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为提升电力设施传感器网络监测效率,通过引入无线物联网技术构建无线传感器网络,并根据电力设施传感器监测性能需求,对无线传感器监测频谱分配问题进行了深入研究,提出了基于优先级的时频资源竞争分配机制;在此基础上,利用MATLAB仿真软件对所提出的频谱竞争分配机制进行了仿真。 相似文献
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无线传感器网络中的节点众多,节点之间仅依靠频谱资源管理机制分配的频段进行数据传输会造成频谱资源紧张。针对这一问题,将认知无线电技术引入分簇的无线传感器网络,并且考虑分簇无线传感器网络节点的能量受限问题提出了一种节能的频谱感知方案。此方案首先让簇内的节点采取双门限能量检测的协作频谱感知方法,在满足目标检测概率和虚警概率的条件下,确定进行频谱感知的最少节点数,降低系统能耗。其次,通过选择合适的簇内节点进行频谱感知,使簇内节点的能耗均衡,簇的生命周期得到延长。 相似文献
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无线多媒体传感器网络(WMSNs)具有实时监控,收集和处理多媒体信息的功能,有广泛的应用前景。较之传统无线传感器网络,WMSNs无线传输多媒体信息需要更大带宽。然而,随着无线通信设备的广泛应用,有限的可用频谱资源日益匮乏。利用动态频谱分配技术,可以扩展WMSNs的通信频段,增强抗干扰能力。考虑到WMSNs节点的物理限制,如计算能力和能量供应,该文提出了适合WMSNs的频谱感知方法和频谱管理方法。频谱感知采用各节点的轮换机制感知整个频段;频谱管理可以确保对授权用户影响最小的信道被首先使用。WMSNs使用上述方法可以感知周围无线电环境,利用空闲私有频段进行无线通信。最后,通过实验证明了该文提出的动态频谱分配技术对WMSNs的有效性。 相似文献
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0引言
随着无线应用的不断拓展,频谱资源的缺乏成为无线应用研究过程中不得不面临的问题,最近的研究表明,频谱资源的不足主要是因为当前对频谱资源的利用不合理造成的。现有不同无线通信系统分配频谱的方法主要基于固定分配方式,即某一无线频谱块分配给某一特定的无线接入网络,然后再把这个无线频谱块分为若干个频谱子块, 相似文献
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4G网络建设已日趋完善,伴随着大量的4G业务需求,运营商的频率资源显得弥足珍贵,而另一方面GSM网络的用户数及承载的语音量成逐年下降趋势。将宝贵的频谱资源应用到LTE这样的高制式网络来提升频谱效率,但是GSM老终端又很难完全退网,传统的Refarming方案为通过静态分配GSM、LTE频谱资源,势必会造成部分频谱浪费。采用频谱共享方案可将频谱进行动态频谱、静态频谱划分,LTE系统与GSM系统通过共享动态频谱资源的方式实现潮汐式共享,从而一方面保证了GSM网络的语音资源,另一方面也提高了LTE网络的容量,从而整体提高网络的频谱利用效率。 相似文献
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4G无线通信系统及其关键技术分析 总被引:1,自引:0,他引:1
一、4G基本概念 下一代无线通信系统——4G的目标是成为一个无所不在的无线通信系统,提供无缝、高QoS、高速率的无线业务。这必然要求人们在现存的体系、频谱分配及利用上进行创新,对无线传输网络、无线业务和应用进行创新。在这些领域中,在某个领域上的创新必然会导致在另一领域上的创新。4G是一个动态的和自适应的系统,可以提供频率分配和管理、动态及快速的自适应多层路由技术、智能无线电及自适应组网技术。在WWRF的出版物中,提出下一代无线网络体系如图1所示,该网络具有以下一些特点。 相似文献
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集群移动通信系统简介国家无线电监测中心杜廷山,李建一、集群移动通信系统的概念集群移动通信系统就是多个部门或单位共用一组动态分配的无线频道的移动通信系统。它将有限的通信信道(即频率资源)动态地、自动地、最优地分配给系统内的全部用户,从而使频谱资源得到充... 相似文献
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The reliability of wireless sensor networks (WSNs) in industrial applications can be thwarted due to multipath fading, noise generated by industrial equipment or heavy machinery and particularly by the interference generated from other wireless devices operating in the same spectrum band. Recently, cognitive WSNs (CWSNs) were proposed to improve the performance and reliability of WSNs in highly interfered and noisy environments. In this class of WSN, the nodes are spectrum aware, that is, they monitor the radio spectrum to find channels available for data transmission and dynamically assign and reassign nodes to low-interference condition channels. In this work, we present the implementation of a channel assignment algorithm in a field-programmable gate array, which dynamically assigns channels to sensor nodes based on the interference and noise levels experimented in the network. From the results obtained from the performance evaluation of the CWSN when the channel assignment algorithm is considered, it is possible to identify how many channels should be available in the network in order to achieve a desired percentage of successful transmissions, subject to constraints on the signal-to-interference plus noise ratio on each active link. 相似文献
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Alireza Ghassempour Hamidreza 《AEUE-International Journal of Electronics and Communications》2005,59(7):401-409
The channel assignment is an important aspect of cellular radio networks. Because of the limitations on the frequency spectrum, the optimal or near-optimal channel assignment has become an essential part of the network operations of wireless personal communication systems. We formulate a new strategy for the channel assignment problem in agreement with the electromagnetic compatibility constraints. We introduce and formulate the extended dynamic programming (EDP), as an extension of dynamic programming for solving the channel assignment problem in a cellular system. Using EDP an algorithm is developed for fixed channel assignment problem and it is tested and compared with other existing methods by solving different problems. In agreement with electromagnetic compatibility constraints, solution strategy based on EDP algorithm finds many valid solutions with minimum possible bandwidth. 相似文献
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Wireless sensor networks are suffering from serious frequency interference. In this paper, we propose a channel assignment algorithm based on graph theory in wireless sensor networks. We first model the conflict infection graph for channel assignment with the goal of global optimization minimizing the total interferences in wireless sensor networks. The channel assignment problem is equivalent to the generalized graph coloring problem which is a NP complete problem. We further present a meta heuristic Wireless Sensor Network Parallel Tabu Search (WSN PTS) algorithm, which can optimize global networks with small numbers of iterations. The results from a simulation experiment reveal that the novel algorithm can effectively solve the channel assignment problem. 相似文献
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基于IPv6技术的无线传感器网络是一门新兴的网络技术,人们对它的研究尚处于起步阶段。在此主要论述IPv6技术在无线传感器网组网应用,对使用无线与有线相结合的通信方法,通信协议和算法的研究,使得视频监控系统信号,通信系统信号以及检测系统信号在同一个通信平台上互不干涉的平稳的传输信息。就IPv6无线传感器网络与现有网络的互联互通方式,关键技术和算法等方面进行概述。 相似文献
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The exponential growth of Internet traffic necessitates high-capacity optical networks and has also highlighted the importance of bandwidth-flexible and multi-granularity transport platforms. Improving both transport capacity and bandwidth flexibility is a significant challenge in optical networks. A bitrate flexible network architecture that is based on orthogonal frequency division multiplexing has been proposed as a promising solution for meeting this challenge. In the current study, we focus on the online routing and spectrum assignment problems in the aforementioned network architecture and introduce a general solution for dynamic bitrate flexible traffic in distributed environments. A novel spectrum representation method based on continuous spectrum segments is introduced into the networks. Segment-based routing and signaling mechanisms provide general solutions that support both the conventional slot-based networks and the ideal fully gridless networks. The routing algorithms and spectrum selection approaches are demonstrated and compared in a simulation. Performance estimation indicates that random spectrum segment assignment achieves the lowest capacity blocking rate in light traffic, whereas the adaptive routing plus minimum residual spectrum scheme obtains the lowest capacity blocking rate under heavy traffic. 相似文献
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从江都市有线数字电视广播系统的DVB前端的设计与组建、条件接收系统(CAS)的设计与论证、电子节目指南(EPG)系统方案的设计、城域HFC接入网的频谱分配、用户终端DVB接收系统的设计等方面,介绍了符合江都市广播电视产业市场化发展需要的DVB—C系统方案。 相似文献