Resource Allocation Of Multi-hop D2D Cellular Networks And Physical Layer Security In Finite Area

Recently,with the development of communication technology and the popularity of mobile terminals,the existing communication network architecture has been unable to satisfy the needs of users.In order to improve the network performance and enhance the users' experience,the fifth generation of mobile communication technology has become the focus of global mobile communications research and technical competition.Device-to-device(D2D)communication has attracted the attentions of experts and scholars because of its improved spectral efficiency of cellular communication system,reduced terminal transmission power and improved system capacity.However,most existing works focused on underlay mode which means cellular links and D2 D links share the same spectrum resources.Secondly,they considered only one hop transmission in the cellular network.Therefore,this paper presents a framework based on stochastic geometry for D2 D multi-channel overlaying downlink cellular networks.In this framework,we assume D2 D users,cellular users and base stations(BS)are spatially distributed according to three different Poisson point process(PPP).Cellular users communicate with BSs in one hop and D2 D users communicate with BSs in two hops.The spectrum resources are partitioned into two disjoint subsets of channels,one subset is for D2 D links and the other is for cellular links.Based on this framework,we drive the theoretical results of coverage probability and average rate in the cellular networks.Then we compare the theoretical results and simulation results and show that our stochastic geometry based framework can be used to accurately characterize the interference behavior of the network.Finally,we utilize different parameter settings to analyze network performance and determine the optimal resource allocation to achieve the best network performance.On the basis of the research on the downlink network,we further study the D2 D multi-channel uplink multi-hop network.Similarly,the cellular transmitters transmit data to BSs in one hop and D2 D transmitters transmit data in two hops,but there exists power control during transmissions.Based on this framework,we drive the theoretical results of coverage probability and average rate in the cellular networks.Then we compare the theoretical results and simulation results and reveal that our framework can be used toaccurately characterize the interference behavior of the network.Finally,we analyze network performance with different parameter settings and determine the optimal channel allocation to achieve the best network performance.Consider that the existing literature only analyzed the infinite area of transmission security,this paper proposes a finite-area wireless network composing of a D2 D transmitter,a D2 D receiver and several eavesdroppers.Then,we analyzes the physical layer security of D2 D communications in finite-area wireless networks.We model the locations of eavesdroppers by realization of PPP.The D2 D transmitter located at the center of the finite region wants to transmit confidential data to a D2 D receiver in the presence of the eavesdroppers.The D2 D receiver is not restricted and can be located anywhere inside the region.Based on this framework,we present the theoretical results of probabilistic characteristics for the achievable secrecy rates and average secrecy rates in both disk regions and regular convex polygon regions,respectively.Then we compare the theoretical results and simulation results and prove that our stochastic geometry based framework can be used to accurately characterize the secrecy of the network.Finally,we utilize different parameter settings to analyze secrecy performance and give insights for network designers on how to achieve good secrecy performance in finite-area networks.