| With the acceleration of the standardization and commercialization of China’s 5G communication system,the wireless communication field is developing at a high pace,high efficiency and diversification to meet people’s demands for high traffic density,high connection density and high mobility.This makes the secure transmission of wireless communication systems face extremely stern challenges.This paper mainly studies the security transmission strategy of the physical layer in untrusted relay network.The main research contents and research results are as follows:Through the research on physical layer security,injected AN signal is used at the source node in wireless communication.Harvesting energy for untrusted relay nodes to amplify and forward signals by using a power splitting scheme based on SWIPT.A MIMO two-way amplifying and forwarding untrusted relay network based on SWIPT is established,and the calculation formula of the secrecy rate under this model is derived.The multi swarm interaction particle swarm optimization(MSIPSO)algorithm based on particle swarm optimization is proposed for complex constraints in untrusted relay networks.In MSIPSO,three subgroups are proposed to achieve a balance between exploration and exploitation.Specifically,an elite subgroup is used to maintain the development ability of the algorithm,a disadvantaged subgroup is used to maintain the search ability of the algorithm,and a medium subgroup is used to ensure the stability of the algorithm.Among these three populations,this paper proposes an individual flow rule to realize the information interaction among the three populations and enhance the diversity and convergence of the algorithm.The proposed algorithm is evaluated on 28 benchmark functions of CEC2013,and the simulation results show that the MSIPSO algorithm has better convergence and stability on most problems.In order to maximize the secrecy rate of the untrusted relay network,two security transmission strategies are proposed according to the established network: the optimal power splitting scheme under total power constraints and the optimal power splitting scheme under independent power constraints.The MSIPSO algorithm is introduced to optimize the proposed schemes.The simulation results show that the optimal power splitting scheme under total power constraints is a secure transmission strategy that maximizes the secrecy rate. |
