认知无线电网络协作频谱共享策略研究

发布时间：2018-01-09 12:31

本文关键词：认知无线电网络协作频谱共享策略研究　出处：《北京邮电大学》2014年博士论文　论文类型：学位论文

【摘要】：随着近年来社会信息化进程的迅速推进以及无线通信产业的飞速发展,不断增长的无线业务和日益匮乏的频谱资源之间的矛盾正变得越发尖锐。旨在缓和这一矛盾、突破传统静态频谱资源管理体制的认知无线电(Cognitive Radio, CR)技术,在过去的十数年里得到了长足发展,并且成为了动态频谱管理(Dynamic Spectrum Management, DSM)体制最为关键的技术基础。在这一技术框架下,非授权无线电系统可以二次利用其他无线系统的授权频段,以减少授权频段在时间和空间上的闲置,进而提高了频谱利用率。在认知无线电网络中,从用户间可用频谱资源分布不均匀的现象要远较传统无线通信网络严重。另一方面,从用户的动态传输需求同样存在极大的不均匀性。显然,这两方面的不均匀性是一对矛盾,将引申出一个重要的问题,也即如何通过对不均匀资源,尤其是不均匀频谱资源的优化分配来实现网络目标和满足不同用户之间差异化的传输需求。这一问题也是认知无线电网络频谱共享所需面对的最大挑战之一,已经吸引了各个方面的广泛关注。协作通信技术被广泛应用于各式无线通信网络,包括认知无线电网络。通过对协作通信网络的概念进行引申,并利用认知无线电终端与共存授权无线通信系统自适应互联互通的能力,可以构造一个认知无线电网络,即认知无线电中继网络(Cognitive Radio Relay Network, CRRN)。它是认知无线电网络的重要推广。该网络范式将协作通信技术的优点和认知无线电技术的优点结合在一起,为解决认知无线电网络中分布不均匀的网络资源的优化分配问题提供了一条捷径。然而,到目前为止,认知无线电中继网络频谱共享方面的理论研究仍然不足以应对在实现无线个人通信5A (Anyone, Anytime, Anywhere, Anydevice, Anything)愿景过程中出现的挑战。基于上述考虑,本文主要就认知无线电中继网络中的协作频谱共享理论展开研究,旨在为下一代无线通信系统中的无线资源管理提供理论依据和指导。根据认知无线电中继网络中参与协作频谱共享的对象的不同,本文的研究分为从用户之间的协作、主用户和从用户之间的协作、主系统和从系统之间的协作这三部分内容。本文第二章针对从用户之间的协作,以认知无线电中继网络从系统中的中继选择和功率分配为切入点展开研究。与该领域其他研究所不同的是,本文考虑了对作为中继的从用户性能的保障。研究模型以三节点协作中继网络(Three-node Cooperative Relay Networks)为基础,分别考虑中继借助中继信道(Relay Channel)和双跳信道(Dual-hop Channel)协助源节点传输的两类典型场景。在满足从用户的发射总功率、主用户的最大接收干扰功率,以及包括作为中继的从用户在内的从用户QoS (Quality of Service)需求等约束条件的前提下,以最大化系统吞吐量为优化目标,求解最优联合中继选择与功率分配问题。该问题的求解分为两个步骤：首先针对源节点和每个候选中继节点进行最优功率分配；然后根据这些最优功率分配所对应的系统吞吐量,选择最优中继。对于一个给定的候选中继,它所对应的最优功率分配问题在第一类典型场景中是一个凸优化问题,可通过对偶法求解；在第二类典型场景中,该问题是一个非凸问题,因而难以求解。为了解决这一非凸问题,本文提出一种基于对偶法和搜索法的算法来获得最优解。此外,为了降低在每个候选中继处重复实施最优功率分配算法所带来的计算复杂度,同时保持较高的系统性能,本文还提出了一种基于主用户最大接收干扰功率门限的次优中继选择算法。最后,仿真结果显示了所提出方案性能的优越性,并且证明了所提出方案能够有效地保证源节点和中继节点间的公平性。本文第三章针对主用户和从用户之间的协作,研究认知无线电中继网络中的协作频谱共享,具体考察一对主从用户的功率优化分配和频谱资源在时域上的优化配置。所考察的场景为能量受限网络,例如随建即连网络(Mobile Ad-hoc Networks, MANETs)和无线传感器网络(Vireless Sensor Networks, WSNs)等。该类型网络资源优化分配的目的不是最大化系统传输性能或者最小化系统能耗,而是最大程度地延长网络的生存周期,从而减少终端电池更换频率,实现终端数据的连续传输。在所考虑的场景中,从用户可以作为中继协助主用户传输数据。作为交换,主用户在待传数据传输完毕后,在传输周期剩下的时间内允许从用户接入授权频谱。与该领域其他研究所不同的是,本文从系统中能量供求关系出发,假设存在与主用户和从用户分别对应的虚拟能量代理,能量代理拥有对应用户残余能量的处置权。通过将用户建模为能量买家,能量代理建模为能量卖家,我们可以在适当的能量价格下,根据最小代价原则,降低并均衡系统在各个协作频谱共享周期内所消耗能量。按照这一思路,基于图解法和牛顿法求解主用户和从用户之间的功率和频谱分配问题,本文提出了一种基于能量价格(Energy Price)的协作频谱共享策略。仿真结果显示,这一策略可以显著延长能量受限的认知无线电中继网络的生存周期,并提高系统频谱效率。不过,如何将这一策略推广到多对主从用户的场景,仍然是一个有待解决的问题。最后,本文第四章对协作频谱共享中的参与者进行适当引伸,考虑主系统和从系统间的协作频谱共享。针对频谱租赁市场中主系统保留频段中存在的大量白色、灰色空间所导致的频谱利用率低下问题,设计了一种混合式频谱共享机制。这种机制与传统的频谱租赁所不同的是,为了进一步提高频谱利用率,允许从用户机会式地共享主系统保留频段。本文考虑了在该机制下从用户由于频谱检测误差在主用户保留频段上给主用户带来的干扰,并且为了补偿其对主系统性能造成的损失,提出了一种基于均衡价格理论的混合式频谱分配策略。此外,本文还进一步提出了一种求解均衡价格的分布式迭代算法。仿真结果显示,混合式频谱共享机制在频谱利用率方面相对于频谱租赁以及机会式频谱共享存在一定优势,并且证明了主从系统均能在此机制下获得更高的收益。
[Abstract]:With the rapid development of rapid development in recent years of social informatization and wireless communication industry, the contradiction between the wireless business growing and increasingly scarce spectrum resources is becoming increasingly acute. In order to alleviate this contradiction, break through the traditional static spectrum management system of cognitive radio (Cognitive Radio CR) technology, has been considerable the development in the past several years, and has become a dynamic spectrum management (Dynamic Spectrum, Management, DSM) the key technology foundation for the system. In this framework, the non authorized radio system can be two times the use of other wireless systems licensed band to reduce the idle spectrum in terms of time and space. To improve the utilization of the spectrum. In cognitive radio network, users from the available spectrum resources uneven distribution of the phenomenon to be far better than traditional wireless communication network Yan Heavy. On the other hand, from the demand of the transmission of dynamic user are also non uniformity. Obviously, inhomogeneity of these two aspects is a contradiction, will draw an important problem, namely how to through the resources is not uniform, especially the optimization of uneven distribution of spectrum resources to achieve network transmission goals and meet the needs of different users. The difference between this problem is also one of the biggest challenges in cognitive radio network spectrum sharing have to face, has attracted wide attention in various aspects. Cooperative communication technology has been widely used in all kinds of wireless communication network, including the cognitive radio network. Extended by the concept of cooperative communication network and, by the cognitive radio terminal and coexistence capacity authorized wireless communication system adaptive interoperability, we can construct a cognitive radio network, cognitive radio relay network Luo (Cognitive Radio Relay Network, CRRN). It is important to promote the cognitive radio network. The network technology advantages and advantages of the paradigm of cognitive radio communication technology together, provides a shortcut to solve the optimal allocation problem of uneven distribution of cyber source in cognitive radio networks.
However, so far, the theoretical research is not sufficient in the realization of wireless personal communication 5A relay network cognitive radio spectrum sharing (Anyone, Anytime, Anywhere, Anydevice, Anything) appear vision process challenges. Based on the above considerations, this paper mainly cooperative spectrum sharing in cognitive radio relay network theory research, in order to provide theoretical basis and guidance for radio resource management in next generation wireless communication systems. According to the object of cooperative spectrum sharing in cognitive radio relay network is different, this study is divided into the collaboration between users, users and from the collaboration between users, from the main system and cooperation system between the the content of the three part.
This paper in the second chapter from the collaboration between users, the cognitive radio relay network from the relay selection and power allocation in the system as the starting point of the research. And other research in the field is different, we consider as relay protection. From the user performance research model with three nodes for cooperative relay networks (Three-node Cooperative Relay Networks) as the foundation, are considered by the relay relay channel (Relay Channel) and dual hop channel (Dual-hop Channel) to help the two typical scenes source node transmission. To meet the total transmit power from the user, the maximum received interference power of the primary user, and includes as a relay from the user, the user from the QoS (Quality of Service) prerequisite demand constraint, to maximize the system throughput as the optimization goal, with problem solving optimal joint relay selection and power. The problem The solution is divided into two steps: firstly, the optimal power allocation for the source node and the relay node for each candidate; the throughput of the system and then the optimal power allocation of the optimal relay selection. For a given candidate relay, the optimal power allocation problem of the corresponding class in the first scenario is a convex optimization problems by duality solution; in second typical scenarios, this problem is a non convex problem, so it is difficult to solve. In order to solve the non convex problem, this paper proposes a dual method and search method based on the algorithm to obtain the optimal solution. In addition, in order to reduce the repeated in each candidate relay the implementation of computing the optimal power allocation algorithm has complexity, while maintaining a higher system performance, this paper also presents a user based on the principal maximum received power threshold suboptimal relay interference Finally, the simulation results show the superiority of the proposed scheme, and prove that the proposed scheme can effectively guarantee the fairness between source node and relay node.
In the third chapter, aiming at the main users and from the collaboration between users, research on cognitive radio relay cooperative spectrum sharing network, optimal allocation in the time domain specific investigation of master-slave user power allocation and spectrum resources. The scene for the energy constrained network, for example, is built with the connected network (Mobile Ad-hoc Networks. Wireless sensor network (MANETs) and Vireless Sensor Networks, WSNs). This type of cyber source allocation is not the purpose of maximizing the transmission performance of the system or to minimize the energy consumption of the system, but to maximize the network lifetime, thereby reducing the terminal battery replacement frequency, realize the continuous data transmission terminal. In consideration of the scene from the user, can be used as the main relay to assist users transmit data. In exchange, the main users in the transmission of data to be transmitted after the rest of the time in the transmission cycle From the user to access the licensed spectrum allows room. And other research in the field is different, the relationship between energy supply and demand from the system view, and assume the existence of primary users and corresponding respectively from the user's virtual energy agency, the right to dispose of the energy agency with the corresponding user residual energy. By the user modeling for energy buyers, Energy Agency modeling for energy sellers, we can in the appropriate energy prices, according to the principle of minimum cost, reduce energy consumption and balance system of sharing period in each cooperative spectrum. According to this idea, the graphic method and Newton method for primary users and from power and spectrum allocation between users based on the problems, this paper proposes a based on the energy price (Energy Price) cooperative spectrum sharing strategy. Simulation results show that the cognitive radio relay network this strategy can significantly prolong the survival of Energy Limited The frequency spectrum efficiency of the system is improved. However, it is still a problem to be solved how to extend this strategy to a number of master-slave users.
Finally, the fourth chapter of cooperative spectrum sharing in the appropriate extension of the participants, and sharing from the cooperative spectrum between systems with main system. Aiming at the main system spectrum leasing market to keep a large white band existed in the low rate of problems caused by the use of grey space spectrum, design a hybrid spectrum sharing mechanism. This mechanism with the traditional spectrum leasing is different, in order to further improve the spectrum utilization, allowing users the opportunity to share from the main system. In this paper we consider the band retained under this mechanism from the user as the spectrum detection error in the main interference band to the main users to retain users, and to compensate the Lord the performance of the system caused by the loss of a balanced price theory based on hybrid spectrum allocation strategy. In addition, this paper further proposes a solution of equilibrium price points The simulation results show that the hybrid spectrum sharing mechanism has some advantages in spectrum utilization, compared with spectrum lease and opportunistic spectrum sharing, and proves that the master slave system can get higher profits under this mechanism.

【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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