— In this paper, we propose serially concatenated trellis coded modulations (SCTCMs) that perform consistently close to the available mutual information for the 2-by-2 compound matrix channel. The proposed SCTCMs use universal SCTCMs for the period-2 periodic fading channel in order to deliver consistent performance over eigenvalue skew. Within the family of channels having the same eigenvalue skew, a time-varying linear transformation (TVLT) is used to mitigate the performance variation over different eigenvectors. The proposed SCTCMs of 1, 2 and 3 bits per transmission require excess mutual information in the ranges 0.110.15, 0.23-0.26 and 0.35-0.53 bits per antenna, respectively. Because of their consistent performance over all channels, the proposed codes will have good frame-error-rate (FER) performance over any quasistatic fading distribution. In particular, the codes provide competitive FER performance in quasi-static Rayleigh fading.
Wen-Yen Weng, Bike Xie, Richard D. Wesel