共查询到19条相似文献,搜索用时 125 毫秒
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针对认知无线电网络可用信道资源随时间和空间环境变化的特点,分析了认知无线电网络MAC协议面临的问题,提出了一种基于全局控制信道的MAC协议方案,在此基础上阐述了两种接入方式及相应适用场合,实现了认知无线电节点对可用信道资源变化的感知,可为认知无线电MAC协议研究及应用提供参考. 相似文献
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无线Mesh网络多信道MAC协议 总被引:2,自引:0,他引:2
分析了WMN多信道MAC协议设计所面临的问题;介绍了几种现有典型的多信道MAC协议,并对其进行了分析;对多信道MAC协议未来的发展作了简要的总结。期望文章使读者对WMN多信道MAC协议的关键技术,特别是协议的设计有一个概括性的了解。 相似文献
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伴随信息化网络时代的来临,无线传感器网络作为一种新兴技术近年来得到了社会各界广泛的关注与应用。无线传感器网络实现的多信道通信技术具有实时监测、感知并将信息传输到相应的管理平台中的功能。本文主要分析了无线传感器网络的结构,无线传感器网络的通信协议与MAC协议,并从多信道频谱感知、多信道MAC协议和多信道广播对无线传感器网络的通行技术进行了深入研究。 相似文献
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介绍了采用超宽带(UWB)技术的Ad hoc无线网络,重点阐述了网络的两个关键技术MAC协议和路由算法协议. 相似文献
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无线网络中多信道技术是解决无线相干性,提高网络容量的有效技术。以单接口多信道为分析对象,对多信道协议进行分类并分析各类的优缺点。根据不同分类的多信道技术分析其存在的安全性问题,进一步提出针对多信道MAC协议特有的攻击行为,通过实验显示该攻击可以对多信道网络性能带来明显的负面效果。 相似文献
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无线MESH网络中的多信道MAC协议概述 总被引:1,自引:0,他引:1
分析了无线mesh网络多信道应用的必要性;介绍了多信道应用的现状,列出了几种典型的多信道协议;对各种多信道协议进行了分析,总结了其优缺点;提出对多信道未来改进方向的看法. 相似文献
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A Detailed Review of Multi-Channel Medium Access Control Protocols for Wireless Sensor Networks 总被引:1,自引:0,他引:1
GholamHossein EkbataniFard Reza Monsefi 《International Journal of Wireless Information Networks》2012,19(1):1-21
Most applications of Wireless Sensor Networks (WSNs) assume the presence of single-channel Medium Access Control (MAC) protocols.
In the usual dense deployment of the sensor networks, single-channel MAC protocols may be deficient because of radio collisions
and limited bandwidth. Hence, using multiple channels can significantly improve the performance of WSN. Recent developments
in sensor technology, as seen in Crossbow’s MICAz Mote, Rockwell’s WINS nodes and IEEE 802.15.4 Zigbee, have enabled support
for multi-channel communications. Several multi-channel MAC protocols with different objectives have been proposed for WSNs
in literature. This paper surveys and classifies the state-of-the-art multi-channel MAC protocols that are proposed for WSNs.
It first outlines the sensor network properties that are crucial for designing a MAC protocol. It subsequently reviews the
existent challenges to design a good multi-channel MAC protocol for the sensor networks. Then, several multi-channel MAC protocols
specifically proposed for the WSNs are inspected in detail and compared with each other. Finally, some open issues in this
area are outlined for future research. 相似文献
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Cross-Layer Based Opportunistic MAC Protocols for QoS Provisionings Over Cognitive Radio Wireless Networks 总被引:6,自引:0,他引:6
Hang Su Xi Zhang 《Selected Areas in Communications, IEEE Journal on》2008,26(1):118-129
We propose the cross-layer based opportunistic multi-channel medium access control (MAC) protocols, which integrate the spectrum sensing at physical (PHY) layer with the packet scheduling at MAC layer, for the wireless ad hoc networks. Specifically, the MAC protocols enable the secondary users to identify and utilize the leftover frequency spectrum in a way that constrains the level of interference to the primary users. In our proposed protocols, each secondary user is equipped with two transceivers. One transceiver is tuned to the dedicated control channel, while the other is designed specifically as a cognitive radio that can periodically sense and dynamically use the identified un-used channels. To obtain the channel state accurately, we propose two collaborative channel spectrum-sensing policies, namely, the random sensing policy and the negotiation-based sensing policy, to help the MAC protocols detect the availability of leftover channels. Under the random sensing policy, each secondary user just randomly selects one of the channels for sensing. On the other hand, under the negotiation-based sensing policy, different secondary users attempt to select the distinct channels to sense by overhearing the control packets over the control channel. We develop the Markov chain model and the M/GY/1-based queueing model to characterize the performance of our proposed multi-channel MAC protocols under the two types of channel-sensing policies for the saturation network and the non-saturation network scenarios, respectively. In the non-saturation network case, we quantitatively identify the tradeoff between the aggregate traffic throughput and the packet transmission delay, which can provide the insightful guidelines to improve the delay-QoS provisionings over cognitive radio wireless networks. 相似文献
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In a regular wireless ad hoc network, the Medium Access Control (MAC) protocol coordinates channel access among nodes, and the throughput of the network is limited by the bandwidth of a single channel. The multi-channel MAC protocols can exploit multiple channels to achieve high network throughput by enabling more concurrent transmissions. In this paper, we propose a hybrid and adaptive protocol, called H-MMAC, which utilizes multi-channel resources more efficiently than other multi-channel MAC protocols. The main idea is to adopt the IEEE 802.11 Power Saving Mechanism and to allow nodes to transmit data packets while other nodes try to negotiate the data channel during the Ad hoc Traffic Indication Message window based on the network traffic load. The analytical and simulation results show that the proposed H-MMAC protocol improves the network performance significantly in terms of the aggregate throughput, average delay, fairness and energy efficiency. 相似文献
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Existing multi-channel Medium Access Control (MAC) protocols have been demonstrated to significantly increase wireless network performance compared to single channel MAC protocols. Traditionally, the channelization structure in IEEE 802.11 based wireless networks is pre-configured, and the entire available spectrum is divided into subchannels and equal channel widths. In contrast, this paper presents a Traffic-Aware Channelization MAC (TAC-MAC) protocol for wireless ad hoc networks, where each node is equipped with a single half duplex transceiver. TAC-MAC works in a distributed, fine-grai-ned manner, which dynamically divides variable-width subchannels and allocates subchannel width based on the Orthogonal Frequency Division Multiplexing (OFDM) technique according to the traffic demands of nodes. Simulations show that the TAC-MAC can significantly improve network throughput and reduce packet delay compared with both fixed-width multi-channel MAC and single channel 802.11 protocols, which illustrates a new paradigm for high-efficient multi-channel MAC design in wireless ad hoc networks. 相似文献
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Currently most wireless sensor network applications assume the presence of single-channel medium access control (MAC) protocols. However, lower sensing range result in dense networks, single-channel MAC protocols may be inadequate due to higher demand for the limited bandwidth. In this paper we proposed a method of multi-channel support for DMAC in Wireless sensor networks (WSNs). The channel assignment method is based on local information of nodes. Our multi-channel DMAC protocol implement channel distribution before message collecting from source nodes to sink node and made broadcasting possible in DMAC. Analysis and simulation result displays this multi-channel protocol obviously decreases the latency without increasing energy consumption. 相似文献
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在对车载自组织网络的特点和研究现状分析的基础上,文章给出了车载自组织网络(VANET)中多维多层的理论模型和网络体系结构,讨论了物理层技术及其相关标准以及MAC层、网络层协议设计的重点和难点,阐述了广播协议的设计思路。 相似文献
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Traditional single-channel MAC protocols for wireless ad hoc and sensor networks favor energy-efficiency over throughput. More recent multi-channel MAC protocols display higher throughput but less energy efficiency. In this article we propose NAMAC, a negotiator-based multi-channel MAC protocol in which specially designated nodes called negotiators maintain the sleeping and communication schedules of nodes within their communication ranges in static wireless ad hoc and sensor networks. Negotiators facilitate the assignation of channels and coordination of communications windows, thus allowing individual nodes to sleep and save energy. We formally define the problem of finding the optimal set of negotiators (i.e., minimizing the number of selected negotiators while maximizing the coverage of the negotiators) and prove that the problem is NP-Complete. Accordingly, we propose a greedy negotiator-election algorithm as part of NAMAC. In addition, we prove the correctness of NAMAC through a rigorous model checking and analyze various characteristics of NAMAC—the throughput of NAMAC, impact of negotiators on network capacity, and storage and computational overhead. Simulation results show that NAMAC, at high network loads, consumes 36 % less energy while providing 25 % more throughput than comparable state-of-art multi-channel MAC protocols for ad hoc networks. Additionally, we propose a lightweight version of NAMAC and show that it outperforms (55 % higher throughput with 36 % less energy) state-of-art MAC protocols for wireless sensor networks. 相似文献