Yes, in the year of 2011, I am going to develop and release an app every month. The reason I am going to try this experiment is simple. I guess many of you must have experienced this.

• I waste loads of time reading hacker news and Google Reader.
• I read about lots of cool stuff, but never end up building something.

I am going to see if atleast by publicly announcing this app-a-month project, I will be able to beat my laziness and get some value out of the hours of seeing the laptop.

I will be blogging about my experiences and things I learn at appamonth.blogial.com and would also be tweeting at @appamonth. Do follow me and encourage me into completing each project.

And Happy New Year to all you guys. Have a great year ahead.

<meta name="generator" content="WordPress 3.0.3" />

Which means, we are running on the latest stable release of WordPress. Previously this blog was running the mu version of WordPress. But from 3.0, the mu version has been merged into the main wordpress code with support for multisite.

Now that the blog is updated to this latest version, all future upgrades are just two clicks away. A big relief from the horrible manual steps of backup, download, copy.

And by the way, wait till the new year begins for an interesting announcement.

Background :

Evolution Of networks

LTE – Long Term Evolution is one of the latest communication technology that is currently being tested and deployed. LTE falls under 3G dubbed as 3.99G and LTE-Advanced is 4G compliant. 3GPP Release 8 defines the standards for LTE and Release 10 pertains to defining the standards for LTE-Advanced. LTE was formulated as a result of study on Evolved UTRA(Universal Terrestrial Radio Access) done by 3GPP. The System Architecture Evolution(SAE) – all IP based network is the core Network Architecture for establishing a LTE Network.

LTE Benefits :

• LTE can provide practical data rates of 100Mbps – downlink and 50 Mbps uplink (20 MHz
• Spectrum)
• LTE has very low latency period of <10ms.
• LTE has very low control plane latency <100ms.
• LTE has high spectral efficiency.
• Scalable bandwidth – 1.25, 1.6,2.5,5,10,15,20 MHz.

The reason behind how every benefit above is achieved is discussed below.

Modulation Technique:

Different Modulation Techniques

LTE uses Orthogonal Frequency Division Multiplexing – OFDM. For modulation it employs 64 QAM( Quadrature Amplitude Modulation Technique) which combines both ASK- amplitude shift keying and PSK- phase shift keying thereby enabling several bits to be transmitted per symbol. Every symbol used will now be a result of a particular amplitude and phase. Also the adjacent symbols are now wider hence bringing down the Bit Error Ratio. In LTE a 64 array QAM is used.

The data is multiplexed in several slow rate channels which sums up to more data. These sinusoidal signals as spaced close together orthogonally without interfering with each other. Hence the available spectrum is efficiently used i.e. more bits per seconds per Hz (Spectral Efficiency).Every sub-carrier is modulated by using QAM technique. OFDM signal is hence a composite of several low rate data streams which are flat-fading channels.
Time Domain – Orthogonality is ensured by limiting the integral number of cycles occurs for each
within a specific time window.
Frequency Domain – Ensured by placing the peak of any one of the carrier wave with the nulls of
rest.
The benefit from such spacing is that the demodulator can now easily and distinctly distinguish between the frequencies and hence the receiver extracts the correct frequencies. This is highly essential in terrestrial environment with several distortions.

Orthogonal Waveform Composition

Each Wave is spaced Orthogonally In the figure.

OFDM Transmitter:
The binary source signal is demultiplexed into several parallel streams. These parallel streams of data are then modulated using QAM technique. These are then converted to time-domain samples by Inverse-FFT. The signal is converted to analog and then the carrier wave is added to it and transmitted.

OFDM Transmitter

OFDM Receiver :

OFDM Receiver

The receiver system receives the analog signal is passed to the low pass filter to reject the 2fc and converted back to digital signal. A FFT converts them back to frequency domain. The output is a set of parallel streams which is passed though a symbol detector and converted to s series stream of the original signal.
Sub Carrier Spacing :
The Transmission bandwidth is usually from 1.25 – 20 MHz with a sub carrier spacing of 15 KHz. This concept of transmitting several narrow-band sub carriers is built into the circuits of the downlink radio station. OFDM used guard interval alias cyclic prefixes( Repeat of end signal at beginning) this eliminates the necessity of receiver side channel equalizer also reduces the inter- symbol interference aiding the high symbol rate modulation technique. This saves power and cost.

Sub-carrier Details
Multiple Antenna :
Since the distributive channel effects are eliminated in OFDM, MIMO – Multiple Input Multiple Output radio antennas can be used effectively also OFDM divides the channel into several sub- frequencies making this is an effective scheme to implement. This boosts the throughput as several independent data streams are transmitted in parallel via different antennas.

MIMO
If the length of the guard interval is equal or less than the MIMO channel order then OFDM generates a set of parallel frequency flat MIMO channels. If the MIMO channel order is more than the guard interval length per tone equalization is used. While designing the interference is taken to our advantage by beamforming, this improves the throughput at the cell edge. NLOS- NON-LINE- OF_SIGHT is effectively achieved. Also the channel has a total of (number of transmission antennas)*(number of receiver antennas). This significantly improves the data rates. Say 6 base station antennas are set up with respect to 6 terminal side receive antennas hence one will be receiving 6 parallel data streams providing a theoretical multiplicating factor of 6 to the throughput. This is called Spatial multiplexing wherein the transmission rate boost is proportional to the number of transmission side antennas. MIMO only increases the spatial paths between the receiver and the transmitter. Hence the bandwidth is not increased to increase the throughput rather the spatial domain is exploited to increase the throughput making it unique and highly efficient.

The above table shows the SNR for a Rx to Tx antennas. It can be inferred that a 41 % increase in SNR making such an implementation highly efficient. This will also enable the signal to propagate further as it has a high SNR. This will hence bring down the installation of number of standalone transmitters in an area bring down the cost greatly.

Interference to advantage :

As a result of multi-path propagation which may also result as a result of obstructions or various interferences there would be loss in packets. The data rate is always favoured to be constant for voice. Whereas in packet-data services it is not required at differential intervals i.e. falling short interval peaks of data rate will not be noticeable. LTE uses this phenomenon instead of suppressing the negative surges of data rate to efficiently uses the mobile resources.

Rate Control
Link sharing :
Link sharing aims at subdividing the available resources to the pertinent users. LTE systems employ dynamic link scheduling with a latency period of ~10ms. The network can adapt to the instantaneous load. The data rate is varied depending on the applications transfer rates required. If rich multimedia content then it switches to better rates. If just voice or chat the it can be switched to lower data rates. The switching between rates can be employed by changing the modulation order - In case of low data rates 16QAM is used if higher rates are required the switched to 64QAM. Since the users share a common channel the resources are dynamically allocated. The basic idea is to transmit at the fading peaks where the channel’s quality is high. This is because this architecture doesn’t use power control (Power varies to keep data rate constant) ,it uses Rate Control as shown. Now the battle is to determine how to allocate the users to channel at these instances. It is done in time, frequency and spatial domains to conserve the mobile resources. OFDM spectral efficiency aids the increase in time duration for each user in the peak mode.

Round-Robin : Round-Robin method can be used to allocate users with respect to time disregarding the channel quality. This is an unfair policy to the user.

Proportional Fair : This is a better method and the one employed in high performance LTE networks. Time Slot for every user I almost the same or atleast fair pit pushes the data when the channel’s condition improves. This is a fair policy to the user

Sub-Carrier Allocation :

The OFDMA orthogonal frequency division multiple access characterizes every user with a sub carrier. In a single channel spectrum several sub carriers are allocated to every used based on his requirement. This scheme is particularly useful in downlink when the number of users is high. If the data rate required is low then scheme is adapted as it consumes less resource and the delay is reduced effectively. The mobile users can be synchronised in time domain and frequency domain. This makes the uplink to be orthogonal and in sync. In LTE the data is sent in resource blocks with each of them encompassing 12 sub-carries in a single time slot. This resource block size is maintained constant.

Time And Freq Domain – user scheduling

The Channel’s quality can also be taken in this scenario wherein the user’s domain pertains to a particular time and frequency period with respect to the channel quality. Here the information on channel quality will have to be in transmission so that the base station can effectively slot the user in that that particular time and frequency domain. LTE reports the channel quality every 1 ms. At low mobility speeds frequency selective scheduling performs equally or even better than stationary as the channel quality varies rapidly hence there is more chance to transmit at good channel quality. The mobile device’s performance varies on different portions on the spectrum since the high frequency (20 MHz/0 causes frequency-selective fading. This best sub-frequencies can be determined by feedback information(Channel quality information) from the mobile device. There are two ways to select the better sub-carrier – Sequential scheduler and matrix based scheduler. The matrix based scheduler performs slightly better. (Inferred from Frequency Selective OFDMA
Scheduler with limited feedback – Wireless Communications and Networking Conference, 2008. WCNC 2008. IEEE published.)

Two Signals are primarily used to assign the resource elements to the UE.
Reference Signal : It is a product of an Orthogonal sequence and PRN sequence(pseudo-
random numerical). 3GPP estimates 510 unique reference signals. Each can be assigned to a cell to
identify it in the network.
Synchronisation Signals : There are two Synchronization signal Primary and Secondary.
They are used in the cell search by mobile device. They are transmitter in the 0 and 10th slot in the
frame.

Uplink Modulation & Sharing:

The mobile device has limited power. The OFDM and OFDMA have high peak to average power ratio which makes it energy consuming hence is not favourable to a mobile device. So in the uplinks a Single-Carrier DFT spread OFDM is used with better Peak to average Power Ratio. This is more efficient in using the power at optimum coverage saving the resources of the mobile device. 3GPP has standardised on using the Single Carrier – FDMA (SC-FDMA). LTE Uplink is Orthogonal in regards with a single cell to which they are connected. A Distributed mapping is chosen for the SC-FDMA to exploit the orthogonality. This reduces the overall peak to average power ratio. The users in a cell can communicate without any interference between them also the null sub-carriers are used.

Uplink Channel Sharing

The mobile device might have frequency domain in channel with a band of sub-carriers in communication with the cell it is connected to. A distant cell will have another device using the same sub-carriers. This could cause interference. Also if the neighbouring cell is closer it causes strong interference. Hence during designing of the network structure the cells are placed at an optimum rage from each other limiting the interference it a low value. With respect to the mobile device its identification can be easily done with respect to its proximity to each cell and removing the interference. The proximity detection also aid in cell switching when the user is in motion.

Error Handling :

The Data sent is in packets hence there might be a loss of packets as a result of noise interference or fading as in any wireless network. Hence LTE implements Two Layered Retransmission schemes to preserve the data. A Fast Hybrid Automatic Repeat request(HARQ) protocol is implemented over a Selective repeat ARQ protocol. i.e. Forward Error Correction bits are appended over the traditional CRCs.

Error Handling

The ruptured data blocks are not discarded and are stored by the receiver. The retransmitted block is combined with it and then decoded. The joining between the blocks is done by incremental redundancy. Every retransmitted block is punctured and transmitted. The puncture patterns can be deducted from the retransmission number.

LTE Network Architecture :
CORE Architecture :

System Architecture Evolution is the Core-Network Architecture. The important factor of this network architecture is that it is heterogeneous. It enables other wireless networks to co-exist (2.5G, 3G) and LTE is merely an extension. SAE has been evolved from the GPRS Core Network. This makes the implementation on the LTE networks cheap and use the existing network infrastructure. This makes LTE a much better choice in comparison with the other wireless technologies. Also the upgrade to the LTE Advanced (4G)will be a much smoother process. The SAE Architecture is an all IP based network. Every service in Network is in PS ( Packet  Service) Domain and not CS (Circuit Switched) Domain. The Architecture also inadvertently supports mobility to other systems like the WiMAX, 2G and 3G( Although latter many not be necessary the former will be essential).

In addition to the GPRS core of the network, the Evolved Packet Core embedded to facilitate LTE. This will provide IP-Based voice and data service simultaneously. Also the scalability of the services application and users will increase. There will also be minimal upgrades once it is embedded into the network as the services become IP based. The Control Plane functions can now be made simpler and easier to implement.

Radio Access Architecture:

The 3GPP has set the standards for the Evolved UMTS(Universal Mobile Telecommunication System) Terrestrial Radio Access Network – E-UTRAN. The Mobile devices connect to these radio networks. The communication is IP packet based making the Entire system unified in the IP network. The packet data based network enables the switch between the speeds for voice-data packets and rich multimedia packets offering high data rates.

Frame-SubFrame

Each Frame consists of 10 sub-frames containing 14 OFDM Symbols. The Frame is of 10 ms duration and each sub frame is 1 ms in duration. Now dividing the sub-frame.

The LTE downlink physical channels consist of ,
Physical Downlink Shared Channel (PDSCH) – consumes 3 ODFM symbols per sub-frame. This is 21% of the
Symbols in the sub-frame, hence 14% over- head for control.
Physical Downlink Control Channel (PDCCH) – consumes 3 ODFM symbols. It states the mobile device specific information to optimise the communication.
Common Control Physical Channel (CCPCH) - It states the cell-wide control information. It is transmitted near to the  centre frequency. It is the CCFI – Control Channel Format Indicator. It is transmitted in the Physical Control Format Indicator Channel(PCFICH). The Cyclic prefixes used can be seen in the diagram, They also have pilots as a reference for the MIMO. Every Resource Block can be divided into 12(sub carrier frequency range) x 14 Symbols and the mapping is bade on scheduling – localized or Distributed( Distributed preferred ).

OFDM Symbols

LTE Channel Architecture :

LTE Channel Architecture

The RLC (Radio Link Control) Services the higher layers. It passes the data to the MAC Layer as Logical channel. The MAC Layer constructs the frame and passes the frame to the Physical Layer. The Packet Data Convergence Protocol ( PDPC) employs ROHC( Robust Header Compression ) to compress the TCP or IP or UDP headers. The ARQ does the error correction and the HARQ brings downs the number of retransmission.
Transport Channels : The logical channel data is framed and sent as transport channel to the physical layer from the MAC layer.
Broadcast Control Channel (BCH) : Broadcast in the network with system information. Downlink Shared Channel : Implements HARQ and discontinuous receive to save energy also aids in resource allocation.
Paging Control Channel (PCH) : Broadcast in the network. It continuously states information on dynamically allocated resources so change can be monitored. Also enables discontinuous reception hence saving power in the device.
Multicast Channel (MCH): Transmission to multiple devices.

Logical Channels Broadcast Control Channel (BCCH): Label broadcast in the network with system information.

Paging Control Channel (PCCH) : Broadcast in the network. It continuously states informationon dynamically allocated resources so change can be monitored.

Common Control Channel (CCCH): transmits control information of the network to the device.

Multicast Control Channel (MCCH): Groups within the network get common information.

System Architecture Evolution SAE :

The E-UTRAN can be integrated only with SAE. The Evolved Packet Core(EPC) consists of two components.3GPP Anchor and the SAE Anchor. The MME connects the radio network to the EPC. The Mobility Management Entity corresponds to the user equipment control plane context by authorising the mobile device and the Public Land Mobile network is identified and registered. Every PLMN is interconnected and is unique to a subscriber. The MME also implements NON- Access Stratum security and idle state mobility handling. The MME support tracking and handover. The 3GPP anchor provides mobility between the GRPS core and the LTE i.e. 3GPP and non 3GPP systems. The SAE Anchor Provides mobility between the LTE and WLAN technologies( Inter- mobility within 3GPP systems).

The Packet network gateway of the EPC registers the mobile device with an IP address. IP based packet filtering can also be done at this stage. Here the bandwidth allocation or limitations can be set to every restricted user which in turn can be used in billing factors to determine the usage. The control over the application can also be done as here the IP level control is present. Further Firewall and content filtering can be implemented here.

Mobility Architecture:

LTE Architecture

Since the mobile devices are under constant motion it is always better and efficient to preserve the IP address rather than give a new one every time it switches between cells. The Network Based mobility management ensures that the homing of IP to the same mobile device is ensured. When the UE switches to another cell. The Network entity providing the IP address to the UE ensures that its location in the MME’s routing table is updated. So that the path is changed based on the cell to which the device is associated. The following are the components involved in the mobility architecture.

PDN Gateway(Packet Data Network Gateway) : This entity assign the IP address to the mobile device it can be IPv4 or IPv6. The PDN Gateways are employed by the PDN in the EPC. The Gateway’s identity is to redirect the device during the handover and authentication. The PDN is usually a Operator network form where the user is connected within the network of the operator to allow faster communication between he mobile devices that are registered to the same operator in the city of state. this brings downs the cost to the service provided as not external factor in involved. This makes the call rates really affordable by the users within the same network. It is also connected to the Internet wherein PDN acts as a gateway. The connection to Internet is set in when online contents are viewed or communication with other subscribers. Also connection between subscribers can be made to save cost by elimination the usage of Internet for voice call within the state.

Servicing Gateway (S-GW) : This aids in the mobility between different 3GPP radio networks E-UTRAN UTRAN and acts at layer 2.

Access Gateway (A-GW) : This facilitates the mobility between 3GPP and NON-3GPP radio networks.

Evolved Packet Data gateway : In case of untrusted non- 3GPP networks the security is established by using IPSec over a validated session from the user to the core. 3GPP has standardised IMSI- International mobile subscriber identity to be given at all the subscribed mobile device this uniquely identifies the mobile device across the different networks this makes the device connectable between Non-3GPP and 3GPP with an identity.
SGSN (Serving GPRS Support Node ) : The SGSN which has inbuilt mobility management forwards the incoming and outgoing packets to the mobile Station the existing 2G and 3G networks data traffic is also passed thorough it.
LTE providing end to end IP service will improve the mobile services and will bring in the concept of singularity to the mobile devices. Wherein all mobile devices ranging from pagers to laptops can be serviced by the same network. The Architecture is built over the existing framework making it easier for the companies to transfer to. Already Companies such as Qualcomm, Motorola, Alcatel-Lucent etc.. have tested and demonstrated the capabilities of LTE network and will soon become the future network overtaking technologies such as WiMAX. Aslo the upgrade to 4G – LTE Advanced will be a lot easier. The most important benefit that I observe is cost effectivness to the Mobile Network operators. When every data that traverses is just packets then the control becomes easier and scalability increases. The operators can provide more benefits at very low cost making high returns.

References :
Specifications :
Official Site : http://www.3gpp.org
Secification : http://www.3gpp.org/ftp/Specs/archive/36_series/36.212/

Texts :
Van Nee and Prasad, OFDM for Wireless Multimedia Communications, Artech House Publishers
Wireless Network Coexistence – Robert Morrow, McGraw Hill
Online Papers :

Single Carrier FDMA and OFDM Based for Uplink in Evolved UTRA/3.9G Systems
Master thesis. Mar 2008 – IEEE
Authors – Sergi Reñe & Humbert Codina. Telecomunications engineering students from the UPC.
1(a)

Network-Based Mobility Management in the Evolved 3GPP Core Network
Authors – Irfan Ali, Motorola Inc. Alessio Casati, Alcatel-Lucent Kuntal Chowdhury, Starent

Networks Katsutoshi Nishida, NTT DoCoMo Inc. Eric Parsons, Nortel Networks Stefan Schmid, NEC Europe Ltd. Rahul Vaidya, Samsung India Software Operations. FEB 2009 – IEEE

Spectral Efficiency Assessment and Radio Performance Comparison between LTE and WiMAX
Authors – Carsten Ball, Thomas Hindelang Nokia Siemens Networks GmbH & Co. KG Munich,
Germany and Iavor Kambourov, Sven Eder Program and Systems Engineering Siemens AG, Mar
2008 — IEEE

LTE spectral efficiency using spatial multiplexing MIMO for macro-cells Vieira, Pedro; Queluz, Paula; Rodrigues, Antonio;
Signal Processing and Communication Systems, 2008. ICSPCS 2008. 2nd International Conference
on 15-17 Dec. 2008 Page

Adaptive Soft Frequency Reuse for Inter-Cell Interference Coordination in SC-FDMA Based 3GPP
LTE Uplinks
Xuehong Mao; Maaref, A.; Koon Hoo Teo;
Global Telecommunications Conference, 2008. IEEE GLOBECOM 2008. IEEE
Nov. 30 2008-Dec. 4 2008

Physical Layer Performance of Long Term Evolution Cellular Technology
Sanchez, J.J.; Morales-Jimenez, D.; Gomez, G.; Enbrambasaguas, J.T.;
Mobile and Wireless Communications Summit, 2007. 16th IST
1-5 July 2007

Standardization of MIMO-OFDM Technology Mujtaba, S.A.;                                                                   Networking and Communications Conference, 2008. INCC 2008. IEEE International

1-3 May 2008
Physical layer verification for 3GPP LTE (FDD)
Sung-won Kim,; Kun-yong Kim,;
Advanced Communication Technology, 2009. ICACT 2009. 11th International Conference on
Volume 02, 15-18 Feb. 2009

MIMO Schemes in UTRA LTE, A Comparison                                                                                            Spiegel, C.; Berkmann, J.; Zijian Bai; Scholand, T.; Drewes, C.;                                                                          Vehicular Technology Conference, 2008. VTC Spring 2008. IEEE 11-14 May 2008

The LTE radio interface – key characteristics and performance Furuskar, A.; Jonsson, T.; Lundevall, M. Personal, Indoor and Mobile Radio Communications, 2008. PIMRC 2008. IEEE 19th International
Symposium on 15-18 Sept. 2008

ARQ Concept for the UMTS Long-Term Evolution
Meyer, M.; Wiemann, H.; Sagfors, M.; Torsner, J.; Jung-Fu Cheng;
Vehicular Technology Conference, 2006. VTC-2006 Fall. 2006 IEEE 64th
25-28 Sept. 2006

Coexistence Analysis Involving 3GPP Long Term Evolution
Xiang Chen; Xiaowei Jin; Moorut, P.; Love, R.; Yakun Sun; Weimin Xiao; Ghosh, A.; Fernandes,
E.; Vehicular Technology Conference, 2007. VTC-2007 Fall. 2007 IEEE 66th
Sept. 30 2007-Oct. 3 2007

Performance Evaluation of Hybrid ARQ Schemes of 3GPP LTE OFDMA System
Kian Chung Beh; Doufexi, A.; Armour, S.;

Personal, Indoor and Mobile Radio Communications, 2007. PIMRC 2007. IEEE 18th International
Symposium on 3-7 Sept. 2007
Multi-antenna system design for 3GPP LTE
Ghosh, A.; Weimin Xiao; Ratasuk, R.; Rottinghaus, A.; Classon, B.;

Wireless Communication Systems. 2008. ISWCS ’08. IEEE International Symposium on
21-24 Oct. 2008
Key features of the LTE radio interface
Erik Dahlman, Anders Furuskär, Ylva Jading, Magnus Lindström and Stefan Parkvall
Ericsson White paper.

He is a pretty good programmer, codes in C and Python for his openmoko phone, has a permanant tab for reddit on his browser and also likes to get into trouble by tweeting about it and getting the website blocked in office.

He came to blogial because he was tired of wordpress.com and the inability to post snippets of code. So I suggested that he began posting all his programming related posts here and use his wordpress account for personal stuff. I have even installed a code syntax highlighter plugin.

It is now easy to post snippets of code in codelog now. Wrap code blocks with <pre lang=”LANGUAGE”> and </pre>  and you are done.

Anyway, happy blogging and once again welcome Sudharshan.

The problem all started with the credit card charge for renewing the fslog.com domain. I have setup Yahoo to automatically renew the domain and this has been done without any glitches. The normal charges for domains is $9.95 per year, but today I saw that they had charged $34.95 for a one year renewal.

I decided to email the customer support for an explanation of this and started my search for the usual “Contact Us” link in the website. After searching for the page for a while, I got to this page.

For a minute or two I was worried whether my reading skills were gone – for there were no way to “contact” them. I had to choose something from three list boxes and press a button to be taken to the next page (4 clicks).

I must admit that I should have learnt from the previous page’s experience that there would be nothing useful in the second page too. But I tried to be a bit optimistic in finding an email address where I can plead them to give an explanation and stop making me to click through these numerous pages. I was wrong in expecting such a huge favour to the users from Yahoo. The only thing I found was some phone numbers which asked me to call them at 6AM – 6PM PST. I don’t even know whether that number is toll-free or they will be charging me money for calling the number.

I tried searching through almost all the help pages and had to stop the insanity. I then decided to call them in the night (I am in India).

Before trying to call, I tried to find whether someone else were successful in finding out the email address. I found a person in Yahoo Answers who had the same problem and found one email address (similar to the one in my whois info). I tried emailing to both, but it failed to deliver. Good – Yahoo doesn’t even maintain their own domains and emails properly.

I decided to get the phone number and found that instead of calling them, you can schedule a call for their support team to call. This option magically enables only whent he tech support team is awake. I tried that and got about 30 minutes waiting in the queue. I started to write this post while waiting for the call. I refreshed the page which showed the time left, and I was taken back to the Contact Us page. Again click continue, get to page 2 and click another link to get to actual timer. Rinse and repeat till 30 minutes is over and you get back the old page 2 which asks me to schedule a call from their support team.

I was getting so frustrated with this, that I have started to type really fast and I don’t know how many speling mistakes and grammatical errors are there in this post.

This is why I hate using most of yahoo’s services. Most of their services have the worst user interface and doesn’t have a proper channel for communication. Of course I do like flickr and delicious – but they were acquired and not developed inside Yahoo.

But take Google, they have the most simple user interface (except orkut maybe). They have a help link somewhere near the top and the help page is the best I have seen so far. They have a blog for most of their popular services where people can see what new features have gone into it.

This is a lesson well learnt and now I should start moving all my domains to a better company which doesn’t try to steal money (any suggestions?).

The worst part is that I am yet to find a proper email address for asking about this issue. I hope that someone from Yahoo reads this and instead of just commenting about how wrong I am about yahoo, takes some action to show that Yahoo really cares for their customers.

First I was surprised at her having to boot up the computer and search for such a task, which had no use to me (other than to get the song out of my head). But later when I thought about it, I realised that how easy it would be if there was some service which people can use to send small snippets of web pages as text messages to mobiles. Of course there are lot of websites which can send free sms, but they are very limiting and depend purely on advertising.

My suggestion is to ask the user to deposit a very small amount of money (say $5) and expose a bookmarklet which can send a piece of text selected from the webpage. I have been in many situations when I have to find out the address or phone number of some place and message it to a friend.

I think this looks like a good idea and doesn’t depend on advertising. I don’t know whether such a service exists or if someone plans to taking this idea and implementing it. I would definitely pay for some service like this which has a really usable interface and works without any more than pressing a send button.

Please do leave your comments on what you think about this idea? Anyone game for it?

But when I tried the name tags, it automatically detected most of the faces and also grouped together most of the people together. All I had to do was to click on the “Setting” link in picasaweb and had to click the Turn name tags ON button. It does some processing (which is blazingly fast) and presents you a film strip to view the different faces and assign them names from either your contact list or new names on the fly.

Even if some of the faces are missed, you can add them when you view the individual photo. Very easy to use interface for organising the world’s information. I wish all the applications (online/offline) were this easy to use. I should also remember this while developing my applications.

Here are some reasons why this will be a huge hit:

• People like to look at old photographs and try to remember everyone’s names. It is fun to do during a sunday afternoon with your family
• Google does most of the initial work for you. Though not very accurate, it does help a lot. Also as you keep updating the photos, it tries to guess the name of the persons in the photo automatically.
• The interface can’t be easier than this. Facebook has such a technique, Flickr also allows you to tag parts of your images. But automatically marking up the images are so easy.
• I found one pic in which I was present which I didn’t know till that point. You could easily identify who were all in a particular event by allowing google to match the faces.

However it all depends on the number of people who use picasa. I find that flickr still holds the number 1 position in image uploading services. Google needs to do some serious marketing for picasa and should also open up some APIs for the other services to upload pictures through it.

Now all google has to do is wait for a few years and let people tag the photos and get a huge collection of people’s images and their names which can be used by Big Brother to rule the entire world. Simple. You also get a report of who was with whom at what time. Easy way to identify your friends when you are gone into hiding after committing a thought crime.

I am going to start using picasaweb for all of my images – would probably need a storage upgrade sometime later.