Relay-Assisted MIMO Multiuser Precoding in Fixed Relay Networks

In this paper, downlink multiple input multiple output (MIMO) multiuser transmission using precoding in fixed relay networks is studied. We propose two relay-assisted MIMO multiuser precoding models. For the first model, multiuser precoding is performed at base station (BS). The fixed relay processes the received signal and forwards it, which is amplify- and-forward. While for the second model, the multiuser precoding is done at relay. Thus, detect-and-forward or decode- and-forward transmission can be used. Based on these models, some multiuser precoding algorithms are investigated. Our simulation results show that fixed relay offers significant gain. And our system architectures give the means on how to utilize fixed relay in MIMO multiuser system.