城域光环网的MAC协议

光环网是构建城域光网络的主要拓扑方式,因此研究城域光环网的MAC协议是十分必要的.主要讨论了城域光环网中的MAC协议,对现有的MAC协议进行了分类和比较研究,分析了其性能指标和技术特点,最后讨论了有待进一步研究的问题.     

WDM突发交换环网的多令牌MAC协议的设计和性能评价

提出了应用于WDM突发交换环网的一系列多令牌MAC协议,其中网络系统中的节点采用TT-TR的节点结构,在即使是像IP这样高度自相似的信息结构大幅度改变的时候,仍能有效地利用网络资源且具有良好的扩展性.最后通过OPNET仿真评估了这些MAC协议的性能,比较了它们的平均包延迟、信道利用率和丢包率.仿真结果表明它们在提高网络性能的同时降低了每个节点的处理开销.     

WDM光包交换城域网关键技术与MAC层协议

介绍了Packet over WDM技术在城域网（MAN）中的两种实现方案，对相应的MAC层协议进行了分析比较，在此基础上对其中应用的关键技术进行了具体说明。最后探讨了未来城域网的发展方向。     

城域盒式WDM技术优势及部署建议

针对现有传统波分复用（WDM）难以同时满足运营商大规模部署和降本增效需求的问题。分析了城域盒式WDM设备较传统WDM设备在开放解耦、低能耗和低成本等方面的优势,并结合互联网数据中心（IDC）和城域云网等需求场景,提出了城域盒式WDM设备的组网部署应用建议,具有较强的可行性。     

基于分类可靠性的WDM环网设计

利用分类可靠性概念解决WDM多纤双向环网中的路由和波长分配问题。基于分类可靠性概念和环网的重用保护波长机制,提出了一种改进的最难重用优先算法。利用该算法,可以在满足每个连接可靠性要求的同时,使整个环网所需的波长里程数最小。     

异质节点分离CRSN中MAC协议设计与性能分析

认知无线传感器网络(CRSN)是一种将认知无线电(CR)技术引入传统WSN中的新型网络,具有一定的应用价值和发展前景.然而,CRSN中的认知功能带来的额外能耗和处理要求及其高成本实现,阻碍了它的进一步发展及应用.基于此,提出将认知功能迁移到另外一类节点——认知节点,并使其拥有较强的处理能力和能量收集能力.认知节点与普通传感器节点按照一定比例进行部署,组成另外一种新型网络——异质节点CRSN (HT-CRSN),这种新型网络能够提高网络性能并降低部署成本.并提出了一种能够适用于这种异质节点传感器网络的工作时序及其一系列可行性的MAC协议(FBP等).通过对所提MAC协议的能耗分析,说明可以通过调整两类异质节点的部署比例和能量收集速率均衡两类异质节点的能耗,进而提高网络生命周期.     

基于节点剩余能量及流量自适应的混合MAC协议

基于节点剩余能量和网络流量变化,文中提出了RA-ZMAC协议,在Z-MAC协议中加入了能量控制和流量自适应机制.当网络流量低时,时隙的一部分时间中节点将进入睡眠状态以节省能耗,随着流量增大,睡眠时间减少.当网络流量继续增大,节点工作到TDMA方式,实现了基于竞争到基于调度的信道接入的平滑转换.RA-ZMAC协议根据节点剩余能量和流量情况改变竞争窗口和退避时间,当节点流量大时增大竞争窗口;节点剩余能量越多,退避时间越短.     

光分组传输城域网信道配置方法的研究

快速可调谐光发射器是未来光分组传输网的关键器件,但其成本较高.为了降低节点成本,文章采用固定波长光发射器替代快速可调谐光发射器,并提出一种用于光分组传输城域网的信道配置方法,其核心是将各波分复用信道进一步细分,同时给每个节点配置两个固定波长的光发射器.数学分析及计算机仿真显示,该方法在请求等待时延、光信道的共享能力等方面,具有与配置快速可调谐光发射器相近的性能.     

APON中MAC协议的研究现状

以高度概括来观察MAC协议,分别从APON承载的业务、带宽分配的对象、承载请求信息的通道和动态带宽分配算法等几个方面介绍了当前MAC协议研究的进展。最后,提出了一个有待研究的新问题。     

城域WDM设备的应用及发展

从干线网建设日趋完善,城域网传输成为干线业务的支撑点.城域网光传输存在MSTP、OADM、CWDM等,OADM成为核心层、汇聚层的主体设备,其技术解决方案和技术特点;其次,介绍了CWDM设备的技术特点和网络应用;最后就两种技术与ASON的发展关系进行了论述.     

MAC Protocol of a Next-Generation MAN Architecture Based on WDM and All-Optical Packet Switching

As media converge to the Internet, MANs will face new demands not only in terms of bandwidth, but also in terms of services. We describe a next generation MAN architecture that has been designed within Dutch project Flamingo. Based on all-optical packet switching, this architecture supports one-to-one, one-to-many and many-to-one communications in the optical domain. Specifically, we focus on the MAC layer of the network. We describe the access and fairness protocols and explain how the all-optical nature of the architecture affects the design of these protocols. We also discuss some performance results that have been obtained via simulation.     

A MAC Protocol for IP Differentiated Services in a WDM Metropolitan Area Network

This paper presents a Media Access Control (MAC) protocol for a WDM passive optical star. The protocol supports scalable service differentiation for Internet traffic in the spirit of the IETF's Diffserv architecture. We describe the functional elements of the protocol (signaling, arbitration, service disciplines and buffer management techniques) and the way they interact to support the Diffserv's Expedited Forwarding (EF) PHB and Assured Forwarding (AF) PHB group, where PHB stands for Per-Hop-Behavior. Extensive simulation results give quantitative estimations of the performance of the protocol under combined EF/AF traffic.     

一种低时延的无线传感器网络MAC协议

简要分析了无线传感器网络MAC层协议的作用,针对MAC协议在低时延方面的不足,提出了一种低时延的MAC协议(L-MAC).该协议采用汇聚树,在满足低功耗的基础上,减少了时延.理论分析和仿真实验表明L-MAC较好地解决了时延问题.     

A Centralized MAC Protocol for QoS Support in UWB-Based Wireless Networks

In this paper we introduce a novel MAC protocol that provides Quality of Service (QoS) support for multimedia traffic in UWB-based wireless local area networks. The proposed protocol allocates transmission opportunities to QoS and best effort traffic using a set of scheduling and resource control algorithms. The algorithms account for the UWB characteristics such as the co-existence of multiple simultaneous transmissions as well as the possibility of dynamically assigning the nodes' transmission rate and power. The simulation results show that the proposed protocol can provide QoS support while optimizing resource utilization. Yuechun Chu received her B.Sc. degree in electrical engineering from Shanghai University, China, in 1996 and M.Sc. degree in electrical engineering from University of Science and Technology of China in 1999. She is currently pursuing the Ph.D. degree in the department of electrical and computer engineering at the University of Massachusetts Amherst. Her research interests include MAC protocol design for UWB-based networks, wireless multimedia applications, and architectures and protocols for wireless networks with QoS guarantees. Aura Ganz is currently an Associate Professor and Director of the Multimedia Networks Laboratory at the ECE Department, University of Massachusetts at Amherst. She has experience in topics related to multimedia wireless networks, optical networks and ubiquitous computing. The research results are validated by a combination of analytical, simulation and prototyping tools. She has published a book “Multimedia Wireless Networks: Technologies, Standards and QoS” (Prentice Hall) and authored over one hundred and fifty peer reviewed publications. Dr. Ganz received her BSc, MSc and Ph.D degrees in Computer Science from the Technion in Israel.     

Scheduling Algorithms for Star-Coupled WDM Networks with Tunable Transmitter and Tunable Receiver Architecture

This paper presents the design and analysis of two scheduling algorithms for a reservation-based medium access control (MAC) protocol for wavelength division multiplexed (WDM) multi-channel optical networks. The network architecture is based on a passive star topology with one tunable transmitter and receiver (TT-TR) per node. The main objective of scheduling algorithm design is to reduce the computation time while maximizing the utilization of the network resources. In this paper, we propose two scheduling schemes called SEQSAM (SEQuential Scheduling AlgorithM) and BALSAM (BALanced Scheduling AlgorithM). Let M denote the number of nodes, C the number of channels, and K the maximum number of packets transmitted by one node to another. SEQSAM uses the M × M traffic demand matrix--obtained during the reservation phase of the MAC protocol--to compute a collision-free schedule for the nodes of the network. BALSAM uses the modified MULTI-FIT algorithm (MMFT) [1] to convert the M × M matrix into a corresponding M × C matrix, which is input to the IBS (Interval Based Scheduling) algorithm [2] that schedules the requests of the nodes. The overall time complexity of SEQSAM is O(M ³) compared to BALSAM algorithm's time complexity of O(M ² CK + M ² + MlogM). Note that the lower bound for any scheduling algorithm operating on a M × M matrix is O(M ²). A simulation-based performance study that considers network utilization, computation time, tuning latency, average packet latency and throughput for 1.2 Gbps and 2.4 Gbps data streams is presented.     

基于波分复用的智能光网节点管理模型

分析了基于波分复用(WDM)技术的下一代智能光网络中节点管理系统的功能模型和管理任务,给出了一种综合考虑业务分级和支持多径路由的算法,可在WDM光网中实现基于性能分析的资源动态配置管理。采用自行开发的资源动态配置软件进行了仿真实验,给出了仿真结果。     

自组网中功率控制的MAC协议分析

针对无线自组网中网络资源缺乏的问题，在MAC协议中引入优化控制传输功率的机制，可以有效地开发现有资源，提高网络性能。本文详细分析了PCMA协议的思想、机制以及对网络性能的影响，指出了协议的缺陷。     

支持MIMO链路的Ad hoc网络中的链路激活型拓扑未知MAC协议

该文提出了支持多输入多输出(MIMO)链路的Ad hoc网络的链路激活型拓扑未知多址接入协议。该协议利用正交拉丁方来为网络链路分配传输时隙,保证每个链路在1帧中至少有1个时隙可以成功传输。推导了该协议的平均吞吐量,并以最大化平均吞吐量为准则给出了选择协议参数的方法。数值结果表明,与已有链路激活型和节点激活型拓扑未知协议相比,本文的协议可以提高网络节点的吞吐量。     

双跳波分复用网络的结构和访问控制协议

本文提出了一种无源星形波分复用网，网络中任意两个用户都能在１￣２跳内通信。本文还提出了波长配置算法，沱能使光器件的调谐范围最小，以降低网络对光器件的要求；它同时还使网络的单跳的比例最大，以降低分组时延。本文还对网络性能进行了理论分析和计算机模拟。