
MIN2 - The 10-bit number that corresponds to the 3-digit subscriber area code.
MMI - Man/Machine Interface - how easy a phone is to use, how fun, how sexy. As phones conform to strict standards, the MMI becomes a key area of differentiation.
Mobile Coverage Area - Geographical area in which two-way radio service can be expected (between base station and mobile unit).
Mobile-ID - The 7 digit mobile telephone number. Does not include area code.
Mobile Attenuation - The power of the mobile can be adjusted (or attenuated) dynamically to one of seven discrete power levels (analog cellular). This is done so that when a mobile comes closer to a base receiver its power is reduced to prevent the chance of interfering with other mobiles operating on the same voice channel in another cell (co-channel interference). Additionally, this is even more important to portable units to keep the transmit power at a minimum to increase the talk usage time before the batteries expire.
Mobile Origination - The initiation of a telephone call by a mobile unit.
Mobile unit - The mobile unit is either a handheld or car mounted transceiver. The mobile unit connects the user to the base station via RF (radio frequency). The mobile unit is also known as the "Subscriber".
MSA - Metropolitan Service Area. A cellular coverage, defined by the FCC, which resides in a densely populated area. here are 306 MSAs in the United States, all of which now have cellular service.
MSPS - Megasamples per second. Sampling rate for analog to digital converters.
MSS - Mobile Satellite Service.
MTSO - Mobile Telephone Switching Office. The switching office that all base station cell sites connect to. It is a sophisticated computer that monitors all cellular calls, keeps track of the location of all cellular-equipped vehicles traveling in the system, arranges hand-offs, keeps track of billing information, etc. he MTSO in turn interfaces to the PSTN by connection to a CO.
MU-Law (U-Law) - An encoding format for the quantization and digitization of analog signals into Pulse Code Modulation (PCM) signals (A/D) and recovery of analog signals from PCM (D/A). U-Law specifies the parameters for compression and re-expansion of the signals during signal transmission and processing. U-Law PCM encoding is used in North America. A-Law is the European format.
Multipath - The presence of multiple signals arriving at the receiver antenna simultaneously. Signals that are in phase will add to one another. Signals that are out of phase will cancel one another.
Multipath fading - Multipath fading A.K.A. Rayleigh fading occurs when the direct-path transmitted wave destructively interferes with it's reflections at the receiving end. The destructive interference is a result of the reflected waves arriving at the receiving end out of phase with the direct-path transmitted wave. Multipath interference can vary in intensity depending on the amount of destructive interference that takes place.
Multiple Access - A method for accomodating more users in the same frequency band.
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NAM - Number Assignment Module. The NAM is the electronic memory in the cellular phone that stores the telephone number and electronic serial number. Phones with dual- or multi-NAM features offer the user the option of registering the phone so that it will have two or more phone numbers.
NAMPS - Narrowband Analog Mobile Phone System. This is an analog cellular FM system using 10 KHz wide channels. Signaling is subaudio.
Narrowband - A signal whose bandwidth is on the order of its information bandwidth.
NMT - Nordic Mobile Telephone. Scandinavia cellular phone system. The latest system uses 30 KHz channels, and signaling is done using 1200 Hz and 1800 Hz tones in much the same way as a modem.
No Answer Transfer - A feature that allows calls to a mobile to be transferred to a predetermined number if the mobile does not acknowledge an incoming call or is not answered.
Non-wireline cellular company, or the Block "A" carrier - The FCC, in setting up the licensing and regulatory rules for cellular, decided to license two cellular systems in each market. It reserved one for the local telephone company, and opened the second system -- the Block A system -- to other interested applicants. Non-wireline or Block A systems operate on radio frequencies from 824 to 848 MHz.
NTIA - National Telecommunications and Information Administration, sponsored by the Commerce Department.
Numbering Plan Area (NPA) - The area code.
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Off-Hook - Circuit condition caused when the handset is lifted from the switch hook of the telephone set. Condition exists during call set-up or conversation.
Off-peak - The periods of time during which carriers offer discounted airtime charges. Usually, off-peak rates are available between 10:01 p.m. and 5:59 a.m. and on weekends and select holidays, but times can vary.
On-Hook - The normal circuit condition when the handset is on the switch hook of the telephone set.
Operator - In cellular, this is the local service provider operating company that owns the cellular system in that particular area.
OQPSK - Offset Quadrature Phase Shift Keying. QPSK with an initial phase offset (of usually 45 degrees); OQPSK has less envelope AM than QPSK.
Origination - A call that is placed by the mobile subscriber, calling either a land-line circuit or another mobile subscriber.
Oscillator - An electronic circuit which generates a signal at a specific frequency.
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PACS - Personal Access Communication System - a candidate for the U.S. PCS
Page - A message which is broadcast from a group of cell sites that carries a mobile ID, for the purpose of alerting the mobile that a call is waiting.
Parity - A self-checking code employing binary digits in which the total number of ones is always odd or even.
PCN - Personal Communication Network. PCNs are usually short range (100's of feet to 1 mile or so) and involve cellular radio type architecture. Services include digital voice, FAX, mobile data and national/international data communications. Also -- A network of pocket-size radio telephones served by clusters of receiver transmitter cells.
PCS - Personal Communications Service. Within the U.S., the 1.9 GHz band has been allocated for PCS systems; the allocated spectrum is 120 MHz wide and is licensed as two 30 MHz segments for the 51 major trading areas, and three 10 MHz segments for the 493 basic trading areas.
PCS-1900 - See DCS-1900
PDC - Personal Digital Cellular, Japanese cellular standard.
Peak: - That part of the business day in which cellular customers pay full service rates. Peak hours are generally 6:00 a.m. - 10:00 p.m.
PHS - Personal Handyphone system, Japanese cordless standard.
Pigtail antenna - The standard cellular antenna for a car. The term "pigtail" refers to the spring-like section in the lower third of the antenna known as the phasing coil.
PL - The mobile power level
PM - Phase Modulation; modulation of the phase of an RF carrier.
PN - Pseudo-random Noise. A digital signal with noise-like properties. Also a wideband modulation which imparts noise-like characteristics to an RF signal.
Port Change - A channel change from one sector to another, but staying within the same cell.
Private Mobile Radio (PMR) - Mobile communication network which is meant for a special group of users, e.g. for one or more enterprises or institutions.
Processing Gain - The ratio of the bandwidth of a spread spectrum signal to the data rate of the information.
PSK - Phase Shift Keying. A digital modulation of the phase of a signal's RF carrier.
Pulse Code Modulation (PCM) - Process in which the modulating signal is sampled, and the magnitude of each sample (with respect to a fixed reference) is quantized and converted by coding to a digital signal. Provides undistorted transmission, even in the presence of noise. The sample frequency must be at least twice the highest modulating frequency for full recovery of the original modulating information (Nyquist).
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QPSK - Quadrature Phase Shift Keying; 4 phase digital modulation.
Quantization - A process in which the continuous range of values of an input signal is divided into non-overlapping sub-ranges (chords) and to each sub-range a discrete value of the output is uniquely assigned a binary number.
Quantization Distortion - The inherent distortion introduced in the process of quantization.
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RBDS - Radio Broadcast Data System.
Receiver - The device that picks up the radio signal from the transmitter, converts it into an audio signal and feeds audio into your sound system or recorder.
Receiver Image A second frequency that a superhet receiver will respond to. The image frequency is two times the IF frequency either above or below the carrier frequency, depending upon whether the receiver design is "low side" or "high side" injection. An RF signal on the "image" frequency of the receiver will produce a difference signal in the mixer just as valid as the intended IF signal created by mixing the oscillator with the carrier.
Reflections - RF waves can reflect off of hills, buildings, moving cars, the atmosphere, and basically almost anything in the RF transmission environment. The reflections may vary in phase and strength from the original wave. Reflections are what allow radio waves to reach their targets around corners, behind buildings, under bridges, in parking garages, etc. RF transmissions bend around objects as a result of reflections.
Relative Signal Strength Indication (RSSI) - A value representing the received signal strength of both the mobile unit and the base station. This value is used to initiate a power change or handoff.
Repertory dialing - Sometimes known as "memory dialing" or "speed-calling". A feature that allows you to recall from nine to 99 (or more) phone numbers from a phone's memory with the touch of just one, two or three buttons.
Return Loss - A measure of VSWR, expressed in dB.
Reverse Control Channel (RECC) - The Control Channel that is used from the mobile station to the base station direction, also known as the control channel uplink.
Reverse Voice Channel (RVC) - The voice channel that is used in the mobile station to base station direction, also known as the voice channel uplink.
RF - Radio Frequency. Also used generally to refer to the radio signal generated by the system transmitter, or to energy present from other sources that may be picked up by a wireless receiver.
RFI - Radio Frequency Interference. A non-desired radio signal which creates noise or dropouts in the wireless system or noise in a sound system. RFI can be generated by a wide variety of sources including electronic organs, computers, switching power supplies, broadcast radio signals and outside radio devices. Radio signal energy can enter a sound system component or alter the audio signals in cabling, producing annoying hiss, whining or intelligible audio signals. Proper shielding and balanced audio cabling are the best defense against RFI problems in a sound system. High quality receivers are the best defense against RFI in wireless microphone systems.
RFID - RF Identification.
RF Noise - Radio signals generated by something other than the transmitter. Usually sounds like hiss, static or hash. RFI (Radio Frequency Interference) may be AM or FM, but the effect is that it either alters the audio signal, or adds background noise to the audio signal.
Roamer - A mobile station which operates in the cellular system other than the one from which the service is subscribed (the home system).
RPE - Regular Pulse Excitation compression algorithm.
RSA - Rural Service Area. A cellular coverage, defined by the FCC, which resides in a less populated area. he FCC designated 428 rural markets across the country to be licensed to cellular operators. The final RSA was activated in May 1992, giving the entire nation access to cellular service.
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Scan Receiver - A receiver that resides in the base station that is dedicated to measure mobile's signal strengths. These measurements are used in the handoff process (but not in the power-up/power-down process, which is handled by each voice transceiver).
Sector-Receive Cell Site - Six or three directional antennas that are used at a cell site to get additional gain required to serve mobiles. A mobile could move completely around a Sector-Receive cell site and never change channels, but would change antennas.
Sector-Sector Cell Site - The cell is broken up into two or more independent sectors that each have their own transmit and receive antennas. A mobile moving around a Sector-Sector cell would change channels (Intra-cell handoff)
Selectivity - The ability of a receiver to reject interfering signals close to the desired carrier frequency.
Sensitivity - The ability of a receiver to operate on very weak RF signal levels.
SHF - Super High Frequency. A signal in the frequency range of from 3 to 30 GHz.
Sidetone - An attenuated portion of the transmit audio returned to the originator. Can be intentional as all phones produce some sidetone and is caused by unbalanced 2-to-4 wire hybrids.
Signal-to-Noise - The ratio of the magnitude of the signal to that of the noise with no signal present, usually expressed in dB.
Signaling Tone (ST) - A 10 kHz tone transmitted by the mobile station on a voice channel to (1) confirm channel change orders (HO tone, 50ms ST), (2) request a flash-hook by the mobile (400ms ST), (3) mobile alert (continuous ST), (4) mobile ending call (1.8sec ST).
SIM - Subscriber Identification Module. A credit card size card which is owned by a subscriber, who slides it into any GSM handset to transform it into 'their' phone. It will ring when their unique phone number is dialed; calls made will be billed to their account; all options and services connected; voicemail can be collected and so on.
SMR - Specialized Mobile Radio. FCC has allocated the 896-901 MHz band (800 MHz band) which uses two paired 25 KHz channels and the 935-940 MHz band (900 MHz band) which uses two paired 12.5 KHz channels. Ten 20 channel blocks have been allocated in these frequency bands. 900 MHz SMR is primarily used for radio dispatch , paging and wireless data communications.
Source Cell - The cell that a mobile is leaving during the hand off process.
Source Channel Falsing - A condition that exists when co-channel SAT exists on the source channel during handoff, so that source channel does not squelch during the handoff process. This results in noise during the handoff process (after the handoff order) that can be heard by both the landline and mobile parties.
Spectrum - The electromagnetic spectrum. A continuous group of electromagnetic frequencies.
Spread Spectrum - A communication technique that spreads a signal bandwidth over a wide range of frequencies for transmission and then de-spreads it to the original data bandwidth at the receiver.
Squelch Circuit - A radio receiver circuit which disables the audio path when the incoming signal is below a predetermined threshold. When the radio signal from a transmitter is too weak to produce a quality audio signal, the receiver will shut off or "squelch."
Standby time - The amount of time you can leave your fully charged cellular portable or transportable phone turned on before the phone will completely discharge the batteries.
Station Class Mark (SCM) - Indicates mobile station type (mobile/transport), and if station has DTX.
Subaudio - Frequencies below the audio bandwidth for speech, which is 300 to 3000 Hz.
Subscriber - The mobile user of the cellular system.
Subscriber Files - Stored at the MTSO and contains all information pertaining to each subscriber. Includes mobile number, home service location, last known location, type of mobile, service denial flags, and special feature options available to that subscriber.
Super Audio - Frequencies above the audio bandwidth, which is 300 to 3000 Hz.
Superheterodyne - The mixing of two signals producing a third signal. Almost all other receivers) utilize an oscillator, producing a signal which is mixed with the incoming radio signal from the receiver antenna to produce a lower frequency signal (the IF signal).
Supersonic Noise Squelch - A fairly popular method of muting the audio output of a receiver when the supersonic noise reaches a preset level. The assumption is that noise buildup above the audio passband (20 to 30 KHz range) is an indication that the signal to noise ratio of the system is inadequate to produce a usable audio signal.
Supervisory Audio Tone (SAT) - One of three tones (5970, 6000, and 6030 Hz) that are transmitted by the base station and transponded by the mobile station. Used to evaluate the complete radio path, both Forward and Reverse Voice Channels. The SAT received by the mobile unit is actually regenerated by the mobile unit with the same amplitude and noise associated with the actual received SAT.
System Identification (SID) - A unique digital code assigned to each cellular system. The home system of each mobile is stored in it's internal memory so that the mobile knows when it is a roamer (outside it's normal service area).
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TACS - Total Access Communication System. This is the analog cellular FM system used in the United Kingdom and Japan. It uses 25 KHz channels and signaling is super audio.
Talk time - The length of time you can talk on your portable or transportable cellular phone without recharging the battery. The battery capacity of a cellular portable or transportable is usually expressed in terms of so many minutes of talk time OR so many hours of standby time. When you're talking, the phone draws more power from the battery.
Target Cell - The cell that a mobile is going to during the hand off process..
Target Channel Falsing - A condition that exists when co-channel SAT exists on the target channel during handoff, so that target channel does not squelch before arrival of the mobile during the handoff process. This results in noise during the handoff process (before the handoff order) that can be heard by both the landline and mobile parties.
TCM - Trellis Coded Modulation.
TDMA - Time Division Multiple Access. TDMA systems are able to transmit multiple voice circuits per channel. A TDMA channel is a single FDMA channel divided up in time into multiple time slots. Three users can take it in turn to share one radio channel. The channels can vary in bandwidth and depending on the type of system, the time slots can transmit all or part of a voice circuit. Each user's speech is stored, compressed and transmitted as a quick packet, using controlled time slots to distinguish them-hence the phrase 'time division'. Its uses 30 KHz channels and a vocoder rate of 8 Kbits/sec. At the receiver, the packet is de-compressed.
Example:
TDMA channel

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30 KHz | Voice circuit #1|Voice circuit #2|Voice circuit #3|Voice circuit #4|

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Depending on the type of system, slots 1, 2, 3, & 4 could each transmit a voice circuit. In this example, 4 telephone circuits are transmitted on a single 30 KHz channel, a 4X increase in capacity over the FDMA example.
TETRA - Trans European Trunked Radio Access - European digital cellular land mobile radio system
Termination - A call that is received by a mobile subscriber, that was placed by either a line-line party or another mobile subscriber.
Third Order Intercept - A measure of how well the receiver resists interference caused by multiple interfering signals. This specification gives a single, excellent measure of how well the receiver resists many kinds of overload. It is directly related to the RF compression level.
TIA - Telecommunications Industry Association - U.S. Standards making body
Toll Ticketing - DAS records that are kept at the MTSO for billing purposes. Contains subscriber number, time of call, called number, location of call origination, location of call termination, and other important statistics for proper billing of subscriber.
Toll Ticketing House - A third party company that takes the DAS toll ticketing records and actually bills the subscribers. Non-payment by subscribers is reported to the operating company so denial of service can be performed.
TPC - Three Party Conference Circuit. Used in three party conference, but more importantly, used during every handoff so that the channel-change transition can be made with less noise by connecting the audio of the source and target cells together before the hand off order is sent. (When a handoff is made during a three-party conference call, and the TPC is being used, 'hard-handoffs' exists and the potential for noise during channel changes increases significantly)
Transmitter - The device worn (or held) by the user which sends or "transmits" the sound from the microphone to the receiver. The transmitter actually converts the electrical signal coming from the microphone into a radio signal and then "transmits" it out through some sort of antenna.
Trunk - In cellular systems, this is the connection between the MTSO and CO and the connections between the MTSO and cell sites.
Tumbling ESN - Fraudulent hardware that changes the mobiles ESN every time a call is originated. Since a roamers FIRST call is often screened only for a bad ESN, an infinite number of fraudulent calls can be placed using a tumbling ESN.
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UAV - Unmanned Aerial Vehicle.
UHF - Ultra High Frequency (generally 300 MHz to 3000 MHz).
UMPS - Universal Mobile Phone Service
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Validation - The method of determining if a mobile should be given service to the cellular system. Validation often requires matching the ESN of the mobile with it's Mobile ID, and then checking the mobile against files that contain subscribers who should be denied service.
VBAP - Voice Band Audio Processor. A CODEC that handles signal conversion at the microphone and speaker.
VHF - Very High Frequency (30 to 300 MHz).
High Band wireless systems are usually 150 MHz to 216 MHz
Low band wireless systems are usually 30 MHz to 50 MHz
Voice-activated dialing - A feature that permits you to dial a number by calling them out to your cellular phone, instead of punching them in yourself.
Voice circuit - half of a full duplex conversation, I.E.one half of a two way conversation. For example, if two people are talking by phone, each of their voices is considered a separate voice circuit.
Vocoder - Voice coder, speech is encoded before transmission to reduce the number of bits required to represent speech.
Voice mail or voice messaging - A computerized answering system that automatically answers your call, plays a greeting in your own voice and records a message.
Voice Mobile Attenuation Code (VMAC) - One of eight discrete mobile power levels that are dynamically adjusted during a cellular telephone conversation. These power steps are in 4 dB increments.
VSAT -Very Small Aperture Terminal; a small (under 2 meter diameter dish) antenna and satellite receiver.
VSELP - Vector Sum Excited Linear Predictive speech compression coding.
VSWR - Voltage Standing Wave Ratio.
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Wireless - Describing radio-based systems allowing transmission or telephone and/or data signals through the air without a physical connection, such as a metal wire or fiber optical cable.
Wireline cellular carrier, or the Block "B" carrier - Under the FCC's initial licensing procedures, the Block B carrier is the local telephone company. The FCC reserved one of the two systems in every market for the local telephone, or wire-line company. Wireline or Block B systems operate on the frequencies 869 to 894 Megahertz.
WLAN - Wireless Local Area Networks. Operating in the 2.4 GHz and 5.8 GHz unlicensed ISM bands and using spread spectrum technology are presently under development. It is expected that data rates of 1 Mbps and 10 Mbps can be achieved at 2.4 GHz and 5.8 GHz, respectively. A WLAN standard operating at 2.4 GHz (IEEE 802.11) is being 'painfully' defined (with four different versions), while European countries are developing an alternative standard (HIPERLAN) for 10 Mbps transmission, using the 5.8 GHz band.
WLL - Wireless Local Loops. Any method of using wireless communication in place of a wired connection to provide subscribers with standard telephone service.
WPBX - Wireless Public Branch Exchanges.
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Battery Comparison

Battery Type	NiCd	NiMH	SLA	Li-ion	Li-Polymer
Energy density (Wh/Kg)	50	75	30	100	175
Cycle life (typical)	1500	500	200-300	300-500	150
Fast-charge time	1 1/2h	2-3h	8-15h	3-6h	8-15h
Self-discharge	medium	high	low	low	very low
Cell voltage (nom.)	1.25V	1.25V	2V	3.6V	2.7V
Load current	very high	medium	low	high	low
Exercise req. (days)	/30	/90	/180	N/A	N/A
Battery Cost	low	medium	very low	very high	high
(estimated, ref., $)	50.00	80.00	25.00	100.00	90.00
Cost per cycle ($)	0.04	0.16	0.10	0.25	0.60
In comm. use since	1950	1970	1970	1990	1997

'Energy density' is measured in watt-hours per kilogram (Wh/kg).

'Cycle life' indicates the typical number of charge-discharge cycles before the capacity decreases from the nominal 100% to 80%

'Fast-charge time' is the time required to fully charge an empty battery.

'Self-discharge' indicates the self-discharge rate when the battery is not in use. "Moderate" refers to 1-2% capacity-loss per day.

'Cell voltage' multiplied by the number of cells provides the battery terminal voltage

'Load current' is the maximum recommended current the battery can provide. "High" refers to a discharge rate of 1C*; "very high" is a
current higher than 1C*.

'Exercise requirement' indicates the frequency the battery needs exercising to achieve maximum service life.

'Battery cost' is the estimated commercial price of a commonly available battery.

'Cost-per-cycle' indicates the operating cost derived by taking the average price of a commercial battery and dividing it by the cycle
count.

'In commercial use since' is the approximate year when the battery became commercially available.

The above information has been reproduced from http://web20.mindlink.net/cadex/link.htm . More information is available there. (Please note that Cell refers to the individual cell, battery refers to the built battery that contains multiple cells)

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Wireless Security

Wireless Communications Security

Prepared by Alan Vanderploeg

Written from a US Perspective but applies to all markets.

Introduction
Wireless communications, which is the use of cordless and cellular phones, has grown dramatically in the past ten years and has become a booming $11 billion market. The capability to communicate with others without being physically connected to a phone line has greatly increased the efficiency of corporate, government, and private sectors. Unfortunately, this capability has also led to a huge security problem, since the radio signals transmitted and received by these devices can be easily intercepted, compromised, and exploited.
These compromises include eavesdropping on conversations and spoofing (or cloning) cellular systems to gain fraudulent access. This high tech crime wave is costing the cellular industry alone over $300 million a year and has hit the above three sectors hard. Telecommunications experts believe this problem will only get worse as cordless and cellular use continues to increase. The cordless and cellular phone industry is just now beginning to design countermeasures into their devices and systems in an effort to combat this growing problem. In the meantime, it is imperative that everyone who uses these devices understand the threat they face, the scope of the problem, and present and future countermeasures they can implement to protect themselves from wireless security compromise.
The focus of this paper explains how cordless and cellular technology works and discusses the communications security threats to these systems, including how this technology is commonly compromised, who is affected, and what is lost. The effectiveness of some of the methods being explored to counter the problem is discussed, and conclusions about this problem and its countermeasures are also offered.
Explanation of Cordless/Cellular Phone Technology
To understand how "Phreakers" (a slang name for phone or cellular hackers) attack the vulnerabilities of these systems, one must understand how these systems work. Cordless phones are simply two-way radios that send an unprotected signal between the base unit (which is connected to a phone line) and the handset. Some of the more expensive versions even have a built-in encryption chip to increase conversation privacy. The ranges of these signals vary depending on the quality of the phone and surrounding interferences such as walls or powerlines, but most cordless phones are capable of transmitting and receiving signals up to 150 feet.
Cellular phones, like cordless phones, are also two-way radios. The cellular phone, however, is much more sophisticated and has a much greater, and in some cases, unlimited range. This is due to the honeycomb-like layout of cellular communications areas. Figure 1 shows a typical cellular system layout. These "cells," or communications areas, are controlled by a network control station, and each cell has a tower that can send and receive multiple radio frequencies.
Each tower periodically (usually once a minute) transmits an identifier signal. The cellular phone listens for this signal, adds a Mobile Identification Number (MIN -- programmed by the phone seller or service shop) and Electronic Serial Number (ESN -- installed by the factory and theoretically unique to each phone) to the signal, and sends it back to the tower, where it is then relayed to the network control station. This process identifies the cellular phone, billing account, and the cell location of the phone.
When a user wants to make a call, the network control station allocates an available frequency in that cell to the phone, charges the appropriate account, and allows the user to transmit a call. As the user nears the next cell, the network control station automatically hands-off the call to another available frequency in the next cell. This gives the cellular phone user a huge range from which to make or receive calls.
Current Threat
Because cordless and cellular phones transmit and receive radio signals, they face two main threats: electronic eavesdropping and cellular spoofing. One could argue that a third threat is the physical loss, damage, or theft of the actual device; however, for the scope of this paper, only the threats as they apply to electronic communications security will be discussed.
Electronic eavesdropping is listening to or recording a cordless or cellular call without the permission or knowledge of the calling and/or receiving parties. Eavesdroppers accomplish this feat by using radio frequency scanners and other receiving equipment to find and listen to the frequencies used by the devices.
This is a fairly simple process to scan cordless phone conversations since most brands operate on similar frequencies. Even baby-monitors and some brands of two-way radios share these frequency ranges. Because of these similar frequency bands, most people have picked up their cordless phone at some time and have been able to inadvertently listen to another person's conversation without that person's knowledge.
Cellular phones use frequencies that are very different from cordless phones, but since cellular phone frequencies are all in the same band range, it is very easy to intercept these frequencies with electronic scanners. Electronic eavesdropping is fairly common. According to Phil Karn, a Canadian telecommunications specialist, "...in a three-month study of Metro Toronto, Bell Canada found that 80 percent of all cellular telephone traffic is monitored by third parties."
While the author admits this number cannot be confirmed, similar studies suggest the actual percentage is anywhere between 20 and 50 percent, depending on the caller's location. Regardless of the actual percent, this is a growing problem. Not only is electronic eavesdropping easy to exploit, it is also readily available, inexpensive, and nearly impossible to detect. Communications magazines and the World Wide Web are full of advertisements and information describing how to eavesdrop on cordless and cellular traffic.
The July 1996 edition of Popular Communications alone has several ads aimed at the "eavesdropping hobbyist" that describe where to purchase scanners, what frequencies to scan, wiring diagrams, parts lists, and instructions on how to modify scanners to receive cordless and cellular frequencies. A good scanner that already receives cellular frequencies can be purchased for under $300. Due to recently enacted legislation, these types of scanners can no longer be produced, but plenty of the pre-ban scanners are still available, and just about any high quality scanner can be easily modified for under $100.
While communications privacy is a concern, it pales beside the threat of cellular spoofing. Cellular spoofing (also known as cloning) is the process where a person provides false identification [about a cellular account] to the cellular communications provider with the intent to defraud. The earliest form of spoofing appeared several years ago in the mobile telephone industry. Eavesdroppers would scan the airwaves until they identified a mobile phone channel. They would then monitor the transmissions on these frequencies and wait for an account owner to request a call.
The following is an example of how the spoofing would occur. The user would say, "Operator, this is Mobile 1111, may I please have 456-2345." The operator would connect the caller and bill Mobile Account 1111 for the call. Later, the eavesdroppers would call the operator and pretend to be Mobile Account 1111, thus charging the call to that particular account. The spoofing process became much more sophisticated with the implementation of high speed digital cellular technology.
Phreakers (or spoofers) now attempt to detect the MIN and ESN of cellular phones. They accomplish this feat by building electrical devices that scan cellular frequencies and detect the identifier signal the phone sends back to the cellular tower. The hacking equipment then strips the MIN and the ESN from the identifier signal. The phreaker takes the MIN and ESN and programs it into another cellular phone. Whenever the phreaker uses the reprogrammed phone, the network control station identifies the reprogrammed cellular phone and bills the stolen account for the call.
Cellular phones (which usually have been stolen) are commonly reprogrammed and sold for $5 or $10 dollars at flea markets and pawn shops. Many of these illegal enterprises "guarantee" the phone for one year. If the cellular service disables the account, the seller will reprogram the phone with a different MIN and ESN, re-enabling the phone.
Since the current trend of business people is to communicate via cellular phone, phreakers like to set up their equipment outside areas where business people congregate. Subways, freeways, traffic jams, downtown parks, and airports are prime spots for phreakers. Their equipment is small, lightweight, portable, and automatic, so all the phreaker is required to do is set up in an innocuous location, turn on the equipment, and wait until the memory of the device is full of numbers.
Scope of the Problem (Who Is Affected and What Is Lost)
Anyone who uses a cordless phone is susceptible to information compromise. Because electronic eavesdropping is easy to exploit and nearly impossible to detect, no one seems to be able to estimate the yearly losses it causes. However, with the rise of touch tone call routers, electronic operators, home shopping via credit cards, and 24-hour account assistance (credit card, banking, insurance, etc.), more people are giving out critical personal and financial information (such as credit card and bank account numbers) over the phone.
This development has led to a significant rise in financial fraud and will continue to do so. As an example of this, this author recently borrowed a friend's portable scanner (purchased prior to the legislation discussed previously) and listened to several wireless transmissions. After a few hours of listening, three credit-card account numbers, automobile insurance account number, and several social security numbers were obtained.
The amount of susceptible information is not limited to financial transactions. Private detectives, industrial espionage agents, drug dealers, and the press corps routinely scan wireless transmissions to increase their knowledge. Former President Jimmy Carter learned this lesson well. After completing a peaceful exchange of power in Haiti, he used a cellular phone onboard his airplane to discuss some of the aspects of the agreement. Several of the news services picked up his transmission via scanners, and made the information public before he landed in Washington DC.
Even small businesses may find themselves the target of electronic eavesdropping. A company that serviced machinery discovered they were losing business to a competitor. An investigation revealed that their competitor was intercepting their service dispatch orders (communicated to the maintenance personnel via cellular phone). The competitor would then dispatch their own personnel and beat the original maintenance crew to the scene, thus getting several of the jobs.
Cellular spoofing is directly costing the telecommunications industry over $300 million a year. While cellular spoofing is not an actual compromise of information (unlike electronic eavesdropping), it does hinder the information security process by increasing the costs of communicating. Whenever illegal (spoofed) cellular calls are made, the phone company charges the cellular account owners with the call. If the owners do not catch the erroneous calls, they unknowingly pay for it. If the owners do catch the call, they have to notify the phone company and asked to have the charge removed.
This inconvenient process (along with looking through each month's phone bill) wastes a large amount of the account owners' time. Jonathan Feinsod, a New York businessman, has had his cellular phone spoofed four times, and it took him over a week to clear up fraudulent bills in excess of $20,000. Kenneth Crupup, a Boston telecommunications consultant, has had his cellular phone spoofed twice. When he refused to change his account number for the third time, his cellular provider disabled his ability to "roam", or use the phone outside of his designated local area.
Events such as these waste a significant amount of customers' time, and tax the resources of both the customer and the cellular provider. The current design of cellular phones leads to this spoofing. The combination of the MIN and ESN was supposed to prevent spoofing and render stolen cellular phones inoperative, since cellular providers could permanently deny service to stolen phones. According to Electronic Industries Association (EIA) cellular standards, the ESN must be factory-set, the ESN must not be alterable, and any attempt to alter the ESN should render the phone inoperative.
In theory, even if phreakers identified the MIN and ESN, they would not be able to reprogram another phone with those numbers. Unfortunately, this theory is weak in practice. Most cellular phones are not constructed so that an attempt to alter their ESN will render them inoperative. ESN chips can be readily obtained or swapped on the black market or from unscrupulous cellular phone service shops. A recent case in Washington, DC revealed that an ESN was "bought" from a local service shop employee in exchange for a one-half gram of cocaine.
Even if one cannot buy an ESN, most cellular manufacturers use industry standard ROM (Read Only Memory) chips to produce an ESN. These chips can be bought in any electronics store and easily reprogrammed or copied to produce bogus ESNs. The most threatening spoofing device is known as a Cellular Cache-Box. It is a combination of a scanner, computer, and cellular phone. The Cache-Box has the capability to not only steal and memorize MINs and ESNs off the air, but also automatically reprogram itself to emulate these numbers.
After using a MIN/ESN pair one time, the Cache-Box purges these numbers from its memory and selects a new pair. This capability makes it nearly impossible to detect the fraud or catch the perpetrator. Although this equipment is rare and very expensive, it does exist and will continue to be a threat to cellular users. All of these factors, coupled with the growing number of people who are susceptible to these threats, make wireless communications extremely vulnerable. Everyone who uses wireless technology must be aware of the threat and begin taking steps to protect themselves from compromise.
Countermeasures
Even though the threat is huge, a number of common sense and technological countermeasures exist to combat electronic eavesdropping and cellular spoofing. Also, the telecommunications industry is beginning to implement new technologies to help lessen the scope of the problem. The cheapest and easiest countermeasure to fight electronic eavesdropping is to use basic communications security procedures.
Everyone who uses a wireless phone should try to minimize (or avoid) revealing any sensitive information over the airwaves. Any communications that reveal sensitive information, such as credit card numbers, financial accounts, social security numbers, passwords, etc. should be transacted over standard hard wired phones. While these devices can be bugged, the likelihood of this occurring is small. One may argue that since most telephone calls are transmitted through microwave towers, the transmissions could be easily intercepted. This is not true because the high volume, high speed, and mix of signals sent through microwave towers make electronic interception at these points nearly impossible.
Good communications security can be very effective, but people tend to forget they are on an unsecure line and accidentally give out sensitive information. Also, this countermeasure may be inconvenient if the user prefers or has to use a cordless or cellular phone to conduct business. Another countermeasure is a high-speed, frequency-switching network. This system constantly changes transmission frequencies throughout the communication. The theory is that eavesdroppers will be unable to identify, track, and listen to calls because the frequencies are constantly changing.
This system, however, still does not prevent the eavesdropper from getting lucky and finding the correct frequency and intercepting sensitive information. Additionally, these systems usually do not have a large number of frequencies available, and once the range of the frequencies has been identified, eavesdroppers can set their scanners to quickly scan only those frequencies. Regardless of the amount of common sense or knowledge of the threat one possesses, there will still be times when one must reveal sensitive information over a wireless phone.
Digital encryption is a solution for this problem. Digital encryption converts analog vocal sounds into digital signals. The transmitting phone uses a mathematical randomization code to scramble the signals and sends the transmission. The receiving phone is able to recognize the encryption code and descrambles the signals. The descrambled signal is then converted back to analog vocal sounds. Because the system randomizes the encryption code and changes it with each transmission, the code is nearly impossible to crack. The two problems with this countermeasure are its expense and availability.
Digitally encrypted cordless and cellular phones are more expensive than non-encrypted phones, and the telecommunications industry has only recently begun producing these devices. Digital cellular networks are slowly replacing analog networks throughout the country, and are only available in certain areas. According to Peter Ruber, "A national digital standard might not be reached until 1997." Until then, wireless users will have to take their own security precautions. While digital encryption seems to be the answer to the eavesdropping threat, there is an additional problem with this technology. The federal government is worried that encryption might hinder national security and federal crimefighting efforts, since legal wiretaps, which provide a large amount of evidence for federal cases, will be unintelligible.
The Clinton administration, backed by the FBI, has proposed the development and implementation of the Clipper chip as the national (and only) encryption standard. The Clipper chip is a microchip that can scramble electronic transmissions, rendering voices and digital data unintelligible. Although this sounds like an idea no one would dispute, it has caused a considerable amount of controversy amongst the telecommunications industry, civil libertarians, and the government. The controversy arises from the fact that the Clipper chip, developed by the National Security Agency, has a built-in cipher key that permits federal agents to descramble transmissions and eavesdrop on them.
Proponents of the chip point to the prospect of terrorists, spies, drug dealers, and other criminals using unbreakable scramblers to conduct business without fear of communication detection. Opponents believe the logic behind the necessity of the Clipper chip is flawed. Their main point is that since other types of electronic encryption are available, criminals could easily disable the Clipper chip and insert their own encryption chip, which would be unbreakable. Also, since there is a key to the Clipper chip, there is a chance that the key could either be broken or compromised, thereby eliminating the Clipper chip's usefulness.
Because of these concerns, the government has put a hold on the plan to implement this technology; however, this issue will continue to be controversial as more manufacturers develop and incorporate their own encryption methods in future hardware. Cellular spoofing is a harder problem to eliminate. Solutions exist, however, that can help reduce the problem. The easiest countermeasure is to keep the phone turned off until the user is ready to make a call. This technique eliminates the periodic transmissions between the network control station and the phone, making it harder to compromise number pairs. However, a phreaker only needs one transmission to steal the number pairs, so the user is still vulnerable.
Another low-tech method is to change the MIN routinely. Cellular providers and service shops can issue new MIN numbers, but this is an inconvenient and time-consuming process for both the user and the provider. It is also ineffective, since the user has no way of knowing whether their MIN/ESN has been compromised, and the phreaker can continue to use these numbers until the user changes the MIN. There are more high-tech (and more costly) countermeasures available. Many phones now incorporate a 4 digit PIN number that must be entered by the user before a call can be made. This feature hinders phreakers since their equipment usually identifies only the MIN and ESN. Most cellular phone designs now incorporate this feature.
Unfortunately, it is an easy step to modify the detection device to scan the transmission and intercept the PIN number, thereby negating the effectiveness of the countermeasure. Another high-tech countermeasure is to make the ESN chips harder to modify. Cellular phone manufactures should redesign the ESN chips and incorporate tamper-resistant circuitry. This step will make reprogramming much harder, eliminating all but the most technically advanced phreakers or phreakers with Cache-Boxes. Until ESN chips are made tamper-proof, phreakers will continue to modify and reprogram cellular phones.
The most effective countermeasure the telecommunications industry can implement is encryption. Encryption will not only help prevent unauthorized eavesdropping and compromise, it will also reduce, and possibly eliminate, cellular spoofing. The encryption design would randomly encrypt the MIN/ESN signal as well as voice communications, allowing cellular phones to identify themselves to the network control station without retransmitting the same digital signal each time. Since the encryption scheme changes with each transmission, it is extremely difficult, time-consuming, and nearly impossible to break, even with high speed computers.
Without the MIN or ESN, phreakers will be put out of business. Because the encrypted MIN/ESN signal changes after each transmission, Cache-Boxes, which retransmit the signals they intercept, would be defeated. The drawbacks to this countermeasure are complexity, cost, and time. The entire cellular system, including the phones, transmitting towers, and network control stations would need a large amount of new software and hardware.
The intricate process of establishing an encryption standard, implementing it, redesigning the current cellular system, and retrofitting the system with the new equipment presents a tough obstacle to overcome. This countermeasure is further complicated by the need to continue supporting both encrypted and nonencrypted systems during system transition. Whether the cellular industry, and ultimately the cellular customer base, are willing to shoulder these costs depends on their willingness to accept the costs and consequences of not implementing encryption countermeasures.
Conclusion
Wireless eavesdropping and cellular spoofing is a serious and costly problem that will continue to grow in the oncoming years as the cordless and cellular market increases. Electronic eavesdroppers and cellular phreakers are becoming more sophisticated in their activities, and the availability, inexpensiveness, and undetectability of this technology make eavesdropping and spoofing both effortless and profitable.
Anyone who uses these devices is vulnerable to compromise and must understand the scope of the threat they face. While the threat is large, several countermeasures exist to reduce the risk of compromise. Also, the telecommunications industry is taking a hard look at the problem and designing new high-tech countermeasures, such as digital encryption, to further combat the threat. Table 1 lists existing and future countermeasures and rates their merits and overall effectiveness.
As shown in Table 1, encryption is the most effective countermeasure to reduce both eavesdropping and cellular spoofing, and plans should be made to implement this system. The Clipper chip is not a good solution for two reasons: (1) There is nothing to prevent criminals from reprogramming their cordless and cellular phones with their own encryption schemes, thus negating the crime-fighting aspects of the Clipper chip; and (2) Since a decryption key exists, there is a good chance that this key will be compromised or that the code will be publicly broken, rendering the entire encryption system useless.
Therefore, a random cryptographic scheme is needed to reduce the chance, and possibly prevent the occurrence of communications compromise. The probability and threat of cordless and cellular compromise is high, and the effects of it are costly. We must, as a society, begin taking steps now to increase our communications security; otherwise, we will continue to risk and incur great losses in both personal and business affairs.

A Summary of Wireless Communications Security Countermeasures
Threat	Countermeasure	Technology Level	Countermeasure	Cost Comments	Overall Effectiveness
Electronic Eavesdropping	Limit sensitive conversations	Low	Low	People tend to accidentally release sensitive info, may not be user-friendly.	Medium
Electronic Eavesdropping	High Speed Frequency Switching	Medium	Medium	Eavesdroppers may still find the correct frequency and intercept sensitive information.	Medium
Electronic Eavesdropping	Digital Encryption	High	High	Cipher code will prevent information compromise, but may hinder crime-fighting efforts.	High
Spoofing	Keep phone turned off until ready to use	Low	Low	Low Cellular phone is harder to spoof, but can still be done when the user makes a call.	Low
Spoofing	Change MIN routinely	Low	Low	This can be effective, but user must routinely change MIN. The phone can still be spoofed at any time.	Medium
Spoofing	Incorporate PIN number	Medium	Medium	This makes it harder to spoof phone, but scanning equipment can be easily modified to intercept PIN.	Medium
Spoofing	Design tamper-proof ESN chips	Medium	Medium	This will prevent cellular phones from being reprogrammed, but will not stop technically advanced phreakers or eliminate the use of Cache-Boxes.	Medium to High
Spoofing	Digital Encryption	High	High	Cipher code will reduce and possibly prevent spoofing, including the use of Cache-Boxes.	High

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MobileHouse Antenna Information

Antenna

Car Antenna

Antenna

Getting energy out from a transmitter and in to a receiver is critically dependent upon the ability of the transmitter to pass energy (radio signals) from its antenna to free space, similarly the same is true of a receiver.
There are a number of factors involved including:-

Frequency (wavelength).

Gain.

Impedance.

Polarisation.

Frequency
Each antenna has a resonant frequency, the frequency at which it is most efficient at either transmitting or receiving energy. The resonant frequency is set by the physical length of the antenna. Frequency and wavelength are related, the wavelength (in metres) is equal to the speed of light (in metres/sec) divided by the frequency (in Hertz - Hz).
Similarly the frequency is equal to the speed of light divided by the wavelength. So in the good old days when Radio 4 was the Long Wave it transmitted on a wavelength of 1500m. The speed of light is 300,000,000 metres a second so 300,000,000 / 1,500 = 200,000Hz or 200 kHz. Go find an old radio and you will find 1500m on the dial, newer ones have 200 kHz (and yes, thank to some interfering French politicians Radio 4 is now on 198 kHz which took away a lovely stable frequency reference - but that’s another story).
A frequency of 1800 MHz (GSM 1800) equates to a wavelength of:-
300,000,000 / 1,800,000,000 = 0.167m
or a wavelength of about 16.7cm. At 900 MHz everything is twice as big, so 900 MHz gives a wavelength of 33.4cm. Antennae are usually referred to by the fraction of a wavelength represented by their physical length, so a full wave antenna at 1800 MHz would be 16.7cm long (In practice it would be a slightly different length to allow for corrections for end effects). A half wave antenna at 1800 MHz would be 8.4cm and so on. Most phone antennae are about 1/4 wavelength long.
Gain
The basic pattern of energy coming from a “perfect” antenna with no gain is a bit like a ball (with the antenna in the middle), the antenna radiates equally in all directions (the “isotropic” antenna). This isn’t always what is wanted. In most mobile phone antennae you want most of the energy coming out near the ground and not too much going vertically into space.
A standard dipole radiation pattern is not isotropic - it looks bit like a doughnut with the antenna in place of the hole.
An antenna can only put out what is put in to it, so when you see adverts for antennae with “gain” (for example 3dB gain) what it means is that the energy is being directed more in one direction than others (It also means the area the energy was redirected FROM will get less.)
Going back to the doughnut, if you press down on the top of the ball it gets wider and shorter, the wider axis is showing gain, the shorter one loss.
You can also put directivity in the azimuth pattern - but for phones this is not a good idea! The most common antenna with gain in azimuth is the common TV antenna (a Yagi antenna design for the curious) which typically has a beamwidth of about 15 to 20°.
Antenna gain is usually expressed in decibels and refers to the gain of the design over the radiation in that direction given by a perfect isotropic antenna or a dipole. As the isotropic antenna and dipole differ anyway it is important to know which is being referred to when comparing antennae. Usually if antenna is described as having “3dB gain” it means compared with a dipole. If it says “3dBi gain” it means compared with an isotropic radiator.
The most common mobile antenna design to show gain is the co-linear. In most cases this will give about 3dB gain over a dipole. Treat all claims for greater gain from non directional antennas with severe suspicion!
Impedance
Impedance is to AC circuits roughly what resistance is to DC circuits (OK - I know that’s a shelf full of text books dismissed in one line!). It isn’t just the length of the antenna which matters but also how you get power into it. For maximum transfer of power the source, transmission line, and load must all have the same impedance In the case of your phone this means the phone, antenna lead, and antenna should all have the same value of impedance.
This value is 50 ohms for most phones so the transmitter and receiver in the phone have a 50 ohm characteristic impedance, the cable is 50 ohms and the antenna impedance should be 50 ohms.
At the base of a 1/4 wave antenna the impedance is indeed about 50 ohms, however at the base of a 1/2 wave one it is several thousand ohms. Making dual frequency antennae (for use on both 900 and 1800 MHz) is a compromise between length, thickness (which also affects impedance) and gain. Nearly all dual frequency antennae will work quite well at one of the frequencies and less well at the other. All are outperformed by single frequency antennas.
Polarisation
Polarisation is the alignment of the electrical part of the radio frequency energy in space. A vertical antenna produces a vertically polarised signal, a horizontal one a horizontally polarised one, and a spiral antenna a circularly polarised one (left or right hand depending upon the way the spiral goes). In theory a horizontal receiving antenna will receive no energy from a vertical transmitter antenna (and this works - many continuous wave tracking radar’s use a left hand circularly polarised signal to transmit and a right hand one to receive so they can transmit and receive on the same frequency at the same time.
However we all know the phone still works lying on the table - so what happens?
The signal from the transmitter strikes many objects along its way and is reflected from them, these reflections are often twisted because of the irregular nature of the reflecting object. By the time the signal reaches you it has lost much of its initial polarisation and become scattered. However it will usually still be the case that most of the signal will maintain its original polarisation and the more vertical you keep the antenna the better your chances of a good signal.
Special Antennas and Signal Amplifiers.
The Co-linear
The true co-linear design is a series of dipoles stacked end to end and fed by different cables such that the radiation patterns inter-react to give a lower angle of radiation with more power in the lower angles than the higher. The antenna called a colinear in mobile phones achieves a similar effect by being partial multiples of wavelengths long and having tuning and loading coils built in ( the single coiled twist in the 1800 MHz antenna shown above and the thicker tube about 1/3 of the way up the 900MHz antenna. The extra length of the co-linear explains why your antenna is longer than you expected based on the calculations at the top of this page.
The Yagi
The Yagi antenna design is probly the most common antenna with gain - nearly all TV antennae are Yagis. Its use in mobile phones is very limited because it gives directional gain in azimuth - you need to know where the base station is and point at it! However it does have its uses, models for 900MHz are made mainly for the Nordic market where mobile phones are the communication method of choice for the popular remote weekend houses. Fitted to a house and pointing at the nearest base station it gives excellent gain and will often turn a no hope signal into a strong one.
Signal Amplifiers
Touted by some as the secret panacea for all ills the linear amplifier (AKA “Burner”, Power Booster, Power Amplifier) came to infamy in the heyday of CB radio when they were brought over from the USA and fitted illegally to Ford Capris and Cortinas by numbers of CB enthusiasts. In general there were two main effects - the car battery ran down very quickly and every receiver for miles around was jammed by the spurious out of band emissions. Some of these amplifiers were quite impressive - 1kW (yes - 1000 Watt) linears sitting on the boot of ratty Fords were not unknown!
Somewhat more civilised amplifiers were fitted to car kits for analogue phones taking their power up to 5 Watts. However since the advent of GSM and PCN the benefits to be gained from these quite expensive boxes have become much less.
As far as PCN is concerned the only benefit is to overcome losses in installations where long cable runs must be employed, for example if you need an antenna on the roof of your house. In this situation the amplifier incorporates both a received signal pre-amplifier and a transmitted signal power amplifier. It is designed to overcome the quite significant losses which occur in co-axial cables at 1800MHz.
Putting one in your car will usually have little or no significant effect.

Car Antenna

If you use your cellphone in your motor-vehicle, an external cellphone antenna is a must !! That’s because cars insulate cellphones from the external GSM signal, an unwanted artifact known as the "Faraday Cage." This Cage can sometimes result in poor voice quality and even dropped calls. A well-installed external car antenna usually fixes the problem. And if you’re in a rural area that’s on the periphery of the GSM coverage range, or even in a building that tends to block GSM signals, there are some novel antenna solutions available. External antennas are available at around US$20, but are invariably professionally fitted as part of the complete installation of a cellphone car kit. Your installer is likely to provide you either with a semi-permanent stick-on antennae design that simply sticks onto the front or back car windows using adhesive tape, magically transferring the GSM signal through the glass and then via a cable to and from the external antenna socket on your GSM cellphone or it’s special car kit. Some installers also provide permanent boot (trunk) and car roof mount designs, but these tend to be more expensive as they invariably necessitate some car-body drilling and additional wiring. There are however many do-it-yourself clip-on designs available that don’t really require any detailed technical knowledge and can be installed in minutes. The most popular though are the installed stick-on types. These external antenna housings usually consist of a base with a screw-on antenna rod. Some rods have an enclosed coil in the middle. Antenna efficacy is usually measured in decibels (dB) - the higher the rated dB specification, usually the better it’s performance. Longer rods of around 50cm usually have a dB level of around 5dB, the smaller 9cm types around 3dB or less. Whatever their length, the antenna rods should be attached to a positionable, swivel-type joint on the base to allow the rod to be positioned backwards and forwards, left to right to optimize efficacy. The base positioning of the antenna on the car is also important: some installers prefer the front or back window, while others drill on the car boot or roof. The back window however is the most popular antenna position, although this invariably depends on the vehicle’s shape. Your external antenna should also feature a position lock "memory" to ensure that the antenna rod stays in the position you set it - especially when used in high-wind areas. Some of the longer antennas tend to create high-pitched whistle effects in winds. Make sure that you can also unscrew the rod: this feature is especially useful if you want to prevent the antenna being mangled by a car-wash behemoth. Smaller, low profile 9 cm front-window mounted antennas are perfect for avoiding these situations. There are also a number of easily fitted removable/portable car antenna solutions. One design simply clips on to the top of a wind-up side window, allowing you to switch cars and still have external antenna support. Once you’ve placed the clip onto the top of the window, you then simply plug (hard wire) the attached antenna cable into the phone’s antenna socket. You can use it with the window open or closed as the cable signal is relayed to the antenna’s external rod via the window clip-on. There is however another side window clip-on design available that does not use any hard wiring. Instead it uses a special cordless pick-up rod inside the car - also connected to it’s external rod via the window clip-on - to "passively" relay the GSM signal to and from the cellphone. With both these clip-on designs, the back right passenger window is recommended. There is yet another flat "patch" passive antenna type that simply sticks down flat onto any window. This solution, although not the most effective, is useful in offices where GSM signals may be blocked by an abundance of concrete and steel in the wall. If you’re in a fixed rural location on the coverage fringe, there are special 10dB corner reflector antennas that can be attached to poles or buildings. No field assembly or tuning is required and they easily attached to your cellphone using ordinary cable connections. If necessary, you might also want to consider special booster devices that increase the power of you cellphone from the average 2W to up to a powerful 8W. *************************************************************************

rbcomm

ORBCOMM offers affordable global wireless data and messaging communications services from space. Click here for more information.
Frequency Allocation
The ORBCOMM system uses 137-138 MHz and 400 MHz frequencies for transmissions down to mobile or fixed data communications devices; and 148-150 MHz frequencies for transmissions up to the satellites. These frequencies, approved for use by LEO satellite systems at the World Administrative Radio Conference in February 1992, were allocated by the FCC to Little LEO mobile satellite services in January 1993. The FCC granted ORBCOMM a U.S. commercial license in October 1994.
System Description
The ORBCOMM system uses LEO satellites instead of terrestrial fixed site relay repeaters to provide worldwide geographic coverage. The system is capable of sending and receiving two-way alphanumeric packets, similar to two-way paging or e-mail. The three main components of the ORBCOMM system are: the space segment - the constellation of satellites; the ground segment - gateways which include the Gateway Control Centers (GCCs) and Gateway Earth Stations (GESs) and the Network Control Center (NCC) located in the United States; and subscriber communicators (SCs) - hand-held devices for personal messaging, as well as fixed and mobile units for remote monitoring and tracking applications.
ORBCOMM System Architecture Diagram
Space Segment
ORBCOMM currently has 35 satellites in its constellation. An additional launch is planned for 2000, enhancing coverage in the equatorial regions of the world.
The main function of ORBCOMM's satellites is to complete the link between the SCs and the switching capability at the NCC in the U.S. or a licensee's GCC. The satellites are "orbiting packet routers" ideally suited to "grab" small data packets from sensors in vehicles, containers, vessels or remote fixed sites and relay them through a tracking Earth station and then to a GCC.

Satellite Characteristics

- Weight: 90 lbs. - Solar Array Power BOL: 160 watts
- Transmitters:

VHF (subscriber links) 1

VHF (feeder links) 1

UHF 1

- Receivers:

VHF (subscriber links) 7 -
1 DCAAS Receiver and 6 Subscriber Receivers

VHF (feeder links) 2 - Propulsion: N2
- Guidance: Autonomous/GPS

More ORBCOMM Satellite Facts
ORBCOMM Satellite Element Sets
Ground Segment
The ground segment, which has most of the intelligence of the ORBCOMM system, is comprised of GCCs, GESs and ORBCOMM's NCC, which is located at ORBCOMM's headquarters in Dulles, VA. The NCC also serves as North America's GCC. Additionally, within the US, there are four GESs located in Arizona, Georgia, New York State and Washington State.
Gateway Control Center (GCC)
Located in a territory that is licensed to use the ORBCOMM system, the GCC provides switching capabilities to link mobile SCs with terrestrial-based customer systems via standard communications modes including X.400, X.25, leased line, dial-up modem, public or private data networks, and e-mail networks including the Internet. Interfaces to the GCC enable reliable, efficient and cost effective integration of the ORBCOMM system into existing or new customer MIS systems.
Gateway Earth Station (GES)
ORBCOMM's GESs link the ground segment with the space segment and will be in multiple locations worldwide. The GESs provide the following functions:

Acquire and track satellites based on orbital information from the GCC

Transmit and receive transmissions from the satellites

Transmit and receive transmissions from the GCC or NCC

Monitor status of local GES hardware/software

Monitor the system level performance of the satellite "connected" to the GCC or NCC

The GES is redundant and has two steerable high-gain VHF antennas that track the satellites as they cross the sky. The GES transmits to a satellite at a frequency centered at 149.61 MHz at 57.6 kbps with a nominal power of 200 watts. The GES receives 3-watt transmissions from the satellite at 137-138 MHz range. These up and downlink channels have a 50 KHz bandwidth. Network Control Center (NCC)
The NCC is responsible for managing the ORBCOMM network elements and the U.S. gateways through telemetry monitoring, system commanding and mission system analysis. It provides network management of ORBCOMM's satellite constellation and is staffed seven days a week, 24 hours a day by ORBCOMM-certified controllers.
The NCC provides the following functions:

Monitor real-time and back-orbit telemetry from the ORBCOMM satellites

Send real-time and stored commands to the satellites

Provide the tools and information to assist engineering with resolution of satellite and ground anomalies

Archive satellite and ground telemetry for analysis

Monitor performance of the U.S. Gateway Earth Stations (GESs)

Monitor status of the ORBCOMM U.S. Message Switch (OMS) and related software

Provide daily and weekly performance totals

For more information on ORBCOMM's Network click here.
Subscriber Communicator (SC)
There are several types of SCs. ORBCOMM's SC for fixed data applications uses low-cost VHF electronics. The simple antenna design and small package provide installation flexibility. The low-power electronics allow for extended operations using batteries, a solar panel or available power.
The SC for mobile two-way messaging is a hand-held, stand-alone unit. Typically, the units have an alphanumeric keyboard and small display screen.
Click here for more information on ORBCOMM Subscriber Communicator manufacturers.

Source: Orbcomm Website

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MobileHouse Mobile App: Build mobile applications easily

Mobile applications creator tool to easily make mobile applications customized for each mobile phone, without programming skills, using a visual interface, web-based, sending the application via SMS Push or Bluetooth with FuturLink APs.

Key Features

Easy creation of interactive rich mobile applications without programming skills.
Advanced functionalities such as click to call, RSS, agenda, forms, maps, templates, etc.
Automatic adaptation of the mobile application to the different mobile phones, through mobile device detection technology, ensuring the correct view of the applications.
Ideal for product catalogues, tourism, events, agendas, stores lists, etc.
Hosting of the created applications.
Web-based solution compatible with most common browsers.

Downloads

MH_MobileApp_Datasheet_EN_1005

Technical Specifications

System

System Requirements for the computer:

Compatible with the following browsers: - Internet Explorer 7+
- Google Chrome
- Mozilla Firefox
Internet connection required

Handset compatibility:

Around 1,400 Java compatible phones (Nokia, Blackberry, Samsung, LG, Sony-Ericsson, Motorola, etc).
For iPhones the content of the mobile application is available on a mobile website.
Android coming soon.

Others

Access MobileHouse MobileApp here.

QUICKLINKS:

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MobileHouse Products
UME-36Pro - Universal Memory Exchanger UME Reporting System - URS CelleSync - Backup and Share Over The Air UFED For Forensics and Law Enforcement

UME Family Products

UME-24

UME-36Pro - Universal Memory Exchanger

Synchronizing a world of content

MobileHouse's UME-36Pro, the newest member in the Universal Memory Exchanger family, is a professional, stand-alone phone memory transfer and backup solution that transfers all forms of content, including pictures, videos, ringtones, SMS, as well as phonebook contacts data between a wide range of mobile phones, smart phones and PDAs. The UME-36Pro was designed with the needs of the mobile phone industry in mind. Rugged and easy to use the UME-36Pro promises mobile communication service providers years of service thanks to CelleBrite's constant firmware updates that keep the UME-36Pro current with the latest cellular phone models. The UME-36Pro still operates with the ease, speed and reliability that customers have come to expect from CelleBrite.

learn How It Works

UME-36Pro Tutorial

Check Supported Phones

Check the UME-36Pro kit contents

Commercial MovieClip

Main Features and Capabilities

Based on Windows CE.
Supports transfer of content across all mobile handset technologies - GSM, CDMA, UMTS, 3G, TDMA, IDEN and more.
Transfer of phones internal memory and SIM card content
Transfer of phonebooks, pictures, videos, ring-tones, and SMS.
Supports multiple language encodings.
Available connectivity: USB, Serial, IrDA and Bluetooth connections to phones.
Transfer, backup and restore of mobile phone content
Supports SymbianTM, Microsoft Mobile™ Palm™ , and Blackberry™ operating systems.
Integrated SIM/Smart Card reader.
Integrated PC connection allowing content backup and management.
Stand-alone device or an integrated PC solution.
User-friendly and self-explanatory.
Easily upgraded through software file downloads.

UME-36Pro offers mobile operators and retailers:

New sources of revenue.
Rapid Return on Investment.
Enhanced quality of service.
Increased customer retention and monthly activation.
An easy way to remove customer hesitation re: upgrading to new phones, applications and services- even from complex multimedia models.
Elimination of barriers to switching networks.

System Highlights

Supports most mobile phones available in the market for all carriers and technologies (see List of Supported Phones).
Protects customer privacy by securely transferring content without exposure to store personnel.
Easily upgradeable to support new handsets via the Internet or flash drive.
Easy to learn and simple to use.
Built in Ethernet card for advanced capabilities.
Built in SIM reader.
Supports SD Card.

************************************************************************************************
Mobile House Instructions

Water Damage

.* The FIRST thing to do when you drop your phone in water is to IMMEDIATELY pull the battery off. DON'T turn the phone off first, pull the battery off.

.* As soon as possible after this place the phone into some clean water, preferably some kind of pure water. If the phone was dropped into salt water, immediately rinse the phone thoroughly in clean water then place the phone into the water. Do not place the battery in the water, consider replacing it or at least dry it out thoroughly with a hair drier.

.* Next step is to disassemble the phone OR take it to a service centre depending on your skills.

.* Completely disassemble the phone and clean each part again in water. Dry the parts with a hair drier and leave at least 24 hours in a warm area to get rid of any water built up under IC's etc. Shake the parts a few times in this period and also attack them with the hair drier again.

.* Check the phone for corrosion etc, if there's none you may be ok. If there's corrosion you really need to remove it, there are many PCB cleaning products on the market for this sort of work. Check with your local electronics store.

.* Next step is to carefully reassemble the phone. Use a new battery if available or borrow one.

.* Using the battery that was soaked is not recommended but normally works ok.

.* All going well the phone still works, if not pull it apart and check that it was assembled properly. If still no go, dry it again with the hair drier and leave for another 24 hours to make sure that it's really dry. In most cases the phone will still work.

**************************************************************************

2010-05-26T06:26:00.002-07:00

...Thames for the "Mobile Phones" ...

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Mobile game

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This article may require cleanup to meet Wikipedia's quality standards. Please improve this article if you can. (December 2008)

A mobile game is a video game played on a mobile phone, smartphone, PDA, handheld computer or portable media player. This does not include games played on handheld video game systems such as PlayStation Portable or Nintendo DS.

The first game that was pre-installed onto a mobile phone was Snake on selected Nokia models in 1997.^[1] Snake and its variants have since become the most-played video game on the planet, with over a billion people having played the game.^{[citation needed]}

Mobile games are played using the technologies present on the device itself. For networked games, there are various technologies in common use. Examples include text message (SMS), multimedia message (MMS) or GPRS location identification.

However, there are non networked applications, that simply use the device platform to run the game software. The games may be installed over the air, they may be side loaded onto the handset with a cable, or they may be embedded on the handheld devices by the OEM or by the mobile operator.

Mobile games are usually downloaded via the mobile operator's radio network, but in some cases are also loaded into the mobile handsets when purchased, via infrared connection, Bluetooth, or memory card.

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[edit] History

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With the creation of the cell phone, one was easily impressed with the fact that the phone required no cables. However, towards the end of the 20th century, cellular phones started to modernize, and people wanted more out of their cell phones.

With the introduction of the "candy bar" style cell phone, the appearance of a cell phone as well as its features and calling capabilities became a lot more important to people. Cell phone games were among the many new features that could be expected in this new type of cell phone.

Older cell phone games were not as expansive or as popular as console games, as the phone's hardware was not suited to high-color screens or sounds beyond differently pitched beeps. The games were usually animated with black squares. A good example of an early cell phone game is Snake. Unlike today's cell phone games, which usually have to be purchased, these games came pre-installed on the cell phone, and could not be copied off or removed.

When the camera phone was introduced to the public, cell phones started to become a lot more common. The storage and graphic capabilities on these new phones were a lot better than the older candy bar style phone, which meant that higher quality games could be created. This of course also meant that companies could make a profit off these games.

Nokia tried to create its own mobile gaming platform with the N-Gage in 2003 but this effort failed mainly because, at the time, the convergence of a cell phone and a handheld gaming platform did not mix. Many users complained of having to talk on the phone 'taco-style' by tilting it sideways in order to speak and hear. There were hardware issues as well, and though some quality games came out, support for the platform was anemic.

Today, cell phone games have come a very long way. Their graphics are about the same as you would expect on a 4th or 5th generation game console (which may not seem like a very big improvement yet is considered one because the game is being played on a cell phone). Cell phone games now tend to take up a large amount of memory on cell phones, which is part of the reason why they still are not too popular. Still, certain games such as "Tetris" and "Solitaire" are somewhat popular cell phone games.

[edit] Industry structure

Total global revenues from mobile games were estimated at $2,600 million in 2005 by Informa Telecoms and Media.the total revenue generated in the year 2008 ia 5800 million US dollar^[2]

[edit] Different platforms

Main article: Mobile software

Mobile games are developed using platforms and technologies such as Windows Mobile, Palm OS, Symbian OS, Adobe's Flash Lite, DoCoMo's DoJa, Sun's Java ME, Qualcomm's BREW, WIPI, iPhone OS or Google Android platforms. Other platforms are also available, but not as common.

Java is the most common platform for mobile games, however its performance limitations lead to the adoption of various native binary formats for more sophisticated games.

[edit] Common limitations of mobile games

Mobile games tend to be small in scope and often rely on good gameplay over flashy graphics, due to the lack of processing power of the client devices. One major problem for developers and publishers of mobile games is describing a game in such detail that it gives the customer enough information to make a purchasing decision. Currently, Mobile Games are mainly sold through Network Carriers / Operators portals and this means there are only a few lines of text and perhaps a screen shot of the game to excite the customer. Two strategies are followed by developers and publishers to combat this lack of purchasing information, firstly there is a reliance on powerful brands and licenses that impart a suggestion of quality to the game such as Tomb Raider or Colin McRae and secondly there is the use of well known and established play patterns (game play mechanics that are instantly recognisable) such as Tetris, Space Invaders or Poker. Both these strategies are used to decrease the perceived level of risk that the customer feels when choosing a game to download from the carrier’s deck.

Recent innovations in mobile games include Singleplayer, Multiplayer and 3D graphics. Virtual love games belong to both of singleplayer and multiplayer games. Multiplayer games are quickly finding an audience, as developers take advantage of the ability to play against other people, a natural extension of the mobile phone’s connectivity. With the recent internet gambling boom various companies are taking advantage of the mobile market to attract customers, Ongame the founders of PokerRoom developed in 2005 a working mobile version of its poker software available in both play money and real money. The player can play the game in a singleplayer or multiplayer mode for real or play money. As well, the MMORPG boom seems to hit the world of mobile games. According to their website CipSoft has developed the first MMORPG for mobile phones, called TibiaME.

Often trivia or quiz games will run out of questions on mobile devices. Some publishers like MobileQs will offer expansion packs to the original game to get around this problem.

[edit] Location-based games

Games played on a mobile device using localization technology like GPS are called location-based games. These are not only played on mobile hardware but also integrate the player's position into the game concept. In other words: while it does not matter for a normal mobile game where exactly you are (play them anywhere at anytime), the player's coordinate and movement are main elements in a Location-based game. The best-known example is the treasure hunt game Geocaching, which can be played on any mobile device with integrated or external GPS receiver. External GPS receivers are usually connected via Bluetooth. More and more mobile phones with integrated GPS are expected to come.

Besides Geocaching, there exist several other location-based games which are rather in the stage of research prototypes than a commercial success.

[edit] Multiplayer Mobile Games

A Multiplayer mobile game is often a re-branding of a multiplayer game for the PC or Console. Most mobile games are single player mobile games perhaps with artificially intelligent opponents. Multiplayer functionality is achieved through:

Some "community" based games exist where players use their cellphones to access a community website where they can play browser-based games with thousands of players. Such games typically have limited graphical content so that they can run on a cellphone, and the games focus on the interaction between a large number of participants.

[edit] Infrared connectivity

Older mobile phones supporting mobile gaming have infrared connectivity for data sharing with other phones or PCs. This connectivity is not practical as any disturbances in the infra-reds line of sight could cause loss of connection, hence this technology was seldom used in mobile games.

[edit] Bluetooth multiplayer games

Mobiles are connected through a wireless protocol called Bluetooth using special hardware. The games are designed to communicate with each other through this protocol to share game information. The basic restriction is that both the users have to be within a limited distance to get connected. A bluetooth device can accept up to 7 connections from other devices using a client/server architecture.

[edit] WAP / GPRS / UMTS / HSDPA multiplayer game

A GPRS connection which is common among GSM mobile phones can be used to share the data globally. Developers can connect a mass number of mobile games with a single server and share data among the players. Some developers have achieved cross platform games, allowing a mobile player to play against a PC. WAP and GPRS best supports turn based games and small RPG games. (Most of the counties have a weak GPRS speed in their carriers. In these types of games, the game communicates with a global server which acts like a router between the mobile phones. Faster connections like UMTS and HSDPA allow real time multiplayer gaming though speeds will still give some level of lag. Currently, there are a lot of multiplayer mobile games entering the market.

[edit] 3G and WiFi

3G allows in most cases realtime multiplayer gaming and is based on technologies faster than GPRS. Wi-Fi is often used for connecting at home. Not every mobile device allows games to use the wifi connection.

[edit] Distribution

Mobile games can be distributed in one of four ways:

Over the Air (OTA) - a game binary file (typically BREW or JAVA) is delivered to the mobile device via wireless carrier networks.
Sideloaded - a game binary file is loaded onto the phone while connected to a PC, either via USB cable or Bluetooth.
Pre-installed - a game binary file is preloaded onto the device by the Original Equipment Manufacturer (OEM).
Mobile browser download - a game file (typically Adobe Flash Lite) is downloaded directly from a mobile website.

In the US, the majority of mobile games are sold by the US wireless carriers, such as ATT, Verizon, Altel, Sprint and T-Mobile. In Europe, games are distributed equally between carriers, such as Orange and Vodafone, and off-deck, third party stores such as Jamba, Jamster, Kalador and Gameloft. Third party, off-deck game stores have not yet taken off (as of 2007) in the US, as the US based carriers use a 'walled garden' approach to their business models.

The popularity of mobile games has increased in the 2000s, as over $3 billion USD worth of games were sold in 2007 internationally, and projected annual growth of over 40%.

In recent years^[when?], there has been a move towards mobile games which are distributed free to the end user, but carry prominent, paid advertising.

[edit] See also

2010-05-26T05:26:00.000-07:00

These are the different Models of "Mobile Phone".

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Mobile operating system

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The Nokia E71 smartphone running S60 3rd Edition, Feature Pack 1 UI on the Symbian OS v9.2

A mobile operating system, also known as a Mobile OS, a Mobile platform, or a Handheld operating system, is the operating system that controls a mobile device—similar in principle to an operating system such as Linux or Windows that controls a desktop computer or laptop. However, they are currently somewhat simpler, and deal more with the wireless versions of broadband and local connectivity, mobile multimedia formats, and different input methods.

[hide]

[edit] History

The increasing importance of mobile devices has triggered intense competition among technology giants, like Microsoft, Apple, and Nokia in a bid to capture the bigger market share pre-emptively.^[1] Palm, Research In Motion and Ericsson are also significant firms in the mobile platform sector. In November 2007, Google formed a Linux-based open source alliance to make inroads into this mobile platform market, raising consumer awareness of the growing mobile platform frenzy.^[2]

[edit] Issues and challenges

Open standards are gaining more ground across the spectrum of related industries^[3]^[4]^[5], whereas proprietary mobile platforms, like Windows Mobile, are losing market share^[6]. Sir Tim Berners-Lee recently re-emphasized his advocacy for open mobile standards in his keynote speech at the first annual meeting of Mobile Internet World held in Boston in November 2007. He warned against a possibility that the Internet connections worldwide may turn into "walled gardens."^[7] Google announced its Linux-based open source mobile platform, Android, along with the formation of the 34-member Open Handset Alliance.

Nonetheless, mobile web does not necessarily mean a horizontal and spatial shift from PC-based web, but a severe structural change to identify the missing links, among other things, between the stationary web at home or in the office and mobile web on the go.

Top agenda items may include:

Continued connectivity between home, cars and Base Stations like Wi-Fi Hot Spots and Femtocell
Interoperability of equipment and applications, and adaptability to the ever-shifting mobile multimedia ecosystem
Behavioral tracking utilizing GPS data versus privacy concern
Real-time links between the wireless world and physical world
Financial transactions, including smart cards, SMS and Multimedia Messaging Service.

[edit] Market description

Mobile platforms are in the nascent stage, and any projection regarding the market growth is hard to make at the present time. It is noteworthy that Intel is taking the initiative to focus on portable devices other than mobile phones. They are Mobile Internet Devices (MID) and Ultra-Mobile PC (UMPC). Meantime, Palm abandoned its plan to develop Foleo, which was to be a companion device for a smartphone.

[edit] Mobile navigation

Canalys has estimated that in 2009 the installed base of smartphones with integrated GPS was 163 million units worldwide, of which Nokia accounted for more than half (51%) having shipped cumulatively 83 million GPS devices. On January 22 2010, Nokia released a free version of Ovi Maps which is expected to double user amount.

[edit] Operating systems

Table showing most of the current mobile operating systems for smartphones, PDAs and netbooks in 2010

Share of Smartphone sales by operating systems in Q2/2009 by Canalys.^[8] (data does not include Palm WebOS, which was introduced in June, 2009)

Operating systems that can be found on smartphones include Symbian OS, iPhone OS, RIM's BlackBerry, Windows Phone, Linux, Palm WebOS, Android and Maemo. Android, WebOS and Maemo are in turn built on top of Linux, and the iPhone OS is derived from the BSD and NeXTSTEP operating systems, which all are related to Unix.

The most common operating systems (OS) used in smartphones by Q2 2009 sales are:

Symbian OS from the Symbian Foundation (50.3% Market Share Sales Q2 2009)^[8]: Symbian has the largest share in most markets worldwide, but lags behind other companies in the relatively small but highly visible North American market.^[9] This matches the success of its largest shareholder^[10] and customer, Nokia, in all markets except Japan. Nokia itself enjoys 52.9% of the smartphone market.^[11] In Japan Symbian is strong due to a relationship with NTT DoCoMo, with only one of the 44 Symbian handsets released in Japan coming from Nokia.^[12] It has been used by many major handset manufacturers, including BenQ, Fujitsu, LG, Mitsubishi, Motorola, Nokia, Samsung, Sharp, and Sony Ericsson. Current Symbian-based devices are being made by Fujitsu, Nokia, Samsung, Sharp, and Sony Ericsson. Prior to 2009 Symbian supported multiple user interfaces, i.e. UIQ from UIQ Technologies, S60 from Nokia, and MOAP from NTT DOCOMO. As part of the formation of the Symbian platform in 2009 these three UIs were merged into a single platform which is now fully open source. It has received some adverse press attention due to virus threats (namely trojan horses).^[13]

RIM BlackBerry OS (20.9% Market Share Sales Q2 2009)^[8]: This OS is focused on easy operation and was originally designed for business. Recently it has seen a surge in third-party applications and has been improved to offer full multimedia support.

iPhone OS from Apple Inc. (13.7% Market Share Sales Q2 2009)^[8]: The iPhone uses an operating system called iPhone OS, which is derived from Mac OS X. Third party applications were not officially supported until the release of iPhone OS 2.0 on July 11th 2008. Before this, "jailbreaking" allowed third party applications to be installed, and this method is still available.

Windows Phone from Microsoft (9% Market Share Sales Q2 2009)^[8]^[14]: The Windows CE operating system and Windows Mobile middleware are widely spread in Asia. The two improved variants of this operating system, Windows Mobile 6 Professional (for touch screen devices) and Windows Mobile 6 Standard, were unveiled in February 2007. It has been criticized for having a user interface which is not optimized for touch input by fingers; instead, it is more usable with a stylus. However, unlike iPhone OS, it does support both touch screen and physical keyboard configurations.

On February 15th, 2010 Microsoft unveiled its next-generation mobile OS, Windows Phone 7. The new mobile OS includes a completely new over-hauled UI called "Metro". It includes full integration of Microsoft services such as Zune, Xbox Live and Bing. The new OS platform has received very positive reception from the technology press.^[15]^[16]^[17]

Android from Google Inc. (2.8% Market Share Sales Q2 2009)^[8]: Android was developed by Google Inc.. Android is an Open Source, Linux-derived platform backed by Google, along with major hardware and software developers (such as Intel, HTC, ARM, and eBay, to name a few), that form the Open Handset Alliance.^[18] This OS, though very new, already has a cult following among programmers eager to develop apps for its flexible, Open Source, back end.^[19] Android promises to give developers access to every aspect of the phone's operation.^[20] This lends many to foresee the promise of further growth for the Android platform.^[21]

Linux operating system: Linux is strongest in China where it is used by Motorola, and in Japan, used by DoCoMo.^[22]^[23] Rather than being a platform in its own right, Linux is used as a basis for a number of different platforms developed by several vendors, including Android, LiMo, Maemo, Openmoko and Qt Extended, which are mostly incompatible.^[24]^[25] PalmSource (now Access) is moving towards an interface running on Linux.^[26] Another platform based on Linux is being developed by Motorola, NEC, NTT DoCoMo, Panasonic, Samsung, and Vodafone.^[27]

Palm webOS from Palm Inc. and Palm OS/Garnet OS from Access Co.: Palm webOS is Palm's next generation operating system.^[28] PalmSource traditionally used its own platform developed by Palm Inc. Access Linux Platform (ALP) is an improvement that was planned to be launched in the first half of 2007. It will use technical specifications from the Linux Phone Standards Forum. The Access Linux Platform will include an emulation layer to support applications developed for Palm-based devices.

bada from Samsung Electronics: The bada mobile phone operating system is still in development, and Samsung expects handsets to be available in the second half of 2010.^[29]The first device to run Bada is called 'Wave' and was unveiled to the public at Mobile World Congress 2010, Wave is a fully touchscreen phone running the new mobile operating system.

Maemo from Nokia: Maemo is a software platform developed by Nokia for smartphones and Internet Tablets. It is based on the Debian operating system.

Maemo is mostly based on open source code, and has been developed by Maemo Devices within Nokia in collaboration with many open source projects such as the Linux kernel, Debian and GNOME.

Maemo is based on Debian GNU/Linux and draws much of its GUI, frameworks and libraries from the GNOME project. It uses the Matchbox window manager and the GTK-based Hildon as its GUI and application framework.

Limo

MeeGo from Nokia and Intel

At the 2010 Mobile World Congress in Barcelona, Nokia and Intel both unveiled 'MeeGo' a brand new mobile operating system which would combine the best of Moblin and the best of Maemo to create a truly open-sourced experience for users across all devices.

[edit] Feature phone operating systems

Common operating systems for feature phones include Nokia's S30 and S40. ^[30]S40 offers APIs for Java ME.^[31]

[edit] References

[edit] Further reading

[edit] External links

[hide] v • d • e Mobile operating systems

Embedded Linux-based	Access Linux · Android · bada · DSLinux · Familiar · iPodLinux · LiMo · MeeGo (Maemo · Moblin) · Mobilinux · MotoMagx · Openmoko Linux · OPhone · SHR · Qt Extended · Qt Extended Improved · Ubuntu Mobile · webOS

Others	BlackBerry OS · GEOS · iPhone OS · Nokia OS (S30 · S40) · Palm OS · PSP OS · Symbian platform (Symbian OS · MOAP(S) · UIQ · S60 · S80 · S90) · SavaJe · Windows Mobile

Related platforms	BREW · Java ME (FX Mobile)

See also: List of digital distribution platforms for mobile devices, Mobile development

Retrieved from "http://en.wikipedia.org/wiki/Mobile_operating_system"

2010-05-26T03:38:00.000-07:00

There are so many types in 'Mobile Phone', In that these are some of them .

Mobile phone

Mobile phone
Several examples of non-flip mobile phones, from the early 2000s.
Inventor	Martin Cooper
Launch year	1973
Company	Motorola
Available?	Worldwide

A mobile phone (also called mobile, cellphone or handphone)^[1] is an electronic device used for mobile telecommunications over a cellular network of base stations known as cell sites. Mobile phones differ from cordless telephones, which only offer telephone service within limited range through a single base station attached to a fixed line, for example within a home or an office. Low-end mobile phones are often referred to as feature phones, whereas high-end mobile phones that offer more advanced computing ability are referred to as smartphones.

A mobile phone allows its user to make and receive telephone calls to and from the public telephone network which includes other mobiles and fixed line phones across the world. It does this by connecting to a cellular network owned by a mobile network operator. A key feature of the cellular network is that it enables seamless telephone calls even when the user is moving around wide areas via a process known as handoff or handover.

In addition to being a telephone, modern mobile phones also support many additional services, and accessories, such as SMS (or text) messages, email, Internet access, gaming, Bluetooth, infrared, camera, MMS messaging, MP3 player, radio and GPS.

The first hand held phone was demonstrated by Martin Cooper of Motorola in 1973, using a handset weighing in at two kilos.^[2] By the end of 2009, the number of mobile cellular subscriptions worldwide reached approximately 4.6 billion, penetrating the developing economies and reaching the bottom of the economic pyramid.^[3]

History

Mobile car phone, 1964

Main article: History of mobile phones

Radiophones have a long and varied history going back to Reginald Fessenden's invention and shore-to-ship demonstration of radio telephony, through the Second World War with military use of radio telephony links and civil services in the 1950s, while hand-held mobile radio devices have been available since 1973.

In 1960, the world’s first partly automatic car phone system, Mobile System A (MTA), was launched in Sweden. MTA phones were composed of vacuum tubes and relays, and had a weight of 40 kg. In 1962, a more modern version called Mobile System B (MTB) was launched, which was a push-button telephone, and which used transistors in order to enhance the telephone’s calling capacity and improve its operational reliability. In 1971 the MTD version was launched, opening for several different brands of equipment and gaining commercial success.^[4]^[5]

Martin Cooper, a Motorola researcher and executive is considered to be the inventor of the first practical mobile phone for hand-held use in a non-vehicle setting, after a long race against Bell Labs for the first portable mobile phone. Using a modern, if somewhat heavy portable handset, Cooper made the first call on a hand-held mobile phone on April 3, 1973 to his rival, Dr. Joel S. Engel of Bell Labs.^[6]

The first commercially automated cellular network (the 1G generation) was launched in Japan by NTT in 1979, initially in the metropolitan area of Tokyo. Within five years, the NTT network had been expanded to cover the whole population of Japan and became the first nation-wide 1G network. In 1981, this was followed by the simultaneous launch of the Nordic Mobile Telephone (NMT) system in Denmark, Finland, Norway and Sweden.^[7]. NMT was the first mobile phone network featuring international roaming. The first 1G network launched in the USA was Chicago based Ameritech in 1983 using the Motorola DynaTAC mobile phone. Several countries then followed in the early 1980s including the UK, Mexico and Canada. .

The first "modern" network technology on digital 2G (second generation) cellular technology was launched by Radiolinja (now part of Elisa Group) in 1991 in Finland on the GSM standard which also marked the introduction of competition in mobile telecoms when Radiolinja challenged incumbent Telecom Finland (now part of TeliaSonera) who ran a 1G NMT network.

In 2001 the first commercial launch of 3G (Third Generation) was again in Japan by NTT DoCoMo on the WCDMA standard.^[8]

One of the newest 3G technologies to be implemented is High-Speed Downlink Packet Access (HSDPA). It is an enhanced 3G (third generation) mobile telephony communications protocol in the High-Speed Packet Access (HSPA) family, also coined 3.5G, 3G+ or turbo 3G, which allows networks based on Universal Mobile Telecommunications System (UMTS) to have higher data transfer speeds and capacity.

Handset Features

A Nokia phone with box.

A printed circuit board inside a mobile phone

Main articles: Mobile phone features and Smartphone

All mobile phones have a number of features in common, but manufacturers also try to differentiate their own products by implementing additional functions to make them more attractive to consumers. This has led to great innovation in mobile phone development over the last twenty years.

The common components found on all phones are:

a SIM card which allows the phone user access to the particular mobile phone operator that they have a subscription with
a rechargeable battery providing the power source for the phone functions
an input mechanism and display to allow the user to interact with the phone. The most common input mechanism is a keypad, but touch screens are also found in some high end smart phones.
basic mobile phone services to allow users to make calls and send text messages.

Low-end mobile phones are often referred to as feature phones, and offer basic telephony, as well as functions such as playing music and taking photos, and sometimes simple applications based on generic managed platforms such as Java ME or BREW. Handsets with more advanced computing ability through the use of native software applications became known as smart phones. The first smartphone was the Nokia 9000 Communicator in 1996 which added PDA functionality to the basic mobile phone at the time. As miniaturisation and increased processing power of microchips has enabled ever more features to be added to phones, the concept of the smartphone has evolved, and what was a high-end smartphone five years ago, is a standard phone today.

Several phone series have been introduced to address a given market segment, such as the RIM BlackBerry focusing on enterprise/corporate customer email needs; the SonyEricsson Walkman series of musicphones and Cybershot series of cameraphones; the Nokia Nseries of multimedia phones, the Palm Pre the HTC Dream and the Apple iPhone.

Other features that may be found on mobile phones include GPS navigation, music (MP3) and video (MP4) playback, RDS radio receiver, alarms, memo recording, personal digital assistant functions, ability to watch streaming video, video download, video calling, built-in cameras (1.0+ Mpx) and camcorders (video recording), with autofocus and flash, ringtones, games, PTT, memory card reader (SD), USB (2.0), dual line support, infrared, Bluetooth (2.0) and WiFi connectivity, instant messaging, Internet e-mail and browsing and serving as a wireless modem. Nokia and the University of Cambridge demonstrated a bendable cell phone called the Morph.^[9]

Software and applications

A phone with touchscreen feature.

The most commonly used data application on mobile phones is SMS text messaging. The first SMS text message was sent from a computer to a mobile phone in 1992 in the UK, while the first person-to-person SMS from phone to phone was sent in Finland in 1993.

Other non-SMS data services used on mobile phones include mobile music, downloadable logos and pictures, gaming, gambling, adult entertainment and advertising. The first downloadable mobile content was sold to a mobile phone in Finland in 1998, when Radiolinja (now Elisa) introduced the downloadable ring tone service. In 1999 Japanese mobile operator NTT DoCoMo introduced its mobile internet service, i-Mode, which today is the world's largest mobile internet service.

The first mobile news service, delivered via SMS, was launched in Finland in 2000. Mobile news services are expanding with many organisations providing "on-demand" news services by SMS. Some also provide "instant" news pushed out by SMS.

Mobile payments were first trialled in Finland in 1998 when two Coca-Cola vending machines in Espoo were enabled to work with SMS payments. Eventually the idea spread and in 1999 the Philippines launched the first commercial mobile payments systems, on the mobile operators Globe and Smart. Today mobile payments ranging from mobile banking to mobile credit cards to mobile commerce are very widely used in Asia and Africa, and in selected European markets.

Power supply

This section needs additional citations for verification.
Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (September 2009)

Mobile phone charging service in Uganda

Mobile phones generally obtain power from rechargeable batteries. There are a variety of ways used to charge cell phones, including USB, portable batteries, mains power (using an AC adapter), cigarette lighters (using an adapter), or a dynamo. In 2009, wireless charging became a reality, and the first wireless charger was released for consumer use.^[10]

Standardization of Micro-USB connector for charging

Starting from 2010, many mobile phone manufacturers have agreed to use the Micro-USB connector for charging their phones.^[11] The mobile phone manufacturers who have agreed to this standard include:

LG
Motorola
Nokia
Research In Motion
Samsung
Sony Ericsson

On 17 February 2009, the GSM Association announced^[12] that they had agreed on a standard charger for mobile phones. The standard connector to be adopted by 17 manufacturers in the Open Mobile Terminal Platform including Nokia, Motorola and Samsung is to be the micro-USB connector (several media reports erroneously reported this as the mini-USB). The new chargers will be much more efficient than existing chargers. Having a standard charger for all phones, means that manufacturers will no longer have to supply a charger with every new phone.

In addition, on 22 October 2009 the International Telecommunication Union (ITU) announced that it had embraced micro-USB as the Universal Charger Solution its "energy-efficient one-charger-fits-all new mobile phone solution", and added: "Based on the Micro-USB interface, UCS chargers will also include a 4-star or higher efficiency rating — up to three times more energy-efficient than an unrated charger."^[13]

Charger efficiency

The world's five largest handset makers introduced a new rating system in November 2008 to help consumers more easily identify the most energy-efficient chargers

The majority of energy lost in a mobile phone charger is in its no load condition, when the mobile phone is not connected but the charger has been left plugged in and using power. To combat this in November 2008 the top five mobile phone manufacturers Nokia, Samsung, LG Electronics, Sony Ericsson and Motorola set up a star rating system to rate the efficiency of their chargers in the no-load condition. Starting at zero stars for >0.5 W and going up to the top five star rating for <0.03>

A number of semiconductor companies offering flyback controllers, such as Power Integrations and CamSemi, now claim that the five star standard can be achieved with use of their product.

Battery

Formerly, the most common form of mobile phone batteries were nickel metal-hydride, as they have a low size and weight. lithium ion batteries are sometimes used, as they are lighter and do not have the voltage depression that nickel metal-hydride batteries do. Many mobile phone manufacturers have now switched to using lithium-polymer batteries as opposed to the older Lithium-Ion, the main advantages of this being even lower weight and the possibility to make the battery a shape other than strict cuboid. Mobile phone manufacturers have been experimenting with alternative power sources, including solar cells and Coca Cola.^[14]

SIM card

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Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (September 2009)

Main article: Subscriber Identity Module

Typical mobile phone SIM card

Mobile phones require a small microchip called a Subscriber Identity Module or SIM Card, to function. The SIM card is approximately the size of a small postage stamp and is usually placed underneath the battery in the rear of the unit. The SIM securely stores the service-subscriber key (IMSI) used to identify a subscriber on mobile telephony devices (such as mobile phones and computers). The SIM card allows users to change phones by simply removing the SIM card from one mobile phone and inserting it into another mobile phone or broadband telephony device.

A SIM card contains its unique serial number, internationally unique number of the mobile user (IMSI), security authentication and ciphering information, temporary information related to the local network, a list of the services the user has access to and two passwords (PIN for usual use and PUK for unlocking).

SIM cards are available in three standard sizes. The first is the size of a credit card (85.60 mm × 53.98 mm x 0.76 mm). The newer, most popular miniature version has the same thickness but a length of 25 mm and a width of 15 mm, and has one of its corners truncated (chamfered) to prevent misinsertion. The newest incarnation known as the 3FF or micro-SIM has dimensions of 15 mm × 12 mm. Most cards of the two smaller sizes are supplied as a full-sized card with the smaller card held in place by a few plastic links; it can easily be broken off to be used in a device that uses the smaller SIM.

The first SIM card was made in 1991, with Munich smart card maker Giesecke & Devrient selling the first 300 SIM cards to Finnish wireless network operator Radiolinja.

Those cell phones that do not use a SIM Card have the data programmed in to their memory. This data is accessed by using a special digit sequence to access the "NAM" as in "Name" or number programming menu. From here, one can add information such as a new number for the phone, new Service Provider numbers, new emergency numbers, change their Authentication Key or A-Key code, and update their Preferred Roaming List or PRL. However, to prevent someone from accidentally disabling their phone or removing it from the network, the Service Provider puts a lock on this data called a Master Subsidiary Lock or MSL.

The MSL also ensures that the Service Provider gets payment for the phone that was purchased or "leased". For example, the Motorola RAZR V9C costs upwards of CAD $500. Depending on the carrier, such a phone may be available for as little as $200. The difference is paid by the customer in the form of a monthly bill. If the carrier did not use an MSL, then they may lose the $300–$400 difference that is paid in the monthly bill, since some customers would cancel their service and take the phone to another carrier.

The MSL applies to the SIM only so once the contract has been completed the MSL still applies to the SIM. The phone however, is also initially locked by the manufacturer into the Service Providers MSL. This lock may be disabled so that the phone can use other Service Providers SIM cards. Most phones purchased outside the US are unlocked phones because there are numerous Service Providers in close proximity to one another or have overlapping coverage. The cost to unlock a phone varies but is usually very cheap and is sometimes provided by independent phone vendors.

Having an unlocked phone is extremely useful for travelers due to the high cost of using the MSL Service Providers access when outside the normal coverage areas. It can cost sometimes up to 10 times as much to use a locked phone overseas as in the normal service area, even with discounted rates. T-Mobile will provide a SIM unlock code to account holders in good standing after 90 days according to their FAQ.

For example, in Jamaica, an AT&T subscriber might pay in excess of US$1.65 per minute for discounted international service while a B-Mobile (Jamaican) customer would pay US$0.20 per minute for the same international service. Some Service Providers focus sales on international sales while others focus on regional sales. For example, the same B-Mobile customer might pay more for local calls but less for international calls than a subscriber to the Jamaican national phone C&W (Cable & Wireless) company. These rate differences are mainly due to currency variations because SIM purchases are made in the local currency. In the US, this type of service competition does not exist because some of the major Service Providers do not offer Pay-As-You-Go services. [Needs Pay-As-You-Go references, rumored T-Mobile, Verizon provide one, AT&T does not as of 12/2008]

Mobile phones in society

Market share

Mobile phone subscribers per 100 inhabitants 1997–2007

The world's largest individual mobile operator is China Mobile with over 500 million mobile phone subscribers. The world's largest mobile operator group by subscribers is UK based Vodafone. There are over 600 mobile operators and carriers in commercial production worldwide. Over 50 mobile operators have over 10 million subscribers each, and over 150 mobile operators have at least one million subscribers by the end of 2009 (source wireless intelligence).

Source	Date	Nokia	Samsung	LG Electronics	RIM	Sony Ericsson	Others	References
IDC	Q1/2010	36.6%	21.8%	9.2%	3.6%	3.6%	25.3%	^[15]
Gartner	Q1/2010	35.0%	20.6%	8.6%	3.4%	3.1%	29.3%	^[16]

In mobile phone handsets, in Q3/2009, Nokia was the world's largest manufacturer of mobile phones, with a global device market share of 37.8%, followed by Samsung (21.0%), LG Electronics (11.0%), Sony Ericsson (4.9%) and Motorola (4.7%). These manufacturers accounted for over 80% of all mobile phones sold at that time.^[17]

Other manufacturers include Apple Inc., Audiovox (now UTStarcom), Benefon, BenQ-Siemens, CECT, HTC Corporation, Fujitsu, Kyocera, Mitsubishi Electric, NEC, Neonode, Panasonic, Palm, Matsushita, Pantech Wireless Inc., Philips, Qualcomm Inc., Research In Motion Ltd. (RIM), Sagem, Sanyo, Sharp, Siemens, Sendo, Sierra Wireless, SK Teletech, T&A Alcatel, Huawei, Trium, Toshiba and Vidalco. There are also specialist communication systems related to (but distinct from) mobile phones.

Media

The mobile phone became a mass media channel in 1998 when the first ringtones were sold to mobile phones by Radiolinja in Finland. Soon other media content appeared such as news, videogames, jokes, horoscopes, TV content and advertising. In 2006 the total value of mobile phone paid media content exceeded internet paid media content and was worth 31 Billion dollars (source Informa 2007). The value of music on phones was worth 9.3 Billion dollars in 2007 and gaming was worth over 5 billion dollars in 2007.^[18]

The mobile phone is often called the Fourth Screen (if counting cinema, TV and PC screens as the first three) or Third Screen (counting only TV and PC screens).^{[weasel words]} It is also called the Seventh of the Mass Media (with Print, Recordings, Cinema, Radio, TV and Internet the first six). Most early content for mobile tended to be copies of legacy media, such as the banner advertisement or the TV news highlight video clip. Recently unique content for mobile has been emerging, from the ringing tones and ringback tones in music to "mobisodes," video content that has been produced exclusively for mobile phones.

The advent of media on the mobile phone has also produced the opportunity to identify and track Alpha Users or Hubs, the most influential members of any social community. AMF Ventures measured in 2007 the relative accuracy of three mass media, and found that audience measures on mobile were nine times more accurate than on the internet and 90 times more accurate than on TV.^{[original research?]}

Uses

Mobile phones are used for a variety of purposes, including keeping in touch with family members, conducting business, and having access to a telephone in the event of an emergency. Some people carry more than one cell phone for different purposes, such as for business and personal use. Multiple SIM cards may also be used to take advantage of the benefits of different calling plans—a particular plan might provide cheaper local calls, long-distance calls, international calls, or roaming. A study by Motorola found that one in ten cell phone subscribers have a second phone that often is kept secret from other family members. These phones may be used to engage in activities including extramarital affairs or clandestine business dealings.^[19]

Cell phone sharing is a phenomenon which exists around the world. It is prevalent in urban India, as families and groups of friends often share one or more mobiles among their members. Two types of sharing which exist are "conspicuous" and "stealthy" sharing. An example of conspicuous sharing takes place when someone calls the friend of the person they are trying to reach in hopes of being able to talk to that individual; stealthy sharing occurs when an individual uses another's cell phone without their knowledge. Phone sharing does not only take place because of its economic benefits, but also often due to familial customs and traditional gender roles.^[20] An example of cell phone sharing occurs in Burkina Faso. There it is not uncommon for a village to only have access to one cell phone. This cell phone is typically owned by a person who is not natively from the village, such as a teacher or missionary. Although the cell phone is the sole property of one individual, it is the expectation that other members of the village are allowed to use the cell phone to make necessary calls. Although some may consider this a burden, it can actually be an opportunity to engage in reciprocal obligations. This type of cell phone sharing is an important for the small villages in Burkina Faso because it allows them to keep up with the expectations of the globalizing world.^[21]

The mobile phone has also been used in a variety of diverse contexts in society, for example:

Organizations that aid victims of domestic violence may offer a cell phone to potential victims without the abuser's knowledge. These devices are often old phones that are donated and refurbished to meet the victim's emergency needs.^[22]
Child predators have taken advantage of cell phones to secretly communicate with children without the knowledge of their parents or teachers.^[23]
The advent of widespread text messaging has resulted in the cell phone novel; the first literary genre to emerge from the cellular age via text messaging to a website that collects the novels as a whole.^[24] Paul Levinson, in Information on the Move (2004), says "...nowadays, a writer can write just about as easily, anywhere, as a reader can read" and they are "not only personal but portable".
Mobile telephony also facilitates activism and public journalism being explored by Reuters and Yahoo!^[25] and small independent news companies such as Jasmine News in Sri Lanka.

Privacy

Cell phones have numerous privacy issues associated with them, and are regularly used by governments to perform surveillance.

Law enforcement and intelligence services in the UK and the US possess technology to remotely activate the microphones in cell phones in order to listen to conversations that take place nearby the person who holds the phone.^[26]^[27]

Mobile phones are also commonly used to collect location data. The geographical location of a mobile phone can be determined easily (whether it is being used or not), using a technique known multilateration to calculate the differences in time for a signal to travel from the cell phone to each of several cell towers near the owner of the phone.^[28]^[29]

Restriction on usage

Main article: Mobile phone radiation and health

There exists a community which believes mobile phone use represents a long-term health risk, although this is currently disupted by the World Health Organization, with forthcoming mobile phone usage recommendations in 2010. ^[30] Certain countries, including France, have warned against the use of cell phones especially by minors due to health risk uncertainties. ^[31] Groups of scientists, such as the US based group Bioinitiative, argue that because mobile phone use is recently-introduced technology, long-term "proof" has been impossible and that use should be restricted, or monitored closely, while the technology is still new.

Use while driving

Main article: Mobile phones and driving safety

Mobile phone use while driving is common but controversial. Being distracted while operating a motor vehicle has been shown to increase the risk of accident. Because of this, many jurisdictions prohibit the use of mobile phones while driving. Egypt, Israel, Japan, Portugal and Singapore ban both hand-held and hands-free use of a mobile phone whilst many other countries –including the UK, France, and many US states– ban hand-held phone use only, allowing hands-free use.

Due to the increasing complexity of mobile phones –often more like mobile computers in their available uses– it has introduced additional difficulties for law enforcement officials in being able to tell one usage from another as drivers use their devices. This is more apparent in those countries who ban both hand-held and hands-free usage, rather those who have banned hand-held use only, as officials cannot easily tell which function of the mobile phone is being used simply by visually looking at the driver. This can mean that drivers may be stopped for using their device illegally on a phone call, when in fact they were not; instead using the device for a legal purpose such as the phones' incorporated controls for car stereo or satnav usage – either as part of the cars' own device or directly on the mobile phone itself.
Cases like these can often only be proved otherwise by a check of the mobile operators phone call records to see if a call was taking place during the journey concerned. Although in many countries the law enforcement official may have stopped the driver for a differing offence, for example, for lack of due care and attention in relation to their driving.

Schools

Some schools limit or restrict the use of mobile phones. Schools set restrictions on the use of mobile phones because of the use of cell phones for cheating on tests, harassment and bullying, causing threats to the schools security, distractions to the students and facilitating gossip and other social activity in school. Many mobile phones are banned in school locker room facilities, public restrooms and swimming pools due to the built-in cameras that most phones now feature.

A recently published study has reviewed the incidence of mobile phone use while cycling and its effects on behaviour and safety.^[32]

Future evolution: Broadband Fourth generation (4G)

Main article: 4G

The recently released 4th generation, also known as Beyond 3G, aims to provide broadband wireless access with nominal data rates of 100 Mbit/s to fast moving devices, and 1 Gbit/s to stationary devices defined by the ITU-R^[33] 4G systems may be based on the 3GPP LTE (Long Term Evolution) cellular standard, offering peak bit rates of 326.4 Mbit/s. It may perhaps also be based on WiMax or Flash-OFDM wireless metropolitan area network technologies that promise broadband wireless access with speeds that reaches 233 Mbit/s for mobile users. The radio interface in these systems is based on all-IP packet switching, MIMO diversity, multi-carrier modulation schemes, dynamic channel assignment (DCA) and channel-dependent scheduling. A 4G system should be a complete replacement for current network infrastructure and is expected to be able to provide a comprehensive and secure IP solution where voice, data, and streamed multimedia can be given to users on a "Anytime, Anywhere" basis, and at much higher data rates than previous generations. Sprint in the US has claimed its WiMax network to be "4G network" which most cellular telecoms standardization experts dispute repeatedly around the world. Sprint's 4G is seen as a marketing gimmick as WiMax itself is part of the 3G air interface. The officially accepted, ITU ratified standards-based 4G networks are not expected to be commercially launched until 2011.

Comparison to similar systems

Car phone: A type of telephone permanently mounted in a vehicle, these often have more powerful transmitters, an external antenna and loudspeaker for hands free use. They usually connect to the same networks as regular mobile phones.
Cordless telephone (portable phone): Cordless phones are telephones which use one or more radio handsets in place of a wired handset. The handsets connect wirelessly to a base station, which in turn connects to a conventional land line for calling. Unlike mobile phones, cordless phones use private base stations (belonging to the land-line subscriber), which are not shared.
Professional Mobile Radio: Advanced professional mobile radio systems can be very similar to mobile phone systems. Notably, the IDEN standard has been used as both a private trunked radio system as well as the technology for several large public providers. Similar attempts have even been made to use TETRA, the European digital PMR standard, to implement public mobile networks.
Radio phone: This is a term which covers radios which could connect into the telephone network. These phones may not be mobile; for example, they may require a mains power supply, or they may require the assistance of a human operator to set up a PSTN phone call.
Satellite phone: This type of phone communicates directly with an artificial satellite, which in turn relays calls to a base station or another satellite phone. A single satellite can provide coverage to a much greater area than terrestrial base stations. Since satellite phones are costly, their use is typically limited to people in remote areas where no mobile phone coverage exists, such as mountain climbers, mariners in the open sea, and news reporters at disaster sites.
IP Phone: This type of phone delivers or receives calls over internet, LAN or WAN networks using VoIP as opposed to traditional CDMA and GSM networks. In business, the majority of these IP Phones tend to be connected via wired Ethernet, however wireless varieties do exist. Several vendors have developed standalone WiFi phones. Additionally, some cellular mobile phones include the ability to place VoIP calls over cellular high speed data networks and/or wireless internet.^[34]

References

^ Ulyseas, Mark (2008-01-18). "Of Cigarettes and Cellphones". The Bali Times. http://www.thebalitimes.com/2008/01/18/of-cigarettes-and-cellphones/. Retrieved 2008-02-24.
^ Heeks, Richard (2008). "Meet Marty Cooper - the inventor of the mobile phone". BBC 41 (6): 26–33. doi:10.1109/MC.2008.192. http://news.bbc.co.uk/2/hi/programmes/click_online/8639590.stm.
^ Heeks, Richard (2008). "ICT4D 2.0: The Next Phase of Applying ICT for International Development". IEEE Computer 41 (6): 26–33. doi:10.1109/MC.2008.192. http://doi.ieeecomputersociety.org/10.1109/MC.2008.192.
^ Mingtao Shi, Technology base of mobile cellular operators in Germany and China, page 55
^ Facts about the Mobile. A Journey through Time
^ Shiels, Maggie. "BBC interview with Martin Cooper". http://news.bbc.co.uk/1/hi/uk/2963619.stm.
^ "Swedish National Museum of Science and Technology". Tekniskamuseet.se. http://www.tekniskamuseet.se/mobilen/engelska/1980_90.shtml. Retrieved 2009-07-29.
^ UMTS World. "History of UMTS and 3G development". Umtsworld.com. http://www.umtsworld.com/umts/history.htm. Retrieved 2009-07-29.
^ Reardon, Marguerite. "Nokia demos bendable cell phone". CNET News, February 25, 2008. Retrieved 20 July 2009.
^ goingcellular.com — Powermat wireless charger now available
^ EUROPA - Press Releases - Harmonisation of a charging capability of common charger for mobile phones
^ "GSM World agreement on Mobile phone Standard Charger". http://www.gsmworld.com/newsroom/press-releases/2009/2548.htm.
^ pressinfo (2009-10-22). "Press Release: Universal phone charger standard approved — One-size-fits-all solution will dramatically cut waste and GHG emissions". Itu.int. http://www.itu.int/newsroom/press_releases/2009/49.html. Retrieved 2009-11-04.
^ Daily Mail
^ "By the Numbers: Top Five Mobile Phone Vendors in the First Quarter of 2010 - IDC". Idc.com. 2009-07-21. http://www.idc.com/getdoc.jsp?containerId=prUS22322210. Retrieved 2010-07-29.
^ "April 2010 Mobile Metrics Report". September 30, 2010. http://www.gartner.com/it/page.jsp?id=1372013.
^ "By the Numbers: Top Five Mobile Phone Vendors in the Third Quarter of 2009 - IDC". Idc.com. 2009-07-21. http://www.idc.com/getdoc.jsp?containerId=prUS22063909. Retrieved 2009-07-29.
^ "Downloads_Guide". Netsize. http://www.netsize.com/Ressources_Guide.htm. Retrieved 2009-07-29.
^ "UK | Millions keep secret mobile". BBC News. 2001-10-16. http://news.bbc.co.uk/2/hi/uk_news/1602044.stm. Retrieved 2009-11-04.
^ Donner, Jonathan, and Steenson, Molly Wright. "Beyond the Personal and Private: Modes of Mobile Phone Sharing in Urban India." In The Reconstruction of Space and Time: Mobile Communication Practices, edited by Scott Campbell and Rich Ling, 231-250. Piscatawy, NJ: Transaction Publishers, 2008.
^ Hahn, Hans and Kibora, Ludovic. "The Domestication of the Mobile Phone: Oral Society and New ICT in Burkina Faso". Journal of Modern African Studes 46 (2008): 87-109.
^ By RICHARD BROOKSThe Press-Enterprise (2007-08-13). "Donated cell phones help battered women | San Bernardino County | PE.com | Southern California News | News for Inland Southern California". PE.com. http://www.pe.com/localnews/sbcounty/stories/PE_News_Local_S_helpphones13.3d74734.html. Retrieved 2009-11-04.
^ By Christy Oglesby CNN (2008-01-11). "Cells, texting give predators secret path to kids". CNN.com. http://www.cnn.com/2008/CRIME/01/11/teachers.charged/index.html. Retrieved 2009-11-04.
^ Goodyear, Dana (2009-01-07). "Letter from Japan: I ♥ Novels". The New Yorker. http://www.newyorker.com/reporting/2008/12/22/081222fa_fact_goodyear. Retrieved 2009-07-29.
^ "You Witness News". News.yahoo.com. 2009-01-26. http://news.yahoo.com/you-witness-news. Retrieved 2009-07-29.
^ McCullagh, Declan; Anne Broache (December 1, 2006). "FBI taps cell phone mic as eavesdropping tool". CNet News. http://news.cnet.com/FBI-taps-cell-phone-mic-as-eavesdropping-tool/2100-1029_3-6140191.html. Retrieved 2009-03-14.
^ Odell, Mark (August 1, 2005). "Use of mobile helped police keep tabs on suspect". Financial Times. http://news.ft.com/cms/s/7166b8a2-02cb-11da-84e5-00000e2511c8.html. Retrieved 2009-03-14.
^ "Tracking a suspect by mobile phone". BBC News. August 3, 2005. http://news.bbc.co.uk/1/hi/technology/4738219.stm. Retrieved 2009-03-14.
^ Miller, Joshua (March 14, 2009). "Cell Phone Tracking Can Locate Terrorists — But Only Where It's Legal". FOX News. http://www.foxnews.com/story/0,2933,509211,00.html. Retrieved 2009-03-14.
^ "What are the health risks associated with mobile phones and their base stations?". Online Q&A. World Health Organization. 2005-12-05. http://www.who.int/features/qa/30/en. Retrieved 2008-01-19.
^ Brian Rohan (2008-01-2). "France warns against excessive mobile phone use". Reuters. http://www.reuters.com/article/idUSL0223157720080102. Retrieved 2010-05-10.
^ de Waard, D., Schepers, P., Ormel, W. and Brookhuis, K., 2010, Mobile phone use while cycling: Incidence and effects on behaviour and safety, Ergonomics, Vol 53, No. 1, January 2010, pp 30 - 42.
^ Young Kyun, Kim; Prasad, Ramjee (2006). 4G Roadmap and Emerging Communication Technologies. Artech House 2006. pp. 12–13. ISBN 1-58053-931-9.
^ "VoIP Support in Nokia Devices". http://www.forum.nokia.com/Technology_Topics/Mobile_Technologies/VoIP/Nokia_VoIP_Framework/VoIP_support_in_Nokia_devices.xhtml. Retrieved 2009-08-16.

External links

Look up mobile phone in Wiktionary, the free dictionary.

Wikimedia Commons has media related to: Mobile phones

How Cell Phones Work at HowStuffWorks
Number of Mobile Subscribers by Country and per 100 people interactive world map.
Cell Phone, the ring heard around the world—a video documentary by the Canadian Broadcasting Corporation
"The Long Odyssey of the Cell Phone", 15 photos with captions from Time magazine
Mobile Phone Buying Guide
Worldtimezone.com
ITU.int
ITU.int
GSMworld.com

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