Capacity considerations for trellis code multiple access systems
Paper in proceedings, 2001
Trellis code multiple access (TCMA) is a
narrow-band multiple access scheme. There is no bandwidth
expansion, so K users are using the same bandwidth
as one single user. The load (the number of bits per channel
use) of the system is therefore much higher than the load
in, for example, conventional CDMA systems. It is shown
here that the maximum number of users in a TCMA system
is usually modest. This fact is based on constellationconstrained
capacity, i.e., the maximum capacity of a system
with a specific constellation of the transmitted symbols.
The minimum required signal-to-noise ratio for reliable
transmission is also given for different code rates.