Research On Interference Suppression Technique In LTE-A MIMO System

As a key technology in LTE-A system,MIMO technology can be used to improve the channel capacity.However,due to the existence of interference,it will seriously reduce MIMO channel capacity,even causes MIMO to degrade as SISO system.The aim of this paper is to perform some related research works,mainly about the interference suppression technique in LTE-A MIMO system.(1)The research on MIMO system is implemented,basing on the theoretical analysis of MIMO channel capacity.MIMO channel capacity is deduced and calculated in the condition of constant parameters and random parameters.On the basis of the above analysis,the study of the effect of interference on the MIMO capacity is performed,which is under the background of multi-cell users.Meanwhile,it is pointed out that the interference between multiple cells is the main cause of the degradation of MIMO channel capacity.(2)Aimed to the problem of interference suppression,this paper analyzes two solutions:the one is interference suppression based on interference alignment,the other is interference suppression based on time reversal.(3)In order to solve the negative effect of non-cooperative interference to the MIMO system,this thesis firstly constructs system model.Then,zero forcing interference alignment algorithm is expounded.Finally,an Simulation results show that,compared with the BD-OCI,the enhance zero forcing interference alignment algorithm has better interference suppression effect in low SNR scenario.(4)Interference suppression technique based on time reversal is proposed in this thesis.Time reversal scheme utilizes the feature of matched output of time reversal channel,which strengthens the target signal power while reduces the interference signal power.As a result,the interference can be suppressed.Simulation results indicate the effectiveness and feasibility of the proposed scheme.