Research On The Key Technology Of Wireless MIMO Interference Channel

Interference alignment known as an advanced concept has drawn great attention in the capacity analysis of wireless interference networks. This technique has broken through the conventional knowledge on the throughput limit of wireless networks and also provided the theoretical basises for the larger-capacity and higher-rate communication in the future wireless communication systems, in which multi-users will cause interferences to each other. During the past several years, many significant breakthroughs have been made both in the characterization of the degrees of freedom(DoF) region for the intereference networks and the exploration of the interference alingment(IA) algorithms. However, for the multi-user MIMO interference network, the existing IA algorithms cannot suprress the interferences effectively due to the complex structures of interferences and the constraint on the dimension of signal space at receivers. In addition, IA algorithms are based on the perfect channel state information(CSI) at transmitters, which requires efficient schemes to achieve such information. Futhermore, as for the analysis on DoF region of the two-user MIMO interference channel, the non-delay signal feedback assumption is not appropriate in the real communication system. Based on these points, the contributions of this paper are as follows:Considering the demand for the CSI at transmitters, we have proposed the non-distortion feedback scheme to obation the CSI by taking the channel estimation error into account and derived the optimal ratio of the feedback slots to the transmission persisting slots.Considering the performation degradation of traditional IA algorithms caused by the constrained dimension of the siganl space, we have proposed the interference cancellation scheme based on the signal decomposion and the weighted reconstruction of interferences. Theoretical analysis and simulations indicate that the prposed scheme can defend against the drop in perfomace and also help to depress the effects from the correlation assumptions on sources.The paper has derived the outer bound of the DoF region for the two-user MIMO interference channel in the view of informtion theory based on the persumption of partial local feedback and delayed CSI at transmitters. We have also proposed the continus-slots tranmission scheme, which can be used to show that the outer bound deduced in this paper is tight.