Research On Channel Estimation And Equalization Technology Based On MIMO-FBMC

Filter bank multi-carrier(FBMC)technology is one of the potential multicarrier waveform technologies for future wireless communication due to its good time-frequency characteristics,low out-of-band interference,and high spectral efficiency.FBMC system can be modulated using quadrature Amplitude Modulation(QAM)and Offset Quadrature Amplitude Modulation(OQAM).Compared with the FBMC/OQAM system,the FBMC/QAM system is not affected by the inherent interference,so it has received higher attention in the current mobile communication system.However,the residual interference of the FBMC/QAM system under multipath channels makes channel estimation and equalization a challenging problem.This thesis mainly studies the design of channel estimation and equalization algorithm in the multiple-input multiple-output(MIMO)FBMC/QAM system.Theoretical derivation and simulation analysis of the designed algorithms are also studied.This thesis is summarized as follows:1.For the residual interference problem in MIMO-FBMC/QAM system under multipath channels,a new pilot structure is proposed.Based on the proposed pilot structure,an allantenna interference cancellation(AAIC)channel estimation method is proposed.The pilot structure takes into account the interference caused by time-frequency adjacent transmission symbols to the pilot symbols and set the adjacent symbols to zero to avoid the interference.The channel estimation algorithm firstly uses the channel impulse response and the prototype filter coefficient to calculate the interference caused by the non-adjacent symbols to the pilot symbols.Then the channel state information is corrected in two steps.The proposed pilot structure and channel estimation algorithm can greatly improve the accuracy of channel estimation by eliminating the residual interference of the system.The simulation results show that the proposed AAIC channel estimation algorithm can decrease the normalized mean square error significantly compared with the traditional algorithm.2.To deal with the inter-antenna interference in MIMO-FBMC/QAM systems,a minimum mean square error(MMSE)equalization algorithm based on double layer interference cancellation(DLIC)is proposed.The algorithm firstly performs MMSE equalization and residual inter-symbol interference cancellation(RISIC)on the received data.Then,the algorithm selects the target data for MMSE equalization and interference cancellation based on the ordered successive interference cancellation(OSIC).The proposed algorithm eliminates the interference caused by multiple factors through calculation,which can effectively track the changes of receive data and significantly improve the equalization effect.The simulation results show that,compared with the traditional equalization algorithm,the designed equalization algorithm can effectively decrease the bit error ratio under a high signal to noise ratio.