【作者】 马保海；

【导师】 肖丽萍；

【作者基本信息】 燕山大学 ， 通信与信息系统， 2015， 硕士

【摘要】 随着无线通信业务的飞速发展,无线电频谱作为一种不可再生资源显得日益匮乏。认知无线电技术由于能够实现频谱的二次利用,而被认为是解决频谱资源短缺问题的有效技术。资源分配技术由于能够在各个用户间合理的分配子载波以及功率来提高频谱利用率而成为认知无线电重点研究课题。本文对基于混合overlay和underlay共享传输模式的认知无线电系统资源分配技术进行了深入研究,具体工作如下:首先,针对一些已存在算法不能够有效利用主用户所能承受干扰上限,提出了一种最大化可用功率利用率的功率分配算法。该算法在主用户干扰阈值内最大化认知用户对主用户产生干扰,以便各个认知用户能够分得更多有效功率,提高可用功率利用率,进而提高认知用户和速率。仿真结果表明该算法能够有效提高认知用户速率。其次,针对多用户混合业务认知无线网络模型,提出了一种基于混合优先级的子载波分配算法。该算法中RT用户优先于NRT用户使用子载波以满足其Qos需求,并且RT和NRT用户都优先使用overlay模式下的子载波,然后再使用underlay模式下的子载波。该算法根据业务类型合理的分配资源,使得不同的业务Qos需求都得到满足。仿真结果表明该算法能够满足各个认知用户的Qos要求。最后,针对FBMC子载波只对相邻的一个子载波产生干扰的特点,提出了一种改进的梯度功率分配算法。该算法首次将FBMC应用于混合overlay和underlay共享模式下的认知无线网络;该算法通过只对距离主用户频带边缘最近的几个子载波进行梯度分配功率,而较远子载波分配相等功率,提高了各个子载波上的功率分配公平性,从而提高了认知用户和速率。仿真结果表明该算法优于传统梯度功率分配算法。更多还原

【Abstract】 With the rapid development of wireless communication services, the radio spectrum as a non renewable resources become increasingly scarce. Because of realization of reutilization of frequency spectrum, cognitive radio is considered to be the effective technique to solve the problem of shortage of spectrum. Due to the reasonably allocates subcarrier and power among users to improve spectrum utilization, resource allocation become a key research topic in cognitive radio. This article focus on research on resource allocation for cognitive radio system based on the shared transmission model of hybrid overlay and underlay, the specific work as follows:Firstly, in view of some existing algorithms cannot effectively use the primary user can bear interference limit, proposed an power allocation algorithm for maximizing rate of utilization of available power. The algorithm in the primary user interference threshold maximize interference of cognitive users generated to the primary user, so that each cognitive user can share more effective power, increasing the available power utilization, and improving the cognitive users sum-rate. The simulation results show that the algorithm can effectively improve the cognitive users sum-rate.Secondly, aiming at multi-user hybrid business in cognitive wireless network model, proposing a subcarrier allocation algorithm based on hybrid priority. The algorithm in time(RT) the user prior to the non timely(NRT) user subcarrier to meet its demand for Qos, and the RT and NRT users to give priority to the use of the overlay mode of the subcarriers, and then use the underlay mode of the subcarrier. The algorithm to allocate resources according to business type reasonable, making the different service Qos needs are satisfied. The simulation results show that the algorithm can satisfy each cognitive user’s Qos requirements.Finally, according to the interference characteristics of FBMC subcarrier that only a pairs of adjacent subcarrier are influenced by pre-subcarrier, an improved ladder power allocation algorithm is proposed. In the proposed algorithm, FBMC technology is applied to the hybrid overlay and underlay shared cognitive wireless network mode for the first time; several subcarriers of distance of the primary user band edge are allocated power based on ladder distribution, and farther subcarriers are allocated equal power, improving fairness of allocating the power to each subcarrier, thus improving the cognitive user sum-rate. The simulation results show that the algorithm is better than the traditional ladder power allocation algorithm.更多还原