Modified super-orthogonal space-time trellis codes for fast-block fading channels

Abstract

In this paper, we present new super orthogonal space-time trellis codes (Mo-SOSTTCs) for channels modeled as fast block-fading, where the channel is constant for each codeword matrix and changes independently from one codeword to the next. We introduce an extra rotation parameter in a codeword matrix for expanded constellation which allows to minimize the parallel paths in the trellis without increasing the complexity in the decoder. Like original super-orthogonal space-time trellis codes (SOSTTCs),  these codes combine set partitioning and a super set of orthogonal space-time block codes, but unlike SOSTTCs we use the product distance criterion instead of coding gain distance criterion to define a set partitioning. Moreover, we also use the symbol Hamming distance and rank criteria together. Simulations results show that the proposed Mo-SOSTTCs provide similar performance than that of the existing SOSTTCs in quasi-static channel case. Furthermore, Mo-SOSTTCs provide better performance in fast block-fading channel.