Research On Key Technologies Of Energy Efficiency Optimization Based On NOMA In Heterogeneous Networks

The need of sustainable development of mobile Internet and Internet of things promotes the mobile network into 5G era.From the development of various emerging services,to the combined application of various spectrum network and the application of emerging technology supporting the key per-formance indicators,5G communication has become heterogeneous networks with heterogeneous spectrum resource,using a variety of emerging technolo-gies work together and supporting variety of business applications.As NOMA can support multiple users to share a same radio resource,it can assist the het-erogeneous businesses to transmit data together with different requirements.How to design the common transmission strategy based on NOMA for hetero-geneous businesses,as well as the performance evaluation of related system are the problems to be solved.Moreover,in order to deal with a surge of mass data terminals in Internet of things,NOMA can be applied to the networks with different spectrums or combined with other network technologies to realize the connection of massive devices and the promotion of SE for the network.At the same time,how to design the NOMA transmission strategy for different network modes,solve the interference from the combination and the loss of EE produced by the interference are needed to be solved.Therefore,this article will apply NOMA to the 5G and the next generation heterogeneous network.From the three views of business heterogeneity,spectrum heterogeneity and technol-ogy heterogeneity,this paper researches on the common transmission strategy,performance evaluation of the network and the optimization problem of EE for the networks with heterogeneous spectrums and technologies.Specific research contents and innovation of the main work are as follows(1)Research on the performance for NOMA based cellular network with the co-existence of M2M and H2H communication under different QoSFor heterogeneous network with the integration of various businesses,dif-ferent businesses have different requirements.The differences between M2M and H2H communication are the requirement of QoS and the packet size of transmission data.While NOMA can be used to solve the latter problem for their co-existence,how to set up the transmission mechanism and response the differences of QoS have not been well considered.This paper is aimed at the research of the co-existence for M2M and H2H communication in cel-lular network,especially for M2M communication with high sensitivity of de-lay.It firstly gives an uplink transmission scheme based on NOMA,then pro-poses a SIC scheme based on QoS,finally deduces the relationship between QoS and outage probability,effective capacity.It also gives the simulation re-sult of the relationship under minimum power.Compared with the traditional OMA schme,our proposed NOMA scheme not only assits the system to obtain a higher EC,but also further reduces the outage probability of the system.(2)Resource allocation in M2M enhanced HCN for EE maximization with NOMADifferent network models can improve the access probability of users and intelligent terminals.They also have the advantage to realize the scene of mas-sive connection.For example,for some intelligent terminals,they cannot con-nect to the cellular network directly and need the help of short distance trans-mission technology to connect to the cellular network.M2M communication based on non-cellular can do this.Then,the MU in the cellular network can be used as relays for these intelligent devices and assist them to realize data transmission.This operation would increase the power consumption of MU in the cellular network.Thus,the reasonable power control for MU in the cel-lular network is needed to ensure a high network EE.This paper considers an M2M enhanced HCN based on NOMA,where MUs are regarded as relays to MTCDs,and help them to connect to the cellular network.They both adopt the strategy of NOMA.EE maximization problem of MUs with user association and power control is formed according to the above strategy.In order to solve the problem,user association based on the matching theory and user power con-trol algorithm based on sequence optimization theory are proposed respectively.In addition,this paper also introduces an exhaustive search algorithm based on sequential optimization,compared which,our proposed algorithm not only has lower complexity,but also can be close to the global optimal solution of power control.(3)Power allocation in NOMA based HCN for EE and SE maximizationThe combination of HCN and NOMA extends their advantages,while it also brings a certain interference problem.Interference problem has already existed in HCN,including interference between different types of BS and in-terference between the same type of BS with spectrum reuse.For NOMA,the overlapping interference among users is used to decode the overlaid signals of users.How to deal with the combination of different interference problems is the primary problem for their combination.Some research shows that the resource allocation can effectively alleviate the interference problems,but the optimization goal of existing resource allocation is relatively simplistic.This paper considers the optimization of SE and EE with power allocation.Firstly,based on NOMA transmission mechanism,multi-objective problem is set up for a joint optimization of SE and EE.Then,according to weight optimization method,the multi-objective problem is transformed into a single objective op-timization problem.Finally,user allocation algorithm based on the correlation and difference of channels,power allocation algorithm based on DC program-ming and CCCP are proposed respectively to solve this problem.Compared with the original OFDMA mechanism and power allocation algorithm,under the same condition,our proposed NOMA transmission mode and power allo-cation algorithm can assist system to obtain higher SE and EE.