Efficient Resource Management Based On SEFDM Multiple Access System

Facing the scene of massive wireless terminal device connection for future wireless communication,and also in order to meet the needs of ultra-low latency and ultra-large throughput in the era of Mobile Internet of Things,SCMA technology,as an emerging resource reuse technology,has attracted widespread attention.Different from the orthogonal multiple access technology,the SCMA technology allows multiple users to use the same resource block at the same time by modulating the sparse spreading code sequence,which improves the capacity and spectrum efficiency of the system.The SEFDM system is a non-orthogonal multi-carrier modulation technology.The SCMA system based on SEFDM transmission further integrates the advantages of SEFDM's high spectrum efficiency and can well alleviate the pressure of spectrum resource shortage.This paper studies the SCMA system characteristics of SEFDM transmission,derives the expression of the system capacity through the knowledge of information theory,and then studies the problem of codebook allocation and power allocation from the perspective of maximizing the system capacity,and further optimizes the system performance.First of all,this subject face with the problem of spectrum resource shortage in the future mobile communication,and analyze the research background,purpose and significance,and then determines the research value of the SCMA-SEFDM communication system.Then from the transmitter side,the SCMA coding principle and process are explained,the form and generation method of SEFDM signal are studied,and the SCMA-SEFDM system implementation architecture is built.From the receiver side,the SEFDM demodulation module based on ID algorithm and the MPA algorithm for SCMA multi-user detection are studied,and then the performance simulation of ID algorithm and MPA algorithm is completed,and the simulation results are analyzed.Secondly,for a single-cell uplink system,the throughput of the system is deduced based on Shannon's information theory,and it is determined to be the target expression of the optimization problem,combined with several constraints on the codebook and power,a mixed integer nonlinear programming problem with non integer variables and integer variables is proposed.Through analysis,this complex problem is decomposed into two sub-problems: the heuristic search algorithm process of codebook allocation and the convex optimization process of power allocation.Through iterative optimization,a suboptimal solution for maximizing the system capacity is obtained.The simulation results show that the resource allocation scheme improves the system performance,and the impact of resource allocation results on the link performance of different users.Finally,the USRP hardware platform is built to realize the SCMA-SEFDM system after resource allocation,and the transceiver function of the actual system is realized according to the codebook allocated by users.By designing the digital up/down converters module of USRP,the actual signal is sent and received,and then the relevant parameters of USRP are configured in the host computer.After testing and correcting the frequency offset,the functions of SCMA high-dimensional codebook modulation and SEFDM multi carrier transmission are realized on USRP,and the demodulation and detection of the received signal are completed.The results show that the proposed resource allocation scheme based on SCMA-SEFDM can give full play to the advantages of efficient resource utilization of the double-non orthogonal system,and has a good application prospect in the future wireless communication.