| In recent years,due to the explosive growth of the number of wireless com-munication devices,the demand for wireless spectrum resources has increased exponentially,and the spectrum scarcity issue has become more serious.On the other hand,with the large-scale commercial application of 5G network-s,the energy consumption of wireless communication devices has increased significantly,and the information security issue has become prominently.To cope with these challenges,information and energy cooperation transmission based on cognitive spectrum sharing has become a promising communication paradigm.However,to make these wireless communication technologies prac-tical,various time-frequency and energy resources must be jointly optimized.Furthermore,there is still needed to research and explore the information se-curity issue in wireless communication networks to achieve secure and reliable information and energy cooperation transmission.In this thesis,under the guidance of wireless communication theory,opti-mization theory,and matrix theory,the problem of cooperative relay commu-nication,radio frequency energy harvesting,physical layer security,and beam-forming in cognitive spectrum sharing networks is investigated and explored.The main contributions and innovations are as follows:1.The problem of information and energy cooperation transmission be-tween the primary system and the wireless-powered D2D communication sys-tem is investigated.A joint time division and power splitting three-phase infor-mation and energy cooperation transmission scheme is proposed for the prob-lem of spectrum efficiency and energy efficiency in cognitive spectrum sharing D2D communication systems.A new optimization problem is formulated to maximize the data rate of the cognitive D2D communication system,and a two-stage solution method is proposed,which first equivalently transforms the original optimization problem to obtain the optimal beamforming vectors and transmit power;Then,the locally optimal solution for the original problem can be obtained by using the fmincon interior-point algorithm.Simulation results demonstrate that the proposed scheme is the best and significantly improves the average rate of the cognitive D2D communication system under differentperformance indicators.2.The problem of secure wireless information and energy cooperation transmission between the primary system and the wireless-powered untrusted secondary system is investigated.An artificial noise-aided joint time division and power splitting three-phase secure wireless information and energy cooper-ation transmission scheme is proposed for the problem of spectrum efficiency,energy efficiency,and security in cognitive spectrum sharing networks with untrusted dual-relay,and the impact of perfect and imperfect channel state in-formation on network performance is studied.A new optimization problem is formulated to maximize the data rate of the untrusted secondary system,and a two-stage solution method is proposed,which first equivalently transforms the original optimization problem to obtain the optimal beamforming vectors and transmit power;Then,the locally optimal solution for the original problem can be obtained by using the fmincon interior-point algorithm,and the computa-tional complexity of the proposed optimization problem is given.Simulation results show that the proposed scheme is the best and significantly improves the average rate of the untrusted secondary system under different performance indicators.3.The problem of secure wireless information and energy cooperation transmission between the primary system and the wireless-powered secondary system is investigated.An artificial noise-aided joint time allocation and power allocation two-phase secure wireless information and energy cooperation trans-mission scheme is proposed for the problem of spectrum efficiency,energy ef-ficiency,and security in cognitive spectrum sharing networks with full-duplex self-energy recycling,and a two-phase time switching full-duplex self-energy recycling transceiver is proposed.A new optimization problem is formulat-ed to maximize the data rate of the secondary user,and a two-stage solution algorithm is proposed,which first reformulates the original problem into a s-tandard convex semidefinite programming problem through vector and matrix reconstruction to obtain the optimal beamforming vectors;Then,the globally optimal solution for the original problem can be found by performing a two-dimensional search.Simulation results show that the proposed scheme not only significantly improves the average rate of the secondary user compared with the half-duplex power splitting scheme,but also guarantees the security of the primary system.4.The problem of secure wireless information and energy cooperation transmission between the primary system and the wireless-powered cognitive D2D communication system is investigated.An artificial noise-aided joint time allocation and power allocation two-phase secure wireless information and en-ergy cooperation transmission scheme is proposed for the problem of spectrum efficiency,energy efficiency,and security in cognitive spectrum sharing D2D communication systems with MIMO full-duplex self-energy recycling,and a two-phase time switching full-duplex self-energy recycling transceiver is pro-posed.A new optimization problem is formulated to maximize the data rate of the cognitive D2D receiver,and a three-stage solution algorithm is proposed,which first gives the optimal form of the relay precoding matrix,and simplifies the original optimization problem;Then,the simplified problem is reformulat-ed into a standard convex semidefinite programming problem through vector and matrix reconstruction to obtain the optimal beamforming vectors;Finally,the globally optimal solution for the original problem can be found by per-forming a two-dimensional search.Simulation results reveal that the proposed scheme further improves the average rate of the cognitive D2D receiver com-pared with the comparison scheme and guarantees the security of the primary system. |
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