Limited feedback design for interference alignment on MIMO interference networks with asymmetric path loss and spatial correlations

Interference alignment (IA) is degree of freedom (DoF) optimal on K-user MIMO interference channels and many previous works have studied the transceiver design of IA. However, these works predominantly focus on networks with perfect channel state information at the transmitters (CSIT) and symmetrical interference topology. In this paper, we consider a limited feedback system with heterogeneous path loss and spatial correlations, and investigate how the dynamics of the interference topology can be exploited to improve the feedback efficiency. We propose a novel spatial codebook design with low complexity, and perform dynamic quantization via bit allocations to adapt to the asymmetry of the interference topology. We also derive a lower bound of the system throughput under this proposed scheme. Both analytical and simulation results show that the proposed scheme can capture the heterogeneity of path loss and spatial correlations to enhance feedback efficiency.