基于物理层安全的不可信移动中继位置优化算法研究

发布时间：2018-06-09 21:10

本文选题：物理层安全 + 保密容量　；参考：《深圳大学》2017年硕士论文

【摘要】：随着无线通信带来的便利性,人们在日常生活中将大量使用无线网络进行敏感和私密信息传输。传统无线网络通过高层加密技术来保证安全性,其假设攻击端的计算能力是受限的。然而,随着分布式计算的高速发展,攻击端的计算能力不断提高,这种假设已经变得越来越不可靠。而物理层安全技术受到了越来越多的关注,其利用合法接收端比攻击端有更好的信号接收质量(例如,信噪比),来保证通信的安全性,避免了依赖于攻击端计算能力受限的假设。而且物理层安全技术代表着加强无线安全的一个尚未开发的资源,而不是仅仅依赖于传统的高层加密机制。最近,物理层安全技术中协作通信方法以其独特的优势吸引了研究者们的注意力,主要包含中继选择和协作人工噪声等方法。但现有文献中的协作通信方法还存在明显缺陷,比如:中继选择方法的性能受限于中继的空间位置分布。为了克服上述缺陷,本学位论文主要针对不可信移动中继,提出位置优化机制来提升系统的保密容量。在该机制中,我们假设不可信移动中继在整个水平面上移动,其移动是根据目标端反馈信息或者自身收到的信息来决定的。新机制的性能不再受限于其空间位置,但要求不牺牲攻击端的窃听容量,否则会引起不可信移动中继的怀疑,进而背叛系统。新机制的优势是易于实施:所有通信节点只用装备单天线、目标端仅需反馈一比特信息、甚至去掉反馈一比特信息这个环节,使通信更具隐蔽性。同时,新系统允许引入协作人工噪声自适应调整机制,来迷惑不可信移动中继,从而使性能得到进一步提升。新机制非常适合以下场景:源端能量受限但是仍然需要通过一个不可信移动中继来进行安全通信。我们首先将传统的移动中继位置优化算法经过适当修改后应用于我们所提的新机制中。尽管它能提高保密容量,但是在某些情况下牺牲了窃听容量,这将会引起攻击端的怀疑,也违背了新机制的约束条件。基于新机制,本学位论文进一步设计了三个执行算法:第一个算法是最简单的,它通过目标端引入固定协作人工噪声和修改反馈判决机制,来满足新机制的要求,但其性能提升有限;第二个算法通过自适应调整协作人工噪声功率来进一步提升系统性能;第三个算法则去掉目的端反馈的环节,使安全通信更具隐蔽性,由于限制条件较为苛刻,性能的提升空间较小。通过分析和仿真实验,我们深入研究了三个执行算法的性能,并针对各执行算法中参数选取问题进行了讨论,给出一些有用的结论。
[Abstract]:With the convenience of wireless communication, people will use wireless network to transmit sensitive and private information. The traditional wireless network guarantees the security through the high level encryption technology, which assumes that the computing power of the attack side is limited. However, with the rapid development of distributed computing, the computing power of attack end is improving, and this assumption has become more and more unreliable. However, the physical layer security technology has attracted more and more attention. It uses the legitimate receiver to have better signal reception quality than the attack end (e.g., signal-to-noise ratio) to ensure the security of communication. The assumption that computing power on the attack side is limited is avoided. And physical layer security technology represents an undeveloped resource to enhance wireless security, rather than relying solely on traditional high-level encryption mechanisms. Recently, cooperative communication methods in physical layer security technology have attracted the attention of researchers because of their unique advantages, including relay selection and cooperative artificial noise methods. However, the existing cooperative communication methods in the literature still have obvious shortcomings. For example, the performance of relay selection method is limited by the spatial location distribution of relay. In order to overcome the above shortcomings, this dissertation proposes a location optimization mechanism to enhance the security capacity of the system. In this mechanism, we assume that the untrusted mobile relay moves across the horizontal plane, and its movement is determined by the feedback information from the target side or the information received by itself. The performance of the new mechanism is no longer limited by its spatial location, but it requires that the eavesdropping capacity of the attack end be not sacrificed, otherwise it will lead to the suspicion of untrusted mobile relay and then betray the system. The advantage of the new mechanism is that it is easy to implement: all communication nodes are only equipped with a single antenna, the target only needs to feedback one bit of information, or even eliminate the link of feedback one bit of information, so that the communication becomes more hidden. At the same time, the new system allows the introduction of cooperative artificial noise adaptive adjustment mechanism to confuse untrusted mobile relay, thus further improving performance. The new mechanism is very suitable for the scenario where the source energy is limited but a secure communication is still needed through an untrusted mobile relay. Firstly, we apply the traditional mobile relay location optimization algorithm to our new mechanism after proper modification. Although it can improve the security capacity, in some cases the eavesdropping capacity is sacrificed, which will cause suspicion on the attack side and violate the constraints of the new mechanism. Based on the new mechanism, this dissertation further designs three execution algorithms: the first algorithm is the simplest, which can meet the requirements of the new mechanism by introducing fixed cooperative artificial noise and modifying the feedback decision mechanism at the target side. But its performance improvement is limited; the second algorithm adaptively adjusts the cooperative artificial noise power to further improve the system performance; the third algorithm removes the feedback link at the end of the target to make the secure communication more hidden. Because the restriction condition is more harsh, the performance promotion space is smaller. Through the analysis and simulation experiments, we deeply study the performance of the three execution algorithms, and discuss the problem of parameter selection in each execution algorithm, and give some useful conclusions.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN918

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