High-speed Mobile MIMO-OFDM System Channel Estimation

Orthogonal Frequency Division Multiplexing (OFDM) technology with anti-multipathinterference ability, high spectrum efficiency, achieve faster data transfer rate and Relatively simpleto implement, etc., which in the field of wireless communications has attracted wide attention, andbecame one of the core3G/4G standard techniques. Multiple Input Multiple Output (MIMO)technology without increasing the overall system bandwidth and the antenna transmission power,exponentially increase the capacity and spectral efficiency of wireless communication system.MIMO-OFDM system combines the advantages of MIMO and OFDM technologies and wasrecognized as key technology of the fourth generation mobile communication system bystandardization organizations. With the rapid development of high-speed railway, the mobile userdemand for high-speed data communication services is increasing in the high-speed mobileenvironment, so the study of high-speed mobile environment OFDM and MIMO-OFDM system isa top priority.This paper show further study about the estimation algorithm of the channel OFDM andMIMO-OFDM systems under high-speed mobile environment. Firstly, the paper analyzes thecharacteristics of the radio channel under the high-speed railway environment and detailed analysisa new Rice fading channel simulation model which is suitable for high-speed railway environment.Secondly, Inter-Carrier Interference (ICI) of OFDM system carried out a detailed analysis underhigh-speed mobile environment and various common channel estimation algorithm andinterpolation algorithms are compared with the simulation analysis by a new Rice fading channelsimulation model; Again, in order to improve high speed mobile OFDM system channel estimationaccuracy, this paper presents a Base Expansion Model (BEM) combined feedback packet DiscreteFourier Transform (DFT) channel estimation algorithm, ICI coefficient term is obtained by BEMchannel estimation, Feedback is obtained by the elimination of ICI, and then by grouping DFTchannel estimation algorithm to eliminate secondary interference of ICI and other items, Thesimulation results proved that the algorithm can effectively improve the overall systemperformance; Finally, in order to improve the high-speed mobile MIMO-OFDM system channelestimation performance，this paper presents a suitable high-speed mobile MIMO-OFDM channelestimation pilot sequence based on the traditional optimal MIMO-OFDM system pilot sequence.Each received-transmit antenna of MIMO-OFDM system can be considered as independentSISO-OFDM system after insertion of the pilot sequence. At this point, each pair received-transmitantenna channel response can be obtained by BEM channel estimation algorithm, the input signal of each antenna can be obtained from the MIMO detection module, ICI coefficient term of each pairreceived-transmit antenna can be obtained by the input signal of each antenna, furthermore thefeedback signal is calculated, Finally, grouping DFT channel estimation algorithm is used toeliminate secondary interference ICI and other items. The simulation confirmed the channelestimation algorithm with basis expansion model combined feedback packet DFT is suitable tohigh-speed mobile MIMO-OFDM systems.