| Currently,The 5th Generation Mobile Communication Technology(5G)system is based on time division or frequency division duplex mode,which has the problem of insufficient spectrum utilization and can not meet the service requirements of 5G in different scenarios.So flexible duplex in 5G millimeter-wave wave communication scenarios has been widely studied.In view of the problem of adjacent channel interference existing in flexible duplex uplink and downlink signals,this thesis studies a adjacent channel interference cancellation algorithm in 5G millimeter wave flexible duplex mode,and carries out theoretical analysis and experimental verification.The main contributions are as follows:Firstly,The existing neighbor interference cancellation algorithms are investigated.The generation mechanism of adjacent channel interference is described,and the cancellation methods of adjacent channel interference are classified and analyzed,which provides theoretical reference for the algorithm of adjacent channel interference cancellation in flexible duplex mode.Secondly,an adjacent channel interference suppression algorithm based on Volterra series joint estimation of power amplifier nonlinear coefficients and wireless multipath channel is studied.A time synchronization method is designed to deal with the time synchronization error of integer order and decimal order.The theoretical performance of the adjacent channel interference cancellation algorithm is analyzed and the influence of time error on the interference cancellation performance is studied.And this thesis propose a optimization model of simplification.Simulink simulation results shows that for the adjacent channel interference signal within 100 MHz bandwidth,the adjacent channel interference cancellation algorithm can achieve the suppression ability of 5?13 d B,making the suppressed signal reach the noise level.Thirdly,the FPGA design and performance test of adjacent channel interference cancellation algorithm are completed.The overall structure of 5G millimeter-wave flexible duplex platform is established;The FPGA implementation module of adjacent channel interference suppression algorithm is designed,and the internal structure and workflow of the module are described.The hardware platform of 5G millimeter wave flexible duplex communication is built,and the adjacent channel interference cancellation performance is actually tested on it.The results shows that the noise level can be suppressed by the presence of adjacent channel interference with INR of 1?6 d B.However,the cancellation ability of adjacent channel interference with INR above 6 d B is limited.The reason is that the algorithm model is selected based on FPGA resources and complexity considerations,so the model can not accurately estimate the nonlinear power amplifier.This thesis focus on the research of adjacent channel interference cancellation algorithm in 5G millimeter wave flexible duplex mode,and its results can provide theoretical basis and engineering reference for the application of 5G millimeter wave flexible duplex communication and the development of subsequent products. |
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