Study On The High-Speed Mobile Channel Estimation

OFDM and MIMO are the key technologies for the next-generation communication system,OFDM is a special multi-carrier transmission technology, which can be useful for a high ratewireless transmission and withstanding the frequency selective fading, it also can eliminate theinterference between symbols. MIMO can greatly increase the system capacity and the frequencyspectrum utilization. The MIMO-OFDM system is proposed according to the advantages anddisadvantages of the two technologies, it combines the advantage of OFDM and MIMO, it is a idealcombination to raise the transmission rate. Wireless channel estimation can ensure that the systemperformance isn't affected by the multipath fading, it can track the change of the channel responseto make the receiver to detect the signal in the premise of known the channel state information, andthe receiver will correct and recover the received signal to improve the performance of the system.This thesis studies on the theory and algorism of channel estimation on the system of OFDM andMIMO-OFDM, the summarization is as follows:Firstly, this thesis introduces the development process of the wireless communication and theimportance of the channel estimation, and the research background and significance of the subjectare discussed, then the transmission characteristics and statistical model of the wireless mobilechannel are introduced.Secondly, the basic theory and the advantages and the disadvantages of the OFDM areintroduced, then this thesis discusses the theory and the algorithm of the channel estimation basedon the pilot, which include LS, MMSE and LMMSE algorithm, and some interpolation algorithmsare discussed, which include literal interpolation, linear interpolation and Gaussian interpolation,their purpose are obtaining the channel response of the data carriers, then the aforementionedalgorithms are simulated with MATLAB to attain the performance compare.Finally, the basic theory of MIMO and MIMO-OFDM are discussed, this thesis makes athorough discussion on the LS and its simplified algorithm based on the pilot, then discusses theoptimal pilot design and obtains the simulation to compare the performance.