Unified approach to single- and multiantenna turbo-TCM: union bound and constituent code optimization over AWGN and fading channels

Abstract

Unified approach to distance spectrum interpretation (DS) of single- and multiantenna turbo trellis coded modulations (turbo-TCMs) is introduced in this paper to analyze the performance and optimize constituent TCMs for AWGN and fading channels. The union bound (UB) on frame-error-rate (FER) and bit-error-rate (BER) appeared as rather tight. Further DS optimization produced the new set of constituent TCMs for the robust single-antenna turbo-TCM. Compared to existing Robertson et al. turbo-TCM, more than 1 dB and 5 dB gains are achieved in the error floor region over AWGN and fast fading channel, respectively. Single-antenna turbo-TCM was further concatenated with inner space-time block code (STBC) and compared to previously optimized multiantenna or space-time (ST) turbo-TCM. Achieving the same spectral efficiency with lower decoding complexity, ST-turbo-TCM offers additional 1 dB and 1.5 dB gains over quasistatic and fast fading channel, respectively.