Difference Between GSM and CDMA
GSM competes with CDMA in the wireless technology sphere with GSM spanning a lion’s share of the market with 82 percent user penetration around the world. CDMA, however, dominates the US market. Technically speaking, GSM (Global System for Mobile) specifies a complete infrastructure for the wireless network, while CDMA (Code Division Multiple Access) refers only to the technology’s radio component.
CDMA defines a principle of communication channel access which uses a special coding scheme and spread spectrum technology. This technology was pioneered by QUALCOMM.
SIM (Subscriber Identity Module) card
The SIM card is an on-board memory device which identifies a user and retains all the information in the handset. The user can swap SIM cards in multiple handsets and the technology enables all information to be carried over to new handset without any kind of hassle. The CDMA equivalent is a service which retains user data, including scheduler information and phone book on the database of the operator. This makes it possible for the users to transfer to new phone models easily and also gives the capability to recover any contact data in case the phone is stolen or lost.
GSM finds favor when it comes to international travel. Since it dominates the globe, users of a GSM service can enjoy quality coverage anywhere in the world, even in its least accessible regions. CDMA users do not have such conveniences; but newer phone models like the iPhone5 have embedded Quad band GSM which can be used all across the globe.
Comparison of CDMA and GSM data transfer methods
The two technologies differ greatly when it comes to transfer of data. GPRS (General Packet Radio Service) is the wireless data technology provided by GSM. It is slower when compared to the high speed technology provided by CDMA which is able to offer Integrated Services Digital Network (ISDN) speeds that can go up to 144kbps. But it should be mentioned that CDMA requires an exclusive connection to the network and may block voice calls when data transfer is in progress.
CDMA and GSM interaction
In cities and other urban environments, there is a high concentration of both CDMA and GSM connection towers. Theoretically, the GSM and CDMA are “invisible” to each other and will not impact each others’ functions. On a practical level, however, this does not seem to be the case. CDMA signals have increased the GSM receivers’ noise floor, which means the unavailability of space to emit a clean signal. This has led to an increase in dropped GSM calls.