Research On Multi-User Interference Alignment In Cooperative Communicaiton System

In next mobile communication system LTE-Advanced, relay and Coordinated Multiple Point (CoMP) are two key techniques of cooperative communication and are concerned widely by researchers.When the number of the users increases in cooperative communication system, interference becomes an essential factor that has influence on the performance of the system. With the existing transmission strategies of conmmunication, how to make more efficient use of space freedom to handle multi-user interference in order to improve the transmission quality of the channel, is worthy of further study.The work was supported by the State Key Laboratory of Wireless Mobile Communication Research Project "Distributed Systems Signal processing and Resource Scheduling Algorithm", and Outstanding Graduate Innovation Fund of the College of Information and Communication Engineering, Beijing University of Posts and Telecommunications,"Capacity of Interference Channel with Relay and Power Allocation".This thesis focused on the technology of interference alignment, and designed the interference-alignment ways for multi-user with power allocation, respectively to the transmission of relay or CoMP.Firstly, this thesis described the technical characteristics of the relay and CoMP, explained the cause of the multi-user interference, and summarized several technologies to deal with multi-user interference, which focused on classic interference alignment technology. For the multi-user case of decode and forwarding of the relay, the optimize interference alignment was designed. The theoretical and simulation results showed that, interference alignment can improve the channel and the rate and degree of freedom in the certain scene. For the multi-user case of quantitize and forwarding of the relay with multi-user, corresponding interference alignment precoding was designed based on the planned process of the relay and simulations from different views showed that, the interference alignment technology enables the sum rate of the channel to increase. For the multi-user case of joint processing in CoMP, the corresponding interference alignment and power allocation with maximize-sum rate were proposed. Simulation of this design showed that, interference alignment can improve11.18%of the cell average spectral efficiency access to better channel performance.