Combination of interference alignment and beamforming in cellular networks

ZHOU Chao, CHEN Zhi, LI Ling-xiang

National Key Laboratory of Communication, University of Electronic Science and Technology of China,Chengdu 610054, China



Abstract:

In this paper, we propose two joint transmit-receive iterative algorithms without the cooperation between different base stations based on the idea of interference alignment (IA) to improve the throughput of relay backhaul links in cellular networks for the case of imperfect channel knowledge,which can be implemented with small changes to existing TD-LTE standards. Unlike the previous interference alignment algorithms¡¯ only reducing the sum interference to the other receivers at the transmitter or the sum received Multi-user interference (MUI) at the receiver, our algorithm shapes the transmission of each data stream at transmitters in order not only to minimize interference to the other users, but also to minimize the interference between different streams objected to the same user, suppressing the MUI and Multi-stream interference (MSI) at receivers. The proposed algorithm I is to maximize the SINR at receivers. But the complexity is relatively high. Algorithm II only needs linear operations and sacrifices a little performance for much lower complexity compared to the Maximize SINR iterative algorithm which needs the inversion operation of matrix. It is also proved that the algorithm converges monotonically. The simulation results show that the techniques have considerable performance gain compared with the previous algorithms. Further research about power allocation is also discussed.ª¤

Key words:  distributed beamforming (BF)  cellular networks  interference alignment (IA)  Multi-user interference (MUI)  Multi-stream interference (MSI)ª¤

DOI£º10.11916/j.issn.1005-9113.2012.06.009

Clc Number:TN929.53

Fund: