Secure Information Transfer In Wireless Communication Systems With SWIPT

The security of information is one of the key issues in the field of wireless communication.As a supplement to the traditional encryption method,the physical layer secrecy technology can greatly enhance security performance in wireless communication systems and has gotten wide attention.On the other hand,the conflict between wide application of mobile devices and slow development of battery technology enables people to seek a way of transmitting energy by wireless signals,and further study simultaneous wireless information and power transfer(SWIPT).Based on physical layer secrecy and SWIPT,the main points of this paper are listed as following:A secrecy rate maximization problem under the total average power and the harvested energy constraints with MIMO(multi-input multi-output)channel is considered.In order to solve this nonconvex problem,the first-order Taylor approximation is introduced to convert the primal problem into a convex semidefinite optimization problem(SDP).Furthermore,due to the traditional interior point method for this SDP has a high complexity,an efficient iterative algorithm based on the projection gradient and the penalty function is designed.Simulation results show that the proposed algorithm can reduce the complexity by two orders of magnitude with nearly the same performance of existing interior point method.In the MIMO system with a cooperative jammer,a joint optimization problem of secrecy rate and harvested energy is considered.By weighted Chebyshev method,this problem is described as a multi-objective optimization problem(MOP).The simulation results show the Pareto boundary and demonstrate that introducing a cooperative jammer can improve the system performance.Finally,a secrecy rate maximization problem in a MIMO system with multi cooperative jammer is studied.In this problem,the imperfect channel state information(CSI)is considered.This problem is nonconvex and has infinite constraints.For solving this difficult problem,a robust optimization algorithm is designed.Simulation results illustrate that the robust algorithm can obtain better performance than non-robust algorithm,and the system performance can be improved by increasing the number of cooperative jammer.