Research On Power Allocation Of Multi-carrier Full Duplex Relay Communication System

Cooperative full duplex(FD)relay is a key technology to improve the spectrum utilization and expand the data transmission range.The loop-interference cancellation technique can effectively reduce the interference between the dual antennas of the FD relay to a certain level,but it cannot achieve the ideal cancellation.Due to the strong anti-interference ability and high spectral efficiency,multi-carrier orthogonal frequency division multiplexing technology is widely used in the wireless communication systems.Consider the openness of the transmission medium and the privacy of the transmitted information,the confidential transmission of multi-carrier FD relay(MCFDR)communication system is one of the issues that researchers should be concerned.Based on the traditional Shannon theory,the physical layer security technology can achieve the confidential transmission with ensuring the effectiveness and reliability.On the other hand,the communication system should meet the real-time user's delay and other quality of service(QoS)requirements except for the physical layer indicators.The secure effective capacity associates the statistical delay QoS with the security rate,which is an important indicator in the resource allocation of secure communication system.In addition,due to the complexity of the wireless channel and the limitations of channel estimation techniques,we need to consider the uncertainty of channel information.In other words,the resource allocation strategy should be robust,and the Worst Case method is one of the widely used robustness optimization methods.Thus,for the MCFDR secure communication system with non-ideal loop interference cancellation,the thesis introduces the delay QoS by the secure effective capacity and studies the power allocation strategy when the relay interference channel has certain information and uncertain information.Then,the thesis solves problems by convex optimization theory and robust optimization theory and analyzes the simulation results.The main works are as follows:(1)This thesis introduces the related mathematical optimization method including convex optimization method,Taylor approximation method and robust optimization method which formulates the robust problem in detail.(2)When the loop interference channel state information(CSI)of the FD relay is perfect with non-ideal loop-interference cancellation,the thesis formulates the optimization problem with total power and FD relay loop interference power constrains.In the MCFDR communication system,the delay QoS driven power allocation strategy is studied by maximizing the effective capacity.For the MCFDR secure communication system,the power allocation strategy is studied by maximizing the security rate.On this basis,we studied the delay QoS driven power allocation in secure communication system by maximize the secure effective capacity.Then,the effective numerical solution is obtained by Taylor approximation,convex optimization method and sub-gradient iterative algorithm.The simulation shows the delay QoS driven power allocation strategy of MCFDR secure communication system can meet the real-time and security of transmission.(3)When the loop interference CSI of the FD relay is uncertain with non-ideal loop-interference cancellation,the thesis studies delay QoS driven robust power allocation strategy in MCFDR secure communication system.After formulating the robustness problem,the Worst Case method and the Bernstein approximation method are used.For the Worst Case method,the uncertainty set of the interference channel error gain is expressed by the general norm and the polynomial model.In the Bernstein approximation method,we rewrite the power constraints by outage probability.Furthermore,according to the protection function and the nature of the norm,the non-convex robust optimization problem is transformed into convex optimization problem,and solved by convex optimization method.The simulation shows the proposed power allocation strategy can realize the tradeoff between the secure effective capacity and the robustness under the uncertain interference channel.