CRS Interference Cancellation in Heterogeneous Networks for LTE-Advanced Downlink

Enhanced Inter-Cell Interference Coordination (eICIC) for co-channel deployment of pico-cells throughout a macro-cell layout is a promising solution to increase system capacity and network coverage in Long Term Evolution (LTE)-Advanced systems. The use of both pico-cell Range Extension (RE) and time domain eICIC (TDM muting) in this scenario has been proved to provide high gains compared to the traditional homogeneous network. Nevertheless, performance results in literature assume ideal Common Reference Signals (CRS) interference cancellation in the pico-UEs during Almost Blank Subframes (ABS), i.e., receivers are capable of perfectly suppressing all CRS interference from all neighbour cells. In this paper we investigate the impact of non-ideal CRS Interference Cancellation (IC) in eICIC systems. We propose a simple RSRP-based CRS IC criterion not requiring any extra signaling. The performance is evaluated and compared to the ideal case in the downlink by means of extensive system level simulations that follow the 3GPP guidelines. Results confirm that TDM eICIC can still provide significant gains when realistic CRS IC is considered.