Design And Implementation Of Dual-polarized Single-carrier High-order QAM Communication Reception System

In the context of point-to-point single-carrier communication,high-order QAM modulation and polarization waveform multiplexing techniques show good prospects for application in order to carry out higher-capacity communication with limited frequency band resources.The higher the order of QAM modulation,the higher the frequency band utilization;while the polarization wave multiplexing technology enables two signals to be transmitted by orthogonal polarization,which can double the spectrum utilization.This thesis focuses on the implementation of dual-polarized high-order QAM in the context of single-carrier wireless communication.The design of the transmitter and receiver sides of the communication scheme is completed,the algorithm design,simulation and implementation of each baseband module are completed,and the system is tested in detail.The specific research work is as follows:First,the system transmission scheme is discussed and studied,the transmission signal is grouped and framed,and the system structure is determined.To verify the feasibility of the algorithm and system scheme,simulations are built under MATLAB,and detailed designs are carried out mainly for the three baseband modules(timing synchronization module,carrier frequency bias phase bias estimation module,and channel equalization module)at the receiver side.Meanwhile,the least-squares problem in the implementation of the channel equalization module is studied,and the Cholesky decomposition scheme is chosen to reduce the complexity of the operation by using the properties of the Hermitian matrix.Then,the baseband algorithm is implemented in Verilog language in a fixed-point manner according to the modular design principle,and the code writing and functional simulation are done in ISE and Model Sim respectively,and the functional implementation and resource consumption are analyzed.Finally,GNU Radio+USRP software radio platform is used to realize the RF part of signal transceiving and transmitting,and on this basis,the system testing work is completed.The final test results show that the system can function in the actual wireless communication process with dual polarization and high-order QAM modulation,and the EVM reaches about 3% with two 256 QAM modulations,which can accomplish the communication reception task well.