TDMA VS CDMA

 
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.