User Guide

PAMS
Technical Documentation
NHP–4
System Overview
Page 3–8
Issue 1 04/99
The AMPS, DAMPS, and GSM capacity examples assume that only one channel
out of every seven can be used. In a crowded metropolitan area, cellular base
stations are arranged like the top part of Figure 3 Each base station is surrounded
by seven others so only one out every 7 channels can be used or adjacent channel
interference will occur. However, such is not the case for CDMA because all users
on a “CDMA Channel” operate on the same frequency. I’ve just used the word
“Channel” in a different way. Users in a given CDMA channel are separated by
different PN code sequences. According to information at the present time there
four designated CDMA frequency channels, so users on a given frequency channel
operate on the same frequency and are separated by different PN code sequences
which are also called “Channels”.
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CDMA Cell Structure
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Transmission range of
any given celll
Transmission range of
any given cell
CDMA03.DRW
Figure 3. TDMA & CDMA Structure
ANALOG & TDMA Cell Structure