Institute of Electrical and Electronics Engineers
In this paper, the authors explain about the cellular system scenario where multiple data streams originating from a Base Station (BS) targeted to multiple cell-edge Mobile Stations (MSs) are transmitted via preinstalled cooperative Relay Stations (RSs) with multiple antennas. Their objective is to guarantee Quality-of-Service (QoS) in terms of predefined signal-to-noise ratio at such users within the transmit power budgets at BS and RSs while minimizing total transmit power. They propose a novel pre-coder design method for power allocation between multiple data streams at BS and RS by using joint zero-forcing strategy in order to avoid Multi-User Interference (MUI) in the signal received by MSs via both the direct and relay links. They also propose low-complexity suboptimal power allocation algorithm.