Research On The Technology Of Interference Suppression In LTE/LTE-A System

With the development of the wireless communication, higher requests are put forward on the transmit rate and throughput of a system. In current LTE/LTE-A version, during the increasing of the cell density and the spectrum utilization unceasingly, the quality of communication system is increasing, but the higher frequency reuse method makes the user located in the edge of the cell coverage, who is affected by the serious same frequency interference from the neighboring cell, which makes the quality of the communication becoming worse.The current algorithm of intercellular interference suppression is mainly focused on the design of transmitter, with the information of downlink channel estimation, the transmitter designs its precoding matrix to satisfy the target of intercellular interference suppression. Considering the advantage of complexity robustness in the transmitter, the algorithm of the interference suppression in the transmitter develops quickly, in recent years, a lot of research results emerge.During the development of the receiver`s technology, the ability of the receiver`s processor is increasing, more and more quickly.Scientists begin to pay attention in the territory of the interference suppression based on the receiver. In the research plan of the 3GPP LTE R12, the advanced Net-Aided receiver has been put forward now, with the help of the less information sharing, such as the intercellular modulation order, or the reference signal information, the receiver uses the advanced algorithm to suppress the intercellular interference.In this dissertation, the intercellular interference environment is discussed firstly, then focused on the current algorithm based on the design of transmitter or receiver, the algorithm and performance analysis are discussed. Then we do some research about the reference contamination problem, the detailed analysis and simulation are discussed in this dissertation, and based on the expectation maximum channel estimation algorithm, we make some improvement, and propose the method of channel estimation, in the method, the parameter searching is ignoring. Then the liner method of interference rejection combiner and MMSE based receiver are discussed, during the detailed derivation and simulation, the conclusion of performance or SINR equivalence is raised. At last, we derive the new method of iterative expectation maximum and intercellular interference rejection combiner, and the interference symbol is regenerated based on the equivalent noise power successively. In different intercellular interference environment, the simulation results are discussed, with the comparison of the MRC receiver, which certify the derived method can satisfy the target of interference suppression, and it can achieve the performance of the MRC receiver in the non-interference environment.