Limited feedback schemes based on inter-cell interference alignment in two-cell interfering MIMO-MAC

In this paper, we propose two kinds of interference alignment (IA) schemes with limited feedback for the two-cell interfering multi-user multiple-input multiple-output multiple access channel (MIMO-MAC). Since IA with limited feedback results in residual interference for the quantization error, more effective schemes are introduced to reduce the residual interference in this paper compared with the ever work. The first kind of schemes means that the precoding matrices at the transmitters are the quantization value after obtaining the IA close-form solution of the precoding and decoding matrices at the receivers. This kind of schemes has been generalized to K users in this paper, and decoding matrices design is considered to reduce the quantization error to improve the performance. For the second kind of schemes, the beamforming vectors are chosen in the codebooks directly which guarantee the inter-cell interference (ICI) are most aligned. Monte-Carlo simulations illustrate that the proposed schemes outperform the existing schemes.