Advanced interference suppression receiver for LTE-advanced systems

Co-channel interference is considered as one of the most important issues of modern wireless communication systems. In order to address the interference issue in LTE-A systems, the linear interference rejection combining (IRC) receiver was introduced. Inter-cell interference suppression in the IRC receiver is provided via simple beam forming on the antenna elements of the receiver, which are calculated using the estimated interference covariance matrix. During the related LTE Rel-11 study item in the 3GPP RAN1 Working Group, the IRC receiver was identified as a promising mechanism for improving the cell-edge user throughput. However, for interfering links employing MIMO schemes with multiple spatial layers or in the case of more than one dominant interfering node, the interference suppression capability of the linear IRC receivers is substantially reduced. In this paper we investigate the performance of advanced non-linear IRC receiver structures for interference suppression. More specifically, we propose a maximum-likelihood detection (MLD) scheme to suppress more than one dominant interfering links. The simulation results show that the proposed MLD receiver structure, employing additional knowledge about the modulation scheme of the interfering layers, improves the cell-edge user throughput (defined as the 5^th percentile value of the cumulative distribution function) by approximately 23% compared to the baseline linear IRC receiver.