Adaptation techniques in wireless packet data services
Nanda, S.; Balachandran, K.; Kumar, S.
Communications Magazine, IEEE
Volume 38, Issue 1, Jan 2000 Page(s):54 - 64
Digital Object Identifier 10.1109/35.815453
Summary:Today's cellular systems are designed to achieve 90-95 percent
coverage for voice users (i.e., the ratio of signal to interference plus
noise must be above a design target over 90 to 95 percent of the cell
area). This ensures that the desired data rate which achieves good voice
quality can be provided “everywhere”. As a result, SINRs
that are much larger than the target are achieved over a large portion
of the cellular coverage area. For a packet data service, the larger
SINR can be used to provide higher data rates by reducing coding or
spreading and/or increasing the constellation density. It is
straight-forward to see that cellular spectral efficiency (in terms of
b/s/Hz/sector) can be increased by a factor of two or more if users with
better links are served at higher data rates. Procedures that exploit
this are already in place for all the major cellular standards in the
world. In this article, we describe data rate adaptation procedures for
CDMA (IS-95), wideband CDMA (cdma2000 and UMTS WCDMA), TDMA (IS-136),
and GSM (GPRS and EDGE)
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