Combined maximum likelihood and SIC detection algorithm for MIMO system

Use of multiple antennas at the transmitter and receiver can increase wireless communication system capacity enormously. Maximum likelihood detection (MLD) algorithm provides the best bit error rate (BER) performance for multiple-input multiple-output (MIMO) system. However, the computational complexity of ML detection algorithm grows exponentially with the number of transmit antennas, which results in difficulty to use in practice system. An improved MIMO signal detection algorithm for MIMO system with low complexity is presented in this paper. The proposed technique combines MLD with successive interference cancellation (SIC) detection. In a MIMO communication system with N_t transmit antennas, after performing QR decomposition of the channel matrix, the MLD with length L is done firstly, the accumulated metrics are calculated and sorted, which gives an ordered set, then SIC algorithm are used to search last N_t - L layers. The proposed algorithm reduces computation complexity of ML detection by the newly adopted parameter L. The trade-off between performance and complexity can be getted by setting L at different values.