GSM and CDMA network technologies are the two main competing technologies set up by cellular service providers across the globe.
GSM is an abbreviation of Global System for Mobile Communications, while CDMA is an abbreviation of Code Division Multiple Access
The technology:
Mobile communication systems have to make use of the microwave frequencies above 800 MHz for transmission and reception of the signals. Different service providers operate in pre allocated frequency bands given to them by the international standards. Below listed are the methods to access these microwave frequencies.
- FDMA (Frequency Division Multiple Access) - FDMA puts each call on a separate frequency.
- TDMA (Time Division Multiple Access) - TDMA assigns each call a certain portion of time on a designated frequency.
- CDMA (Code Division Multiple Access) - CDMA gives a unique code to each call and spreads it over available frequencies.
- GSM is a global standard based on TDMA.
How these technologies affect the common man:
In case of GSM:
- If you opt for GSM technology, you have the freedom to choose handset separately from the wide variety of big handset companies like Nokia, Motorola, Sony Ericsson, etc who retail their products in the market.
- You can then purchase a SIM card from any of the GSM service providers like Hutch, Airtel, etc and insert it in to your handset and start talking.
- You even enjoy the freedom to switch the service provider and still continue with the same handset.
- GSM service providers are well networked globally. Therefore it offers much better international roaming. You must check for roaming call rates and coverage in the regions or countries where you visit frequently.
- Another major benefit that GSM users enjoy is that if you travel to other countries you can make use your same GSM cell phone there too( if it is a quad-band phone 850/900/1800/1900 MHz). To save yourself from roaming charges from your service provider, you can purchase a local SIM card with call value and a local number in the country you are visiting.
In case of CDMA:
- Here the handset is network locked. You have to buy a complete package from the service provider that includes both, the handset and the connection (prepaid / postpaid).
- Two main CDMA players in India are Reliance and TATA.
- Earlier it was difficult for Reliance users who wanted to retain the same number but wanted to change their reliance handsets, to do so. However now it is possible by making use of the handset change card that is available in a nominal amount.
- TATA however made it very user friendly. Due to its T - SIM enabled handsets; it is easier for TATA users to change their handsets.
- Reliance and TATA now have a range of entry level, mid-segment and features rich advance handsets available with them. However in this case the choice of handsets is limited to the models offered by the Service Provider.
- You cannot change the service provider and still keep the same handset.
- Voice clarity in CDMA network is supposed to be better as it uses same frequency across all cells.
- Here you need to check for International roaming tie ups if you travel abroad frequently. You do not enjoy the freedom like GSM mobiles.
- TATA is soon launching T-SIM to enable international roaming with one world one number concept.
Before choosing a CDMA or GSM Mobile phone from any mobile store, you need to understand the features and services provided by these mobile phones well