Research On Spectrum Resource Allocation Scheme Based On Minimized Interference In SCMA System Uplink

Sparse Code Multiple Access(SCMA)technology is proposed by Huawei.It is a new air interface core technology for the second and fifth generation mobile communication networks.It adds a sparse coding comparison table to improve the efficiency of wireless spectrum resource utilization by implementing multiple-access multiple users in the code domain.A SCMA uplink-based spectrum resource allocation method is designed in this paper,which mainly solves the problems of the existing technical solutions,such as the serious interference caused by the reuse of spectrum resources by communication users,and the low utilization of spectrum resources and the low system and rate.This method satisfies SCMA uplink user transmission rate Qo S requirements,and designs a spectrum resource allocation method that minimizes the user 's interference signal on subcarrier K.By using a unique user codebook allocation method,And the Shannon limit not only guarantees that the user service reaches the maximum transmission rate,but also can optimize the system's throughput.The SCMA user codebook allocation scheme based on the interference information of other users received by users in the subcarriers proposed in this paper is implemented simply by listing the interference of other users received by all users in each subcarrier in turn.And select the subcarrier with the least interference for transmission.In the study of SCMA user codebooks,two design methods are mainly used,namely the factor graph matrix design method and the multi-dimensional constellation graph design method.First,the factor graph matrix is used to obtain the sparse spreading matrix,and then the sparse spread Frequency matrix to determine the structure of the codeword.Then use the multi-dimensional constellation diagram to optimize the codebook,so that the channel can get better shaping gain.Then based on the obtained SCMA uplink system and rate and SCMA user codebook allocation scheme based on minimizing interference,a throughput optimized spectrum resource allocation method that meets Qo S requirements is proposed.In the process of studying the maximum throughput,a special mapping relationship is needed.This special mapping relationship is the mapping relationship between the Qo S requirements and the spectrum bandwidth of the SCMA uplink base station.First of all,we need to use the analog method to compare the subcarrier channel as a multiple access channel,and further use the Shannon formula to find the SCMA uplink and rate.In the proposed sum rate formula,the Qo S requirements and spectrum bandwidth are included.Transform the obtained user and rate expressions,and transform them into Qo S requirement expressions on both sides of the equation and the spectrum bandwidth expressions of the subcarriers,and then the mapping relationship of the spectrum bandwidth can be obtained.The optimization function is constructed by taking SCMA uplink throughput maximization as the objective function.In this way,the optimal throughput of SCMA uplink can be obtained on the basis of achieving Qo S.