Super-Orthogonal Space-Time Trellis Codes with Differential Phase Modulation for Noncoherent Mobile Communication Systems

In this paper, we show how to design superorthogonal space-time trellis codes (SOSTTCs) using the differential binary phase-shift keying (PSK) modulation for noncoherent communication systems, for which the knowledge of the channel state information (CSI) at the receiver is not necessary. Moreover, a new decoding algorithm with reduced decoding complexity is proposed. In all simulations, a geometric two-ring channel model is employed to evaluate the performance of the SOSTTCs. The simulation results show that the proposed decoding algorithm has the same decoding performance compared with the traditional decoding strategy, while the new algorithm reduces significantly the overall computing complexity. It is also shown by simulations that the system performance depends greatly on the antenna spacing and on the angular spread of the incoming waves. At the end, we compare the performance of the SOSTTCs using both the differential and coherent encoding schemes. As expected, the coherent scheme outperforms the differential scheme by a coding gain of approximate 3 dB.