4.1 Introduction to CDMA
CDMA stands for Code Division Multiple Access – a cellular technology which was adopted by the Telecommunications Industry Association in 1993. This technology was originally known as IS-95 and is currently known as ‘CDMAOne’. The first commercial deployment was in the year 1995 and by 1998 there were 16 million subscribers which rose to 35 million by 2001. Currently, there are more than 450 million subscribers of CDMA in the world.
CDMAOne is a complete set of wireless technologies based on TIA/EIA-95 CDMA standards including both the IS-95A (Interim Standard of the US Telecommunications Industry Association) and IS-95B and related services such as cellular, fixed wireless (e.g. WLL), PCS, etc. The IS-95A standard, which is the basis of commercial second generation CDMA systems, was first released in 1993 with a revision in 1995. The IS-95B standard combined the IS-95A, ANSI-J-STD-008 and SB-74 standards in a single document. IS-95A contains the structure of wideband 1.25 MHz CDMA channels, power control, hand-offs, call processing, registration techniques, etc. IS-95B defines the standards for 1.8–2.0 GHz CDMA PCS systems. As the IS-95B systems are capable of offering 64 kbps packet-switched data in addition to voice services, it is called the 2.5G technology. . While IS-95A provides CS data connections at 14.4 kbps, IS-95B provides 64 kbps packet-switched data. Hutchinson was the first operator to deploy IS-95A while the IS-95B was first deployed ...