The capacity region of multiple-rate codes for multiple-access channels
Yu‐Sun Liu, B. Hughes · 2002
Investigates the limits imposed by information theory on multiple-access codes in which each user has multiple transmission rates, but where only certain combinations of users' rates are desired to operate reliably at the same time. The capacity region for this problem is determined for both synchronous and frame-asynchronous multiple-access channels. Unlike the classic M-user multiple-access channel, the synchronous capacity region is not in general equal to the convex hull of the frame-asynchronous region. In the special case of T-out-of-M user codes, it is shown for symmetric multi-user channels that synchronism does not improve the symmetric capacity for M/spl Gt/T.>