Differential space-time spreading using iteratively detected sphere packing modulation and two transmit antennas

A novel differentially encoded space-time spreading (DSTS) scheme using two transmit antennas and Sphere Packing (SP) is proposed, which we refer to as the DSTS-SP arrangement. The advocated SP-aided system outperforms DSTS dispensing with SP and requires no channel knowledge. We also demonstrate that the performance of DSTS-SP systems can be further improved by serially concatenated convolutional coding and by performing SP-symbol-to-bit demapping as well as channel decoding iteratively. Explicitly, the proposed turbo-detected DSTS-SP scheme exhibits an E_b/N_o gain of 17.0 dB at a bit error rate (BER) of 10_-5 over an uncoded identical-throughput system and an E_b/N_o gain of 1.9 dB over the equivalent 2 bits/symbol effective throughput QPSK-modulated turbo-detected DSTS scheme