Research Of Interference Alignment In Relay System

With the research and application of4G wireless communications, multi-cell interference, as a key constraint, gets more attention to further enhance the overall system capacity. However, the conventional method cannot handle these problems well. Interference alignment technique is agreed as an important way to solve the multi-cell interference effectively. On the other hand, since the requirements of system capacity increasing quickly, cooperative multi-cell network become an important feature of next generation communication networks, because of the interference and low signal to noise ratio (SNR), the transmission of users at cell edge has not been effectively resolved, the introduction of relay can effectively enhance cell coverage, improve SNR of users at cell edge. But relay also bring greater challenges on interference handling.In this paper we explore the application of interference alignment in the relay system. We solve the degree of freedom of typical relay network systems, and work out the encoding and decoding algorithms applied to the relay network relay. In this paper, by introducing ideas of virtual instantaneous relay, relay system of multi-user and multi-cell has been studied, systems freedom degree limit and reasonable method by combination with interference neutralization. Compared with other method without interference alignment, in a multi-user scenario, when the number of users is three, the system can be increased by25%the maximum degree of freedom, and in the multi-cell scenario, when the number of users is not bigger than16, there is also some improvement on degree of freedom.Based on the capacity issues of relay system, the practical transceiver algorithm design is also an important part of the alignment interference research. For the relay system, it requires joint design of transmitter, relay and receiver, which bring new challenges to interference alignment algorithm design. The paper studies the important design problem for interference alignment algorithms, which is transceiver algorithm design, as an example, transceivers suitable algorithm of multi-user relay network is given, and the transmission algorithm is optimized from the view of sum-rate. Simulation results show that interference alignment algorithm and send matrix optimization results.