Optimal Cooperative Beamforming Design for MIMO Relay Channels

Abstract

Motivated by the rapid growth of wireless applications with multiple antenna terminals, multiple input multiple output (MIMO) relaying has gained much attention now a days due to its improved data rate, coverage extension and improved signal to noise ratio (SNR). In this paper, a transmit beamforming design for MIMO decode-and-forward (DF), MIMO amplify-and-forward (AF) and MIMO compress-and-forward (CF) half-duplex two-hop relay channels with a direct source–destination link is considered. Network model consist of source, relay and destination. Design includes four different cases in terms of the number of antennas deployed at source, relay and destination node which contains 2:2:1 scenario, Ns:1:1 scenario, Ns:Nr:1 scenario and Ns:Nr:Nd scenario. Here, beamforming design is based on exact capacity formulation and low-complexity explicit expressions are used. Effect of parameter such as number of antennas on the performance of MIMO relay channels is also investigated. Optimal beamforming design for MIMO AF relaying scheme achieves high performance gain and higher information rates than MIMO DF and MIMO CF relaying scheme.