HFC网络技术研究

当前，经过HFC(光纤同轴混合)／CATV(有线电视)网络传送高比特率信息流到用户的通信系统正快速发展着，作为因特网的接入媒介，HFC／CATV网络近来更加普及了。这种网络由一个中央执行系统，一个CMTS(电缆调制解调器终端系统)和数百个CM(电缆调制解调器)组成，通过它们，用户可将自己的计算机连入网络中。为此较详细地分析和研究了HFC网络传输技术及其应用前景。     

HFC双向网络中CM宽带接入技术研究与实现

Cable Modem接入技术是当前实现"三网合一"和解决信息高速公路"最后1 km"高速宽带接入技术的最佳解决方案之一.详细介绍了当前HFC网络中Cable Modem接入技术的理论基础--DOCSIS协议标准,提出了交互式HFC双向网络中的Cable Modem接入技术解决方案,设计、制作并调试了以TMS320C5402,AD9853和AD8348为核心,符合ITU-T协议标准的全双工Cable Modem.     

双向CATV网络的构建

ＨＦＣ网络是传统有线电视广播走向双向化的一种很好的实现方式。下文较为详细地分析了ＨＦＣ网络的结构和演变,然后对电信和有线电视网络升级改造的方式进行了探讨。     

HFC与Cable Modem宽带接入技术

对 HFC网的现状和 Cable Modem宽带接入技术的前景作了介绍和分析 ,重点介绍了 CableModem接入技术 ,包括系统组成、协议分层结构、信号在 CM与 CMTS之间的传送规则等 ,最后就Cable Modem接入技术与几种常用的接入技术进行了比较。     

Ad Hoc网络中MAC协议的研究与展望

MAC协议是无线AdHoc网络的一个重要研究领域，特别是暴露终端和隐终端问题的解决尤为重要。文中介绍了当前AdHoc网络中MAC协议研究的最新成果，并对这些协议进行了分析比较，最后给出了进一步的研究方向。     

HFC网络QoS探讨

DOCSIS1.1标准规范的服务质量（QoS)是共享媒体HFC网络基于策略服务质量控制的标准，利用分类、排队、调度机制可以实现基于应用流、用户、服务提供者的可预测的服务水平，这是HFC网络满足新业务要求的关键。     

Cable Modem技术及其在Internet接入中的应用

在Internet接入研究中,电缆调制解调器（Cable modem)是一种先进的高速解决方案。简要介绍了Cable modem出现的背景,阐述了Cable modem的基本原理及特性,最后详细介绍了Cable Modem的国际标准和利用Cable Modem接入Internet的几种方式,并指出了其应用前景。     

基于HFC的校园接入网技术

高速接入Internet有多种方式，利用光纤混合同轴网（HFC）是一种比较理想的接入方式。介绍如何利用HFC组建校园网，并结合教学对校园网的需求对HFC组网与用双绞线组网进行了比较。     

双向HFC技术及应用

双向传输的 HFC (Hybrid Fiber Coax)除了能将前端信号传输到各用户外 ,还可以从用户或分配点将信息传输到前端和其他用户 ,可以实现正反两个方向信号的同时传输 ,提供多功能的服务。文中介绍了双向 HFC及 CableModem (电缆调制解调器 )的主要技术 ,并讨论了其存在的问题     

HFC网络MAC协议的冲突化解算法分析与改进

对HFC网络MAC协议注过程中的几种竞争冲突的化解算法进行分析，并提出了一种自适应P坚持算法，实验表明该算法的性能比其他可实现算法更好。     

HFC网络的MAC协议多优先级机制的改进算法

HFC网络的MAC协议内容包括多优先级业务的操作，通过对目前IEEE802.14协议提供的优先业务的能力进行研究，发现它的抢先竞争时隙分配器的能力有不足之处，为此提出一种支持多优先级的竞争时隙动态分配算法，用于改进IEEE802.14协议的冲突化解算法。     

MLAP: a MAC level access protocol for the HFC 802.14 network

Interactive residential broadband/multimedia services are expected to be the next main event in the cyberspace experience. The large excess bandwidth (well over 300 MHz) available in today's cable TV (CATV) hybrid fiber/coaxial (HFC) plants is an ideal candidate to provide the underlying communications infrastructure for interactive digital services to the home; cable operators that have not yet upgraded their all-coaxial plants to HFC are quickly moving in this direction. MLAP is a flexible ATM-friendly MAC protocol that is capable of supporting various types of traffic with diverse quality-of-service requirements. We introduce a very versatile MAC protocol for the HFC 802.14 network. MLAP can provide integrated broadband services to the home, internetwork easily with ATM wide area networks, support QoS constraints for various types of traffic, and operate over a variety of physical layer protocols. Our presentation is only an extended summary of our medium-sharing protocol proposal to the IEEE 802.14 WG. We consider only error-free system operation. MLAP provides for the use of timers for the recovery of error situations in the network. MLAP is also supported by a management suite of protocols for management of the overall system     

一种无线传感网络节能MAC协议

在无线传感网络中,传感节点是能量受限的,因此能耗在这种网络显得十分重要,关系到整个网络的生命周期与性能.而无线传感网络的MAC协议对节点的节能有着重要的作用.本文在已有研究的基础上加以改进形成一种更有效的感知流量信息进行节能的MAC协议.该协议同S-MAC协议一样也是采用睡眠的机制,但不同于S-MAC的是该协议中监听与...     

Architecture and performance of a MAC protocol for the HFC system

The IEEE 802.14 standard committee is currently working on a project to find a cost-effective means of providing access to integrated networks for people to enjoy multimedia programs and to work at home. An advanced system based on the cable TV system called hybrid fibre coax (HFC) is being studied. Since some properties of the HFC system preclude the possibility of directly using existing medium access control (MAC) protocols for its data link layer, a MAC scheme based on time division is discussed in this paper. This MAC scheme can be extended for wireless networks. © 1997 John Wiley & Sons, Ltd.     

一种无线ATM网络的MAC协议

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。     

星形无线网络专用MAC协议SNS-MAC

通过对现有几种流行的MAC的协议进行分析总结,提出一种旨在最大限度提高能量效率的星形网络专用MAC协议——SNS MAC协议,使无线网络在工业现场中能够延长寿命,更大地发挥其作用.     

基于令牌的无线传感器网络MAC协议

为了更进一步减少信道冲突和网络能耗,提出一种基于令牌的链式无线传感器网络MAC协议.协议自定义信标帧和数据帧,在传感器节点完成时间同步后,以信标帧中的令牌为控制信息对相邻两个传感器节点进行收发控制,实现数据从链尾节点到链头节点的顺序上传.研究表明,该协议不仅能够满足系统的稳定性要求而且能够有效降低功耗.     

UW‐MAC: An underwater sensor network MAC protocol

As over 70% of the earth's surface is covered by water, it is desirable to deploy underwater sensor networks (UWSNs) to support oceanic research. UWSNs use acoustic waves and are characterized by long and variable propagation delays, intermittent connectivity, limited bandwidth and low bit rates. Energy savings have always been the primary concern in wireless sensor network protocols; however, there are applications where the latency and throughput are prioritized over energy efficiency and are so significant that the application would not be able to satisfy its requirements without them. Although existing duty‐cycle MAC protocols are power efficient, they introduce significant end‐to‐end delivery latency, provide poor throughput and are not suitable for the challenging environment of a UWSN. In this paper, we utilize CDMA as the underlying multiple access technique, due to its resilience to multi‐path and Doppler's effects prevalent in underwater environments. We propose UW‐MAC, a CDMA‐based power‐controlled medium access protocol that uses both transmitter‐based and receiver‐based CDMA inside a formed cluster, and uses a TDMA schedule to make the cluster heads communicate with the base station. Our MAC algorithm targets the latency and throughput needs in addition to its ability to increase the overall network lifetime. We discuss the design of UW‐MAC, and provide a head‐to‐head comparison with other protocols through extensive simulations focusing on the performance in terms of latency, throughput, and energy consumption. Copyright © 2009 John Wiley & Sons, Ltd.     

RSU-coordinated multichannel MAC protocol in vehicular ad hoc network

A road side unit (RSU)-coordinated multichannel media access control (MAC) (RMM) protocol was proposed in vehicular ad hoc network,which aimed to improve the transmission efficiency of non-safety messages.Under the coordination of RSU,nodes had more opportunities to make SCH reservations on control channel,and the contention-free message transmissions were thus realized.The proposed RMM protocol could use the service channel during the whole synchronization interval for non-safety message transmissions,and thus the saturated network throughput and channel utilization were improved,and the transmission delay was reduced.Compared with other existing protocols,extensive analysis and simulation results demonstrate the superiority of the RMM protocol.