Multiple phase decoder for MIMO systems

In this paper, we propose a multiple phase decoder (MPD) for MIMO communication systems with M-PSK signals. The proposed decoder is based on a phase descent search (PDS) algorithm. The PDS algorithm is based on coordinate descent iterations and constraints elements of the solution to have unit magnitudes. In the MPD, the PDS algorithm is used multiple times with different initializations. The solution from the PDS algorithm with the minimum cost is chosen as the final solution of the proposed decoder. Simulation results show that, for QPSK modulation, the proposed decoder can approach the performance of the Maximum Likelihood decoder. Comparing to the sphere decoder, the MPD offers a lower complexity, especially at low signal-to-noise ratios and with a large number of transmit antennas. Thus the proposed decoder may be regarded as an alternative to the sphere decoder for MIMO systems.