A Differential Turbo Detection Aided Sphere Packing Modulaled Space-Time Coding Scheme

A signal construction method that combines orthogonal design with sphere packing has recently shown useful performance improvements over the conventional orthogonal design. In this contribution, we extend this concept and propose a novel sphere packing (SP) modulated differential space-time block coded (DSTBC) scheme, referred to here as (DSTBC-SP), which shows performance advantages over conventional DSTBC schemes. We also demonstrate that the performance of DSTBC-SP systems can be further improved by concatenating sphere packing aided modulation with channel coding and performing SP-symbol-to-bit demapping as well as channel decoding iteratively. We also investigate the convergence behaviour of this concatenated scheme with the aid of extrinsic information transfer (EXIT) charts. The proposed turbo-detected DSTBC-SP scheme exhibits a \´turbo-cliff" at E_b/N₀ = 6 dB and provides E_b /N₀ gains of 23.7 dB and 1.7 dB at a BER of 10^-5 over an equivalent-throughput uncoded DSTBC-SP scheme and a turbo-detected QPSK modulated DSTBC scheme, respectively