Research On Interference Alignment Technology In Wireless Communication System

In recent years, with the rapid development of global communication technology, the number of users in a communication system grows with each passing day. The complexity of the communication environment is more and more high, and the attendant problem is increasingly scarce spectrum resources. So how to improve the utilization rate of limited spectrum resources, and how to improve the transmission rate of the system, reliability and quality of service for the future wireless communication is an important research subject.Interference is an inevitable problem in the wireless communication. In a multi-user system, the inter user interference has become the main factor that limits the capacity of the system. Interference of traditional management methods are the interference as noise and interference cancellation and channel orthogonalization etc, but these methods have their defects. Interference alignment(IA) technology is a new anti-jamming technology. It can greatly enhance the capacity of the system, so it becomes widely attention and deeply research. Proposed interference alignment technology opens up a new look for the efficient use of spectrum resources, so it becomes a research hotspot in the field of wireless communication in recent years. Communication system is often used to relay technology, after using this technology, not only can extend the communication distance, and can improve the quality of signal transmission and it has become one of the key technology of the wireless communication. This paper studied joint space-frequency interference alignment algorithm of subcarrier grouping processing for MIMO-OFDM system and an optimization algorithm based on eigen-submatrix in interference alignment for MIMO two-way relay network. The main work of this paper is as follows:Firstly, to make up for the traditional one-dimensional domain interference alignment beam-forming solutions in less space, so the space frequency in MIMO-OFDM system combined with interference alignment algorithm is researched and the proposed optimization scheme is subcarrier grouping processing. It effectively solves the problem of adjacent-channel interference between adjacent subcarrier, and for the alignment group of each linear independent design optimal precoding, and at the same time performing interference alignment operation. The simulation results show that in this chapter the optimization scheme is applied to the interference alignment algorithm, not only improves the system capacity, and reduces the complexity of the algorithm.Secondly, in view of the traditional relay zero forcing algorithm has been unable to solve the interference problem of two-way relay in asymmetric networks, this paper studied interference alignment algorithm in MIMO two-way relay network and proposed optimization algorithm based on eigen-submatrix. The algorithm used to solve for the asymmetry of the data flow between users, by using feature submatrix criterion, design interference alignment optimization algorithm and the feasibility plan and consider all the users in the system of performance. The simulation results show that in this chapter the proposed algorithm not only optimizes the performance of the whole system, but also improve the system capacity and transfer rate.