Non-orthogonal Based Study Of Cognitive Radio Technology

Nowadays,the pace of development of the communications industry becomes accelerating.Requirements of data rate and response speed of wireless communications are getting higher and higher under the impetus given by multimedia services.The 5th generation of telecom system presents a challenge for spectrum resources and the way to assecc network.As for the frequency spectrum,cognitive radio has been studied in recent years to expand more resources.The latest issues focus on the interference caused by cognitive users to licensed users.Low sidelobe characteristic of non-orthogonal multiple access technology is precisely to solve this problem.Thus,the combination of the two technologies must have an important impact on the field of commercial communications.This paper firstly introduced TV white space and the development status of cognitive radio.Then turn to the principles of three non-orthogonal multicarrier,including the process schemes,modulations,symbol maping and the design of prototype filter.And analysis of advantages and disadvantages of the waveforms.Then explore the performance on Hardware-in-the-Loop Simulation platform.Analyze the different waveforms interference to existing commercial systems such as DVB-T and LTE,and get the results of the electromagnetic compatibility characteristics of different signals.During the simulation,this paper compared the bit error rate performance under different interfering waveforms and concluded that non-orthogonal multicarrier cause less interference to primary users.Based on these verifications,this paper proposed a new spectrum sharing strategy in the base station level.Further study of FBMC performance under different channels are carried out,including fading channels and carrier frequency offset.Two approached named extended-FFT and PPN-FFT are compared under CFO interonment.And LDPC coding is applied for FBMC system to improve its perpromance.After analysis of the results,this paper concluded that FBMC is more suitable for transmission in fading channels and more suitable for deployment in the Internet of Things network.