Research On Channel Estimation In FBMC System

In the past three decades,mobile communications have experienced rapid development.From 1G to 4G,with the increasing access rate of mobile data networks,human society has rapidly entered the era of mobile Internet.With the deployment of 4G networks in the world,academic and industrial research on 5G is in full swing.In the face of new application scenarios such as low latency,high-bandwidth,and large-scale machine communications in 5G networks,traditional OFDM-based broadband mobile communication systems cannot meet new applications because of their low spectral efficiency and high out-of-band leakage.The academic community generally believes that the FBMC system is one of the key technologies that are expected to solve this problem.Therefore,the following research has been done in this thesis around the FBMC system:1.Firstly,a FBMC simulation model is constructed by Matlab based on the fast implementation method of FBMC system.Secondly,based on frequency sampling method and window function method,the FBMC system prototype filter is optimized,and the performance of the prototype filter is slightly better than PHYDYAS.Finally,the advantages of FBMC are compared with traditional CP-OFDM systems.2.The main channel estimation methods such as interference cancellation,interference utilization and interference avoidance in the SISO-FBMC system are studied.The influence of the protection neighborhood size on the interference cancellation method is studied.The effects of auxiliary pilot and multi-point auxiliary pilot methods on signal PAPR are studied.The complexity of the channel estimation based on multi-point auxiliary pilot scheme is reduced by reducing the neighborhood;the estimation performance of different interference approximation method is studied,and the outer iteration based on channel coding is introduced in the iterative-based interference approximation channel estimation to improve the performance of channel estimation is studied.The channel estimation performance of the pairs of real pilots scheme is studied.By using the transform domain method and the improved pilot structure,the channel estimation performance of the pairs of real pilots scheme is greatly improved.3.The MIMO system is briefly introduced.Combining with FBMC,the MIMO-FBMC system model and channel estimation principle are introduced in detail.Based on the system model,a MIMO-FBMC simulation system is built.The discrete pilot scheme based on the protection neighborhood is studied.The pilot assistant method is introduced into the discrete pilot estimation of MIMO-FBMC system by using a specially designed pilot pattern.The pilot occupancy is reduced and the system estimation performance is improved.The estimation performance of interference approximation method in MIMO-FBMC system is researched,and an interference approximation method to reduce pilot occupancy is studied.Further,an improved pilot method is proposed in this paper,which can not only reduce the spectrum resources occupied by pilots,but also decrease the complexity of the channel estimation,and the system's channel estimation performance is only slightly lower than the above-mentioned improvement scheme.