认知无线网络中资源管理的若干关键技术研究

发布时间：2018-06-13 05:49

本文选题：认知无线网络 + 资源管理　；参考：《北京邮电大学》2014年博士论文

【摘要】：随着信息技术和无线数据业务应用的飞速发展,未来无线通信网络面临着无线资源短缺的挑战。固定的频谱分配方式虽然避免了网络间干扰,但是由于用户和业务分布的不均衡性和突发性等特性,其频谱利用率很低。认知无线电技术通过动态的频谱分配和利用,在不改变固有带宽的条件下,实现了频谱在时、频、空维度上的多维复用,提高了频谱的利用效率。认知无线网络通过无线资源管理技术对频谱进行动态的接入和利用,以在不影响授权用户正常通信的前提下为认知网络提供QoS支持。论文针对认知无线网络中资源管理的功率分配、用户接入、以及链路维护等关键技术展开研究,提出了相应的创新性解决机制,并通过详细的理论分析和计算机仿真对所提算法的性能进行了验证。论文的主要工作和创新点包括三个方面,总结如下： 1)在基于overlay频谱共享方式的认知无线网络中,以最大化认知网络容量和认知用户满意度为目标,提出了联合功率分配和用户调度的迭代算法。首先,分析频谱感知技术对资源管理的影响,分析由旁瓣泄露带来的网络间干扰。其次,在认知网络接入点总功率约束和授权用户干扰约束条件下,建立了以最大化认知网络容量和认知用户满意度为目标的多目标凸优化模型,并得到联合功率分配和用户调度的迭代算法。最后,通过仿真验证了迭代算法对网络性能的提升。 2)在自组织认知无线网络中,为了保证认知用户持续发送MAC帧,设计了准同步优先级多信道接入方案。首先,基于认知用户之间的频谱感知时间差,设计了具有异步竞争接入模式的时间帧结构,认知用户在接入公共控制信道的过程中通过优先级调整增强其接入能力。然后,在饱和认知网络中,用一阶有限状态离散马尔科夫链模型对时隙存在状态建模,并分析了该接入方案的系统吞吐量和接入时延性能。最后,在非饱和认知无线网络中,用3状态离散马尔科夫链模型对认知用户的存在状态建模,并分析了基于修正准同步优先级多信道接入方案下的系统吞吐量,接入时延和连续接入概率等性能。 3)在自组织认知无线网络中,为增强认知用户的通信持续性,设计了一个具有链路维护功能的MAC协议。首先,设计了父频谱表,得到了父频谱表的生命周期,对父频谱表中的子信道进行了功能划分,具有冗余和备份功能的子信道用于弥补由频谱移动性带来的丢包。其次,设计了自适应的感知时间帧结构,为认知用户传输数据提供了更多的时间。然后,根据认知用户存在状态设计了三种接入模式,通过为连续性认知用户提供多次接入机会提高其接入概率。最后,分析了MAC协议的网络性能,功能信道对网络间干扰带来的增益,设计父频谱表的感知时间开销。
[Abstract]:With the rapid development of information technology and wireless data service applications, wireless communication networks are facing the challenge of shortage of wireless resources in the future. Although the fixed spectrum allocation method avoids inter-network interference, the spectrum efficiency is very low due to the uneven and unexpected distribution of users and services. Through dynamic spectrum allocation and utilization, cognitive radio technology realizes multi-dimensional multiplexing of spectrum in time, frequency and space dimensions without changing the inherent bandwidth, and improves the efficiency of spectrum utilization. Cognitive wireless networks dynamically access and utilize the spectrum through wireless resource management technology to provide QoS support for cognitive networks without affecting the normal communication of authorized users. In this paper, the key technologies of resource management in cognitive wireless networks, such as power allocation, user access, and link maintenance, are studied, and the corresponding innovative solutions are proposed. The performance of the proposed algorithm is verified by detailed theoretical analysis and computer simulation. The main work and innovations of this paper are summarized as follows: 1) in the cognitive wireless network based on overlay spectrum sharing, the goal is to maximize the capacity of cognitive network and the satisfaction of cognitive users. An iterative algorithm for joint power allocation and user scheduling is proposed. Firstly, the influence of spectrum sensing technology on resource management and inter-network interference caused by sidelobe leakage are analyzed. Secondly, under the condition of total power constraint of access point and interference constraint of authorized users, a multi-objective convex optimization model with the aim of maximizing cognitive network capacity and cognitive user satisfaction is established. An iterative algorithm for joint power allocation and user scheduling is obtained. Finally, the simulation results show that the iterative algorithm improves the performance of the network. 2) in self-organized cognitive wireless networks, a quasi-synchronous priority multi-channel access scheme is designed to ensure the continuous transmission of MAC frames by cognitive users. Firstly, based on the spectrum sensing time difference between cognitive users, a time-frame structure with asynchronous competing access mode is designed. The cognitive users enhance their access ability by priority adjustment in the process of accessing the common control channel. Then, in saturated cognitive networks, a first-order finite state discrete Markov chain model is used to model the presence of slot states, and the system throughput and access delay performance of the access scheme are analyzed. Finally, in unsaturated cognitive wireless networks, a three-state discrete Markov chain model is used to model the existing states of cognitive users, and the throughput of the system based on the modified quasi-synchronous priority multi-channel access scheme is analyzed. 3) in order to enhance the communication persistence of cognitive users in self-organized cognitive wireless networks, a link maintenance MAC protocol is designed. First, the parent spectrum table is designed, and the life cycle of the parent spectrum table is obtained. The sub-channels in the parent spectrum table are divided into functions. The redundant and backup sub-channels are used to compensate for the loss of packets caused by spectrum mobility. Secondly, adaptive perceptual time frame structure is designed to provide more time for cognitive users to transmit data. Then, according to the status of cognitive users, three access modes are designed to improve the access probability by providing multiple access opportunities for continuous cognitive users. Finally, the network performance of MAC protocol, the gain of the functional channel to the inter-network interference, and the sensing time overhead of the parent spectrum table are analyzed.
【学位授予单位】：北京邮电大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN925

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