Multiuser detection algorithm based on belief propagation in multiple-input multiple-output systems

In MIMO (multiple-input, multiple-output) systems, signals from different transmitting antennas interfere at each receiving antenna and multiuser detection (MUD) algorithms may be adopted to improve the system performance. This paper proposes a novel multiuser detection algorithm in MIMO systems based on the idea of "belief propagation" which has achieved great accomplishment in decoding of low-density parity-check codes. The proposed algorithm has a low computation complexity proportional to the square of transmitting/receiving antenna number. Simulation results show that under low signal-to-noise ratio (SNR) circumstances, the proposed algorithm outperforms the traditional linear minimum mean square error (MMSE) detector while it encounters a "floor" of bit error rate under high SNR circumstances. So the proposed algorithm is applicable to MIMO systems with channel coding and decoding. Although in this paper the proposed algorithm is derived in MIMO systems, obviously it can be applied to ordinary code-division multiple access (CDMA) systems.