Optimization And Analysis Of Wireless Resources Based On NOMA

The development of cellular networks is changing with each passing day.On the one hand,new types of-mobile terminals are appearing explosively in the network,which leads to a growing number of long-term data users;on the other hand,the emer-gence of new types of machine-based devices in the Internet is in line with people's Internet of Things(IoT)era.The pursuit of a convenient and fast life has led to a grad-ual increase in requests for data with small and sudden bursts of access.These demands make the cellular network's limited spectrum resources more strained.In order to im-prove the resource utilization of the system,the cellular network needs Non-Orthogonal Multiple Access(NOMA)technology.In this way,in a single-cell uplink system,a base station can enable multiple users to reuse the same resource block at the cost of in-creasing demodulation complexity,and improve the multiplexing efficiency of a single resource block in the system.In order to prevent the growth of data in a single cell and the increase of equip-ment become the barriers to successful user access and reasonable resource utilization in the cell,this thesis studies the uplink single cell resource allocation method based on NOMA technology.The specific work and contribution points are described as follows:(1)Multi-Dimensional Constellation(MDC)Sparse Code Multiple Access(SCMA)modulation scheme is extended to a multi-slot dynamic scenario,and the capacity of dynamic SCMA system is optimized by resource allocation.The study first proposes a Fractional SCMA(FrSCMA)technique to find out the corresponding resource allo-cation results when the system using this technique has optimal capacity through con-vex optimization;then this result is applied to multi-slot scenarios.A dynamic SCMA system model was proposed and a multi-slot resource allocation method in a dynamic SCMA system was designed.The theoretical analysis and simulation results show that the dynamic SCMA system using FrSCMA technology can achieve a speed 10%higher and closer to the NOMA system than the MDC-SCMA system without increasing the demodulation complexity.(2)A random access method based on user's transmission rate demand packet-Rate Division Multiple Access(RDMA)is proposed,and an iterative optimization scheme is designed to divide suitable rate boundaries of groups and reasonable number of re-source blocks.With RDMA,the base station can group all activated terminals at the knowledge of only the probability density distribution of the transmission rates of the machine type communication terminals,and thereafter allocate a reasonable number of resource blocks in each group.After the allocation is completed,each terminal will access the corresponding group according to the rate limit of each packet received,and randomly occupy the resource block to send data within the group.Theoretical analysis and simulations show that RDMA can reduce the access blocking probability of termi-nals in Massive Machine Type Communication(mMTC)using only a small amount of signaling overhead,and 20%more users can access than system successfully.The resource allocation scheme in the NOMA system proposed in this thesis can effectively improve the reuse efficiency of resource blocks in the communication sys-tem.It is of great significance to the application of resource allocation in the NOMA system.