Transmit Signal and Bandwidth Optimization in Multiple-Antenna Relay Channels

Transmit signal and bandwidth optimization is considered in multiple-antenna relay channels. Assuming all terminals have channel state information, in full-duplex relaying, the cut-set capacity upper bound and decode-andforward rate are evaluated by formulating them as convex optimization problems. For half-duplex relays, bandwidth allocation and transmit signals are optimized jointly. Moreover, achievable rates based on the compress-and-forward transmission strategy are presented using rate-distortion and Wyner­Ziv compression schemes. It is observed that over the range when the relay is close to the source, decode-and-forward is almost optimal, whereas compress-andforward achieves good performance when the relay is close to the destination.