Performance of transmitter preprocessing aided cooperative relaying with fixed infrastructure relays

In this correspondence, we study the performance of cooperative communications with the aid of multi-user transmitter preprocessing (MUTP), both at the base station (BS) and multi-antenna enabled fixed infrastructure based decode and forward relay stations (RSs), for uplink (UL) and downlink (DL) transmissions where, multi-user interference (MUI) and inter-relay interference (IRI) are the domineering channel impairments. MUTP formulated under instantaneous, statistical and imperfect channel state information assumptions at the RSs and BS for UL and DL respectively is based on singular value decomposition and, further at the RSs for DL is based on minimum mean square error principle. Specifically, we investigate the performance of the considered system in the context of weak and dominant MUI at the RSs in UL and dominant IRI at the mobile stations in DL. Our simulation studies show that MUTP aided system achieves better bit error rate than multiuser detection based system.