VLSI-implementation issues of turbo trellis-coded modulation

Turbo trellis-coded modulation (TTCM) is a very promising approach for future communication systems. It combines the advantages of channel coding with multilevel signals and the powerful turbo-codes concept. In this paper we consider VLSI implementation aspects of TTCM. We show that techniques, known from binary turbo-decoders, can be applied to TTCM to reduce the implementation complexity significantly. In detail we explore iteration control, quantization, scaling, and the MAP architecture using a bit-true model of an 8-state TTCM decoder.