Selection Of Multiple Access Options And Resource Allocation Methods In 5G

In the next generation of wireless communications(5G),higher demands are placed on wireless communication technologies in terms of user experience rates,mass linkages,latency and reliability,which require academia and industry to explore a host of new key points technology to meet the expectations.In many key technology exploration,it is very important to design a new air interface technology to meet the requirements of 5G for massive links,etc,and Sparse Code Division Multiple Access(SCMA)technology is a typical example.The SCMA can set the number of subcarriers to access the system and the number of non-zero elements in the codebook according to the specific situation so as to realize the mass link of the system.However,SCMA requires more sophisticated multi-user detection algorithms than OFDMA(Orthogonal Frequency Division Multiple Access).Therefore,this dissertation firstly studies the SCMA and OFDMA technologies,then studies the resource allocation method based on game theory in the case of choosing SCMA.The specific work contents are as follows:First of all,according to the advantages and disadvantages of SCMA and OFDMA,a multiple access technology selection scheme is established by means of software-defined air interface concept.This scheme constructs a selection mechanism between SCMA and OFDMA.The selection mechanism is based on Energy Efficiency Function as a criterion for determining the switching of two types of multiple access technologies,the energy efficiency function is defined as the ratio of the system to the rate of power consumption.The higher the energy efficiency function,the less power the characterization system consumes and the higher rate of the system.2.In the selection of SCMA technology,since the codebook resources in the existing codebook allocation scheme are all randomly allocated,it is not considered that different codebooks are used to generate different interference noises in the communication channel.In this paper,we take full account of the diversity of codebook allocation,and propose a SCMA codebook and corresponding power allocation scheme based on game theory under the premise of limited codebook resources and power resources.In the proposed codebook allocation scheme,the minimum interference noise and the corresponding codebook are selected and allocated to the corresponding users to improve the system's rate.According to the simulation results,the proposed codebook allocation scheme can get better rate performance than the random codebook scheme,especially at low signal-to-noise ratio.3.According to the codebook distribution scheme mentioned in this paper,we continue to do a deep research on each user's power allocation method and propose a scheme based on game theory for each user.In the proposed power distribution scheme,the relevant system model is first established and the corresponding Nash equilibrium solution is obtained,which is the optimal solution of this optimization scheme.Then,the system's rate under the codebook allocation with the corresponding power allocation scheme based on the game theory and the common random codebook allocation with the power average allocation scheme are compared emphatically,and the system's rate of the proposed codebook allocation and power allocation scheme are performance better.