Research On Non-orthogonal Multiple Access With Multiple Description Coding For Image Transmission Technology

With the rise of social networks,images become the important information carriers.Hence,people's requirement for image quality gradually improving,leading to amounts of data,so The Fifth-Generation(5G)communication arises at the historic moment.Due to the explosive growth of the amount of data,the limited spectrum resources are becoming more and more scarce,while the high-frequency resources have not yet been developed.Under this background,non-orthogonal multiple access technology(NOMA)is considered to be the most potential candidate technology in 5G communication because of its superior spectral efficiency.Although the emergence of NOMA technology has improved the system throughput,many problems(packet loss,error code,end-to-end delay,etc.)in the communication system have seriously affected the reliability of data transmission,so taking appropriate error control measures has become the key to ensure the quality of data communication.Multiple description coding(MDC)technology can not only achieve efficient data compression,but also significantly improve the reliability of data transmission.Based on the above analysis,this paper makes a joint research on non-orthogonal multiple access technology and multiple description coding technology.The main work and innovations are as follows:Firstly,a non-orthogonal multiple access image transmission system(MDC-NOMA)based on multiple description coding is proposed in this paper.In the system,under the premise that the base station is unknown to the instantaneous channel,the transmitter first carries out multiple description coding of the signal to form a plurality of descriptions of equal importance,and then allocates power for each description and carries out superimposed coding.Finally,the superimposed signal is sent to a plurality of users through the base station.In this scheme,the effects of channel conditions on outage probability and traversal rate are considered at the same time.Under the condition of Rayleigh fading channel,the closed-form expressions of outage probability and traversal rate of MDC-NOMA system are derived.The experimental resultsverify the correctness of the theory of the proposed scheme,and the superiority of the scheme is proved by comparison with the traditional scheme.Secondly,based on the correctness of MDC-NOMA system theory,the digital image transmission system of this scheme is built in this paper.In the system,the image is first encoded to form multiple descriptions,and then digitally modulated.According to the channel state information of the user,the modulated signal is allocated power and superimposed coding.Finally,the superimposed signal is modulated by orthogonal frequency fivision multiplexing(OFDM)and then transmitted into the Rayleigh fading channel.The experimental results show that the MDC-NOMA image transmission system can achieve better image reconstruction quality and significantly improve the visual experience of users.