by David Chang
Do you use a cellphone? – Who doesn’t?
Do you know your cellphone service carrier? – Probably.
Do you understand the technologies built into your cellphone? – Maybe.
Do you know what’s coming next? – Probably not!
Cingular, T-Mobile, Sprint PCS and Verizon are the four biggest cellular service providers in the U.S. Cingular and T-Mobile are GSM carriers, which stands for Global System for Mobile Communications. GSM uses time division multiple access (TDMA) to divide and allocate radio frequencies into slots, which allows a single frequency to support multiple (up to eight) simultaneous data channels. GSM was first introduced in 1991 and it has become the standard in Europe and Asia . Sprint PCS and Verizon are CDMA carriers, which stands for code-division multiple access. Unlike GSM, CDMA uses spread-spectrum techniques. Instead of assigning a specific frequency to each user, CDMA uses the full available spectrum. CDMA was first introduced as a military technology during World War II by English allies to transmit data through multiple frequencies to distract the Germans from picking up the complete signal. It is a newer and better technology than GSM, and forms the basis of the next generation of phones.
Analog cellular phones have been defined as first-generation phones. Digital cellular phones are marked as second-generation. So, what will third-generation (3G) phones be like? 3G phones will have high data-transfer speed, always-on data access and greater voice capacity. 3G wireless networks will transfer data at speeds of up to 384kbps. What a huge improvement over common wireless data transfer speeds, which are often slower than a 14.4kb modem in the U.S.! 3G technology will make music and video downloads possible on your cellular phone. Video conferences by phone will become commonplace.
3G technology will soon launch in China . Many cellular phone manufacturers have introduced multiple products to support the new technology. The Chinese wireless phone industry will become even bigger as it merges with 3G technology. The future of cellular phones has arrived.
Sources:
http://www.phonescoop.com/glossary/term.php?gid=1
http://www.darwinmag.com/learn/curve/column.html?ArticleID=182