Channel Estimation Scheme In MIMO-OFDM

Multiple input multiple output (MIMO) technology can improve the systemcapacity by multiple antenna to transmit and receive signals without increasing thesystem transmission power under limited bandwidth constraints.Orthogonal frequencydivision multiplexing (OFDM) technology is multi-carrier modulation technologieswhich can effectively overcome the signal fading by multipath propagation.OFDMtechnology convert the frequency selective channels into parallel fading sub-channel.MIMO-OFDM technology which combined with MIMO technology and OFDMtechnology can make full use of space resources to improve the system capacity,and iseffective against frequency selective fading. It is the core technology of the newgeneration communication system.Wireless channel has very strong randomness insignal transmission process.The original signal data is difficult to analyze at thereceiver for the fading from the channel. Channel estimation technique can effectivelysolve this problem by estimating the wireless channel fading instantaneouscharacteristics. The fading from the channel will be compensated.This paper simulated the relationships between the capacity of MIMO systemand the different number of antenna. Then the technology of OFDM channelestimation technology will be studied. The least square algorithm compared with theleast mean square error algorithm, the results show that the minimum mean squarealgorithm has better performance than the least square algorithm. On this foundation,a new method of embed pilots estimation was proposed for OFDM-MIMO doublyselective channel.The features of this algorithm is simple in computation, highspectrum efficiency and does not need to insert the pilot frequency sequence.Finally,the performance of the algorithm was simulated in different signal to noiseratio,different Doppler frequency shift and different numbers of sampled signal. Thesimulation results show that, the new channel estimation method is better than thetraditional scheme. It has great advantages in the system reliability than the traditionalscheme.