针对无线宽带系统面临的窃听问题，提出一种基于信道时域弱特征随机加扰的物理层加密算法. 发送用户利用特征值分解将非奇异的授权用户信道特征矩阵分解成多个并联子信道，然后选择具有强特征的子信道发送有用信息，将具有弱特征的子信道转化为快时变信道，使授权用户接收信号趋于稳定，窃听用户接收信号质量恶化. 仿真结果表明，该算法通过特征选取可降低对授权用户的信道要求，同时降低窃听用户的SINR使窃听保持较高的误码率，从而提高系统安全性.
To combat wiretapping of wireless wideband system, this paper presents a method for wireless wideband system physical layer secrecy in the time domain. The method adds random noise based on weak channel characteristic. First, the transmitter decomposes the nonsingular channel characteristic matrix into
some sub-channels. The sub-channels with strong characteristic are selected to transmit useful information, and weak ones are transformed into a random channel. The signal received by legitimate receivers becomes steady, while the eavesdropper’s turns random. Simulation results show that the method can lower the requirements to the legitimate channel state while decrease SINR at eavesdroppers to keep its error probability high so as to enhance system security.
[1] WYNER A. The wire-tap channel [J]. Bell System Technical Journal, 1975, 54(8): 1355-1387.
[2] Csisz?r I, K?NER J. Broadcast channels with confidential messages [J]. IEEE Transactions on Information Theory, 1978, 24(3): 339-348.
[3] GOEL S, NEGI R. Guaranteeing secrecy using artificial noise [J]. IEEE Transactions on Wireless Communication, 2008, 7(6): 2180-2189.
[4] NEGI R, GOEL S. Secret communication using artificial noise [C]//Proceedings of IEEE Vehicle Technology Conference, Dallas, Texas, 2005: 1906-1910.
[5] LI Xiaohua, HWU J, RATAZZI E P. Using antenna array redundancy and channel diversity for secure wireless transmissions [J]. Journal of Communications, 2007, 2(3): 24-32.
[6] LI Xiaohua, HWU J. Array redundancy and diversity for wireless transmissions with low probability of interception [C]//Proceedings of the 2006 IEEE International Conference on Acoustics, Speech and Signal Processing. Piscataway, USA. IEEE, 2006: 525-528.
[7] 穆鹏程，殷勤业，王文杰. 无线通信中使用随机天线阵列的物理层安全传输方法 [J]. 西安交通大学学报，2010, 44(6): 62-66.
MU Pengcheng, YIN Qinye, WANG Wenjie. A security method of physical layer transmission using random antenna arrays in wireless communication [J]. Journal of Xi’an Jiao tong University, 2010, 44(6): 62-66. (in Chinese)
[8] 洪涛，宋茂忠，刘渝. 切换天线发射的低截获率通信信号物理层安全传输 [J]. 应用科学学报，2011, 29(4): 368-373.
HONG Tao, SONG Maozhong, LIU Yu. Signal transmitted from switched antenna array with low interception probability for physical layer security [J]. Journal of Applied Sciences-Electronics and Information Engineering. 2011, 29(4): 368-373. (in Chinese)
[9] MUKHERJEE A, SWINDLEHURST A L. Utility of beamforming strategies for secrecy in multiuser MIMO wiretap channels [C]//IEEE Communication, Control, and Computing of Forty-Seventh Allerton Conference, 2009.
[10] GHOGHO M, SWAMI A. Physical layer secrecy of MIMO communications in the presence of a Poisson random field of eavesdroppers [C]. IEEE International Conference on Communications Workshop on Physical Layer Security, Kyoto, Japan, 2011: 1-5.
[11] EKREM E, ULUKUS S. The secrecy capacity region of the Gaussian MIMO multi-receiver wiretap channel [J]. IEEE Transactions on Information Theory, 2011, 57(4): 2083-2113.
[12] ZHOU Xiangyun, MCKAY M R. Secure transmission with artificial noise over fading channels: achievable rate and optimal power allocation [J]. IEEE Transactions on vehicular technology, 2010, 59(8): 3831-3842.
[13] TAHIR M, JAROT S P W, SIDDIQI M U. Wireless physical layer security using channel state information [C]//International Conference on Computer and Communication Engineering (ICCCE), Kuala Lumpur, Malaysia, 2010: 1-5.
[14] XIE Xianzhong, GOU Nan. UWB relay with physical layer security enhancement [C]//Proceedings of 2010 IEEE International Conference on Ultra-wideband, 2011: 1-4.
