Research On Inter-carrier Interference Cancellation In MIMO-OFDM System

The MIMO-OFDM system has the advantages of both MIMO and OFDM technology, ithas a higher bandwidth efficiency, a larger system capacity, a relatively better immunity tofrequency-selective fading and other characteristics which is suitable for high-speed datatransmission; Therefore, MIMO-OFDM technology has become one of the key technology ofthe4G mobile communication system. However, the system is sensitivity to frequency andphase, it is especially vulnerable to carrier frequency offset, which is break down theorthogonality between sub-carries, leading to inter-carrier interference(ICI), which degradessystem performance.The scheme how to reduce the effect of the ICI in the MIMO-OFDMsystem is the main content in this paper.First, this paper introduces the basic principle of the OFDM system and MIMO-OFDMsystem, presents several causes of ICI, describes the both of systems mathematical model andanalyses briefly the existing ICI cancellation method.Second, this paper proposes a novel ICI cancellation method because the existing methodmay lead to phase error caused by phase rotation, the proposed method employing the noveladjacent and symmetric sub-carries mapping scheme, the two types of sub-carrier mappingtechnique improve the system anti-noise performance, validates the effectiveness of thealgorithms through simulation;Then, this paper proposes a method of2/3transmission rate encoding to improve thesystem bandwidth efficiency by reducing the ability of suppressing ICI, but this kind ofalgorithm applies only to the better environment and the ability to suppress ICI has certainlimitations;Finally, this paper proposes a combination of symbols ICI cancellation Scheme whichhas a good balance between suppress the ICI, reduce BER performance and the bandwidthefficiency, validates the effectiveness of the algorithms through simulation.