Research On Relay Strategy In Physical Layer Security Of Wireless Network

With the development of mobile communication networks,limited spectrum resources have become the main reason restricting the performance of cellular networks.Device-to-device(D2D)communication is based on cellular networks and it can share spectrum resources with cellular users.It can be used to increase the utilization spectrum in the network.It will become one of the key technologies in 5G communication in the future.Because mobile devices generally have small battery capacity and poor computing performance,physical layer security has received increasing attention as an alternative to traditional encryption methods.This paper first focuses on improving the overall quality and efficiency of the cellular base station area.The main purpose is to reduce the power consumption of the D2 D user nodes while ensuring the physical channel security of the cellular user nodes.In order to meet these two requirements,this research uses D2 D user nodes as relay nodes or jammer nodes to assist cellular user nodes to prevent eavesdropping.Due to the mobility of the nodes in the D2 D network and the instability of the network structure,the pairing of DUE and CUE is likely to change,which leads to more communications and calculations between nodes.If these are handled by the base station,it will undoubtedly increase the burden on the BS.In this paper,a distributed algorithm is proposed to distribute the calculation to each node in the network.Optimize the efficiency of the entire D2 D network by maximizing the physical layer security of cellular users and minimizing the power consumption of D2 D users.Each network node uses a distributed algorithm to divide the global optimization problem into multiple simple sub-problems,which reduces the burden on the base station and is more suitable for the instability of the D2 D network structure.The second half of this paper focuses on introducing the concept of social networks to improve the physical layer security of D2 D networks.The paper transforms the social relationship between nodes into a trust relationship.The node who is communicating can use free trusted D2 D users as jammers to improve the physical layer security of D2 D network.A trust update mechanism is used to encourage free D2 D nodes to participate in the communication of D2 D nodes that need to send information as jammers.If a free D2 D node chooses to work as a jammer,it will sacrifice its own power and communication opportunities.But the trust update mechanism will compensate for the jamming action of node,it will increase the probability that the node will get assistance from other nodes during the next communication.Paper uses game theory to model the system,and finally get the jamming decision of D2 D nodes to improve the security of the physical layer of the system.