Design And Implementation Of Power Domain NOMA Downlink Based On Software Radio Platform

Non-orthogonal multiple access(NOMA)technology has proposed since the rapid development of wireless network and the explosive growth of mobile data services.NOMA offer multiple users the same tramsmission resources,so NOMA provides higher spectrum utilization and wireless communication system capacity than orthogonal multiple access.Conventional NOMA communication system usually adopt orthogonal frequency division multiplexing(OFDM)technology as the multi-carriers modulation scheme.OFDM must apply cyclic prefix as symbol guard interval to tackle with multipath interference,but at the cost of transmission rate reduction.Also,OFDM has the defect of high peak-to-average power ratio(PAPR).To solve these two problems,scholars applied multiwavelet transform in NOMA system.This thesis majors in implementing a powerdomain NOMA downlink by software-defined radio(SDR)technology,and adopting multiwavelet packet modulation scheme into the downlink.In this thesis,wireless communication downlink is set as deployment scenario and NOMA technology,multiwavelet theory are studied.Pratical SDR platform based powerdomain NOMA and MW-NOMA downlink system is proposed and implemented,and these two downlinks performance are tested.The specific research work are as follows.The principles of NOMA,OFDM carrier modulation and multiwavelet carrier modulation are studied,among which several key issues such as power-domain superposition technology,successive interference cancellation(SIC)technology,OFDM,multiwavelet theory and Mallat algorithm,are expounded in detail.Referring to the communication quality,signal frame organization,Schmidl?Cox synchronization and channel equalization are also taken into account.Researching on SDR technology,including the SDR hardware platform USRP and its software development kit GNURadio.Above-mentioned principles and theories are implemented in the form of python or C++ code,integrated into the GNURadio software framework to implement NOMA and MW-NOMA software links,and drive USRP to implement the physical downlink.Implemented works are tested,and compared to peer studies.Core indicators are bit error rate(BER)and,PAPR,the optimization indicator of multiwavelet packet carrier modulation.Since there is no previous implementation study of MW-NOMA links and no statistical tool in GNURadio to measure PAPR,the test and analysis of PAPR is mainly carried out in Matlab.However,in order to ensure the feasibility of implementation,the Matlab link in this thesis apply all technical items of the physical link,such as pilots and subcarrier allocation,signal synchronization and equalization links,etc.