Interference Cancellation and Detection for More than Two Users

In multiple access channels, when users know each other's channels, precoders can be designed utilizing channel information to cancel the interference at the receiver without sacrificing the diversity or the complexity of the system. Recently, it was shown that when there are only two users, a receiver can completely cancel the interference of the two users and provide full diversity for each user. Unfortunately, the scheme only works for two users. In this paper, we extend the scheme to more than 2 users. In other words, we propose a system to achieve interference cancellation and full diversity with low complexity for any number of users. Then, we extend the results to any number of users with any number of transmit and receive antennas. Our main idea is to design precoders, using the channel information, to make it possible for different users to transmit over orthogonal directions. Then, using the orthogonality of the transmitted signals, the receiver can separate them and decode the signals independently. We also analytically prove that our system provides full diversity to each user. Simulation results confirm our analytical proof and show that our proposed scheme outperforms other existing interference cancellation schemes.