GSM Mobile Technology Vs CDMA Mobile Technology

About me,

I use two mobile phones, a CDMA (RIM) phone and a GSM (Hutch) phone. Hence I am in a position to comment on both the technologies and their intricacies. I have also used BSNL- Cellone, Airtel and Ushafone and thus possess a unique insight on these telecos.

Reliance India Mobile (RIM)- A telecom company, which stopped at nothing short of revolutionizing the Indian Telecom sector. I still remember the time when we had to shell out obnoxious amount of money for local calls. That all did change, but nothing short of a revolution could have made the transition so swift and so overwhelming. Today from the age of paying for incoming calls we are in the age where distance is no longer a yardstick for pricing calls; the network which one uses is. Today we have one of the cheapest rates for Telecommunications in the world (The irony here is that, data- Internet is still very expensive when compared with the likes of South Korea, Malaysia etc.).

RIM, since its very outset has been embroiled in controversies, but like its parent company it has managed to brave them, and come out even stronger.

The main advantages that RIM had were

1) Reliance entered the Telecom market rather late compared to its contemporaries and was saved from large investments into outdated technology. It therefore was not forced to recover the cost of such expensive equipment. This is the main argument the GSM providers give for their high call rates.

2) CDMA, the technology in itself is far superior from GSM technology. The entire RIM infrastructure was built to take on Brobdingnagian and gigantic amounts of data. Hence their ability to take on so many subscribers in so little time so effortlessly.

3) Initially with the DAPO offer, when people had to deposit post-dated cheques, the response which it got was abysmal and I dare say, deserved. But since then the prices have dropped several notches, to the level that they gave out mobile phones at Rs. 500/- But, the real genius was the person who thought of financing the sets in such a clever and subtle manner. This approach is what won them customers in the first place. Once the wall of the GSM ‘fort’ the great Indian Middle class was breached, the rest was to follow inevitably.

4) Now that the company has been established, has experienced fabulous growth and has been recognised as the “common man’s phone”, it has launched several schemes, where they, like their GSM counterparts have enabled the customer to buy old set or sets from third party vendors.

5) Street smarts, more than anything helped the company sell its products. The entire 40p scam was sheer brilliance despite of the fact it was a gimmick. But in an industry where dirty and bogus marketing gimmicks had long been the modus operandi, this offer which actually did have a shred of truth was almost angelic and grabbed the attention of the masses.

6) Digital Phone- At a time when the likes of Nokia 3300 ruled the roost, RIM gave the general public what GSM providers couldn’t even dream of. Their phones were small, handy, had features that the GSM phone thrice its price would tend to offer. Never before had the public seen anything as remarkable as R- World, which for long had been absolutely free.

7) Pricing- India, despite of all the hoopla about the rising incomes of people is still an immensely price sensitive market. Pricing here is of paramount importance. RIM, was a little late in understanding this, but when it did, it did well and was smart enough to strategise all its future plans around the pricing pivot.

I can go on listing what advantages Reliance had, but the fact is that RIM had converted all their disadvantages into advantages, and anyone who does that is bound to succeed.

We are in the age of mobile communication. Everybody wants a mobile phone, and if Reliance has its way, soon everyone will. But what the hell. when you go to buy a Hutch or Airtell connection, they don't tell you to buy the instrument with it. But when you go to get a Reliance one, then the instrument has to be bought, even if you don't like it.

Why? Because companies like Airtel, Hutch, Cellone, etc. use GSM technology whereas Reliance and Tata use CDMA. So what's the difference?

GSM technology imparts a greater range for it's signal. In short, they don't need so many towers to cover a city or town with the signal. CDMA, on the other hand, can transmit signals over fairly short distances only. Therefore they need more towers to catch the signal.

With GSM technology, all power is in the chip. So if you have to upgrade the capacity, the chip has to change. In CDMA, the tower and the server is upgraded. Since the chip is embedded in the phone, you cannot take it out. So the upgrades are done by the company. With CDMA, getting online onto the internet is much easier because the phone instruments are made like that. Slowly, GSM is catching up on the internet front but the instruments are much more expensive.

All this happens because of the inherent difference in the way signals are transmitted and received. CDMA is used to cover short distances, whereas GSM can cover long distances. So it is upto the company to decide what it wants to use, and up to you whether you want freedom to choose your phone or take what is offered.

Dear friends,

Most of you posted a request for a review covering all aspects of GSM and CDMA phones. And all of you needs a non technical review. But as GSM and CDMA are very technical terms in nowadays electronics I must say something about the technical aspects too.

HISTORY

The GSM was originated in Europe (Global System for Mobile) in the year 1990 and gained world wide popularity because of its modern network features which are available to the individual mobile phone user. CDMA or code division multiple access was developed by Qualcomm Inc. and it became an international standard in 1995.

TECHNICAL ISSUES

As you know the mobile personal communication systems uses microwave frequencies above 800MHz for their transmission and reception purposes. They all are operating in some predefined or pre allocated frequency bands according to the international standards.

For operating in these microwave frequencies they all need some access methods. And these methods are:

1. Frequency division multiple access (FDMA)

2.Time division multiple access (TDMA)

3.Code division multiple access (CDMA)

Thus CDMA is one access technology which cell phones uses to transmit and receive data. You can understand the meaning of FDMA, TDMA and CDMA eazily by just noting the word meaning for ezch letter. That is FDMA puts each call on a separate frequency and TDMA assigns each call a certain portion of time on a designated frequency for the above mentioned purpose. But CDMA gives a unique code to each call and spreads it over the available frequencies. All these are multiple access systems because more than one user can use the specified CELL ( not cell phone!) at a time.

But GSM or Global System for Mobile uses the above mentioned TDMA ( Time Division Multiple Access ) for mobile communication purposes ! In other words GSM is a global standard based on TDMA and a very popular one in the entire Europe, Middle East, Asia and Africa and not an access code as CDMA but one global standard.( Remember it always....CDMA vs GSM is really misleading! it is CDMA vs TDMA..!)

GSM operates in the 900 MHz band (890 MHz - 960 MHz) in Europe and Asia and in the 1900 MHz band in the United States. Besides these facts we must know the limitations and advantages of each systems in a brief way. All these facts are highly technical but I will try my best to write the details suite for all the mouthshut readers.

First TDMA of GSM.

The data transmission in TDMA is actually not continuous. It occurs in bursts. But the time between these bursts for a single mobile phone user is very very short, so that he never knows that the speech of the other person is discontinuous!

As TDMA uses different time slots for transmission and reception your handset never need a duplexer. But it simply need a switch to transfer between transmission and reception sesseions!

But the CDMA system has a soft capacity limit. That is increasing the number of users will decreases the system performance.( any comments Reliance users..?..!!).

Channel data rates are very high in CDMA systems. But sel-jamming is a major problem.

AND NOW SOME INTERESTING FACTS

Above are the technical facts you must know. But as you are very familiar with GSM of BSNL, AIRTEL, ESCOTEL etc. and the CDMA of Relience I know you are also eager to know about some commonly misunderstood things.

GSM is a widely spread standard and CDMA is a patented technology. That is you must pay a royalty for using CDMA! Also GSM covers the entire Europe , Asia except Korea, Africa and Middle East. So being a GSM user you have virtually an international roaming. You can eazily use a GSM phone in any of these countries while roaming.

GSM users are almost 8 times in number than CDMA users worldwide. By being a GSM user you will be part of the largest mibile community.

And coming to voice quality GSM is far better than CDMA, as I mentioned it earlier. CDMA base stations consumes less power than GSM and also covers a large distance. That is the cell size in CDMA is larger compared to GSM.

In general I say both GSM and CDMA are frontier technologies and both have good and bad qualities. And in the case of mobile handsets the fact is that GSM handsets are very popular and many of the new facilties are readily available in GSM phones with lesser price. The reason is simple...nokia and motorola needs profit...and they will invest more in GSM because GSM has 8 times more users than CDMA.

In the case of data rates also GSM is nowadays improving with their new GPRS. With GPRS it is expected that a data rate of about 171 kbps may be provided however on a shared basis between multiple users. GPRS enables an existing GSM system to communicate with any application or network that uses packet switching. GPRS thus allows subscribers to connect to the Internet to access applications as web browsing, mail and FTP.

So answering the question, CDMA vs GSM is not like Relience vs BSNL...! In the later case you can easily pick one first..!

Thank you.

Kannan.

Cell-phones-a word not unknown. Ever since the cell-phone bug has hit India some have been using it for style and some have been using it for communication. I have been using it for both. The cell-phone market has really been booming since the last couple of years thanx to the “videshi” mobile companies coming here and also to thanx to the advertising and marketing agencies which have been luring customers to them. Also thanx to the TRAI which has been regulating the cost per calls bringing it lower and lower in order to benefit the customers.

Not going too back time when people in India started to use mobile-phones in the later 90’s decade it was used just used as a means of communication that to make and receive calls. It was when the cellular service offering companies jumped in to the picture and revolutionized the whole cell-phone thing. At that time if u would have asked what is this GSM thing not many would have been able to answer that.

Talking about GSM, CDMA at that time was not at all in the picture (in India). It is about the last two years when companies like Reliance and Tata started their CDMA services the people have come to know which is good and which is bad.

The major players in the GSM market are Hutchison Max, Airtel, Idea, BSNLetc. All of these are offering their GSM based services (I will explain what GSM is later). Now when Tata launched it CDMA service it nearly went unnoticed and Reliance was also stepping into the telecom industry. So the GSM players asked Reliance a question:

Hutch, Airtel, Idea: Humare pass GSM hain, customers hain, alag handsets hai, aur value added services aayengi…Tumhare pass kya hai?

and Reliance answered : Mere pass CDMA hai aur backing ke liye fibre-optic cable aur Karlo Duniya Mutthi mein Tagline hai..ha ha ha ha.. and Reliance launched its CDMA services in India which achieved success in a very short time.

So what really is GSM:

The GSM (Global System for Mobile Communications) standard for cell phones was established in Europe in the mid-1980s. GSM operates in the 900-MHz and 1800-MHz bands in Europe and India, in the 1900-MHz band in the U.S. To connect to the service providers GSM users use Subscriber identification module (SIM) cards. SIM cards are small removable memories that go in and out of GSM phones. They store all the connection data and identification numbers you need to access a particular wireless service provider. GSM works on TDMA(Time Division Multiple Access) which allots a particular time period on a particular frequency. GSM systems also are more secure than CDMA systems because of its way of operation which is kind of on-off thing.

Coming to CDMA

CDMA stands for Code Division Multiple Access. Now this is entirely different compared to TDMA or GSM systems. In CDMA data (that is the voice signal that is being digitized) is spread out over the entire frequency bandwidth. Multiple calls are superimposed on each other on the channel, with each assigned a unique sequence code. CDMA is a form of spread spectrum, which simply means that data is sent in small pieces over a number of the discrete frequencies available for use at any time in the specified range. All of the users transmit in the same wide-band chunk of spectrum. Each user's signal is spread over the entire bandwidth by a unique spreading code. At the receiver, that same unique code is used to recover the signal. Because CDMA systems need to put an accurate time-stamp on each piece of a signal, it uses the GPS system for this information and operates in both the 800-MHz and 1900-MHz frequency bands.

This was a small piece of technical information about CDMA and GSM.

Ofcourse coming to the non-technical aspects in my opinion there are advantages and disadvantages of both GSM and CDMA which I am stating below:

Advantages of GSM service:

--> Variety of handsets available for choosing. U can get a new handset almost every month (of course if u have money lol) . Its just about removing the SIM from old handset to a new handset. And most importantly GSM services are not handset dependent.

--> Various service providers are available for choosing. If u aren’t satisfied with one switch over to other. This is probably its biggest advantage. You r not in contract of any of the service providers for any time. So u can switch over whenever u want.

--> Call Costs are becoming lower and lower everyday.

--> Call quality is much more pure and secure in GSM.

--> More and more value-added services like GPRS, EDGE etc are coming everyday.

--> Power is less consumed in GSM handsets compared to CDMA handsets.

--> If u have a tri-band GSM phone u can use it in almost any part of the world.

Disadvantages:

--> Call costs will still remain higher compared to CDMA. Roaming costs are much lower in CDMA compared to GSM.

-->GSM phones can be tampered with. They have their unique IMEI number which is used to lock the fone permanently but nowadays software’s are available which can tamper them too.

--> If ur SIM is lost then all data is lost unless u have it stored in the fone’s memory.

CDMA Advantages:

-->The first and the most important advantage in CDMA is the cost of calls is lower than GSM. Although this difference is becoming transparent day by day still roaming costs will remain low.

-->CMDA services in India are backed up India’s most wealthy companies Tata and Reliance.

-->Rite now the call quality is better than GSM. But as soon as the subscriber base increases the call quality will start going low because of the way in which CDMA system works.

Disadvantages:

-->Although many handsets are available in CDMA service u don’t find as much variety as u would in GSM handsets.

--> The biggest disadvantage for CDMA handsets is they aren’t compatible with GSM handsets. U cannot use a CDMA handset with a SIM card. So u gotta stick around with one handset for a long time.

-->Another disadvantage is that in CDMA only 2 service providers are there Reliance and Tata. While Tata is still improving so u gotta stick to Reliance u have no option. Ofcourse Reliance is too increasing day by day.

--> The web based services like messenger, downloading ringtones etc from websites are not yet available in CDMA services yet.

At the end I would like to tell u that I have stated the advantages and disadvantages of both CDMA and GSM services now it depends on u which service u choose.

GSM and CDMA are different standards for mobile communications. While GSM was developed in Europe, the US ? which usually does not like to follow Euro standards ? devised it?s own CDMA.

The two acronyms expand into Global System for Mobiles and Code Division Multiple Access, respectively, and they differ in the way the available bandwidth is shared between multiple users.

Code Division Multiple Access, or CDMA is the name of a generic technology for multiplexing data, which means that it is a method by which more than one user can use the bandwidth, so that there are multiple channels of communication.

This is done by assigning a code to each channel, which can be understood only by the receiver of that channel. For the other channel?s receivers, even if they try to listen to the signal, since they do not have the code, they will not be able to understand it.

Since CDMA uses this technology for bandwidth sharing, hence it?s name.

As for GSM, it uses two slightly different technologies, i.e. Time Division Multiple Access (TDMA) and/or Frequency Division Multiple Access (FDMA). While in TDMA, each channel is allocated a small time slot in which it can transmit/receive, in FDMA, each channel gets it?s own frequency range, much like analog TV or radio.

Now from the user?s perspective, what are the differences? firstly, CDMA voice quality is nowhere near as good as GSM. While this is not yet apparent in India, where the number of subscribers are relatively low, the fact remains that as the number of subscribers increase, the voice quality will go down. If you have used a CDMA phone in the US, you know what I am talking about.

The voice sounds harsh, metallic and unnatural. In GSM no such problem is there?the voice quality will not fall below a certain low limit. In fact, this is the main reason why GSM is now gaining popularity in the US, where previously CDMA was dominating.

Second obvious difference is that there is no SIM card in CDMA, while GSM phones will not work without a SIM card. Some CDMA providers do have a SIM card like device, which they call UIM, TIM etc. Thirdly, the power consumption is slightly higher in CDMA phones, because of the nature of transmission (always on kind of scenario).

Finally, GSM is more of a world wide technology, as it is in use in most countries in Europe and Asia, and now also in North America. CDMA, in contrast, is supported only in few countries ? US, Japan, Korea, India and probably a couple of others.

A GSM phone is the best bet for compatibility across the world, provided of course it has tri-band support (GSM uses three bands of frequencies).

GSM, CDMA, TDMA

What do all these acronyms CDMA, TDMA and GSM mean?

Which is Better?

Digital cellular systems arose as a direct result of the growing popularity of mobile voice services. Analog and digital phones operate on opposite ends of the radio wave spectrum, making neither type of phone compatible with the other's calling network.(Except Dual mode phones, work with both analog and digital networks). Although the analog cellular system worked well, by the late 1980s, demand was exceeding capacity in many regions. To minimize the possibility of congestion on the cellular network, digital cellular services were developed.

There are a number of different standards and technologies for wireless phones. This combination of standards and technologies can become very confusing for anyone. For a phone to work in an area other than the ''home'' area, it must be in a system that supports the technology used by that phone and in the frequency which the phone is designed to work.

Wireless system Carriers have selected one or two of these technologies which best serve their target customers. All of these technologies can serve individual subscribers well with pros and cons for each of them.

CDMA

CDMA stands for Code Division Multiple Access and incorporates spread spectrum, works by digitizing multiple conversations, attaching a code known only to the sender and receiver, and then dicing the signals into bits and re-assembling them.

TDMA

TDMA stands for Time Division Multiple Access and is a digital technology that allows multiple users to share the same voice channel by having each conversation transmitted alternately over short lengths of time.

GSM

GSM stands for Global System for Mobile communication. GSM is a TDMA digital system that converts voice and access information to digital data, and communicates those data in bursts during brief time slots allocated to multiple subscribers sharing a radio channel. This system is being used by some of the PCS operators here in the country.

PCS

PCS stands for Personal Communications Services is the name adopted by the new, wireless service providers who have been awarded licenses to operate new phone systems in the 1900 MHz frequency range. The term ''PCS'' is often used in place of ''digital cellular,'' but true PCS means that other services like paging, caller ID and Email are bundled into the service. Those same technologies are called ?digital cellular? if they are transmitting at 800 MHz. There are two ''types'' of PCS services namely narrowband and broadband.

For all of the historical and technological reasons outlined above, it appears that GSM, or some combination of GSM and CDMA, will become the long sought after grail for a global wireless standard. A universalization of wireless technologies can only stand to benefit the compatibility and development costs and demands on all wireless commerce participants.

If you are presently in the market for a new phone, my advise to you is to ignore the hype surrounding the technologies and look at service provider instead. Judge each with an eye to price, phone choice, coverage, and reputation. Technology should play a very small roll in your choice. If you follow this advice, you'll probably be much happier with the phone and service you inevitably wind up with.

Bluetooth Demystified

Bluetooth by now has become a well established communications standard for short-distance wireless connections. A standard developed that allows any sort of electronic equipment -- from computers and cell phones to keyboards and headphones -- to make its own connections, without wires, cables or any direct action from a user. This ground-breaking technology, finds applications almost everywhere you look. It replaces the many proprietary cables that connect one device to another with one universal short-range radio link. Everything from printers, desktops, keyboards to mobile phones now use this revolutionary technique.

Bluetooth is in short a wireless technology. Talking about wireless technology the first thing that come to our mind is the Infra red transmission and reception, the technology used in remote controls. Why bluetooth then?? Infrared communications are fairly reliable and don't cost very much to build into a device, but there are a couple of drawbacks. First, infrared is a ''line of sight'' technology. For example, you have to point the remote control at the television to make things happen. The second drawback is that infrared is almost always a ''one to one'' technology. Data can be sent only in one direction at a time. Bi-directional data transfer is not possible.

Bluetooth is designed to overcome the drawbacks of infrared technology. The following makes it different or better than other similar technologies.

· It's wireless. When you travel, you don't have to worry about keeping track of a briefcase full of cables to attach all of your components, and you can design your office without wondering where all the wires will go.

· It's inexpensive.

· You don't have to think about it. Bluetooth doesn't require you to do anything special to make it work. The devices find one another and strike up a conversation without any user input at all.

Bluetooth is a Radio Frequency (RF) specification for short-range, point-to-multipoint voice and data transfer. It can transmit through solid, non-metal objects and its nominal link range is from 10 cm to 10 meters, but can be extended to 100 meters by increasing the transmit power. It is based on short-range radio links, and facilitates ad hoc connections for stationary and mobile communication environments.

Bluetooth technology has been designed to operate in noisy radio frequency environments, and uses a fast acknowledgement and frequency-hopping scheme to make the link between the communicating devices. Bluetooth radio modules prevent and protect itself from interference by hopping to a new frequency after transmitting or receiving a packet of information. Compared with other systems operating in the same frequency band, the Bluetooth radio typically hops faster and uses shorter packets.

The bluetooth system needs to communicate with devices that are in its neighborhood and also with some that are a little far away. It therefore has two power levels of operation. A lower power level that covers a shorter personal area within a room, and a higher power level that can cover a medium range, such as within a home. Software controls and identity coding built into each microchip ensure that only those units preset by their owners can communicate.

Bluetooth devices communicate in two different ways

1. Point to point.

2. Point-to-multi-point.

A piconet is a set of devices that can be connected via bluetooth with one unit acting as the master for synchronizing purposes and the others acting as slaves. Several piconets can be connected together where each piconet is characterized by a specific frequency hopping sequence.. All the users participating on the same piconet are synchronized to this hopping sequence. All the devices remain in STAND BY mode before any piconet is formed. To start a piconet any of the devices can initiate the connection procedure, which then becomes the master of the piconet and thereby for all subsequent devices added to the piconet.

A connection is made by a PAGE message if the address is known. An INQUIRY message is used in cases where the address is unknown. This message is typically used to find Bluetooth devices, including public printers, fax machines and similar devices with an unknown address.

A power saving mode is used for connected units in a piconet if no data needs to be transmitted. The master unit can put slave units into HOLD mode, where only an internal timer is running. Slave units can also demand to be put into HOLD mode. Data transfer restarts instantly when units transition out of HOLD mode. The HOLD is used when connecting several piconets or managing a low power device such as a temperature sensor.

Privacy is an important factor in any communication device. It becomes more relevant in the case of bluetooth since the devices think for itself rather than the user intervening in the communication procedure. Authentication and encryption are therefore necessary. Authentication is a key component of any Bluetooth system, allowing the user to develop a domain of trust between personal Bluetooth devices, such as allowing only the owner's notebook computer to communicate through the owner's cellular telephone. Encryption is used to protect the privacy of the connection.

Bluetooth is an ever-blooming field pushing the frontiers of wireless technology. The big plus point that Bluetooth has is its wide range of applications. Bluetooth devices are also cheap and are readily available to the consumers. We have currently gone a long way in this field, but there are miles of untouched territory ahead. Only time can tell us if we have seen all or if we have just kissed the tip of the iceberg.

Hai Friends

I wish to take this forum to congratulate this government for the efficiency displayed in its functioning.

Suddenly, the government is making major policy changes in nano-seconds; implementing them - all to help you, me, my bhanja and his saas.

Before you scream, Let me tell you that I am talking about this great ''Unified Telecom License make-over''

We all know how this government superbly created a mess.

My professor used to say this. ''Either you are pregnant or not pregnant. There is no such thing as almost Pregnant''.

The mantri-bapu satsang proved my professor wrong. They created a new english word and a wholehearted chaos called ''Limited Mobility''. This immediately brought visions of a policy in cretches limping and trying to crawl - Yes, that is what is meant by ''Limited Mobility''.

Enter Our e-bay minister - Shri Shouri (which literally means a fellow with lot of noice)

Within two weeks, TRAI makes a recommendation for this change over. Prescribes a policy. Within 48 hours, The Group Of Ministers meet and approve it in a discussion lasting less than 30 minutes. The very next day, the Cabinet meets and approves this policy in less than we all could say ''duniya meri mutti men''. In less than a week, The government notifies the licensing norm. Within two hours of notification, Reliance

pays the license fee. And, God smiles in heaven. The money involved was Rs.3,000 crores from all the basic operators.

And, the railway overbridge near my residence is getting constructed for the past seven years by the Government. The Railway and PWD now say it will easily take another four more.

If only, My Sarkar is clearing all decisions like this swift. To start with, They can start by deciding what should be the standard for water, chocolate and coco-cola!!

We all know this. But, what is perhaps overlooked is the silent death of something called ''ROLL-OUT OBLIGATIONS''. This means that all basic license holders need not pay hefty penalties for not extending lines to rural india. This penalty was already with the government in the form of Bank Guarantee. The roll out obligation penalty was stiff. The Government levied more than 50 crores for each circle for each month of

violation.

This penalty was hanging like Domicles sword over all basic providers - That is Bharti, Tata, Reliance and Others.

And here is the secret. This penalty was to have been enforced from December 2003 for the initial license holders. This means in less than 20 days, the Government would have gained huge penalty for the basic license. This penalty would have helped the government to something they call UFO fund, to finance rural telephony service. This penalty would have come out of the license capital of the basic operators.

For example, TATA Teleservices Maharashtra alone would have paid Rs.516 crores for non-compliance.

Now, our helpful Sarkar has silently waived this off.

And, the justification offered to us is great. They have now levied something called ADC (Access Deficit Charge) on all calls made in India. That is we have to now pay for the penalty of roll-out obligations. You, me, my bhanja and his saas.

We are now subsidising Bharti Mittal, A mbani and Ratan Tata's pocket money of around Rs.3,000 crores, which they have cooly saved. At the last minute. The penalty which was threatened by the Government (Promod Mahajan ji, where are you?) is now paid by you and me.

My chai waala now says that this is pretty normal in an election year. Everyone needs some paise for chai paani. A little sum saved like Rs.3,000 crore is always handy for this.

The moral of the story is - If the Government acts fast, We loose Rs.3,000 crores.

I now tell them. Let the railway overbridge be built in it's own sweet time. I don't mind. Just Don't show your election efficiency! That will be costly for me..

S Bhatia

with permission from

To be Really Honest, Evenb I don't know the Technical Mambo- Jambo of these Technologies, but I do know the fair diffrence between them. For a novince or a person, who is new to mobiles n cell phones, this would be a intro to CDMA and GSM.

Lets Start....

So what are these CDMA and GSM ? Well These two are the Latest and Hottest technologies in India, which are current backbone of our Mobile phones. Even though both services have similar goals, yet they both are have few specific Features depending on the type of user.

GSM :

1) This is the Service which our older providers Like Airtel,Essar, Escortel etc are providing.

2) This service is Provides features like -

(a) Call Forwarding:

It lets you forward your calls to another Mobile or a

Landline Number.

(b) Voice Mail:

This is Similar to your Answering Machines.

(c) Call Waiting:

When you are talking to some one, then this feature can

add one more line to your Mobile. Meaning thereby you

can receive a special beep(s) indicating that someone is

calling you.

3) It enables you to use your mobile while your are away from your Town/City. This is Called Roaming. You can Choose between National or Internationl Roaming.

4) They come in two options. Pre-Paid and Post Paid.

(a) Pre - Paid:

You are supposed to buy a Coupon ( worth few hundred buck )

Every month. The amount adds to your previous

Balance.

(b) Post Paid:

You get a Monthly / Bimonthly Bill, just like your normal Landline

phone.

5) GSM enable Phones requires a tiny Chip called (SIM Card). This Card stored your phone book, SMS and your own number.

6) You can change your handset anytime you want. All you have to do is place the SIM Card in the New phone.

7) The call Charges range from Rs 2-3 per min for outgoing calls. (ALL INCOMING CALLS ARE FREE IN INDIA)

CDMA

1) These are the one BSNL and Relience are offering.

2) They are providing - FREE SMS ..... Rs 40 - Rs 1 Per min outgoing call (CDMA to CDMA)

3) Though this service is not as expencive as GSM yet the first time investment is too much. (Around Rs 20,000-/ )

4) You require a special handset, which is programed by your mobile service provoider.

5) You do NOT have any roaming in CDMA. This means You can only use your cell phone within few kilometers.

6) It is also called as WLL ( Wireless Local Loop ).

So after all said and done....if your job requires to call quite often and you do not go out of town to much, then Your pick should be CDMA. Otherwise if you are on the move all the time ,then GSM is for you.

Which ever phone you pick, just remember the MOBILE MANNERS and HAPPY TALKING !

What are the major differences between CDMA and GSM?

1. Both are different and competing standards. CDMA is more popular in USA. GSM is a European standard. GSM is based on TDMA.

2. CDMA phones are internally coded with Service Provider information and Phone Number. GSM phones use SIM Cards.

3. You can change the SIM card of GSM instrument, and move over to another service providers. At times, the GSM phones are SIM-Locked (programmed to work with a particular provider only), but they can be unlocked with some trickery (Ask your friendly GSM Phone Dealer)

CDMA phones are bound to the service providers, which means if you want to change your service provider, you have to throw away your phone.

1. CDMA technology has better utilization of available bandwidth. That allows more calls to be carried with same infrastructure. That also brings costs down.

Now, w.r.t. India, what do I choose?

Very Simple:

1. Do you do roaming? within Country, off the roads (which means if you are travelling from Mumbai to Pune, do you need connectivity in between?)

This is provided only by GSM right now. It is not that CDMA can not provide it. But the network is not in place yet. So go for GSM in that case. If are you are kind of a person who sticks to cities, CDMA can do (look for a CDMA provider that provides Roaming)

1. Do you do international travel to Europe, south east Asia or for that matter even to US? do you want your phone to work every where?

You have only one choice.. Go for GSM. Yes, in US, T-Mobile and Cingular provide GSM service. Entire Europe and SouthEast Asia, you can use your GSM phone (Orange is almost everywhere, plus there are Hazaar local companies). just activate international roaming or take a local prepaid card. CDMA is not used in Europe as of now.

1. are you a person who keeps changing a phone instrument every now and then? with newer technology?

Stick to GSM. Upgrading a CDMA instrument means throw the old one. GSM you can still sell the old handset or give it to someone.

I have used CDMA and GSM both. Within India, CDMA is still raw and new. Now they have started Roaming (Thanks to Goburment's Reliance-Friendly policy).

so I am sticking to GSM right now. Will keep looking at development on CDMA front.

What should you do?

Lobby Hard. Lobby Hard to bring Airtime lower. Lobby to make calls completely free within same provider. (e.g. Airtel to Airtel, Reliance to Reliance).

Spread the good word.

If you are among those who still cannot decide whether to go in for Reliance's Code Division Multiple Access (CDMA)-based 'limited mobility' phones or the 'full-fledged' cellular phone services provided by GSM (Global System for Mobile) operators, here's some tips for you guys.

Which one is cheaper, which one better? While a number of issues still need clarity from the regulatory angle, let us take a close look at what Reliance is offering compared to a GSM phone.

First, the service: one of the limitations of a WLL (limited mobility) phone is that the user cannot go beyond a short distance charging area (SDCA) - which is roughly a radius of 25 km.

While Reliance has attempted to overcome the problem by offering multiple registrations, this still is not the equivalent of the roaming services offered by cellular operators.

For instance, if a subscriber in Delhi travels frequently to Mumbai, Reliance will register the subscriber in both the cities at an additional cost of Rs 20 to Rs 30.

So when the subscriber is in Mumbai, all calls landing on the user's Delhi phone number will be forwarded to a pre-allocated number in Mumbai. The user does not have to change the handset or put in a new SIM card for availing this facility.

However, when the user is in transit between the two cities, the phone does not work, unlike a GSM phone which offers roaming anywhere in the world.

Reliance is also offering text messaging services to cash in on the popularity of SMS. However, for the moment, any text message sent by a Reliance phone user can only be received by another Reliance user as GSM operators do not recognise this as a legal service. Even Tata Teleservices, another WLL operator, is awaiting clarity on this issue.

When it comes to data services, there is not much difference between GSM cellular operators and Reliance in terms of offerings.

Subscribers on either network will be able to send and receive e-mail, surf the Net, watch video clippings, send multimedia messages, and download games and ringtones.

The difference here is that while Reliance offers these services to all its subscribers, cellular operators offer such services only to those subscribers who have taken a General Packet Radio System (GPRS) connection - which requires a GPRS-enabled handset. The difference is also in the way the services are priced.

While Reliance is charging a regular talk-time rate of 40 paise a minute and a monthly fee of Rs 100 (under the club membership head), cellular subscribers have to pay a monthly fee ranging from Rs 250 to Rs 600, depending on the offerings, in addition to specified tariffs for each service.

For sending a multimedia message (MMS), cell users pay Rs 3 per MMS. For making voice calls, Reliance is charging 40 paise a minute. The finer print here is that this tariff is applicable only for calls made to another Reliance WLL subscriber.

Reliance is also offering STD calls at 40 paise a minute, but this too applies only to Reliance-to-Reliance calls.

If, for instance, you wish to call up a BSNL subscriber, you pay the standard Rs 4.80 per minute. The proposition looks strong only when you consider that Reliance is hoping to get one crore subscribers. But that may be some time away.

Initially at least, the WLL subscribers will end up making most of their calls outside the Reliance network and for this the user will have to pay an additional access charge, which ranges from 30 paise to 50 paise a minute, as specified by the Trai.

For instance, if a Reliance user calls a cell subscriber, the tariff applicable will be a maximum of 70 paise a minute.

In comparison, a cellular subscriber pays just 10 paise more at 50 paise a minute when calling any of the 11.5 million cell users and 80 paise a minute when calling a WLL subscriber.

While WLL operators can claim the advantage of offering free incoming calls, come April 1 cellular subscribers will also get free incoming calls - thanks to Trai's recent tariff order. Some of the cellular operators have in fact already implemented a free incoming call regime.

However, Reliance is offering a 15-second pulse rate as compared to the 60-second pulse being offered by cellular operators. This means that if you make a 15 second call on a Reliance phone, you pay only 10 paise while on a cellular phone you pay the entire 50 paise.

On the other hand, the acquisition cost of a Reliance phone is on the higher side with subscribers having to pledge the billing money three years in advance in the form of post-dated cheques.

The billing includes Rs 400 as monthly rentals, Rs 100 as club membership fee and Rs 100 as finance cost for the handset.

Subscribers also pay a hefty Rs 3,000 as club entry fee for availing themselves of value-added data services, though in reality this money is being charged for the handset, which, by the way, is not free with the connection.

That makes a total of Rs 24,600 for three years. In return, you get 400 minutes of talk-time free each month - that is 14,400 minutes for three years.

There is a three-month trial period when you can exit. If the subscriber wants to quit after the three-month period, he or she stands to lose Rs 40 from each of the post-dated cheques.

GSM Services

Regular cellular subscriptions are slightly more expensive than WLL phones. Apart from monthly rentals or fixed tariff plans that range from Rs 400 to Rs 1,500, cell users also pay additional charges for caller line identification, security deposits and activation fees. But overall, there is not much of a difference at the moment between Reliance's WLL phones and GSM phones in terms of tariffs and services.

If you are someone who doesn't travel much, are not SMS crazy, do not want to be disturbed in transit while travelling, and are looking for an alternative to fixed-line phones, and do not mind getting locked to an operator for three years, the Reliance WLL phone is not a bad choice.

Otherwise, you get a wider choice among GSM players.

Hi to you all,

For a new member of this group, I learned a lot from all the comments that you had given.

Actually, my question is to all of the friends who has commented on CDMA vs GSM.

Can someone briefly explain these questions?

1-How does CDMA security and authentication works?

2-How does GSM security and authentication works?

3-Which one is more secure CDMA or GSM?

4-How is eavedropping occurs in these technologies?

I have read that eavedropping in CDMA is diffucult than GSM?

What do you think?

Thanks in advance for your comments,

Best Regards,

Emre

Well….Ever since I had heard about CDMA and GSM, I was confused till recently I read an article. I was dying to explain about these two to someone. Coz’ unless I am successful in making someone understand the difference between CDMA and GSM I won’t get it right myself. So thanks to the person who requested this topic.

As it is seen that mobiles have been a basic need of today’s world, one should have all the knowledge about the tiny monster.

Let me keep it simple.I hate being too technical.I shall try to keep my writing as simple as possible so that a lay man does understand the basic difference between these two without putting too much pressure on the small brain.

You heard about CDMA first when big players Tata and Reliance came to the battlefield. However GSM is an old word as compared to CDMA. They are altogether different.

The basic difference between these two is : CDMA (Code Division Multiple Access) phones use WLL (Wireless in Local Loop) technology while GSM (Global System for Mobile) use cellular technology. CDMA is used by Reliance and Tata while GSM is used by other services like orange and Bpl.

So, the difference is the kind of technology they use. We will talk about the two technologies (WLL and Cellular) later.

CDMA and GSM handsets are different too. You might not see any difference in the physical structure but they are different from inside. CDMA handsets are general preprogrammed by the supplier with identity numbers relevant to specific local networks. You can not switch from one operator to another say from Reliance to Tata with the same handset, unless the phone is reprogrammed.

If you are planning to being loyal to Tata then you will have to submit the Reliance handset to Papa ka beta and then take a new handset from Ratan. One more important thing is you can’t get the CDMA phones from the grey market. But this doesn’t hold good for GSM phones. GSM phones are the common mobile phones you are seeing around. They are widely used. You just pick a GSM phone ( you have the option to buy ot from the grey market too), and if you are not satisfied with one operator ( say Orange) you can switch to BPL by throwing your Orange SIM card in the dustbin or giving to an old enemy and buying a new SIM card from BPL. Ofcourse your number will then change. But this is a good way to picha chudao from old girl friends.

Hope this makes you people clear about CDMA and GSM.

Shall discuss about WLL and Cellular technology in the nest review.

And please …don’t forget to post your comments (though more compliments are expected) about my review. This is my only third article. You comment oops …compliments will definitely encourage me to write more.

Enjoy !!!

I do not think it is possible to switch between the carriers. As the requirements for each carrier differs and the cell phone manufacturers make models depending on the carriers. For eg in US, CDMA is provided by Verizon and Sprint(major 2 CDMA providers), each of them have thier own provisioning data to connect to the networks. Preferred roaming list would be different and unique serial numbers that have to match phone numbers in the database. Unlike GSM where you can just swap out SIM cards, CDMA is totally different. Lets wait until Qualcomm chipsets comes out with a SIM card kind of modules.

With the launching of CDMA based mobiles, a few new abbreviations have flooded the market and 2 of the prominent ones amongst them are: CDMA and WLL. Though, thanks to the marketing_tactics_, their introduction was done in such a careful manner that made a lot of people believe that WLL with CDMA go hand in hand. Here, I shall attempt to resolve this confusion along with giving a brief overview of GSM and CDMA w.r.t. WLL.

WLL, which stands for Wireless in Local Loop, is nothing but a SYSTEM that connects subscribers to the Public Switched Telephone Network(PSTN) using radio signals as a substitute for copper(i.e. the conventional land-lines) for all or part of the connection between the subscriber and the switch/exchange. Local Loop is better known as the User Access Network, and so in layman terms, WLL is like being wireless in the network, closest to the user.

WLL can be implemented across 4-5 categories of wireless technology, the important one being Digital Cellular in Indian context. Further in this category, there are technologies like TDMA(forming the basis of GSM), and CDMA along with a few others. Each of these technologies have a mix of strengths and weaknesses for WLL applications. Although GSM currently dominates mobile digital cellular(around 2/3rd share), there has been little activity in using GSM on WLL platforms. This is because of design of GSM Architecture was to handle international roaming, as a consequence of which, it carries a large amount of overhead making it unwieldy and costly for WLL applications. Off late, though, there have been some developments to introduce GSM in WLL as well.

On the other hand, CDMA, a spread-spectrum modulation technique, employs a wide range of frequency for transmission and the system's low-power signal is spread across wide-frequency band. It offers higher capacity than the other digital standards and relatively high-quality voice. An additional advantage is that CDMA is inherently secure. GSM on the other hand has to use 2 levels of encryption, and with regards to India, the variant of the encryption algorithm(A4.1/A4.2) that is allowed, has been proven to be weak and prone to a variety of attacks.

Thus, the bottomline is though that WLL is related to CDMA as much as it is related to GSM, but as far as deployment is concerned, CDMA definitely has the upper hand. It now totally hinges on to the service providers on how to make the best use of it.

There is a lot of fluff flying about in india due to the launch of limited mobility. before I go into the details of gsm and cdma, one thing should be clear that both these technologies can be used for long distance communications. the reason as to y cdma was introduced in india under the limited mobility banner is totally regulatory and political. the government in 1994 had already sold licenses to gsm players for hundreds of crores and then later it allowed the operators providing basic services to offer mobile services using cdma. that is when the gsm players started crying foul cause the basic players were not charged extra for mobile services.

now to clear up the technical details:

GSM:

GSM (Global System for Mobile Communications) leads the world as the fastest growing, reliable and advanced digital technology available in the marketplace today. GSM provides integrated voice mail, high-speed data, fax, paging and short message services capabilities. GSM operates on the multiple spectrum frequency bands used around the world - 1900MHZ, which is used in North America and Japan and 900MHz and 1800 MHz for India and Europe. the GSM phone has a SIM card. The SIM (Subscriber Information Module) card - a.k.a. ''smart card'' - holds all of a subscriber's personal information and phone settings. In essence, it is the subscriber's authorization to use the network. It also holds the phone number, personal security key and other data necessary for the handset to function. The card can be switched from phone to phone, letting the new phone receive all calls to the subscriber's number.

Can u use different SIM cards on your phone?

All of the cellular phones we rent and sell are unlocked, that is, not ''locked in'' with any specific provider or SIM card. Therefore, as long as the frequencies are compatible, you can use any SIM with your phone.

CDMA: ''code division multiple access'' was the method developed by the US military in the 1940. it relied on frequency hopping and spread spectrum to disallow the call from being tapped and thus being read. each call is given a separate code and sent over the same spectrum. an analogy will be: if there r 10 ppl in a room; say 2 english speaking, 2 chinese, 2 hindi and so on and everyone starts speaking at the same time then only people of the same language would understand each other and they would reject the languages they cannot understand. similiarly each cdma caller and receiver has a similiar code and an intruder without the same code will get only noise. these codes are dynamically shifted or hopped over different frequencies.

CDMA is supposed to have a number of advantages over gsm like higher capacity of users per cell, more clarity, less call drops etc.

in India reliance has implemented a version aclled CDMA 2001x. MTNL and BSNL have the older american version called IS-95.

world over GSM is more prevalent with whole of Europe majorly onto it. Cdma is there is north america(cause they have to b always differnt) and korea. it also coexists with gsm in china and india.

you cannot however replace the chip on a cdma phone and receive calls from another operator cause that chip is sold to the operator under royalty by a company called Qualcomm. this is the company that developed CDMA to be used in consumer networks. So once u change the operator the phone is kaput.

for further details or queries mail me or go to: https://cdg.org and https://gsmworld.com

Let me put my points in a vis-a-vis manner.

• First of all GSM (Groupe Spécial Mobile) now commonly known as Global System for Mobile communications, was started in Europe to study and develop a pan-European public land mobile system.

Their main criteria was:

Good subjective speech quality

Low terminal and service cost

Support for international roaming

Ability to support handheld terminals

Support for range of new services and facilities

Spectral efficiency

ISDN compatibility.

# The first CDMA (Code Division Multiple Access) networks were commercially launched in 1995, and provided roughly 10 times more capacity than analog networks - far more than TDMA or GSM. Qualcomm, holds the licenses and is responsible for the development of its technology.

Their main features were:

supporting more traffic

benefits to carriers and consumers

better voice quality

broader coverage

stronger security

• GSM uses what's known as ''time division multiple access''

(TDMA), which crams less data into the spectrum. GSM digitizes and compresses voice data, then sends it down a channel with two other streams of user data, each in its own time slot. It operates at either the 900, 1800 or 1,900MHz frequency bands.

# CDMA is a ''spread spectrum'' technology, allowing many users to occupy the same time and frequency allocations in a given band/space. As its name implies, CDMA assigns unique codes to each communication to differentiate it from others in the same spectrum. In a world of finite spectrum resources, CDMA enables many more people to share the airwaves at the same time than do alternative technologies.

• GSM technology is in use by more than one in ten of the world's population and it is estimated that at the end of 2002 there were 787 million GSM subscribers across the 190 countries of the world.

# CDMA has become the fastest-growing of all wireless

technologies, with over 100 million subscribers worldwide.

• Today's second-generation GSM networks deliver high quality and secure mobile voice and data services (such as SMS/Text Messaging) with full roaming capabilities across the world.

# CDMA phones currently use a wider band than what was allotted to GSM. Hence, applications which are bandwidth-hungry, like video or music can be more easily handled by CDMA. The current generation of GSM is called 2G. Faster versions like 2.5G or 3G (for 3rd generation) will overcome the bandwidth problems and offer multimedia capability as good as CDMA.

• At present in India, we can simply change the SIM of a

particular service provider, Orange, BPL, Airtel etc. if we dont like their service.

# At present in India, Tata, Reliance or BSNL use the same CDMA technology and all such sets will be interchangeable. If you dont like the service from one provider, you can switch to another using the same handset.

Finally, if you ask my opinion, I use a GSM handset, and feel it is a better choice, but sticking to my optimistic view about CDMA Technology, I feel their developers have tremendous potential and who knows, it could be a dominant technology in the future.

From an Indian perspective, there is a thin line of difference between these two technologies. Here CDMA is in its infant stage. Although it far exceeds the quality and features of a GSM network, when it comes down to basic calling and messaging feature, there's little difference. The sound quality is a bit better on CDMA probably because of high speed network. Also on CDMA, the call drop ratio and busy network conditions are extremely low. However the technology does not support Roaming. Also one of the limitations of a CDMA-WLL (limited mobility) phone is that the user cannot go beyond a radius of 25 km. It allows a person to make a call only when he is within the range.

The major difference comes when you talk about Data Transfer (to send and receive e-mail, surf the Net, watch video clippings, send multimedia messages, and download games and ringtones)

CDMA has higher data transfer rate which is helpful if you want to surf internet using the handset. CDMA data connectivity is like a cable internet, where you are always connected. All you need to do is open up some websites and surf, check emails etc. And you are charged only for what you download and not for the time you are connected.

WAP technology (which is present in GSM handsets) on the contrary charges you for the time you are connected. It is similar to the dialup modem. You dial up the service, get connected, surf, get disconnected. And all this for a hefty charge, enough to burn a hole in your pocket which is not worth the connection speed you get.

With the introduction of GPRS the difference in data transfer rates between both the technologies has been greyed out. GPRS provides high data transfer speed and like CDMA is an always-on network. However GPRS is supported by only a few handsets. So if you want to stick to GSM, make sure you buy a GPRS capable handset and be future ready.

As my final verdict, since the CDMA environment is being tried and tested, dont just jump into it to become a guinea pig. Rather stick to GSM operators and wait for CDMA to evolve in India.

The battle between GSM and CDMA technologies in India is hotting up! While the initial tilt was towards the GSM with players like Bharti, Hutch, Spice, BPL, Essar and BSNL preferring it, the TATAs and the Reliance have now entered the market putting their bets on CDMA. GSM stands for Global System for Mobile communications, and CDMA stands for Code Division Multiple Access. The GSM is built around the TDMA, or the Time Division Multiple Access concept.

Basically, the two technologies address differently the same fundamental problem of mobile communication, how to divide the finite frequency of airwaves between multiple users at the same time, or, how to make more than one person to carry on a conversation on the same frequency without causing mutual interference.

In common analogy, imagine a room full of people, all trying to carry on one-on-one conversations. In GSM(TDMA), each couple takes turns talking. They keep their turns short by saying only one sentence at a time. As there is never more than one person speaking in the room at any given moment, no one has to worry about being heard over the background din. In CDMA, each couple talk at the same time, but they all use a different language. Because none of the listeners understand any language other than that of the individual to whom they are listening, the background din does not cause any real problems.

In technical jargon, GSM(TDMA) does it by chopping up the channel into sequential time slices. Each user of the channel takes turns transmitting and receiving in a round-robin fashion. In reality, only one person is actually using the channel at any given moment, but he only uses it for short bursts. CDMA on the other hand, uses a special type of digital modulation called Spread Spectrum, which takes the user's voice stream bits and splatters them across a very wide channel in pseudo-random fashion. The receiver undoes the randomization in order to collect the bits together in a coherent order.

GSM(TDMA) started getting used in mobile communication early in the mid-1980's. A lot of time, energy and money has been spent upon improving the quality of the GSM(TDMA) technology, and because of these efforts, GSM(TDMA) won over as the standard of mobile communication in most developed nations, particularly in Europe, and as on date 500 million mobile customers all over the world use GSM(TDMA). Services like mobile banking, ticket booking, info services are today exclusively available on GSM(TDMA) networks only. A GSM(TDMA) mobile has a SIM card, which provides more functionality and is convenient(eg, change your phone, but keep your phone numbers and settings). Above all, you can take a GSM(TDMA) phone to virtually anywhere in the world and keep talking.

CDMA has its roots in pre-World War II America. In 1940, a Hollywood actor turned inventor, Hedy Lamarr, along with George Antheil, co-patented a way for torpedoes to be controlled; the U.S. Navy at that time discarded their work as architecturally unfeasible. But in 1957, engineers at Sylvania Electronic Systems Division, Buffalo, New York, took it up, and used it to secure communications for the U.S. during the 1962 Cuban Missile Crisis. After remaining classified for a long time, the CDMA technology was finally declassified in the mid-1980's. Only in 1995 CDMA was, for the first time, used for mobile communication in the U.S.A. Today, the CDMA customer base hovers around 80 million, concentrated mainly in South Korea, North America, Australia, Taiwan and parts of China. Infact the very entry of CDMA into non-U.S. countries is the direct result of politics by the U.S. giant, Qualcomm which put its weight behind the CDMA technology. For example, Beijing clearly linked the entry of CDMA into the country to its US WTO deal. A CDMA phone does not have a SIM card, and therefore you have to stick to the phone you have been provided with.

Proponents of CDMA claim high communication security, high carrier efficiency meaning that the network can serve more subscribers at a time, smaller phones, low power requirement, ease of operation for the network operators, and extended reach beneficial to rural users. CDMA's detractors say that due to its proprietary nature, all of CDMA's flaws are not yet known to the engineering community. Also, as CDMA is relatively new, the network is not set up to provide as many facilities as GSM(TDMA). Being the standard for mobile communication in very few countries, CDMA also cannot offer international roaming, a large disadvantage.

Ideally, the GSM(TDMA) technology's talk-range from a tower is 35 kms in comparision with CDMA's 110 kms, and the power output of a GSM(TDMA)phone is 2W, in comparision with CDMA phone's 200 mW i.e., CDMA implies lesser radiation hazard. But the talk time is generally higher in a GSM(TDMA) phone due to its pulse nature of transmission, in comparision with a CDMA phone which transmits all the time.

CDMA technology has a Soft Accommodation feature, that is, when the number of users of the network goes up, the voice quality progressively gets poorer. Though GSM(TDMA) will not accommodate more than a finite number of users(the user will get the Network Busy message if this number is exceeded), there won't any be deterioration in voice quality due to traffic. In addition, GSM(TDMA) network is also equipped with Frequency-Hopping, i.e., when a lower frequency is cluttered, the mobile phone effortlessly jumps to a higher frequency(e.g., from 900 MHz to 1800MHz). GSM(TDMA) technology also employs the EFR(Enhanced Frequency Rate) add-on, which improves the voice quality greatly.

If a GSM(TDMA)phone determines that there is no intelligent data to transmit, it blanks out the audio, but to keep the listener comfortable, it inserts what is known as Comfort Noise, which mimics the volume and structure of the real background noise. This fake background noise assures the caller that the connection is alive and well. On the otherhand, in CDMA phones, background noise can be effectively suppressed even while the user is talking, so that Comfort Noise, as it is, is unnecessary.

CDMA technology facilitates a Soft Handoff, i.e., when a mobile phone has to choose between two cells, and then shift from one of them to another as you travel, the transition is very smooth. In GSM(TDMA), the handoff is a Hard Handoff, i.e., the phone first stops receiving and transmitting on the old channel, and then commences transmitting and receiving on the new channel. Therefore, if you are making a call during a handoff, the call needs to be dropped.

One of the main problems facing CDMA technology these days is channel pollution, and signal deterioration inside buildings. But CDMA really comes into its elements when you are out in the countryside with few sites covering large expanses of land. CDMA also has a very high data transmission rate, from 153.6 to 614 kbps. Hence the Reliance India Mobile's claim to supply internet at 144 kbps speed.

But the GSM(TDMA), which can provide only 56 kbps data transmission speed today, is also catching up very fast, and moving towards the next generation protocols, the GPRS and the EDGE.

The final conclusion is that it is not so much over technology that a customer decides which network to adopt. It is basically performance! Whichever mobile communication provider puts in better efforts in giving a higher performance, the subscriber is bound to follow that path!

Well I jus bought the reliance cdma cellphone and its kinda good and bad. first the bad stuff,

• the handset gets heated up quite fast and drains the battery really fast, even though the battery is about 850mAh which is higher than most common GSM phones.

• in a cdma service there is no way you can hear a nearby conversation or as we call crosstalk is impossible. but in the reliance phone you can sometimes catch a conversation quite clearly.

• the data service offered by reliance really sucks. first of all it doesnt connect quickly. and when it does, it does in an erratic fashion.

• next is the browser which is inbuilt in the handset. its made by a certain Jataayu software, which happpens to be a b'lore company. whenever I want to check my mail, esp Yahoo, then it takes me all the way to my inbox and then when I click on a mail it always gives me a message not found error. now I really dont know wether this is a yahoo problem or the browser problem. oh and btw all these pros and cons are for the LG RD2030 handset.

• the voice quality is ok but the call gets terminated without you pressing the'end' button.

• sometimes the call doesnt get placed. in the sense the call get through to the called party but the caller gets a total silence. when you switch off the phone and restart it, the call gets placed properly. so is the handset at fault here?

• in some areas the signal strength is really low.

now for the goodies,

• the handset is really snazzy and looks really good.

• call rates are quite appreciable.but the interconnect regime is yet to take place.so its a wait and watch game.

• data service is an added facility.

• voice quality is definitely better than older cdma phones.