Resource Allocation Schemes Based On Physical Layer Security For Full-duplex Systems

With the popularization of smart terminals and the rapid growth of the number of mobile subscribers,the next generation mobile communication technology will suffer from serious challenges due to the shortage of wireless resources such as bandwidth.Full-duplex communication technology has received extensive attention among researchers due to its high spectrum utilization efficiency.Particularly,full-duplex has become an effective communication method for ensuring high spectrum efficiency with the increasing maturity of self-interference cancellation techniques.In view of the shortage of energy and spectrum resources,we study an efficient transmission scheme that maximizes the throughput of a full-duplex relay communication system that combines simultaneous wireless information and power transfer(SWIPT)and non-orthogonal multiple access(NOMA)technologies.In view of the imperfect self-interference cancellation and inter-user interference cancellation of NOMA users,this paper studies the Energy Efficiency Maximization(EEmax)problem in NOMA systems including full-duplex relays.Different from the traditional concept of secure communication,considering the poossible illegal communication among users,we study the resource allocation for legitimate surveillance rate maximization based on cooperative relaying and full-duplex proactive eavesdropping from the perspective of ensuring public security.Due to the broadcast nature of wireless channel,the transmission of private information in the wireless channel faces the risk of illegal eavesdropping.Therefore,in this paper,we study the resource allocation scheme with guaranteed security for multi-user full-duplex(FD)multiple input multiple output(MIMO)eavesdropping channels,moreover,the robust design is taken into account for the imperfect channel state information(CSI).The main results and contributions are summarized as follows:1.A SWIPT NOMA system based on the FD relay is studied.In particular,under the permission of ensuring the Qo S requirements and energy harvesting constraint of the cell-edge user,we investigate the data rate maximization for the cell-center user,who also acting as the FD relay.In our considered system,the cell-center user with good CSI receives signals from the base station and forwards information to the cell-edge user simultaneously in FD mode.At the same time,power splitting is adopted by the cell-center user with part of the received signals for information forwarding while the others for energy harvesting.The data rate maximization problem is carried out by joint design of the power allocation ratio,the transmit beamforming and the power splitting ratio.To deal with the extremely non-convex nonlinear fractional feature of this problem,in this paper,we deduce the semi-closed form solution by using the stepwise optimization method,and further gain the optimal solution by solving the problem iteratively.Moreover,a low complexity PSO-based suboptimal scheme is also developed.Numerical results not only verify the optimality of the proposed optimal solution but also demonstrate the effectiveness of the proposed suboptimal scheme.2.A NOMA system is investigated,where the near NOMA user is able to communicate with base station(BS)directly while the far NOMA user needs the help of a full-duplex(FD)relay.Wireless power transfer(WPT)is applied to our system where the FD relay integrated with power splitting architecture can be powered wirelessly by the ambient radio signals simultaneously.We assume that self-interference cancellation and inter-user interference cancellation are imperfect at the near NOMA user.For the purpose of maximizing the energy efficiency of the NOMA system,the power splitting ratio and transmit beamforming are researched for the BS and relay with the guarantee of Qo S requirements for two users.The formulated problem appears to be a nonlinear fractional programming,which is highly nonconvex and the global optimality is hard to obtain.By introducing Charnes-Cooper's transformation and inner approximation method,we develop an iterative algorithm to gain the near optimal solution.Simulation results show that the proposed joint optimizing algorithm outperforms the existing scheme in terms of energy efficiency as well as the effect of SI cancellation on performance gain.3.A system for cooperative surveillance with two legitimate monitors in the wireless transmission system is proposed,so as to compensate for the defect that one single monitor is unable to meet the demand.Specifically,in our considered system,one monitor acts as a relay to enhance the communication among illegal users and surveillance capability of monitor.Meanwhile,the other monitor works in FD mode that receiving information and sending jamming signal simultaneously to ensure effective surveillance.Assuming that the CSI is perfectly/partially known in our system,the key object is to maximize the surveillance rate by optimizing the transmit beamforming vectors of two monitors.For the case that the CSI is perfectly known,the formulated problem is non-convex and difficult to solve directly.By analyzing the CSI of different conditions under the background of physical context,we derive its corresponding closed-form solution,and then obtain the transmission strategy.For the case that the CSI is partially known,the troublesome infinite constraints are transformed into a finite number of linear matrix inequality constraints by introducing the S-procedure lemma,and then the optimal solution is obtained.Simulation results show that our proposed full-duplex cooperative surveillance scheme improves the monitoring efficiency significantly compared with the traditional single monitor system.4.In this paper,we study robust resource allocation for the multi-user FD MIMO communication systems.Particularly,we aim at minimizing uplink(UL)transmit power and downlink(DL)transmit power simultaneously while guaranteeing the quality of service(Qo S)requirements regarding secure UL and DL communication,under the consideration of the imperfect channel state information(CSI)of both the wiretap channels and the inter-user interference channels.In view of the conicting of two objectives,we propose a multi-objective optimization(MOO)framework to achieve the trade-off between them.The formulated MOO problem is non-convex and intractable.By employing the weighted Tchebycheff,the Taylor series expansion and the S-procedure approaches,we convert the MOO problem into the convex one and propose an iterative algorithm to solve it optimally.Simulation results not only demonstrate an interesting trade-off between the considered conicting objectives,but also show the effciency of our proposed robust resource allocation designs.