Research And Implemention On High-order Modulation And Demodulation In Millimeter-wave Single-carrier Wireless Communication System

Because of the gradual expand of wireless communication technologies,people are increasingly demanding the communication speed and communication quality.Millimeter-wave communication has the advantages of large capacity,high integration,and strong anti-interference ability,so it has a wide range of application scenarios in the future.Using it's rich bandwidth in the millimeter-wave band,high-order modulation can greatly increase the communication speeds.However,due to the propagation characteristics of the millimeter-wave band and the non-ideal characteristics of the RF,it will face a lot of problems and challenges when comes to implementation.For example,the problem of channel distortion must be considered.And the high-order modulation is very sensitive to the phase noise,so it must be processed.Focused on these two problems,this thesis mainly studies the algorithm of equalization and phase noise compensation to the millimeter-wave high-order modulation and demodulation system.The specific research work in this thesis is as follows:Firstly,the algorithms in QAM receiver including equalization and phase noise compensation have been studied.Because of the ISI caused by multipath effect,this thesis compares the difference between the frequency domain equalization and the time domain equalization and then simulates the performance of the two equalizers.Since the MMSE equalizer has better performance,the frequency domain MMSE equalizer is adopted.Then the influence of phase noise on the system is analyzed.In order to process the phase noise,two kinds of algorithms are proposed.One is based on the radius optimization,the other is based on the Gray sequence.Secondly,according to the algorithm studied in this thesis,the circuit design of the system baseband and simulation are implemented.At the transmitting end,this thesis designs and implements 64 QAM signal modulation with a bandwidth of 1GHz.At the receiving end,equalization module and phase noise compensation module are designed.In the equalization module,a 1024-point FFT processor is designed for the length of the data block,which has a high processing speed.In the phase noise compensation module,an eight parallel correlator is designed to implement phase noise compensation algorithm based on Gray sequence.Finally,a millimeter-wave communication system is set up in this thesis.And some of the important parameters like phase noise,modulation mode and bandwidth of the system are tested.The result of the test verifies the correctness of the transmitter,and the relevant data sets the foundation for the implemention of the receiver.