Reduced complexity MSDD of STBC over fast Rayleigh fading channel

It is known that multiple symbol differential detection (MSDD) can narrow the gap between differential detection and coherent detection. But the MSDD of space-time block code (STBC) has very high complexity. This paper presents two reduced complexity algorithm, which have very low computational complexity, especially over fast Rayleigh fading channel. The first one is simplified M-algorithm (SMA); which has the same performance with M-algorithm but lower complexity. The second one, denoted as improved multiple differential feedback detection (IMDFD), which can solve the error propagation problem of MDFD algorithm with a bit increasing computation complexity, especially at low signal-noise ratio. Simulation results show that these two algorithm are effective to fill the gap with extending the observation interval. With the number of constellation dot increasing, the interval of performance between SMA and IMDFD algorithm is enlarged, the SMA algorithm has better performance with higher complexity.