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Design And Implementation Of Continuous Phase Modulation Low Complexity Demodulation Based On USRP RIO Platform

Posted on:2020-04-04Degree:MasterType:Thesis
Country:ChinaCandidate:S W ShenFull Text:PDF
GTID:2428330590983072Subject:Electronics and Communications Engineering
Abstract/Summary:PDF Full Text Request
“Heaven and Earth Integrated Information Network” is one of the 2030 major projects of national science and technology innovation that was first launched for national strategic needs.In the Heaven and Earth Integrated Information Network,radars and satellites require high-power outputs,and their power amplifiers typically operate near saturation points.Continuous Phase Modulation(CPM)has the advantages of being insensitive to the nonlinearity of the power amplifier and high spectrum utilization,and has obvious advantages in radar and satellite communication.Since the number of CPM signal states increases rapidly with the increase of hexadecimal number and memory length,the demodulation complexity of CPM signal is high.In this paper,from the perspective of reducing the number of CPM signal states,a suboptimal detection algorithm based on Laurent decomposition is proposed,solve the problem of high complexity.Firstly,this paper introduces CPM signal model,grid state,modulation method and traditional demodulation method Maximum Likeli Sequence Detection(MLSD),based on CPM signal model,BER performance analysis and MLSD demodulation Simulation under the algorithm.MLSD is the best demodulation of CPM,but its complexity and calculation will increase greatly with the increase of the hexadecimal and memory length of CPM signal.It will make the implementation of CPM system more difficult,affecting the application and development of CPM in engineering implementation.Then,for the problem that the MLSD algorithm has high complexity and large computational complexity,the Laurent decomposition is applied to the MLSD to reduce the demodulation complexity.The Laurent decomposition can decompose the CPM signal into a linear superposition of a finite number of Pulse Amplitude Modulated(PAM)signals.When Laurent decomposition and MLSD are combined,it can be divided into optimal detection and suboptimal detection according to the difference in the number of selected PAM signals.The optimization detection is that all PAM signals of Laurent decomposition result in demodulation.The suboptimal detection discards the PAM signal with low energy ratio,retaining only a few PAM signals occupying most of the energy and using it to replace CPM signals.demodulation.By comparing the receiver complexity,computational complexity and bit error rate performance of the two schemes,the suboptimal detection is selected as the demodulation scheme of this paper.The simulation results show that the proposed method can greatly reduce the complexity of CPM signal demodulation under the condition that the bit error rate performance is extremely smal.Finally,in order to verify the effect of suboptimal detection in engineering implementation,this paper builds a CPM signal demodulation system on the Universal Software Radio Periphera Reconfigurable I/O(USRP RIO)platform,and implements MLSD and Optimize the detection of two algorithms.The two algorithms were tested and compared.The test results show that the suboptimal detection has the above advantages and is feasible.Based on MLSD algorithm and Laurent decomposition,this paper proposes suboptimal detection of CPM demodulation,completes its theoretical simulation and implements it on USRP RIO platform.This paper solves the problem of high complexity of CPM signal demodulation and contributes to the development of CPM engineering.
Keywords/Search Tags:Continuous Phase Modulation, Maximum Likelihood Sequence Detection, Laurent Decomposition, Pulse Amplitude Modulated, Universal Software Radio Periphera Reconfigurable I/O
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