【作者】 张光宇；

【导师】 贾敏；

【作者基本信息】 哈尔滨工业大学 ， 电子与通信工程（专业学位）， 2016， 硕士

【摘要】 认知无线电的主要目的是在主用户不占用频谱或是感知用户自身传输不会对主用户的通信质量造成影响的情况下,感知用户可以利用授权频谱,从而提高频谱的利用率。认知无线电技术主要包括频谱感知,功率控制和频谱管理技术。传统的认知无线电技术主要针对主用户和感知用户静止的认知网络。随着IEEE802.22标准的提出,移动性的研究逐渐成为了研究热点。因为认知网络在多媒体接入技术中应用广泛,而多媒体接入技术的协议多是基于时间分配的,因而本文重点研究了主用户移动场景下感知用户的时间分配方法。本文首先构建了认知无线电网络下主用户在感知用户的干扰域内和干扰域外的时间分配模型。其次,从用户移动的角度给出了单个感知用户可用的传输时间,并提出了感知时间门限的问题。即由于主用户的移动性,频谱感知算法不会因为感知时间越长感知越准确。为了给出实际中可以应用的时间参数设计方法,特别针对随机模型中最为常用的随机游走模型,本文给出了单感知用户占用频谱情况下最优传输时间和感知时间门限的表达式。再次,为了探究认知无线电系统的容量,研究了移动场景下感知用户容量的问题,得到了在主用户移动场景下,在主用户通信所能允许的最大干扰概率一定时,感知用户传输的总时长不变的结论。最后,本文研究了保证主用户通信情况下,感知用户通信的传输中断概率和受到主用户的干扰概率。更多还原

【Abstract】 The main purpose of cognitive radio is that cognitive users can use the licensed spectrum when primary users don’t occupy the spectrum or primary users’ communication qualities not influenced by the cognitive user’s transmission, so as to improve the efficiency of spectrum utilization. Cognitive radio techniques mainly include spectrum sensing, power control and spectrum management techniques. Traditional cognitive radio techniques mainly aim at the primary user and cognitive user in static scence. With the development of the IEEE 802.22 standard, the research on the mobility of the user has become a hot research topic, because of the cognitive network’s widely used in multimedia access technology, and the protocol of multimedia access technology based on the allocation of time. Therefore, this dissertation focuses on the mobile scenarios of primary usersand time allocation method of cognitive users.In this dissertation, we firstly construct the time distribution model of the primary user in and out of the interference region of the cognitive radio network. Secondly, from the view of the user’s movement, the available transmission time for a single user and the problem of sensing time threshold is put forward. Because of the mobility of the primary users, the spectrum sensing algorithm sensing the primary users can not be more accurate using the longer of the sensing time. In order to give the time parameter design method of the application, especially for the random walk modelwhich is most commonly used, the dissertationgives a single user’s optimal transmission time and sensing time threshold. Thirdly, in order to explore the capacity of the cognitive radio system of cognitive users’ capacity in mobile scenarios when the probability of interferenceis lower than the maximum interference probability the primary users’ communication allowed. A conclusionis drawn that the total transmissiontime of all the cognitive users is constant. Finally, this dissertation studies the transmission outage probability and the interference probability of the cognitive user to ensure the communication of the primary user.更多还原