Using Quantized Feedback to Cancel Interference in Multiple Access Channels

When two users transmit signals to a common receiver, one can design precoders to cancel the interference for each user if each user knows all the channel information perfectly. Also the diversity for each user is full. However, in practice, perfect channel information is not available. In this paper, we design precoders for two users with two transmit antennas and one receiver with two receive antennas using quantized feedback. We propose to construct a codebook using Grassmannian line packing. By choosing precoders from the codebook properly, our proposed scheme can cancel the interference and achieve full diversity for each user. Simulation results confirm our analytical proof.