The Research Of Inter-cell Interference Cancellation For Downlink Of LTE-A System Based On CoMP

LTE-Advanced system which based on orthogonal frequency division multiplexing access(OFDMA) can eliminate intra-cell interference, but still can’t mitigate inter-cell interference(ICI).Coordinated Multi-Point transmission/reception(CoMP) is one of the candidate techniques forLTE-Advanced systems to increase the system performancein the both uplink and downlink. Inthis paper, it manly introduces the application of CoMP technology in downlink.CoMP technologymakes use of the characteristic of MIMO channel, and uses the precoding technique to restrainICI.Although CoMP increasesthe complexity of system, but its advantages of improving systemperformance is more worthy of our study.First， this paper simplyintroduces theICI cancellation traditionaltechnology, the workingprinciple of CoMP technology and its application in LTE-A systems.Then this paper introduces thechannel model and the principle and realization of the classical algorithm, analyzes the advantagesand disadvantages of classical algorithm. Aimming the defects of the classical algorithm, this paperpresents improved algorithm. Classic precoding algorithm, based on global cooperation channel,can suppress all the interference, which has a certain degree of performance lossfor LTE-A. So thispaper presents a modified precoding algorithm M_MMSE, which based on local cooperationchannel, can suppress the partial interference. Classical user scheduling algorithm does not makefull use of superioritybrought about by CoMP combined processing technology, so this paper putsforward M_PF algorithm, which can make the cooperate set as a virtual cell and makes globalsearch, so that the allocation of resources will be more effectively.Last, this paper tells theprincipleand the implementation of the improved algorithm, and makes simulation respectively insingle user and multi-user environment. In addition, this paper also considers of the physical layerand link layer comprehensively, combines the M_MMSE algorithmwith the M_PF algorithm.Through the simulation results the CoMP technology advantages can be seen: enhance thesystem average throughput. In addition, the simulation results also confirmed that the presentedalgorithm can reduce the system error rate, and the combination of M_MMSE with M_PF can betterimprove the performance of the system.