Performance analysis of MIMO relay receiver over interference limited region

Abstract: In the multiuser MIMO system, the quality of service (QoS) is an important issue especially for cell edge users in multi-cell downlink system. The utilization of multiple-input multiple-output (MIMO) relay stations (RSs) provides solution for improving the signal-to-interference plus noise ratio (SINR) from neighbouring base station (BSs) to each relay station (RS). In the design of the receive weight vector, it is necessary to include interference channels because the capacity between BS and RS relies on receiver performance and it forms the bottleneck for capacity of relay station users. In this paper, we use a geometric approach to derive the effective channel gain, which can be obtained from the space spanned by the left singular vectors of the channel. The performance of the system is analysed using the geometric approach considering the relationship between the desired and interference channels. We propose a receiver called the maximum lower bound of expected SINR receiver (MLESR) to maximize the lower bound of the expected SINR. Through the performance analysis of the MLESR over the interference-limited region, we derive closed terms for the performance bounds in terms of number of RS antennas and the interference channel rank according to the rate of MLESR with respect to an ideal case, i.e., a no interference case.