Low complexity high throughput algorithms for MIMO AF relay networks

A multiple-antenna amplify-and-forward (AF) two-hop interference network with multiple links and multiple relays is considered. We optimize transmit precoders, receive decoders and relay AF matrices to maximize the achievable sum rate. Two constraint sets are discussed: first, individual per user and total relay sum power constraints. We propose an algorithm to maximize the total signal to total interference plus noise ratio (TSTINR). Second, this algorithm is extended to individual user and individual relay fixed transmit power constraints. Additionally, we derive algorithms for the total leakage interference plus noise (TLIN) minimization and the weighted minimum mean square error (WMMSE) approach to sum rate maximization. Interestingly, our simulations show that, for both constraint sets, our TSTINR algorithm outperforms the TLIN algorithm generally and outperforms WMMSE in medium to high Signal-to-Noise-Ratio (SNR) scenarios, while TSTINR and TLIN requires less computing time than WMMSE generally.