Science and technology

Date: February 12, 2015

CDMA GSM

Define CDMA and its  working. also differentiate between GSM and CDMA? (200 WORDS)

 CDMA (Code Division Multiple Access) refers to any of several protocols used in so-called second generation (2G) and  third generation (3G) wireless communications. As the term implies, CDMA is a form of multiplexing , which allows numerous signals  to occupy a single transmission channel, optimizing the use of available bandwidth.CDMA employs analog-to-digital conversation in combination with spread spectrum technology.

Working of CDMA technology-

Audio input is first digitalized into binary elements. The frequency of the transmitted signal is then made to vary according to a defined pattern (code), so it can be intercepted only by a receiver whose frequency is programmed with the same code, so it follows exactly along with the same code, so it follows exactly along with the transmitter frequency. There are trillions of possible frequency-sequencing codes , which enhances privacy & makes cloning difficult.

CDMA networks use a scheme called soft handoff, which minimizes signal break up as a handset passes from one cell to another.

Difference between CDMA and GSM-

 GSM (Global system for Mobile communication) & CDMA(code division  Multiple Access) are two dominant technologies for mobile communication. CDMA is based on spread spectrum technology which makes the optimal use of available bandwidth. GSM uses both time Division multiple access & Frequency division. More security is provided in CDMA technology as compared to the GSM technology as encryptation is inbuilt in the CDMA. A unique code is provided to every user & all the conversation between two users are encoded ensuring a great level of security for CDMA users. GSM is used over 80% of world’s mobile networks except USA, where CDMA is almost exclusively used. CDMA has faster data rate as compared to GSM as EVDO data transfer technology is used in CDMA which offers a maximum download speed GSM uses EDGE technology.GSM phones emit about 28 times more radiation on average as compared to CDMA phones.