A Research On NOMA-based Uplink Video Transmission

In recent years,with the development of communication technology and the upgrading of user equipment,various video applications have emerged one after another,such as:Video Internet of Things,telemedicine,short video content creation,etc.This leads to the explosive growth of video data,and it is difficult for the limited wireless resources in the wireless network to meet the uplink transmission requirements of these video data.As one of the most promising wireless communication technologies,NonOrthogonal Multiple Access(NOMA)improves spectral efficiency through multiplexing in the power domain,and can provide higher throughput under limited wireless resources.throughput,which provides a feasible solution to this problem.Most of the existing NOMA-based solutions have been studied for data transmission in wireless networks.Although a few works have carried out research on NOMA-based video transmission,the research contents of these works focus on NOMA-based video distribution,broadcasting and other video downlink transmissions.The video uplink transmission based on NOMA still needs to be further studied.In the NOMA-based uplink communication process,multiple devices share radio resources to send signals to the base station through superposition coding.The base station,on the other hand,decodes the signals of each device sequentially through successive interference cancellation.In order to adapt to the changing wireless channel environment,the variable rate video stream through scalable video coding is a better choice than traditional video.This thesis uses NOMA technology to increase the available transmission rate of the device,and then uploads the highest possible video quality according to the available transmission rate of the device to achieve better average video quality.In NOMA-based video uplink transmission,multiple devices share wireless resources,which leads to inter-device interference becoming the primary challenge.On the other hand,what this thesis studies is the uplink transmission of video.Compared with general data transmission,the volume of video data is larger,and the video has certain structural characteristics.How to effectively use the device energy to achieve the best video quality is also a big challenge.Considering the above problems,this thesis is divided into two research points to study the video uplink transmission based on NOMA.(1)For the NOMA-based video uplink transmission system in which a single base station serves multiple devices,this thesis designs a discrete video quality model according to the characteristics of variable rate video.Then,the transmit power of all devices is uniformly controlled by the base station to achieve the highest average video quality while avoiding blindly increasing the transmit power when the device cannot effectively improve the video quality.This thesis models this process as a power control problem that maximizes average video quality.Considering the non-convexity of the problem,this thesis transforms the problem into a standard form of monotonic optimization problem based on its hidden monotonicity,and designs a power control algorithm based on the polyblock outer approximation.A series of simulation experiments verify the excellent performance of the video model and algorithm proposed in this thesis.(2)With the development of video applications,there are more and more video devices,and the distribution is more and more dense.This will require more base stations to serve these devices,so this thesis further studies video uplink transmission in multiple cells.In the video uplink transmission of multiple cells,inter-cell interference is an influencing factor that cannot be ignored.In addition,the device-base station association will also greatly affect the inter-cell interference and thus affect the power control of the device and the quality of the uploaded video.Considering the above factors comprehensively,NOMA-based video uplink transmission in multiple cells can be modeled as a mixed integer nonlinear programming problem.We decompose the problem into two parts to solve,namely the device-base station association problem and the power control problem.Then combined with coalition formation game and greedy algorithm to jointly optimize device-base station association and device transmit power.Finally,some simulation experiments designed in this thesis demonstrate the convergence and superiority of the proposed algorithm.