The Reseahch Of Eliminating Ici In Ofdm System

OFDM is a multi-carrier modulation technique. It has been widely used because of its anti-interference,high spectrum utilization and easy to realize.However, the Doppler effect leads to the system frequency offset,loses orthogonal and causes inter-carrier interference.This paper focuses on the research of ICI elimination in OFDM system.It includes three parts, i.e., the reason of ICI,the method of ICI elimination and based on ICI self-cancellation channel estimation.①As the conventional ICI self-cancellation including the inversion adjacent data, conjugate adjacent data,symmetric data inversion and conjugate plural weighted, are not very useful to solve phase rotation and peak-to-average ratio,the paper proposes a improved self-cancellation algorithm, which combine the symmetric inversion with conjugate plural weighted. The simulation result shows that this method eliminates the interference dramatically, increases CIR and degrades BER.②In order to solve the bad performance of channel estimation,this paper presents a new method,called “Based on ICI Self-cancellation Channel Estimation”. First,it uses redundant information to encode the transmitted signal,then ICI self-cancellation eliminate the ICI of received signal,so we can get more accurate channel estimation.③Furthermore,this paper compares the performance of different ICI self-cancellation with LS LMMSE,SVD5,SVD16,SVD20.The results show that high order SVD applied in ICI self-cancellation can improve the system performance, and degrade the complexity.