Research On Physical Security In Mobile Ad Hoc Network

Along with rapid ascension of the computer performance, security technology based on the traditional encryption algorithm is more and more easily cracked, and the broadcast characteristic of wireless network make information public transmission, wireless network security is facing severe challenges.In order to solve the security problems, wireless network security technology in physical layer, because of its natural advantages, is receiving more and more attention and research.In this thesis, we mainly study the performance of the slow fading channel based mobile ad-hoc network physical security technology.First of all, using the randomness of wireless channel characteristics to take authentication on all kinds of wireless terminal.Wireless channel reciprocity and uniqueness allow users don’t need to use a shared key for authentication, can directly make use of the channel characteristics for authentication.In the authentication method, we study three kinds of the channel characteristics: the combination of amplitude and phase, and only amplitude, and only phase.The simulation tests show that we can obtain better performance with using hybrid channel characteristics of the amplitude and phase.Considering the particularity of mobile wireless networks, we combine the RAKE receiver technology to enhance the performance of authentication method when the transmission power is low, the simulation results prove the effectiveness of the RAKE receiver technology.Then, key generation based on the wireless channel characteristics, and using network coding to take key distribution.In this paper, the randomness of mobile ad-hoc network channel characteristics provide adequate resources for key generation, at the same time, we put forward a new method of network coding and its advantage is no center node for key distribution.In the rules of this method, despite all the relay nodes are involved in the calculation process of encryption and decryption, but because communication is multipath channel transmission and each path channel is independent of each other, so all the collaboration of relay nodes will be lack of a complete transmission information and unable to decipher the key, we achieve the target of confidential information transmission and proves the reliability of this method.Finally, in the Rayleigh fading channel environment, we study the secrecy capacity probability of normalized target, using the Maximum Ratio Combining technology of channel diversity technology to enhance the performance of the mobile ad-hoc network security communication.Based on contrast of theoretical analysis and simulation results, channel diversity technology, even in low SNR environment, make receiver can always obtain relatively high secrecy capacity, and continually take confidential information transmission, these results are evidence that our performance of the proposed method is efficient.