Hi Gary and Shane:
GSM is the standard in Europe. It is based on TDMA
(time division multiple access)- essentially different
users within a cell use different time slots. CDMA
stands for code division multiple access. It is a spread
spectrum system, where different users share the entire
bandwidth, and a signature is use to separate users.
GSM is the standard in Europe, and among digital wireless
systems, is the dominant system in the USA. In California,
Airtouch uses CDMA, but PacBell uses TDMA. The big gains
of CDMA have been primarily in Asia. Although it is often
claimed that CDMA has a capacity advantage of about 3 over
TDMA, this advantage has never been demonstrated in practice,
so that if CDMA has an advantage over TDMA, it is rather small.
Both TDMA and CDMA have a huge capacity advantage over analog
cellular systems.
The bottom line is that CDMA is an up and coming system, but
the probability that it will displace TDMA is exactly zero.
My guess is that both systems will probably coexist, with
GSM remaining slightly dominant. I would guess that you are
probably talking about chips that can handle both standards
(TDMA and CDMA).
Best regards,
Bernard Levy |
