A Reliability-Based Detection Algorithm for MIMO Relay System

Cooperative Communication enables wireless devices with relatively less antennas to share their antennas and create virtual multiple-antenna transmitter, thereby achieving transmit diversity to combat fading caused by multi-path propagation in wireless environment. At the receiver in a multi- input multi-output (MIMO) relay system, we can still utilize the traditional detection algorithm, such as zero-forcing successive interference cancellation (ZF-SIC), which have been widely employed in the Vertical Bell Laboratories Layered Space-Time (V- BLAST) system model. However, the inevitable error- propagation in the procedure of such algorithms may cause great performance degradation, which cannot meet the demand for high data rate while maintaining high quality wireless communications. In this paper, we develop a reliability-based detection algorithm that includes a new log likelihood ratio (LLR) calculation for MIMO Relay system to alleviate error propagation. In addition, to further improve the system performance, we utilize a pair-wise LLR combining scheme suits for cooperative communication system with incremental relaying protocol. Simulation results show that our proposed algorithm outperforms the traditional ones in a MIMO Relay system.