Trellis coded modulation design for multi-user systems on AWGN channels

Trellis coded multiple access (TCMA) is a multiple access scheme where different users in a multiuser system employ different trellis coded modulation (TCM) schemes as the only means of separation. The superposition of individual signals can be considered to be a super trellis coded modulation (super TCM) scheme, which is the combination of individual TCM schemes. In this paper, first we propose some design rules for individual TCM schemes which produce a super TCM scheme that performs well on an AWGN channel. For simplicity, we further constrain that all users have the same coding scheme. The only difference among them is their individual constellations. Then we provide a design procedure for these individual constellations. This paper also includes some examples which show the design procedure. Finally, we compare several TCMA systems by their performance analysis and simulation results.