Spatial Channel Estimation-Based FDD-MIMO Interference Alignment Systems

摘要

The practical feasibility of interference alignment (IA) is a major challenge in real-world implementation. The majority of the research contributions assume ideal channel reciprocity, which may be valid in time division duplex systems. In frequency division duplex (FDD) systems, large codebooks are utilized for channel quantization, and consume the feedback channel capacity. In this letter, a spatial channel estimation method is proposed for FDD-MIMO IA systems. The method utilizes the path correlation between the forward and reverse channels, where channels are on different frequency bands. A transformation matrix is employed to estimate the angles of departure of the forward channel. The proposed method shows a significant improvement of the sum rate without the need of feedback overhead bits.