【作者】 陈劼；

【导师】 李少谦；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2008， 博士

【摘要】 认知无线电技术从研究初期较窄的概念范畴,到如今作为未来通信的十大热点技术之一,涉及网络架构和从物理层到网络层等多个层面关键技术的研究。本文从认知无线电技术特性出发,提出了基于认知无线电的分级频谱共享网络架构,并对该网络架构下的频谱管理与分配,性能优化中的跨层设计等关键技术进行了研究。本文首先在第一章中探讨了认知无线电的研究背景与研究意义,回顾和总结了认知无线电网络架构以及关键技术的研究与存在问题,从认知无线电技术特性对于认知无线电网络架构及关键技术的影响出发,指明了本文的研究动机和出发点。针对认知无线电网络中的频谱异构性以及存在的干扰,在第二章中提出了基于认知无线电技术的分级频谱共享网络架构,包括分级频谱共享思想、实现该网络架构所需的可用频谱识别、分类方法与准则,以及不同业务应用情况下如何利用不同类型频谱的通信机制。构建了该网络架构下的协议栈模型框架,明确了协议栈中与分级频谱共享特性密切相关的功能。该网络架构可以灵活方便地实现网络结构优化和满足动态频谱分配的需要,且能有效地扩展可用频谱资源。第三章提出了分级频谱共享网络中ad hoc通信模式下基于博弈论的协作式频谱礼仪,通过利用认知用户之间共享有用信息,协调认知用户之间的行为,从而满足用户的通信需要。仿真表明,该频谱礼仪能快速收敛,且具有较强的抗干扰能力。根据第二章中的通信机制,第四章提出了分级频谱共享网络架构中不同类型频谱的选择准则,以及不同频谱类型对应不同情况下的频谱分配控制机制,指出根据网络情况及其相应的通信机制来确定选择分布式控制方式、集中式控制方式或者二者相结合方式。此外,提出了基于图论模型、考虑用户需求的两种频谱分配算法,一种仅考虑用户需求,另一种除考虑用户需求外,还考虑频谱分配中的公平性问题。前者能更好地满足用户需求,而后者能很好地满足用户需求和公平性。论文最后部分研究了分级频谱共享网络的跨层优化问题。提出了结合频谱特性的路由选择策略,运用最大化最小干扰余量准则,从而选择稳定性高的路由,该路由选择策略优于随机选择策略,能有效地降低对授权用户的干扰。同时,提出了链路调度与功率控制联合设计算法,主要考虑干扰受限的情况下,如何保证在最短时间内,使得有向链路的通信需求都得以满足。该算法使系统的吞吐量以及调度性能都得到明显提高。更多还原

【Abstract】 Cognitive radio technology, which is considered as a confined concept in coined stage, has become one of ten hotspot communication technologies in the future. Its researches involve network architecture and key technologies from PHY layer to network layer. From the perspective of characteristic in cognitive radio, this thesis proposes a network architecture based on cognitive radio, which is called as Hierarchical Spectrum Sharing Network (HSSN). Furthermore, some key technologies in such network are studied, such as spectrum management and allocation, and cross-layer design for performance optimization.In Chapter 1, background and significance of researching on cognitive radio is firstly investigated, then the research status and problems of researching on its network architecture and key techniques are reviewed and summarized, meanwhile, based on the impact of cognitive radio’s characteristic on the network architecture and its key technologies, the main research motivation and startpoint of this thesis is also indicated.In Chapter 2, based on the spectrum heterogeneity and interference in cognitive radio network, hierarchical spectrum sharing network based on cognitive radio is proposed which involves the idea of hierarchical spectrum sharing, the method and rule of available spectrum identification and classification implementing such network, and the communication mechanism how to use different spectrum categorizes for different service requirement. Furthermore, the framework of protocol stack model for the HSSN is constructed, in which the function modules that is tightly related to characteristic of the HSSN are determinated. The HSSN can realize optimization for network architecture and be satisfied with requirement of dynamic spectrum allocaion, while it can significantly provide a considerable extension to the available spectrum.In Chapter 3, a cooperative spectrum etiquette based on game theory is proposed for ad hoc mode in the HSSN. By using shared information between cognitive radio users, the actions between them are coordinated to meet the requirement of communication. Simulation results indicate this etiquette can quickly converge while it has the ability of strong anti-interference.According to the communication mechanism proposed in Chapter 2, the selection rules corresponding to different spectrum types in the HSSN are also proposed in Chapter 4. Meanwhile, the spectrum allocation control mechanism for different spectrum categories under different service requirement is explored. It points out that decentralized control, centralized control or both is selected according to different network status and the corresponding communication mechanism in such network. Moreover, using the method of graph theory, two spectrum allocation algorithms considering user requirement are proposed. One algorithm only considers requirement, while another algorithm considers both user requirement and fairness. Simulation results indicate that the former are better satisfied with user requirement while the latter are better satisfied with user requirement and fairness.Finally, the cross-layer optimization in the HSSN is researched. The route selection strategy combined with spectrum characteristic, which adopts the rule of maximum the minimum interference margin for selecting high stability route, is also proposed. This strategy is better than random selection in effectively reducing the interference to primary users. Meanwhile, the algorithm of link scheduling joint with power control, which considers how to guarantee meeting requirement of directional link in short time under interference limited, is also presented. Simulation results show that throughout and the scheduling performance in the system can obviously be improved.更多还原