Research On Physical Layer Security Cooperative Technology Based On Game Theory

Cooperation communication network can effectively use the broadcast nature of the wireless network and obtain the spatial diversity gain by cooperating with relays, as one of the current hot spots. However, the introduction of relay and cooperation brings great hidden dangers for secrecy and new challenges for the security problems research. Focusing on the deepest layer characteristics of the wireless communication, physical layer security provides new ideas for solving the security problems of cooperation communication network. Currently, wireless physical layer cooperatio n technology still includes these problems, 1). There is no effective selection method for selfish relay in dynamic network, so the transmitter can not maximize its secrecy rate. 2). There is no method to prohibit relay from unfriendly behavior, so the secrecy rate decreases. 3). There is no security coalition method for multi-source multi-destionation nodes, so the secrecy rate decreases. 4). In multi- node wireless network, the traditional game mechanism can make those nodes choose non-cooperative strategy and reduces the network necklace secrecy rate. In order to solve these problems, this paper study the physical layer security cooperation technology based on game theory from National Natural Science Foundation.The paper first proposes two relay selectio n methods according to selfish relay and unfriendly relay: a relay selection method to ensure the security of wireless network using twice quotation mechanism based on game theory and an unfriendly relay selection method based on game. Then, we study the p hysical layer security method of cooperation between nodes according to multi-source multi-destination nodes network and wireless multi- hop communication network and solve the problem of improving the network secrecy rate. The main content includes:1. A relay selection method to ensure the security of wireless network using twice quotation mechanism based on game theory has been proposed. The method introduces the virtual currency that encourages and regulates the cooperation relationship between different nodes, and introduces the incentives mechanism of twice quotation competition based on virtual currency measurement: All relays must compete quoting twice, if the relay selected by the transmitter during the first quotation is not selected during the seco nd quotation, it accepts the punishment to be isolated. Relays decide their quotation based on the energy and computing cost, and mark secrecy rate as a price; their dominant strategy is to report the true cost in twice quotation competition, only in this way can they get reward by transmitters. According to the secrecy rate and quotation, transmitters will select one relay, which makes the maximum secrecy rate gains. Simulation and analyses show that the proposed method is suitable for dynamic wireless net work scenarios, when the transmission power is 10 mW, the average secrecy rate is improved by 40% compared with traditional method, and the secure transmission of the network can be ensured.2. An unfriendly relay selection method based on game has been proposed. First, we establish a game model, and the benefit function and purpose: the purpose of the transmitter is to decrease the eavesdropping channel capacity by cooperative jamming of unfriendly relay, while the purpose of eavesdropper is to decrease the main channel capacity by cooperative jamming of unfriendly relay. Then, we get the values of cooperative power bought from unfriendly relay to transmitter and eavesdropper, respectively, and the channel condition which can make the unfriendly relay service for transmitter. Finally, the transmitter selects the relay that meets the channel condition and pays for it to obtain the corresponding cooperative jamming and maximize the secrecy rate. Simulation results show that the transmitter can select the unfrie ndly relay which provides the maximum benefit for it through this method, when transmission power is 10 mW, the secrecy rate is increased nearly 50% compared with the traditional methods.3. A security coalition method based on game theory has been proposed. First, we introduce a benefit-sharing mechanism of cooperative game for the adaptive security coalition method, and model the transmitter coalition. And then we make the increased part of total network secrecy rate compared with the initial as the transferable benefit, and allocate it to all transmitters in the coalition. After that, the transmitters iterate through the average utility under all coalitions, and find the largest benefit coalition. Finally, transmitters form this coalition autonomously, the transmitter which is badly in need of sending signal or the transmitter with the worst eavesdropping channel conditions under the same need sends signal, the rest cooperate by sending artificial noise. Simulation and analyses show the fairness and effect iveness of this method, when sending power is 20 mW, the average network secrecy rate under the Gaussian channel compared with the initial stated is improved by 1.8bits/s/Hz.4. A method for physical layer security cooperation based on evolutionary game is proposed. First, the paper defines strategies(sending artificial noise or signal) and benefits(secrecy rate under different strategy combination) according to evolutionary game. Then, the transmission nodes adjust strategy to maximize benefits based on current network state and difference between cooperation benefit and average expected benefit. Finally, the conditions can be obtained that the transmitting nodes can achieve stable cooperation, and the network evolution from an unstable state to a stable cooperation state to improve the necklace secrecy rate of the system. Simulation and analysis results show that under the Gaussian channel conditions, compared with traditional game method, the proposed method’s network necklace secrecy rate can be improved by 1bits/s/Hz.