Design And Implementation Of Baseband Algorithm For Dual-polarized Single-carrier High-order QAM Communication

Nowadays,as one of the pillar industries of our country,the information industry is developing rapidly.In particular,the advent of 5G Communications,the 4G era of100Mb/s data rate to the extent of 1GMb/s,to people’s social life has brought great changes.In order to meet the needs of end-to-end communication for larger data capacity and higher spectrum utilization,the research on the more efficient and stable modulation and demodulation method-single-carrier high-order QAM modulation and more diverse multiplexing technology-dual-polarization multiplexing is carried out,become one of the research directions in the field of communication.In this thesis mainly studies the design and implementation of baseband algorithm based on dual-polarization multiplexing and high-order QAM modulation:Firstly,the theoretical basis of symbol synchronization algorithm is studied,and the algorithm is constructed under the condition of 1024QAM modulation and dual-polarization multiplexing.In view of the different simulation models,this thesis presents the principle design of the algorithm and the simulation results,which prove that the algorithm can still complete the sampling time correction and eliminate the small phase offset between the symbols under the condition of 1024QAM modulation and dual-polarization multiplexing,get the convergent constellation map,its EVM is around 1.7%.After the Gardner algorithm written by Verilog is simulated and verified at board level.It is proved that the algorithm can realize bit synchronization of data and get convergent constellation graph,whose value is around 2.44%.Then,the dual-polarization interference cancellation method is studied,under the condition of 1024QAM modulation and dual-polarization multiplexing,the algorithm is constructed,and the simulation model in MATLAB environment is built to verify the feasibility of the algorithm and various performance indicators.In view of the different simulation environment,the principle design and simulation results of the algorithm are given,and it is proved that the algorithm can eliminate the polarization interference and get the convergent constellation diagram under the condition of 1024QAM modulation and dual-polarization multiplexing,the EVM is around 1.8%.Finally,the VC707 Development Board of Xilinx Company,low cost AD9361 card of Adi Company and 0C20-2S58DV high performance crystal oscillator are used to build the hardware verification platform.This thesis designs and realizes each module of the transmitter,designs the scheme of algorithm platform,and gives the scheme of register configuration of AD9361.On the basis of hardware debugging,the single-carrier dual-polarization high-order QAM transmission system was tested,and the feasibility of frame header lookup,Carrier wave synchronization,bit synchronization and XPIC algorithm was verified,finally,the convergent constellations can be obtained.The EVM of 1024QAM is about 3.34%in wireless channel,and that of256QAM is 4.5842%in dual-polarized channel.Then combined with the work of others in the project team,the bit error rate of V route and H route can achieve less than a level of 10^-4.