可充电协作认知无线网络的中断性能分析

发布时间：2019-06-07 09:53

【摘要】：近年来,基于无线通信的智能设备、应用以及服务呈现出了爆发式的增长。然而,无线通信可用的频谱资源有限。在目前的频谱分配机制下,频谱的利用率较低。因此,可提高频谱利用率的认知无线电技术引起了专家和学者们的广泛关注。基于认知无线电技术的通信系统可以充分利用有限的频谱资源,并提供质量更好的服务。另外,无线传输的特性决定了传统无线通信系统的传输速率和服务质量无法满足很高的要求。因此,能够同时提高无线通信的质量以及频谱利用效率的协作认知网络非常值得研究。再者,作为一个无线通信系统普遍存在的问题,持续的能量供给也是协作认知网络中的一个重要的问题。因此,本论文将携能通信技术应用于协作认知网络。本论文主要从信息论的角度,针对可充电协作认知网络的通信质量以及物理层安全这两个问题进行了研究,并且就不同参数对系统通信质量以及安全性能的影响进行了详细的分析。另外,本论文还针对可充电协作认知网络中不同的协作策略,即单个中继和多个中继协作,分别进行了研究。并且,对这两种协作策略可实现的性能进行了对比分析。考虑到Nakagami-m衰落信道比Rayleigh衰落信道更接近实际无线信道,所以本论文采用Nakagami-m衰落信道。具体来讲,本论文的主要研究内容及成果如下:第一,分析了可充电协作认知网络中的主用户在单中继协作和多中继协作机制下,分别可实现的速率的表达式。然后,根据中断概率的定义,得到了主用户分别采用单中继和多中继协作时,中断概率的具体表达式。第二,研究了不同系数对系统中断性能的影响并对直接传输,单中继协作以及多中继协作在不同系数下的中断性能进行了对比。其中,就次要用户可实现的速率以及主用户可实现的速率的折衷这一指标来讲,单中继协作策略优于直接传输和多中继协作。也就是说,在采用单中继协作策略的系统中,次要用户可以获取到更多的利益。第三,针对可充电协作认知网络中的安全中断问题进行了研究,分析了可充电协作认知网络在单中继和多中继协作策略下主用户分别可实现的安全容量,并根据安全中断概率定义,通过推导得到了具体的表达式。第四,研究了不同系数对系统安全性能的影响,并对单中继协作以及多中继协作策略下的安全中断性能进行了对比,发现单中继协作策略下主用户的安全中断性能优于多中继协作策略。
[Abstract]:In recent years, intelligent devices, applications and services based on wireless communication have shown explosive growth. However, the spectrum resources available for wireless communication are limited. Under the current spectrum allocation mechanism, the spectrum efficiency is low. Therefore, cognitive radio technology, which can improve spectrum efficiency, has attracted extensive attention of experts and scholars. The communication system based on cognitive radio technology can make full use of the limited spectrum resources and provide better quality services. In addition, the characteristics of wireless transmission determine that the transmission rate and quality of service of traditional wireless communication systems can not meet the high requirements. Therefore, the cooperative cognitive network, which can improve the quality of wireless communication and spectrum utilization efficiency at the same time, is worth studying. Moreover, as a common problem in wireless communication systems, continuous energy supply is also an important problem in cooperative cognitive networks. Therefore, this paper applies portable communication technology to cooperative cognitive network. In this paper, from the point of view of information theory, the communication quality and physical layer security of rechargeable cooperative cognitive network are studied. The influence of different parameters on the communication quality and security performance of the system is analyzed in detail. In addition, this paper also studies different cooperation strategies in rechargeable cooperative cognitive networks, that is, single relay and multiple relay collaboration. Moreover, the performance of the two cooperation strategies is compared and analyzed. Considering that Nakagami-m fading channel is closer to actual wireless channel than Rayleigh fading channel, Nakagami-m fading channel is used in this paper. Specifically, the main research contents and achievements of this paper are as follows: first, the expressions of the rates that can be realized by the main users in the rechargeable cooperative cognitive network under the single relay cooperation mechanism and the multi-relay cooperation mechanism are analyzed. Then, according to the definition of interrupt probability, the concrete expression of interrupt probability is obtained when the main user uses single relay and multi-relay cooperation respectively. Secondly, the effects of different coefficients on the interrupt performance of the system are studied and the interrupt performance of direct transmission, single relay cooperation and multi-relay cooperation under different coefficients is compared. Among them, the single relay cooperation strategy is superior to direct transmission and multi-relay cooperation in terms of the tradeoff between the rate that can be realized by secondary users and the rate that can be realized by primary users. In other words, in the system with single relay cooperation strategy, secondary users can get more benefits. Thirdly, the problem of security interruption in rechargeable cooperative cognitive networks is studied, and the security capacity of primary users in rechargeable cooperative cognitive networks under single relay and multi-relay cooperation strategies is analyzed. According to the definition of safe interrupt probability, the concrete expression is obtained by derivation. Fourth, the influence of different coefficients on the security performance of the system is studied, and the security interrupt performance of single relay cooperation and multi-relay cooperation strategy is compared. It is found that the security interrupt performance of the primary user under the single relay cooperation strategy is better than that of the multi-relay cooperation strategy.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN925

【相似文献】