Constellation Shaping And Implementation Of 64QAM-OFDM System

As human society gradually enters the information society,people's demand for more efficient information transmission methods and faster information transmission rates has increased significantly.The 5G standards and industrial processes have entered a substantive acceleration stage.With 5G as a continuation of 4G,its core technology still focuses on OFDM technology.OFDM technology is widely used by researchers because of its high spectrum efficiency,excellent anti-narrow-band interference and multi-path fading ability.Its sensitivity to frequency offset and its high peak-to-average power ratio have brought about the application of OFDM technology.resistance.At present,the research verification of OFDM systems in universities at home and abroad mostly stays at the level of Matlab simulation.Few experimenters use real wireless communication platforms to perform transmission tests and algorithm verification in real scenarios.Therefore,it is of great significance to build an effective and reliable communication system by using the software radio experimental platform and test and verify the improved algorithm in the actual environment.This thesis firstly introduces the software radio experimental platform USRP equipment and software tool LabVIEW,and introduces the basic content of OFDM technology.Then,the basic concept of OFDM technology is analyzed,and the OFDM signal model is deduced.Based on USRP hardware platform and LabVIEW software tools,a complete system including guard interval filling,carrier synchronization and symbol timing synchronization,channel estimation and pilot filling module is implemented.The transceiver program of the OFDM wireless communication system was tested in a laboratory indoor environment to verify its feasibility.Finally,the traditional 64-QAM constellation map has a higher peak-to-average ratio,and a new constellation layout is proposed by this article.Under the premise of still satisfying the gray coding rule,the peakto-average ratio of the system is reduced from 3.68 dB to 2.50 dB.The constellation mapping is implemented on the OFDM wireless communication platform designed in this paper.The communication test is also completed in the indoor laboratory environment.The experimental results show that the OFDM wireless communication platform built in this paper can achieve the modulation and demodulation of wireless communication in a real and effective manner.The designed improved 64-QAM constellation scheme can also be successfully implemented,which fully proves the feasibility of the improved scheme designed in this paper and the reliability of the OFDM wireless communication system.