GSM stands for Global System for Mobile Communications. CDMA is an acronym for Code Division Multiple Access. These are the two systems used to transmit and carry cellular phone signals today.
GSM uses fdma and tdma technology. The bandwidth is divided into timeslots that the user can use at specific times.
CDMA allots a potion of the bandwidth and codes it specifically for the individual user.
There are several factors to consider before signing up with a cellular service. All the major carriers such as Sprint, AT&T, use either one of the systems.
Both systems are used worldwide, although specific areas have various coverage. Depending on where you live, you must check which cellphone carriers has the better signal in your location. Some rural areas have stronger CDMA signal whereas other GSM may be stronger in other parts.
Different countries may have both CDMA and GSM systems. However, different bandwidths are assigned to a specific area. GSM uses three bandwidths: GSM 900; GSM 1800; and GSM 1900. GSM 900 and GSM 1800 are used in Asia and Europe, while the United States operated on GSM 1900. A cellphone that can operate on all three bandwidths have tri-band capability.
On the other hand, CDMA makes the entire frequency band available to the user. It is only that a certain portion is coded to each individual user. Certain portions of Asia use CDMA technology, while the United States and most of the world use GSM technology.
If you plan to take your phone outside of the United States, you must have roaming capability. Service providers that use GSM are able to use the networks of other GSM providers in another country, enabling a user to use the same phone and SIM card while abroad. This is not possible with CDMA.
CDMA is thought to be more secure of the two systems. This is because instead of sharing the bandwidth and just getting assigned a timeslot for its use, a portion is actually encoded to the individual user.
5. Speed of Data Transfer.
If you want to use your phone to download songs, send and receive pictures and other things aside from making phone calls, you should consider the speed at which the data is transferred and received. Between the two technologies, CDMA is considered to be faster compared to GSM.
6. Cellphone or SIM card Technology.
A CDMA format relies on the cellphone provider and this system uses an R-UIM card. This means that the cellphone is locked or cannot be used for other service providers. On the other hand, GSM technology is open for any cellphone and any carrier. By switching SIM cards, the user can change phones and yet maintain the same service provider. In the united states, SIM cards are used with GSM phones.
Between the two systems, GSM is more popular and more widely used than CDMA. Although CDMA is faster and more secure, the coverage of GSM is greater and allows the user greater flexibility, which accounts for its popularity. To date, there are about a quarter million CDMA users compared to over a billion GSM subscribers.