Design And Implementation Of An SDR-based Receiver For NOMA System

With the development of the society, the demand for new mobile telecommunications technology becomes higher and higher. As a result, the research for 5G is on the way after the 4G network is established.Non-orthogonal multiple access (NOMA) is one of the key radio access techniques of the physical layer for 5G,which can help improve spectral efficiency. However, in order to be tailored to verify the feasibility and efficiency of the communications technology, practical products had to sacrifice the efficiency and suffer from high cost before Software Defined Radio (SDR)was developed. With the feature of high flexibility and good reconfigurability,people only need to upgrade the software in the process of technology upgrading and the SDR system is considered as a potential technique, which is suitable for future mobile base station. Thus, design and implementation of an SDR-based receiver for NOMA system is of great importance.In the introduction part of the paper, the background and the state of the art of telecommunications technology are briefly introduced. In the second part,after summarizing the SDR technique, the GPP-based structure is selected for the NOMA system. Then OpenAirInterface (OAI) platform and USRP platform are presented.The third part shows the design and implementation of an SDR-based transceiver for NOMA system. Details of the implementation of the transmitter and the receiver are imposed in this part. The real-time over-the-air experiments are carried out to verify the NOMA technique.A multi-thread parallel processing method is proposed in the fourth part.With help of the design of decoding slot, processing procedure of one subframe becomes independent from each other. And ten threads are initiated for baseband signal processing, which helps increase the performance of the system.Experiments are conducted to show that the system is useful and helpful for validating new techniques of 5G.