基于信噪比的认知中继网络物理层安全研究

发布时间：2018-03-31 03:30

本文选题：认知中继网络　切入点：物理层安全　出处：《江苏大学》2017年硕士论文

【摘要】：急剧增长的移动业务需求促使着高速、可靠、安全的无线通信技术不断进步,而频谱资源稀缺、利用率低及无线链路低可靠、易窃听等问题却束缚着其发展。结合认知无线电与协作通信的认知中继网络(Cognitive Relay Networks,CRN),在获得更多分集增益的同时提高无线电频谱资源的利用率,是近些年通信领域的热门研究之一。而通信规模的扩大也带来了更加严峻的安全威胁,计算能力的增长正逐渐放大当前基于加密理论的安全机制的缺陷,一种基于信息论的绝对安全技术——物理层安全(PHY-Security)技术引起广大研究人员的兴趣。本论文研究了物理层安全技术在CRN中的应用,不同于通常以安全容量、安全中断概率、安全误码率等作为安全性能度量,本文从信噪比/信号与干扰加噪声比(SINR)角度进行分析。这里以实现信息的安全传输及不影响主用户通信质量为前提,次用户中继簇对接收的信号进行波束成形加权,同时混淆发送一定空间形式的人工噪声。主要工作可概括为以下两部分:1.针对采用放大转发(AF)策略的CRN模型,考虑实际场景中次用户中继簇存在低负载与高负载两种情形,分别提出对应的优化目标:低负载情形,意味着中继簇可以提供足够多的总发射功率,这里以最大次接收节点的SINR为目标;而高负载时,目标是在满足接收节点SINR的最低需求下,尽可能少的使用系统的发射功率。对所描述的功率分配问题都通过半定松弛(SDR)技术转换成一个等价的凸问题后求解,并对高负载情形下通过二分搜索法进一步优化性能。借助CVX工具包仿真验证了推导出的方案,中继簇无论处于何种负载,系统性能都得到显著改善;此外,通过复杂度分析表明方案均可在多项式时间求解,以及通过分析KKT条件证明了半定松弛的正确性。2.针对绿色通信背景下的CRN,引入同时同频全双工中继技术,提出一种实现高能量效率的安全传输方法。在考虑了自干扰消除率、中继转发平性基础上,去获取更多的系统能量效率和。分别考虑两种中继节点选择的转发策略:放大转发与译码转发(DF),次用户中继簇使用协作波束成形与人工噪声技术转发,通过结合SDR的爬山算法进行优化求解。最后,仿真结果与分析表明系统能量效率和都得到有效的提升;而且相对于DF,选择AF的情形能够获取明显更高的性能。
[Abstract]:The rapidly growing demand for mobile services has led to rapid, reliable and secure wireless communication technologies, while spectrum resources are scarce, utilization is low, and wireless links are low reliability. The cognitive relay network, Cognitive Relay Networks, combines cognitive radio and cooperative communication to gain more diversity gains and improve the utilization of radio spectrum resources. It is one of the hot research in the field of communication in recent years, and the expansion of communication scale also brings more serious security threat, and the increase of computing power is gradually magnifying the defects of the current security mechanism based on encryption theory. A kind of absolute security technology based on information theory-PHY-SecurityTechnology has aroused the interest of many researchers. This paper studies the application of physical layer security technology in CRN, which is different from the usual security capacity and security interrupt probability. As a measure of security performance, the security error rate is analyzed from the angle of SNR / signal-to-interference / noise ratio. The premise is to realize the secure transmission of information without affecting the communication quality of the primary user. The secondary user relay cluster weighted the received signal by beamforming and confused and sent a certain spatial form of artificial noise. The main work can be summarized as the following two parts: 1. Aiming at the CRN model based on the amplification and forwarding (AFA) strategy, the main work can be summarized as follows: 1. Considering the low load and high load of secondary user relay cluster in the actual scenario, the corresponding optimization objectives are proposed: low load situation, which means that the relay cluster can provide enough total transmit power. The target here is the SINR of the maximum secondary receiving node; in high load, the target is to meet the minimum requirements of the receiving node SINR, Using the transmission power of the system as little as possible. For the described power allocation problems are converted into an equivalent convex problem by using the semidefinite relaxation SDR technique. With the help of the simulation of CVX Toolkit, the system performance of the relay cluster is improved significantly, regardless of the load, and the system performance is optimized by the binary search method in the case of high load, in addition, the proposed scheme is verified by the simulation of the CVX Toolkit, and the system performance is improved significantly. The complexity analysis shows that the scheme can be solved in polynomial time, and the correctness of semidefinite relaxation is proved by analyzing the KKT condition. A secure transmission method with high energy efficiency is proposed. To obtain more system energy efficiency and. To consider two relay node selection forwarding strategies: amplifying forwarding and decoding forwarding DFS, secondary user relay clusters using cooperative beamforming and artificial noise forwarding, Finally, the simulation results and analysis show that the energy efficiency and energy efficiency of the system are improved effectively, and the performance of AF can be significantly higher than that of SDR.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN925

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