LDPC-Coded Single Symbol Decodable Quasi-Orthogonal Space-Time Block Code

In this paper, we consider a concatenation scheme of a LDPC (Low-Density Parity-Check) code and a new QOSTBC (Quasi-Orthogonal Space-Time Block Code). The QOSTBC with four transmit antennas generally achieves full rate, a half or full diversity, while its decoding complexity becomes high by using a pair of maximumlikelihood detectors. To improve this decoding complexity, we propose a new QOSTBC scheme named SSD-QOSTBC (Single Symbol Decodable Quasi-Orthogonal Space-Time Block Code). As this scheme converts a non-linear decoding process of the QOSTBC to a linear process, the decoding complexity is equal to the OSTBC (Orthogonal Space-Time Block Code). Moreover, the SSD-QOSTBC can be linearly concatenated with LDPC codes by its linear decoding. Simulation results show that the LDPC-coded SSDQOSTBC is superior in terms of BER performance to the LDPC-coded OSTBC in quasi-static flat Rayleigh fading channels.