Research On Pilot-aided Channel Estimation In MIMO-FBMC System

Filter Bank Multi-Carrier(FBMC)technology is considered to be a candidate to replace Orthogonal Frequency Division Multiplexing(OFDM)as the transmission technology in 5G because of its low out-of-band leakage and high spectrum utilization.Due to the inherent interference,the channel estimation technique in the OFDM cannot be applied to FBMC system directly.This thesis focuses on the channel estimation technique in FBMC system.In order to eliminate the effect of imaginary interference on channel estimation,the preamble-based and scattered pilots are studied firstly.We analyze the Interference Approximation Method(IAM)of preamble-based pilot,and the Modified Interference Approximation Method(MIAM)and the Auxiliary Pilot(AP)method of the scattered pilots.Next,the FBMC and Multiple-Input Multiple-Output(MIMO)technology are combined to construct MIMO-FBMC spatial multiplexing system.Then,we extend the IAM method to MIMO-FBMC system,and propose an improved method to improve spectrum utilization.The improved method reduces the number of zero pilots and avoids inter-antenna interference by alternately transmitting pilots on odd-even subcarriers.The simulation results show that the improved method proposed in this paper improves the spectral efficiency under the guarantee of performance.Since preamble-based pilots are not applicable in fast fading channels,the MIAM and AP methods are extended to the MIMO-FBMC system by referring to the design method of scattered pilots in MIMO-OFDM systems,and the feasibility is verified by simulation.The fifth chapter focus on the channel estimation algorithm in FBMC system.Aiming to eliminate the noise which conventional DFT-based algorithm do not eliminate,two improved algorithms are proposed:DFT-based channel estimation with threshold and adaptive optimal CIR length.These two improved methods improve system performance by further eliminating interference from noise sampling points.The simulation results show that the performance of the two improved algorithms proposed in this paper is superior to the conventional algorithm.In this thesis,the pilot-aided channel estimation technique in FBMC system is studied systematically.We focus on the pilot design schemes and channel estimation algorithms for FBMC systems and propose a variety of method.The research results of this paper provide theoretical support for the practical application of FBMC technology.