Full-Rate Differential Spatial Multiplexing from Orthogonal Designs

In earlier paper we proposed a differential spatial multiplexing (SM) scheme based on complex square orthogonal designs, referred to as differential orthogonal spatial multiplexing (DOSM). The receiver of DOSM does not require estimation of channel fading coefficients, channel power, signal power, or noise power to decode the data symbols and the decision is based on the two consecutively received codewords. In, the transmission matrix of DOSM is based on complex square orthogonal designs which cannot achieve full data rate. Hence, we presented a constellation rotation strategy to enhance the rate of DOSM. In this paper, we construct the transmission matrix of DOSM from complex rectangular orthogonal designs and find that full-rate DOSM can be achieved with increased encoding block length. An upper bound of the pair-wise error probability (PEP) for DOSM in Rayleigh fading channels is derived. Simulation results show that the proposed DOSM outperforms the differential space-time block code (DSTBC) with full diversity and the existing differential SM schemes in terms of error-rate performance over quasi-static Rayleigh fading channels.