Interference Alignment Algorithm For Multiuser MIMO Interference Channel With Relays

Interference Alignment(IA) technology can effectively overcome the shortcomings of traditional interference management methods so as to improve the degrees of freedom(DoF). Interference Alignment has become an effective interference management method. For interference channels without relay(s), IA requires global channel state information(CSI)available at all transmit nodes to achieve the target DoF. Which leads to a great signaling complexity.This thesis aims at designing interference neutralization(IN) methods for multiuser interference channel with relay(s) to decrease the complexity of the algorithm. The main contributions of this thesis are as following:1. Firstly,the system models of K-user interference channel and K-user interference channel with a MIMO relay have been set up.The principles of IA algorithm in different models are studied, and the performance achieved through IA are evaluated via simulations.2. For the K-user interference channel with an instantaneous DF relay, a transmission method is designed to cancel the interference by combining IA with IN,which can achieve more DoF with lower antennas on the relay;When the relay works on AF mode,an IN method which can work with arbitary antennas on Txs and Rxs is designed.Meanwhile,the feasibility is analyzed based on different numbers of antenna.3. Finally, for the K-user interference channel with a half-duplex relay,according to the above-mentioned algorithm,a method to achieve the diversity gain easily is designed by means of solving the beamforming matrix at the relay accurately.Compared with the old algorithm,this method achieves the diversity gain when using relay to manage the interference without losing the channel capacity.