Research On Optimization Of Mobile Edge Computing System Based On Non-orthogonal Multiple Access And Wireless Cooperative Rela

Under the promotion of the next generation of network technologies,users are able to access diverse services,but many applications also impose significant computational pressure on user devices.Mobile Edge Computing(MEC)plays an increasingly important role in the era of the Internet of Things(Io T)and is one of the key technologies in 5G.It can help users offload computational tasks through computation offloading,fully utilizing idle computing resources to reduce and transfer computational pressure,effectively addressing the challenges faced by users in computation-intensive applications.Non-Orthogonal Multiple Access(NOMA)is a new type of wireless networking technology that combines cognitive radio and spread spectrum communication technologies.This system can fully utilize existing resources while maintaining high user capacity,reduce the requirements for channel quality in wireless transmission,and improve system reliability and scalability,making it widely applicable.Cooperative relaying technology can effectively extend communication range and improve interruption performance by deploying relay nodes in wireless networks,saving data transmission energy and improving communication performance.The combination of NOMA and cooperative relaying technology can fully leverage the advantages of both technologies applied in communication networks,further improving the effectiveness and reliability of information transmission in communication systems.Reconfigurable Intelligent Surface(RIS)technology is a newly proposed wireless communication technology in recent years,which can effectively improve the spectrum efficiency of wireless communication by adjusting the phase shift of passive elements to enhance the received signal power of wireless receivers.In this thesis,we conducted in-depth research on a mobile edge computing system that combines NOMA,cooperative relaying,and RIS technologies,focusing on system modeling,protocol design,problem modeling,problem solving,and system performance simulation.First,we studied a collaborative edge computing system with multi-carrier NOMA combined with cooperative relaying technology.In this system,in order to improve the performance of the MEC system,a new protocol was proposed that can fully utilize the high spectrum efficiency of multi-carrier and NOMA technologies for task offloading.Under the new protocol,with the objective of minimizing the energy consumption of user terminals and cooperative nodes,considering the task execution delay constraints of user terminals and cooperative nodes,the resource allocation optimization problem of the MEC system was formulated.Then,by using algebraic transformation,big-M method,layered optimization,successive convex approximation(SCA)technique,and golden section method,the formulated optimization problem was solved,and an efficient system optimization algorithm was proposed.Second,we studied a cooperative edge computing system assisted by Reconfigurable Intelligent Surface that combines NOMA,cooperative relaying,and RIS technologies.In this system,RIS technology was introduced to improve the signal transmission environment,and a new protocol was proposed where the high spectrum efficiency provided by multi-carrier and NOMA technologies was fully utilized in task offloading.In order to minimize the energy consumption of users and relays under task delay constraints,the resource allocation in the MEC system was optimized,including RIS passive array reflection coefficients,subcarrier and power allocation,offloading and computation time allocation,and task partitioning,under the proposed protocol.The resource allocation problem was solved by techniques such as alternating optimization,and an effective task offloading and computation optimization algorithm was proposed.Finally,simulation results show that the joint offloading and computation approach proposed in the MEC system combining NOMA and cooperative relaying outperforms existing single-scheme and other benchmark schemes in terms of system performance,including energy consumption,task execution delay,and system throughput.The proposed algorithms demonstrate their effectiveness in improving the performance of the mobile edge computing system with the integration of NOMA,cooperative relaying,and RIS technologies.