Capacity analysis for multiple-input multiple-output relay system in a low-rank line-of-sight environment

This article focuses on channel model and capacity of multiple-input multiple-output (MIMO) relay system in a low-rank line-of-sight environment. According to the channel characteristics of MIMO and the correlations among antenna arrays, the expression for system capacity is deduced. Various factors influencing MIMO relay system are analysed based on this expression, and the numerical simulation is performed for verification. The simulation results show that system capacity is greatly increased by adding relay nodes. However, the antenna array spacing and angle at the transmitting and receiving ends, relay node position, Rice K-factor and other factors can all produce certain effects on the capacity of MIMO relay system.