Investigation on Feedback Channel State Information for Interference Rejection Combining Receiver in LTE-Advanced Downlink

This paper investigates a scheme for deriving feedback information for the interference rejection combining (IRC) receiver, which can suppress inter- cell interference, in order to perform adaptive modulation and coding (AMC), user scheduling, and transmission precoding at the serving eNodeB appropriately in the LTE/LTE-Advanced downlink. In this paper, we evaluate the negative impact of inappropriate feedback information for the IRC receiver, i.e., not including the interference suppression effect, and the effectiveness of appropriate feedback information on the user throughput performance. Simulation results assuming two transmitter/receiver antenna branches and an uncorrelated channel show that interference suppression for the IRC receiver does not affect the precoding matrix selection when selecting a common precoding matrix for the transmission bandwidth. Furthermore, even when the IRC receiver calculates the feedback information excluding the effect of interference suppression, the user throughput improves compared to that for the conventional MMSE receiver, which cannot suppress the inter-cell interference. However, when comparing the performance of the IRC receivers that calculate the feedback information when including and excluding the effect of interference suppression, the results show that the degree of improvement in the user throughput when excluding the interference suppression effect degrades due to inappropriate feedback information.