Joint Power-domain And Code-domain NOMA And Resource Allocation Scheme

In the face of the performance requirements of ultra-high speed,massive connection and ultralow time delay of the future mobile communication network,NOMA technology has attracted wide attention,as a strong candidate of the next generation of multiple access interface technology.Compared with the traditional OMA,NOMA allocates resources to users in a non-orthogonal way,so that different users can transmit information on the same time-frequency resource block,which greatly increases the network capacity and meets the needs of large-scale connection of users' devices.Firstly,the traditonal NOMA technology is introduced by this thesis.According to the different allocation methods,it is mainly divided into two schemes: PD-NOMA in power domain and SCMA in code domain.The feature of PD-NOMA is that users with different power levels share resource blocks,while SCMA achieves multi-user reuse through high-dimensional sparse code words.The basic concept of NOMA is introduced by this thesis,including transmitter model and encoder principle,receiver model and multi-user detection technology,as well as SCMA codebook design method.Secondly,the NOMA model of the joint power domain and code domain is proposed in this thesis.On the basis of the traditional Noma scheme,the hybrid NOMA combines the power difference of PD-NOMA and the codeword sparse of SCMA,so that users with different power levels can reuse SCMA codebook,further increasing the number of users and expanding the network capacity.At the transmitting end,users are divided into far and near user groups according to the channel gain strength,and the two groups reuse the same SCMA codebook for network access.At the receiving end,the joint detection of SIC and MPA is adopted.The two groups of signals are separated by SIC,and then the two groups of users are decoded by MPA respectively to realize multi-user detection.Finally,to solve the resource allocation problem of joint NOMA model,a codebook auction scheme and a power allocation scheme based on Stackelberg layered game are proposed.For the convenience of analysis,the resource allocation problem is decomposed into two sub-problems:codebook allocation and power allocation.To solve the problem of codebook allocation,a codebook auction scheme is considered based on the channel gain of users.Subcarriers are allocated to users with better channel gain in the way of auction,which not only considers the fairness of users,but also improves the system capacity.To solve the power allocation problem,a Stackelberg game model based on maximizing energy efficiency is considered in this thesis.According to the decoding requirements of the receiving end,the near-users form the leader subgame,and the far-users form the follower subgame.The two sides dynamically update and obtain the power allocation scheme that maximizes energy efficiency.