Weigh in on the debate between GSM and CDMA.
GSM and CDMA are shorthand for "Global System for Mobile" and "Code Division Multiple Access" respectively. GSM has more than 450 million subscribers, which covers more than 80% of the market share globally. But the story is different for USA, having CDMA as a dominant standard for mobile communications.
European Telecommunications Standards Institute (ETSI) developed GSM as a description protocol for 2G cellular networks and was first introduced in 1991. GSM works on narrowband TDMA technology. GSM digitizes date and then compresses it. After the compression is done the data is sent down through a channel with two other user data streams, each having its own time slot. GSM can operate either at 900 MHz or 1800 MHz frequency band. GSM incorporates Hard Hand-off while call is transferred from one cell tower to another.
CDMA is a multiplexing form, which optimizes the bandwidth by allowing numerous signals to occupy a single transmission channel. It uses ultra-high-frequency (UHF) technology in cellular telephone system. It operates at 800 MHz and 1.9 GHz bands. With spread spectrum technology CDMA employs ADC (analog-to-digital conversion). The CDMA channel is generally 1.23 MHz wide.