On performance of residue number system coded differential space-time-frequency coding

Space-time-frequency (STF) coding has emerged as a technique for transmitting high data rate over wideband mobile channels. Most of the proposed architectures in the literature maximize diversity gains from one diversity domain and frequency diversity is predominantly dependent on the intrinsic frequency-selective nature of the fading channel. In this paper we propose differential space-time-frequency (DSTF) modulation scheme. The available bandwidth is divided into several orthogonal subbands by a frequency encoder and redundancy is added to maximize coding (frequency) gains. For improved noncoherent detection at the receiver, iterative decoding employing hard decision-feedback of differentially encoded space-time block code on each carrier is concatenated with an outer frequency encoder. It is shown through analytical expressions that with appropriate code design, the proposed DSTF coding scheme can maximize the diversity gains over space, time, and frequency domains.