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2010-05-16T00:20:00.001-07:00

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;>Ferreelectric RAM(FRAM or FeRAM)
;>WIRELESS APPLICATION PROTOCOL-WAP
;>3G WIRELESS TECHNOLOGY

3G- WIRELESS TECHNOLOGY

2010-05-15T20:26:00.001-07:00

INTRODUCTION

The first generation of mobile phones consisted of the analog models that emerged in the early 1980s. The second generation of digital mobile phones appeared about ten years later along with the first digital mobile networks. During the second generation, the mobile telecommunications industry experienced exponential growth both in terms of subscribers as well as new types of value-added services. Mobile phones are rapidly becoming the preferred means of personal communication, creating the world's largest consumer electronics industry.Third Generation (3G) mobile devices and services will transform wireless communications in to on-line, real-time connectivity. 3G wireless technology will allow an individual to have immediate access to location-specific services that offer information on demand.

EVOLUTION OF 3G

A complete evolution to 3G wireless technology is mandated by the end of 2000 in Japan and by the end of 2001 in Europe. The first pre-commercial 3G network was launched by
NTT DOCOMO in Japan in May 2001. The first commercial launch of 3G was also by NTT DoCoMo in Japan on 1 October 2001, although it was initially somewhat limited in scope, broader availability was delayed by apparent concerns over reliability. In January 2002 SK Telecom (Telecom Company in South Korea ) launched second commercial network .

The first European pre-commercial network was at the Isle of Man by British Telecom, and the first commercial network in Europe was opened for business by Telnor in December 2001 with no commercial handsets and thus no paying customers.The first commercial United States 3G network was by Monet Mobile Networks, but this network provider later shut down operations. The second 3G network operator in the USA was Verizon Wireless in October 2003 In December 2007, 190 3G networks were operating in 40 countries, according to the Global Mobile Suppliers Association (GSA).

In 2008, India entered into 3G Mobile arena with the launch of 3G enabled Mobile and Data services by BSNL in Bihar([Patna]). BSNL is the first Mobile operator in India to launch 3G services. After that ([MTNL]) launched [3G] in Mumbai & Delhi. Government owned Bharat Sanchar Nigam Ltd has already been provided with a 3G license and has been operating its services in 380 cities by the end of March 2010. Nation wide auction of 3G wireless spectrum in April 2010 has been announced, and 3G services by private service providers are expected by the September 2010.

The implementation of 3G wireless systems raises several critical issues, such as the successful backward compatibility to air interfaces as well as to deployed infrastructures. Compatibility and interworking between the new 3G wireless systems and the old legacy networks must be achieved in order to ensure the acceptance of new 3G wireless technology by service providers and end-users.

FIRST GENERATION WIRELESS TECHNOLOGY

The first generation of wireless mobile communications was based on analog signalling. Analog systems, implemented in North America, were known as Analog Mobile Phone Systems (AMPS), while systems implemented in Europe and the rest of the world were typically identified as a variation of Total Access Communication Systems (TACS). Analog systems were primarily based on circuit-switched technology and designed for voice, not data.

SECOND GENERATION WIRELESS TCHNOLOGY

The second generation (2G) of the wireless mobile network was based on low-band digital data signalling. The most popular 2G wireless technology is known as Global Systems for Mobile Communications (GSM). GSM systems, first implemented in 1991, are now operating in about 140 countries and territories around the world. An estimated 248 million users now operate over GSM systems. GSM technology is a combination of Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA). The first GSM systems used a 25MHz frequency spectrum in the 900MHz band.
In addition to GSM, a similar technology, called Personal Digital Communications (PDC), using TDMA-based technology, emerged in Japan. Since then, several other TDMA-based systems have been deployed worldwide and serve an estimated 89 million people worldwide. While GSM technology was developed in Europe, Code Division Multiple Access (CDMA) technology was developed in North America. CDMA uses spread spectrum technology to break up speech into small, digitized segments and encodes them to identify each call. CDMA systems have been implemented worldwide in about 30 countries and serve an estimated 44 million subscribers. While GSM and other TDMA-based systems have become the dominant 2G wireless technologies, CDMA technology is recognized as providing clearer voice quality with less background noise, fewer dropped calls, enhanced security, greater reliability and greater network capacity. The Second Generation (2G) wireless networks mentioned above are also mostly based on circuit-switched technology. 2G wireless networks are digital and expand the range of applications to more advanced voice services, such as Called Line Identification. 2G wireless technology can handle some data capabilities such as fax and short message service at the data rate of up to 9.6 kbps, but it is not suitable for web browsing and multimedia applications.

2G+ WIRELESS NETWORKS

The virtual explosion of Internet usage has had a tremendous impact on the demand for advanced wireless data communication services. However, the effective data rate of 2G circuit-switched wireless systems is relatively slow -- too slow for today's Internet. As a result, GSM, PDC and other TDMA-based mobile system providers and carriers have developed 2G+ technology that is packet-based and increases the data communication speeds to as high as 384kbps.
2G+ systems are based on the following technologies: High Speed Circuit-Switched Data (HSCSD), General Packet Radio Service (GPRS) and Enhanced Data Rates for Global Evolution (EDGE) technologies.
HSCSD - HSCSD is one step towards 3G wideband mobile data networks. This circuit-switched technology improves the data rates up to 57.6kbps by introducing 14.4 kbps data coding and by aggregating 4 radio channels timeslots of 14.4 kbps.

GPRS- GPRS is an intermediate step designed to allow the GSM world to implement a full range of Internet services without waiting for the deployment of full-scale 3G wireless systems. GPRS technology is packet-based and designed to work in parallel with the 2G GSM, PDC and TDMA systems that are used for voice communications and for table look-up to obtain GPRS user profiles in the Location Register databases. GPRS uses a multiple of the 1 to 8 radio channel timeslots in the 200kHz-frequency band allocated for a carrier frequency to enable data speeds of up to 115kbps. The data is packetized and transported over Public Land Mobile Networks (PLMN) using an IP backbone so that mobile users can access services on the Internet, such as SMTP/POP-based e-mail, ftp and HTTP-based Web services.

EDGE- EDGE technology is a standard that has been specified to enhance the throughput per timeslot for both HSCSD and GPRS. The enhancement of HSCSD is called ECSD, whereas the enhancement of GPRS is called EGPRS. In ECSD, the maximum data rate will not increase from 64 kbps due to the restrictions in the A interface, but the data rate per timeslot will triple. Similarly, in EGPRS, the data rate per timeslot will triple and the peak throughput, including all eight timeslots in the radio interface, will exceed 384 kbps.

THIRD GENERATION WIRELESS TECHNOLOGY

3G wireless technology represents the convergence of various 2G wireless telecommunications systems into a single global system that includes both terrestrial and satellite components. One of the most important aspects of 3G wireless technology is its ability to unify existing cellular standards, such as CDMA, GSM, and TDMA, under one umbrella. The following three air interface modes accomplish this result: wideband CDMA, CDMA2000 and the Universal Wireless Communication (UWC-136) interfaces.

Wideband CDMA (W-CDMA) is compatible with the current 2G GSM networks prevalent in Europe and parts of Asia. W-CDMA will require bandwidth of between 5Mhz and 10 Mhz, making it a suitable platform for higher capacity applications. It can be overlaid onto existing GSM, TDMA (IS-36) and IS95 networks. Subscribers are likely to access 3G wireless services initially via dual band terminal devices. W-CDMA networks will be used for high-capacity applications and 2G digital wireless systems will be used for voice calls.

CDMA2000 is backward compatible with the second generation CDMA IS-95 standard predominantly used in US.

The third radio interface, Universal Wireless Communications – UWC-136, also called IS-136HS, was proposed by the TIA and designed to comply with ANSI-136, the North American TDMA standard.

3G wireless networks consist of a Radio Access Network (RAN) and a core network. The core network consists of a packet-switched domain, which includes 3G SGSNs and GSNs, which provide the same functionality that they provide in a GPRS system, and a circuit-switched domain, which includes 3G MSC for switching of voice calls. Charging for services and access is done through the Charging Gateway Function (CGF), which is also part of the core network. RAN functionality is independent from the core network functionality. The access network provides a core network technology independent access for mobile terminals to different types of core networks and network services.

PROTOCOL LAYERS IN 3G INFRASTRUCTURE

Global Mobility Management (GMM): protocol that includes attach, detach, security, and routing area update functionality.

Node B Application Part (NBAP): provides procedures for paging distribution, broadcast system information and management of dedicated and logical resources.

Packet Data Convergence Protocol (PDCP): maps higher level characteristics onto the characteristics of the underlying radio-interface protocols.PDCP also provides protocol transparency for higher layer protocols.

Radio Link Control (RLC): provides a logical link control over the radio interface.

Medium Access Control (MAC): controls the access signaling (request and grant) procedures for the radio channel.

Radio resource Control (RRC): manages the allocation and maintenance of radio communication paths.

Radio Access Network Application Protocol (RANAP): encapsulates higher layer signaling. Manages the signaling and GTP connections between RNC and 3G-SGSN, and signaling and circuit-switched connections between RNC and 3G MSC.

Radio Network Service Application Part (RNSAP): provides the communication between RNCs.

GPRS Tunnel Protocol (GTP): protocol that tunnels the protocol data units through the IP backbone by adding routing information. GTP operates on top of TCP/UDP over IP.

Mobile Application Part (MAP): supports signaling between SGSN/GGSN and HLR/AuC/EIR.

AAL2 Signaling (Q.2630.1, Q.2150.1, Q.2150.2, AAL2 SSSAR, and AAL2 CPS): protocols suite used to transfer voice over ATM backbone using ATM adaptation layer 2.

Sigtran (SCTP, M3UA): protocols suite used to transfer SCN signaling protocols over IP network.

FEATURES OF 3G

Data rates: 3G technology can provide a minimum data rate of 2 Mbit/s for stationary or walking users, and 384 kbit/s in a moving vehicle

Security: 3G networks offer greater security than their 2G predecessors. By allowing the UE (User Equipment) to authenticate the network it is attaching to, the user can be sure the network is the intended one and not an impersonator.
In addition to the 3G network infrastructure security, end-to-end security is offered when application frameworks such as IMS are accessed, although this is not strictly a 3G property.

APPLICATIONS

The bandwidth and location information available to 3G devices gives rise to applications not previously available to mobile phone users. Some of the applications are:

Mobile TV – a provider redirects a TV channel directly to the subscriber's phone where it can be watched.
Video on demand – a provider sends a movie to the subscriber's phone.
Video conferencing – subscribers can see as well as talk to each other.
Tele-medicine – a medical provider monitors or provides advice to the potentially isolated subscriber.
Location-based services – a provider sends localized weather or traffic conditions to the phone, or the phone allows the subscriber to find nearby businesses or friends.

REFERENCES

NATIONALWIDE WIRELESS.NET
SLIMSOUISSI.ADVANCES RESEARCH.NOVATTEL WIRELESS INC.
CDMA DEVELOPMENT GROUP.WHITE PAPERS
GOOGLE
ANSWERS.COM
SCRIBD.COM

Wireless Application Protocol

2010-05-08T02:37:00.000-07:00

INTRODUCTION

The Wireless Application Protocol is a standard developed by WAP Forum, which is a group founded by Ericsson,Nokia, Motorola and Phone.com. Now software companies such as Microsoft, Oracle, IBM, and Intel along with several hundred other companies holds membership in the WAP Forem.

GOALS OF WAP

1. Independent of wireless network standard.

2. Open to all.

3. Proposed to the appropriate standards bodies.

4. Scalable across transport options.

5. Scalable across device types.

6. Extensible over time to new networks and transports.

WAP defines a communication protocol as well as an application environment. In essence, It is a standardized technology for cross-platform, distributed computing. WAP is similar to the World Wide Web.The WAP model closely resembles the Internet model of working. In Internet a WWW client requests a resource stored on a web server by identifying it using a unique URL, that is, a text string constituting an address to that resource. WAP client applications make requests very similar in concept to the URL concept in use on the Web.Standard communication protocols, like HTTP and Transmission Control Protocol/Internet Protocol (TCP/IP) manage these requests and transfer of data between the two ends. The content that is transferred can either be static like html pages or dynamic like Active Server Pages (ASP), Common Gateway Interface (CGI), and Servlets.

WORKING

A WAP request is routed through a WAP gateway which acts as an intermediary between the “bearer” used by the client (GSM, CDMA, TDMA, etc.) and the computing network that the WAP gateway resides on (TCP/IP in most cases). The gateway then processes the request, retrieves contents or calls CGI scripts, Java servlets, or some other dynamic mechanism, then formats data for return to the client. This data is formatted as WML (Wireless Markup Language), a markup language based directly on XML. Once the WML has been prepared (known as a deck), the gateway then sends the completed request back (in binary form due to bandwidth restrictions) to the client for display and/or processing. The client retrieves the first card off of the deck and displays it on the monitor.

The deck of cards metaphor is designed specifically to take advantage of small display areas on handheld devices. Instead of continually requesting and retrieving cards (the WAP equivalent of HTML pages), each client request results in the retrieval of a deck of one or more cards. The client device can employ logic via embedded WMLScript (the WAP equivalent of client-side JavaScript) for intelligently processing these cards and the resultant user inputs.

To sum up, the client makes a request. This request is received by a WAP gateway that then processes the request and formulates a reply using WML. When ready, the WML is sent back to the client for display. As mentioned earlier, this is very similar in concept to the standard stateless HTTP transaction involving client Web browsers.

There are three essential product components that you need to extend your host applications and data to WAP-enabled devices. These three components are:

WAP Microbrowser – residing in the client handheld device

WAP Gateway – typically on wireless ISP’s network infrastructure

WAP Server - residing either on ISP’s infrastructure or on enduser organization’s infrastructure .

WAP Mcrobrowser

A WAP micro-browser is a client software designed to overcome challenges of mobile handheld devices that enables wireless access to services such as Internet information in combination with a suitable network server.

WAP Gateway

WAP Gateway is a piece of software that sits between the mobile device and the external network like the Internet. The gateway does the job of converting Internet content i.e. the WML pages into byte code (WMLC) to reduce the size and number of packets, which can be understood by a WAP device.

A WAP Gateway contains following functionalities

1. Protocol Gateway- The protocol Gateway translates requests from the WAP protocol stack to the WWW protocol stack(HTTP and TCP/IP).

2.Content Encoders and Decoders- The content encoders translate web content into compact encoded formats to reduce the size and number of packets travelling over the wireless data network.

WAP Server

It is simply a combined web server and WAP gateway. WAP devices do not use SSL( secure socket layer protocol-cryptographic protocol that provide security for communications over networks such as the Internet.), instead they use WTLS( a security protocol for wap). Most existing web servers should be able to support WAP content as well. Some new MIME(multipurpose internet mail extentions) types need to be added to your web server to enable it support WAP content. MIME stands for Multipurpose Internet Mail Extension, and in the web context, MIME can be thought of as a piece of header information that comes down with every file sent from a web server to a browser.

FEATURES OF WAP

1. Interoperability: WAP is an open license-free standard, which ensures that WAP-compliant devices are interoperable.

2. Scalability: WAP applications scale across a variety of wireless transport options like GSM SMS, GSM USSD, IP, CDMA, etc., and also across a wide range of wireless terminals from hand sets to powerful PDAs.

3. Extensibility: WAP has been designed as a future-proof technology. It is extensible over time to new networks and transports thereby protecting the mobile network

4. Flexibility: WAP is a flexible solution that caters to the requirements of various types of applications by providing service options like connection mode and connection-less services, with or without end-to-end security.

5. Reusability: WAP specification extends and adapts existing Internet standards such as HTTP, IP, Proxy technology, SSL, TLS, XML, HTML,etc., to wireless environment instead of defining a new set of standards.

ARCHITECTURE

The WAP Protocol Stack is implemented via a layered approach (similar to the OSI network model). These layers consist (from top to bottom) of :

Wireless Application Environment (WAE)- WAE provides a network neutral and device independent application environment framework, which enables a wide range of applications (user-agents) to be used on wireless terminals.

Wireless Session Protocol (WSP)- WSP layer provides mechanisms and semantics based on the Internet standard, Hyper Text Transfer Protocol (HTTP/1.1) along with additional functionalities such as:

1.protocol feature negotiation (capability negotiation)

2. compact encoding of data

3. session suspend/resume

4. long lived session states

5. asynchronous request

Wireless Transaction Protocol (WTP)- WTP layer provides a lightweight transaction service, i.e., a request/response service, which can operate efficiently over a secure, or insecure datagram service.WTP is message oriented protocol, which makes it suitable for interactive browsing applications.

Wireless Transport Layer Security (WTLS)- WTLS( similar to Transport Layer Security TLS used in the internet) was developed to address the problematic issues such as limited processing power and memory capacity, and low bandwidth - and to provide adequate authentication, data integrity, and privacy protection mechanisms.

Wireless Datagram Protocol (WDP)- WDP provides the higher layers of the stack with a consistent interface to underlying bearer. WDP operates transparently over one of the available bearer services there by making the upper layers of the WAP stack independent of the bearer. Since the services offered by underlying bearers vary widely, WDP contains adaptation layers to map WDP functions to services offered by different bearers.

Bearers (GSM, IS-136, CDMA, GPRS, CDPD, etc.)

The WAP stack can be configured in four different ways to provide four different types of services. Following are the four types of services offered by WAP :

1. Connectionless service: The WAP protocol stack used for this service consists of only WSP layer operating directly over WDP layer.

2. Connectionless service with security: This configuration is similar to connectionless service but provides security by having WTLS layer between WSP and WDP layers.

3. Connection oriented service: The configuration of protocol stack used for this service consists of WSP, WTP and WDP layers with ordering of the layers same as that shown in Figure WTP and WDP layers together provide a connection oriented transport service in this configuration.

4.Connection oriented service with security: This configuration consists of all the layers of WAP stack.

CONCLUSION

The primary focus of WAP technology is to create a global wireless internet by bringing services offered by internet to mobile phone users. Industry leaders in handset manufacturing representing over 90% of the world market and mobile network operators representing about 300 million subscribers are adopting this technology. WAP has been designed to benefit wireless subscribers, handset vendors, network operators and service providers. Subscribers get access to a wide range of services available on Internet from their mobile phones and other wireless interoperable open standard, whichis is handset vendor independent. Some critics and second-guessers have pondered the need for a technology. WAP’s use of the deck of cards “pattern” and use of binary file distribution meshes well with the display size and bandwidth constraints of typical wireless devices. Scripting support gives us support for client-side user validation and interaction with the portable device again helping to eliminate round trips to remote servers. WAP is a young technology that is certain to mature as the wireless data industry as a whole matures; however, even as it exists today, it can be used as an extremely powerful tool in every software developer’s toolbox.

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Ferroelectric RAM(FRAM/FeRAM)

2010-05-03T03:21:00.000-07:00

Ferroelectric RAM ( also called FRAM or FeRAM) is a non-volatile Random Access Memory that uses a ferroelectric film capacitor to store data. Possessing the characteristics of both ROM and RAM devices, FRAM features high speed acess, high endurance in write mode, low power conception, non-volatility and excellent tamper resistance. FRAM is one of the growing number of ailernative non-volatile memory technologies.

HISTORY

The developement of FRAM started in late 1980's. Much of the current FRAM technology was developed by Ramtron a fabless semiconductor company. One major licensee is Fujistu, who operates the largest semi conductor foundry production line with FRAM capability. Fujistu produces devices for Ramtron. Texas instruments has collobrated with ramtron to produce FeRAM test chips in a modified 130 nm process. By the end of 2005 Ramtron reported that they were evaluating prototype samples of an 8 megabit FeRAM chip manufactured using Texas Instruments FeRAM process. In the same year Fujistu collaborated with Sieko-Epson in the developement of a 180 nm FeRAM process. Reaserches in this field have also been conducting at Institutions like Cambridge university, Totento university, IMEC-Belgium, Samsung, Thoshiba, Oki, Matsushita, Infineon, Hynix and Symetrix.

WORKING

DRAM consists of a large number of capacitors and thier signaling transistors and thier associated wirings. Each storage unit -called a cell- consists of one capacitor and one transistor so it is called a 1t-1c device. Data is stored as the presence or absence of charge in the capacitor. While writing the signaling transister is activated , the cell is drained to write a 0-bit,or send current to it from supply line to write a 1-bit. While reading the charge is drained to an amplifier if a pulse of charge is noticed in the amplifier it reads a 1bit in the cell, and no pulse reads a 0-bit in the cell.

stucture of a FeRAM cell

In a FeRAM cell capacitor ferroelectric material (lead zirconate titanate-pzt) is used. The dielectric constant of a ferroelectric material is much higher than that of a linear dielectric because of the semi-pemanant dipoles formed by the structure of the ferroelectric material. When an external electric field is applied the dipoles will align in the direction of the field and even after the charge is removed the dipoles retain their polarization. This feature used to store data in FeRAM cell. Two possible electric polarizations are used to store binary 0's and 1's in each cell. If the positive remnant polarization(+Pr) is used to store the 0'bit, then negative remnant polarization(-Pr) is used to store a 1'bit.

structure of a 1transister FeRAM cell and it's working machanism

Writing is done by appying a field across the ferroelectric by charging the plates of the capacitor. This will force the atoms inside the ferroelectric to 'up' or 'down' orientation depending on the polarity of the applied charge and by thus to store '1' or '0'.

To read data from FeRAM cell the transister will force the cell into a perticular state, for eg. consider it is '0'. If the cell already contained a '0' nothing will happen in the output. If it already held a '1' then it wiil cause the reorientation of the atoms in the ferroelectric and will produce a current pulse in the output. Reading FeRAM is a distructive process (because it overwrits the data) and it requires the cell to be rewritten if it is changed.

ADVANTAGES

1.Density- The cost of a memory system is mainly depends upon the density of its components.While comparing with other memory systems FeRAM can have higher coponent density.

2.Power Consumption-Power consumed by FeRAM is very law when compared with others. In the case of a DRAM cell charge applied to the matalic plates leaks across the insulating material so continuous power supply is needed to refresh the cells and for a flash memory high voltage is required for pushing the electrons so the power usage will be high.

3.perfomance- Since read- write operations in FeRAM is associated with the movements of atoms, which is very faster FeRAM could be much faster than other existing mechanisms.