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1.
The concept of wireless ATM is now being actively considered as a potential framework for next-generation wireless communication networks capable of supporting integrated multimedia services with different QoS requirements. Several key subsystem design issues for wired ATM and wireless networks need to be readdressed in the scope of the wireless ATM. One of the main key subsystem issues is the development of the appropriate medium access control (MAC) protocol, which has the capability to extend the statistical multiplexing of the wired ATM network into the wireless medium. In this article the authors address the problem of a suitable MAC protocol for the specification of a wireless ATM network and outline the design objectives. In addition, the authors address some other challenging key issues that the wireless medium and wireless network architecture impose on the ATM stack protocol  相似文献   

2.
带休眠算法的无线传感器网络MAC协议   总被引:1,自引:0,他引:1  
由于无线传感器网络中每个传感器节点的能量有限,所以需要有效的MAC协议来保持能量的高效利用。在MAC协议中引入休眠算法是其中一种重要的节能方式。现有的带休眠算法的无线传感器网络MAC协议已有很多种,主要分为2大类:一类是以S-MAC协议为代表的基于休眠/监听排程方案来达到节能目的的MAC协议;另一类是以WiseMAC为代表的基于低功率信道检测方案的MAC协议。对现有的主要几种有代表性的带休眠算法的无线传感器网络MAC协议进行了描述,分析了它们各自的优缺点,并进行了对比和总结。  相似文献   

3.
Designing energy-efficient Medium Access Control (MAC) protocols has a significant influence on the energy performance of wireless sensor network (WSN). In this paper we present a survey of the recent typical MAC protocols regarding energy effi ciency for WSN. According to channel access policies, we classify these protocols into four categories:contention-based, TDMA-based, hybrid, and cross layer protocols, in which the advantages and disadvantages in each class of MAC protocols are discussed. Finally, we point out open research issues that need to carry on to achieve high energy efficiency for the design of MAC protocols in WSN.  相似文献   

4.
Nodes in wireless sensor networks (WSNs) are battery powered and oftentimes deployed in remote and hostile locations. Energy conservation is, therefore, one of the primary goals of MAC protocols designed for these networks. Contention-based protocols employ static or variable duty cycles to minimize energy dissipated in idle listening. TDMA-based protocols, on the other hand, use reservation and scheduling to minimize energy loss. Further energy savings may be obtained by taking the nature of the network traffic into consideration. Several WSN applications such as surveillance applications and habitat monitoring applications generate bursty traffic. In this paper, we combine the advantages of contention-based and TDMA-based protocols to form Advertisement-based Time-division Multiple Access (ATMA), a distributed TDMA-based MAC protocol for WSNs, that utilizes the bursty nature of the traffic to prevent energy waste through advertisements and reservations for data slots. We provide detailed comparisons of the ATMA protocol with contention-based protocols (S-MAC, T-MAC and ADV-MAC), a TDMA-based protocol (TRAMA) and hybrid protocols (Z-MAC and IEEE 802.15.4) through extensive simulations and qualitative analysis. The simulation results show that with bursty traffic, ATMA outperforms these existing protocols in terms of energy consumption with reductions of up to 80%, while providing the best packet delivery ratio (close to 100%) and latency among all the investigated protocols for several simulation scenarios studied.  相似文献   

5.
在水下无线传感器网络中,MAC (Medium Access Control)协议为相互竞争的用户之间公平地分配信道资源.介绍了水声通信的特点以及在此环境下设计MAC协议所面临的主要问题,归纳水下无线传感器网络MAC协议的设计原则和分类方法.通过分析当前典型的各类MAC协议的主要机制,详细比较这些协议的特点、性能差异和...  相似文献   

6.
孙鹏  李光明  汪付强  庞泳 《电讯技术》2016,56(12):1417-1424
在无线传感网( WSN)体系结构中,介质访问控制( MAC)协议负责调配网络中节点的信道接入,具有保障网络高效通信的重要作用。混合类MAC 协议综合了竞争类MAC 协议以及调度类MAC协议的特点,在融合两种机制的优点的同时克服其缺点,为无线信道资源的分配提供了更加灵活和全面的策略。首先概述了无线传感网MAC协议设计要点及分类,然后重点分析了无线传感网中经典的混合类MAC协议及国内外前沿的研究进展,并进一步归纳对比了各协议运行机制、性能及不足,得出混合类MAC协议的应用相关性及差异性的结论,最后总结了无线传感网混合类MAC协议研究现状并指出了未来的研究重点,以期为相关领域的研究人员提供参考。  相似文献   

7.
Broadband wireless access (BWA) offers attractive features such as ease and speed of deployment, fast realization of revenues, and low infrastructure cost. This paper focuses on medium access control (MAC) alternatives that can find application in an LMDS/LMCS network capable of supporting multimedia traffic. Multifrequency demand assignment TDMA-based schemes appear (at the moment) to be a suitable choice in this context. The selected protocol should be dynamically capable of providing multirate capabilities and quality-of-service guarantees. An obvious candidate for the aforementioned purpose is the LMDS-specific MAC proposal in the DAVIC 1.2 recommendation. For purposes of comparison, we also examine the evolving IEEE 802.14 MAC convergence protocol and MCNS (multimedia cable network system) DOCSIS (ITU J-112) MAC standard that are intended to support similar applications and services in an HFC (hybrid fiber coax) environment. The three protocols are examined under noiseless and noisy channel conditions. Previous results on LMDS channel characteristics are summarized and used for modeling noisy channel conditions. The candidate protocols are compared in terms of mean access delay, throughput, and collision multiplicity statistics, when contention of users is involved. The effect of dynamic slot allocation on the performance of the candidate protocols is also examined  相似文献   

8.
龚海刚  刘明  余昌远  王晓敏  陈力军 《电子学报》2007,35(10):1843-1848
媒质接入控制是无线传感器网络设计的关键问题之一.由于媒质接入控制协议直接控制着节点无线通信模块的活动,而无线通信模块是传感器节点能量消耗的主要来源,因此MAC协议节能效率的好坏将严重影响网络的性能.基于TDMA的MAC协议具有固有的节能特性,即通过合理的TDMA调度避免传输碰撞以及减少节点空闲监听的时间.本文提出了ED-TDMA协议,一种面向事件驱动的传感器网络应用的TDMA协议.该协议根据当前源节点的数目动态地改变TDMA帧的长度,提高了信道利用率;同时采用位图方式的TDMA调度,极大地减少了TDMA调度的开销,节约了能量.此外,通过引入簇内覆盖的思想,使得簇内的活动节点数目为一常数,同时减少了工作节点的数目,从而延长网络的生命周期,并在一定程度上提高了系统的可伸缩性.实验结果显示,ED-TDMA协议更适用于网络负载较低、节点密度高的无线传感器网络.  相似文献   

9.
This paper deals with wireless ATM and in particular with MAC (Medium Access Control) mechanisms. The requirements for wireless ATM MAC are discussed, and contentionbased and TDMA/reservation based MAC protocols are compared. The objective is to find out the suitability of current wireless MAC schemes for ATM interworking, in comparison to new wireless ATM MAC proposals. Two candidate mechanisms, EYNPMA used in HIPERLAN type 1, and a modified MDR protocol, are discussed in more detail and their performance in different traffic scenarios is evaluated through simulations.  相似文献   

10.
Wireless networks are now very essential part for modern ubiquitous communication systems. The design of efficient routing and scheduling techniques for such networks have gained importance to ensure reliable communication. Most of the currently proposed geographic routing protocols are designed for 2D spatial distribution of user nodes, although in many practical scenarios user nodes may be deployed in 3D space also. In this paper, we propose 3D routing protocols for multihop wireless networks that may be implemented in two different ways depending on how the routing paths are computed. When the routing paths to different user nodes from the base station in the wireless network are computed by the base station, we call it centralized protocol (3DMA‐CS). A distributed routing (3DMA‐DS) protocol is implemented when respective routing path of each user node to the base station is computed by the user node. In both of these protocols, the user (base station) selects the relay node to forward packets in the direction of destination, from the set of its neighbours, which makes minimum angle with the reference line drawn from user (base station) to the base station (user), within its transmission range. The proposed protocols are free from looping problem and can solve the void node problem (VNP) of multihop wireless networks. Performance analysis of the proposed protocol is shown by calculating end‐to‐end throughput, average path length, end‐to‐end delay, and energy consumption of each routing path through extensive simulation under different network densities and transmission ranges.  相似文献   

11.
Medium access control (MAC) protocols coordinate channel access between wireless stations, and they significantly affect the network throughput of wireless ad hoc networks. MAC protocols that are based on a multichannel model can increase the throughput by enabling more simultaneous transmission pairs in the network. In this paper, we comprehensively compare different design methods for multichannel MAC protocols. We classify existing protocols into different categories according to the channel negotiation strategies they employ. The common problems that may be encountered in multichannel design are discussed. We then propose a hybrid protocol that combines the advantages of the two methods of a common control channel and a common control period. The simulation results show that our proposed protocol can significantly outperform two representative protocols. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

12.
节能是无线传感器网络介质访问控制(MAC)协议的首要目标,综合近年来MAC协议的研究成果,针对S-MAC、T-MAC等几种典型协议进行分析,研究出将拓扑结构控制机制引入MAC协议,可进一步降低能耗。给出了一种基于GAF拓扑控制思想的MAC协议、GS-MAC协议。GS-MAC协议可以降低处于空闲侦听状态的节点数量,是一种高效节能的协议。仿真表明,引入拓扑控制后可以达到进一步节约能耗的目的。  相似文献   

13.
Wireless ATM (W-ATM) networks have been studied extensively. The extension of ATM network services to the wireless environment faces many interesting problems. The original ATM network was designed for high-speed noiseless, reliable channels. None of these characteristics are applicable to the wireless channel. One of the most critical aspects of a W-ATM network is the medium access control (MAC) protocol used by mobile terminals (MTs) to request service from the base station (BS), which has to consider the quality of service (QoS) of the specific application. In this article the authors analyze some MAC protocols, particularly those for TDMA systems, and discuss their advantages and disadvantages  相似文献   

14.
In this article, a comprehensive survey of the medium access control (MAC) approaches for wireless mobile ad hoc networks is presented. The complexity in MAC design for wireless ad hoc networks arises due to node mobility, radio link vulnerability and the lack of central coordination. A series of studies on MAC design has been conducted in the literature to improve medium access performance in different aspects as identified by the different performance metrics. Tradeoffs among the different performance metrics (such as between throughput and fairness) dictate the design of a suitable MAC protocol. We compare the different proposed MAC approaches, identify their problems and discuss the possible remedies. The interactions among the MAC and the higher layer protocols such as routing and transport layer protocols are discussed and some interesting research issues are also identified. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

15.
A prototype microcellular wireless asynchronous transfer mode network (WATMnet) capable of providing integrated multimedia communication services to mobile terminals is described in this paper. The experimental system's hardware consists of laptop computers (NEC Versa-M) with WATMnet interface cards, multiple VME/i960 processor-based WATMnet base stations, and a mobility-enhanced local-area ATM switch. The prototype wireless network interface cards operate at peak bit-rates up to 8 Mb/s, using low-power 2.4 GHz industrial, scientific, and medical (ISM)-band modems. Wireless network protocols at the portable terminal and base station interfaces support available bit rate (ABR), variable bit rate (VBR), and constant bit rate (CBR) transport services compatible with ATM using a dynamic time-division multiple-access/time-division duplex (TDMA/TDD) MAC protocol for channel sharing and data link control (DLC) protocol for error recovery. A custom wireless control protocol is also implemented between the portable and base units for support of radio link related functions such as user registration and handoff. All network entities including the portable, base and switch use a mobility-enhanced version of ATM (“Q.2931+”) signaling for switched virtual circuit (SVC) connection control functions, including handoff. In the first stage of the prototype, the application-level API is TCP/UP over ATM ABR service class using AAL5. Early experiments with the WATMnet prototype have been conducted to validate major protocol and software aspects, including DLC, wireless control, and mobility signaling for handoff, Selected network-based multimedia/video applications requiring moderate bit-rates (~0.5-1 Mb/s) in the ABR mode have been successfully demonstrated on the laptop PC  相似文献   

16.
Wireless ATM networks: technology status and future directions   总被引:3,自引:0,他引:3  
The concept of “wireless ATM” (WATM), first proposed in 1992, is now being actively considered as a potential framework for new-generation wireless communication networks capable of supporting integrated, quality-of service (QoS) based multimedia services. In this review paper, we outline the technological rationale for wireless ATM, present a system-level architecture, and discuss key design issues for both mobile ATM switching infrastructure and radio access subsystems. The WATM radio access layer issues covered in this paper include: spectrum allocation; spectrum etiquette; modem technology; and medium access/data link control (MAC/DLC) protocols. Mobile ATM aspects such as ATM signaling extensions for handoff control, location management, and mobile QoS control are discussed. A summary of current wireless/mobile ATM technology development and standardization status is given, including an outline of our WATMnet prototype. The paper concludes with a discussion of future directions for wireless ATM technology such as Internet protocol (IP) integration and mobile multimedia terminals/applications  相似文献   

17.
陈飞  李哲 《信息技术》2006,30(6):80-82
主要研究了无线ATM网络对MAC的需求,并介绍了适用于无线ATM的一种新的MAC方案。该协议支持不同类型信息传输,比如恒定比特率(CBR),可变比特率(VBR),可用比特率(ABR),未指定比特率(UBR)。另外此协议还提供了对宽带ATM主干网的无缝连接。同时也支持与ATM相关的QoS级别。对于该协议关注的各种情况的主要原理进行了讨论。  相似文献   

18.
This paper presents an energy efficient medium access control (MAC) protocol for delay‐sensitive data transmission over wireless sensor network. In general, energy consumption and delay depend on channel monitoring interval (CMI) and data sensing period at each sensor node. Based on this fact, we propose a new preamble structure to effectively advertise CMI and avoid the overhearing problem. In order to pursue an effective tradeoff between energy consumption and delay, we also develop a CMI determining algorithm that searches for a sub‐optimal solution with a low computational complexity in a distributive way. Finally, experimental results are provided to compare the proposed MAC protocol with existing sensor MAC protocols. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

19.
无线传感器网络(Wireless Sensor Network,WSN)一般由部署在监测区域内大量廉价微型传感器节点组成,通过无线通信方式形成一个多跳(mutli hop)的自组织(self organizing)网络系统。MAC层协议设计是无线传感器网络设计中的一个重要研究方面,通过对当前众多MAC协议的研究,提出了一种无线传感器网络MAC层协议的分类方法,通过分析比较典型的MAC层协议,给出了MAC层协议设计的评价标准。  相似文献   

20.
As infrared wireless LANs for in-building applications become more popular because of their many advantages, it is of interest to design such LANs to support the ATM protocol and therefore provide wireless access to fixed ATM networks. The architecture of such a LAN is presented in this article. Emphasis is placed on the protocol stacks of the model to provide seamless operation with the wired network, on the cellular topology, and on the MAC protocol. Under the proposed topology the system performance is revealed in terms of packet dropping probability, average access delay, channel throughput, and statistical multiplexing gain for a range of system parameters  相似文献   

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