GSM is a combination of FDMA and TDMA means that the 100 people who want to communicate can be divided into five groups of 20 each in different rooms where they can communicate in a queue one after another. CDMA is just as name CDMA access technology means that all the 100 people will communicate simultaneously in the same room, but each person will have a unique code to differentiate that person from others. GSM technology is used 2G mobile carrier standards while CDMA is 3G mobile carrier standards. GSM is introduced by industry Consortium and CDMA is introduced by chipmaker Qualcomm. We can check out some features of both GSM and CDMA and then check out the difference between them.
2G - GSM :
- Access mode - TDMA/FDD
- Came about in 1987
- Carrier - 200 KHz
- Downlink frequency - 925-960 MHz
- Uplink frequency - 890-915 MHz
- Radio interface - TDMA
- Handoff - Hard handover
- Frame duration - 4.615 ms
- Modulation technique - GMSK
- In 2G GSM time slots in a frame fault rate - 8
- Technology - 2G
- Channel bit rate - 270.33 kbps
3G - CDMA :
- Access mode - CDMA with FDD/TDD
- Came about in 1957
- Carrier - 5 MHz
- Downlink frequency - 2.110-2.170 GHz
- Uplink frequency - 1.920-1.980 GHz
- Radio interface - CDMA
- Handoff - Soft handoff
- Frame duration- 10 ms
- Modulation technique - QPSK
- While in 3G-WCDMA time slots in a frame fault rate - 15
- Technology - 3G
- Channel bit rate - 5.76 Mbps
Difference between GSM and CDMA
- GSM is a digital mobile telephony system whereas CDMA is a channel access method used by various communication technology but both fall under multiple accessing.
- GSM is based on a wedge spectrum called a carrier whereas CDMA is based on spread spectrum technology.
- In GSM networks, it is much easier to swap phones and CDMA can switch phones with carrier's permission.
- GSM provides less security as compared to CDMA.
- GSM widely used technology while CDMA restricted to less number of countries.
- GSM offers maximum download speed around 384 kbps while CDMA offers maximum download speed around 2 Mbps.
- GSM phones emit about 28 times more radiations on an average as compared with CDMA.
- GSM provides voice and data to be used at the same time, but in CDMA only once can be used at the same time.
- GSM is too much older technology while CDMA is advanced technology.
- GSM and CDMA are both uses a different frequency band.
- GSM is slowly being phased out in favor of the CDMA.
- CDMA uses more power while GSM uses low power.
- CDMA offers much faster data rates, GSM has low data rates.
- GSM allocates comparatively fewer subscribers than CDMA.
- GSM is more reliable and CDMA is less reliable.
- GSM used frequency planning to maximize the use of the limited bandwidth whereas CDMA used code planning.