Zero-forcing throughput maximization for regenerative multi-user relaying

We provide a computationally inexpensive zero-forcing downlink precoder design for regenerative relaying with multiple users. The design objectives are throughput maximization and rate balancing subject to separate transmit power constraints for the base station and relay. For throughput maximization, we provide also a distributed solution with low signaling overhead. The considered system model consists of a single multi-antenna base station and multi-antenna relay that both serve multiple users with single-antenna receivers. Two-stage transmission is considered, in which the additional interference caused by the over-the-air (OTA) transmission between the base station and relay is taken under consideration. It is shown that proper OTA signaling has major impact on improving the system performance.