Performance Analysis And Energy Efficiency Optimization Of D2D-aided Cellular Networks

Device-to-Device(D2D)communication is one of the key technologies in the 5th generation mobile networks.By allowing D2D users(DUs)to reuse the spectrum resources of cellular users(CUs),it can effectively alleviate the current increasing shortage of spectrum resources.Though,unreasonable resource allocation in the D2D cellular networks will cause serious interferences and reduce system performance.In order to solve this problem,this thesis uses stochastic geometric to model D2D-aided cellular networks,conducts a comprehensive performance analysis of the system,and uses the deduced results to optimize the energy efficiency of the networks.In addition,for further improving energy efficiency,this thesis considers the scenario of D2D energy harvesting cellular networks,and designs a reasonably distributed resource allocation algorithm.Firstly,this thesis uses appropriate stochastic geometric tools to model and analyze mutual interferences to evaluate network performance.Specifically,considering the repulsion between the positions of CUs and DUs,the positions of CUs and DUs are modeled as a Poisson point process(PPP)and a Poisson hole process(PHP),respectively.In this thesis,two methods are adopted to obtain approximate expressions for the coverage probabilities of CUs and DUs,and these expressions have been verified by simulations.In addition,this thesis uses the second method to derive the approximate expression of the user ergodic data rates and the sum data rate of networks.The impacts of the key parameters(user density,power,and repulsion radius,etc.)on the system performance are analyzed.Based on the obtained expressions,this thesis provides a description and numerical simulation on the energy efficiency optimization problem of the networks.Secondly,in order to further improve the energy efficiency of D2D-aided cellular networks,this thesis equips D2D devices with energy harvesting capabilities.Considering the energy limitation of D2D devices and the serious interferences caused by unreasonable resource allocation,this thesis proposes a distributed resource allocation scheme based on stochastic learning and Stackelberg model.On the basis of protecting the quality of service of CUs,this scheme optimizes the spectrum and energy harvesting time slot allocation of DUs.The spectrum efficiency of D2D-aided cellular networks is also improved.Based on the proposed scheme,this thesis conducts simulation experiments and compares them with other algorithms.Simulation results validate that the proposed scheme achieves an advanced performance relatively.In this thesis,for D2D-aided cellular networks,the performance analysis and energy efficiency optimization based on PPP-PHP hybrid model are studied.The corresponding distributed resource allocation scheme is designed and implemented.The proposed model and scheme are applicable to D2D-aided cellular networks and provide a reference value for network designers.