有线电视与电话公司面对的机会和挑战

目前世界上一些国家的有线电视公司在通过自己的电缆网开展电话业务，也有不少电话公司利用宽带业务网经营ＣＡＴＶ业务。本文介绍了一种光纤／电缆混合系统，电话网和ＣＡＴＶ网的经营者可使用它向用户提供ＣＡＴＶ和电话业务。     

CATV宽带IP的网络建设

本文讨论了ＣＡＴＶ建设宽带ＩＰ网络的优势,ＣＡＴＶ宽带ＩＰ网络的建设原则和设计原则,ＣＡＴＶ宽带ＩＰ网络开放的业务,详细讨论了ＣＡＴＶ宽带ＩＰ网络的建设。     

在电信网上开发CATV传输业务的建议

本文在概述ＣＡＴＶ传输网，电信与ＣＡＴＶ传输网的兼容性，国际ＣＡＴＶ与电信市场的竞争和国内ＣＡＴＶ网发展概况基础上，提出在电信网上开发ＣＡＴＶ传输业务的策略。     

利用县区光纤CATV网开展通信业务

利用县区光纤ＣＡＴＶ网开展通信业务□黄国城（福建省莆田市涵江区广播电视新闻中心３５１１１１ＣＡＴＶ光纤网络中引进电话通信业务，是宽带传输网络多功能开发的重要项目，县区光纤ＣＡＴＶ可进行系统内业务通信。现代的ＨＦＣ网采用７５０ＭＨｚ频谱，相当于１１０个...     

电信与有线电视将融合成统一的B—ISDN网

简要叙述了国内外ＣＡＴＶ与电话相结合的发展趋势，ＣＡＴＶ信息交换技术，用户网技术的进展和ＣＡＴＶ网络与通信网的关系，并强调了电信部门要大力开发ＣＡＴＶ业务。     

CATV宽带IP的网络建设

本了ＣＡＴＶ建设带宽ＩＰ网络的优势,ＣＡＴＶ宽带ＩＰ网络的建设原则和设计原则,ＣＡＴＶ宽带ＩＰ网络开放的业务,详细讨论了ＣＡＴＶ宽带ＩＰ网络的建设。     

在CATV网上开展自选影视（VOD）新业务

ＣＡＴＶ光纤／同轴电缆混合网络可以加以综合利用，开展ＶＯＤ业务。本文给出ＶＯＤ网络的一般结构，讨论了Ｔｉｍｅ Ｗａｒｎｅｒ公司的“全功能服务网”方案，并对在上海市ＣＡＴＶ网上开展了ＶＯＤ业务提出了一些设想。     

在HFC网上开展多业务接入的研究

分四个阶段讨论了利用ＨＦＣ网络开展多业务接入的过程。可以看出，利用ＨＦＣ接入方案，从最初传送模拟ＣＡＴＶ业务，然后过渡到数字ＣＡＴＶ业务和交互式ＶＯＤ业务，再进一步开展双向话音和数据业务，最终可通过ＳＤＶ网络形式实现视像／话音／数据等全业务的接入并为将来过渡到ＦＴＴＨ打下基础。     

关于加速发展山西CATV技术业务之思路与对策

本文介绍９０年代以来英、美、日、韩、俄等国与我国ＣＡＴＶ业务发展与电信市场竞争趋势，提出了我省ＣＡＴＶ发展思路与对策，指出邮电与广电系统联合建设是促进我省ＣＡＴＶ业务发展的健康，有序，快速的方案。     

使用VSAT的企业组网

使用ＶＳＡＴ的企业组网ＳｔｅｖｅｎＷ．ＳｗｅｅｎｅｙＥｎｔｅｒｐｒｉｓｅＮｅｔｗｏｒｋｉｎｇＵｓｉｎｇＶＳＡＴｓ到目前为止，欧洲与北美的国际电信业务市场一直是由区域电信经营者（ＴＯ）占主导地位。竞争主要限于增值网络和有管理的数据网络业务，因为它们本身...     

Learning automata routeing in connection-oriented networks

Learning automata are used at the source nodes of a connection-oriented network to dynamically route newly arriving virtual calls to their destination. First, two new learning automata are introduced. Then, these two learning automata, as well as the well-known L Learning automaton and the deterministic shortest-path algorithms are used in a simulation program to route virtual calls. The more frequent the updating and the more recent network state information used, the better the performance. In the sequence, the virtual link length is developed as a function of both the number of packets and the number of virtual calls at the network link. This virtual link length is used in the learning automata routeing algorithm and is shown via simulation to be superior to the minimum packet delay or shortest-queue-type link length, usually used in real networks. Thus, in connection-oriented networks, not only the packet but also the virtual call traffic characteristics should be used in the routeing decisions. Furthermore, when the network state information is out-of-date, or when there are few virtual calls and each one carries a large number of packets, then the virtual link length should be based more on the number of virtual calls than on the number of packets at this link. On the other hand, when the network state information is current and there are many virtual calls and each one carries a small number of packets, then the virtual link length should be based more on the number of packets than on the number of virtual calls at this link.     

Bayesian inference of network loss and delay characteristics with applications to TCP performance prediction

In large-scale dynamic communication networks, end systems cannot rely on the network itself to cooperate in characterizing its own behavior. This has prompted research activities on methods for inferring internal network behavior based on the external end-to-end network measurements. In particular, knowledge of the link losses and link delays inside the network is important for network management. However, it is impractical to directly measure packet losses or delays at every router. On the other hand, measuring end-to-end (from sources to destinations) losses or delays is relatively easy. We formulate the problems of link and delay estimation in a network based on end-to-end measurements as Bayesian inference problems and develop several Markov chain Monte Carlo (MCMC) algorithms to solve them. We show how these link loss and delay estimates can be used to predict point-to-point transfer control protocol (TCP) throughput in the network. We apply the proposed link loss and delay estimation algorithms, as well as the TCP throughput estimation algorithms, to data generated by the network simulator (ns-2) software and obtain good agreements between the theoretical results and the actual measurements.     

基于列生成的毫米波多连接链路配置调度算法

多连接技术允许用户同时建立和保持与多个小区/接入点的连接,通过网络元素之间的协调在吞吐量和可靠性方面大幅提高网络性能。针对毫米波通信中超高频段的链路中断问题,研究了多连接基于链路配置的调度算法,以提高链路调度效率,降低复杂度。首先,在系统模型中采用链路配置作为优化变量;其次,设计了多连接比例公平的调度准则;最后,提出一种基于列生成算法的链路配置调度优化算法,利用Dantzig-Wolfe分解将原问题分解为限制主问题和定价问题,并结合分支定界方法获得最优解。仿真结果表明,所提算法能够在数值上逼近全局最优,并且比现有的毫米波蜂窝网络链路调度方案增益平均提高40%以上。     

一种适用于星地网络的流量负载均衡算法

在星地网络的背景下,为了降低由于地面网络链路负载过高导致的传播时延,提出了一种适用于星地网络的负载均衡算法。算法基于网络的链路容量设置一个链路资源利用率作为阈值,当发现路径出现过载的时候分成两步进行路径的预规划：第一步,运用蚁群算法为链路过载的数据流选择其他的路径,以满足地面网内部的负载均衡;第二步,如果仍出现链路超阈值的情况,通过卸载延迟容忍数据流来执行地面与卫星网络之间的负载均衡。仿真结果表明,设定自适应的过载阈值可以有效降低链路的拥塞,与现有算法相比该算法不仅可以更加均匀地分配地面网络中的流量,而且借助卫星网络使地面网络的平均时延降低了18.3%,提高了网络的服务质量。     

Moralism: mobility prediction with link stability based multicast routing protocol in MANETs

In recent research, link stability is getting tremendous attention in mobile adhoc networks (MANETs), because of several impediments that occur in a reliable and robust network. Link stability metric is used to improve network performance in terms of end-to-end delay, data success delivery ratio (DSDR) and available route time (ART). Energy consumption, bandwidth and communication delay of major concern in ad hoc networks. A high mobility of MANET nodes reduces the reliability of network communication. In a dynamic networks, high mobility of the nodes makes it very difficult to predict the dynamic routing topology and hence cause route/link failures. Multicast in MANETs is an emerging trend that effectively improves the performance while lowering the energy consumption and bandwidth usage. Multicast routing protocol transmits a packet to multicast a group at a given time instant to achieve a better utilization of resources. In this paper, node mobility is considered to map better their movement in the network. So, the links with long active duration time can be identified as a stable link for route construction. Variation in signal strength is used to identify whether the direction of the node is towards or away from estimating node. We consider signal strength as QoS metric to calculate link stability for route construction. Efforts are made to identify the link with highly probable longer lifetime as the best suitable link between two consecutive nodes. We predict the movement time of nodes that define the route path to the node destination. Exata/cyber simulator is used for network simulation. The simulation results of the proposed routing protocol are compared with on-demand multicast routing protocol and E-ODMRP, which works on minimum hop count path. Analysis of our simulation results has shown improvement of various routing performance metrics such as DSDR, ART, routing overhead and packet drop ratio.     

地域通信网链路威胁评估研究

链路威胁评估是进行干扰资源分配的基础.针对目前新型干扰技术出现的新情况和对网络重要链路实施干扰的新需要,首先分析了现阶段针对地域通信网的3类干扰技术,在此基础上,给出了通信网络环境下评估链路威胁的指标体系,并采用基于路径的方法对链路战术重要性进行了计算,最后运用多属性决策方法在具体网络场景下对链路威胁等级进行了评估计算...     

一种低时延的短波自组网优化链路状态路由协议

优化链路状态路由(Optimized Link State Routing,OLSR)协议是一种先验式路由协议,网络中的所有节点通过周期性地发送控制消息来计算全网路由信息。在短波自组织网络中,节点周期性地发送控制消息会占据大量的信道资源,大幅增加网络的控制开销,浪费短波有限的带宽资源,导致网络通信性能急剧下降。其次,受到地形地貌、天线方向和接收性能的个体差异等影响,造成无线链路不稳定,导致网络中存在非对称链路,增加了通信端到端时延。为此,提出了一种低时延的短波自组网OLSR协议。该协议在执行MPR(Multipoint Relay)选择算法时综合考虑了节点的连接度和链路可靠性,在优化MPR节点个数的同时选择链路可靠性较大的节点作为MPR节点,在进行路由选择时能够利用网络中的非对称链路。仿真结果表明,该协议能优化数据包投递成功率、吞吐量、端到端时延和网络控制开销等性能指标。     

Fingerprint and speaker verification decisions fusion using a functional link network

By exploiting the specialist capabilities of each classifier, a combined classifier may yield results which would not be possible with a single classifier. In this paper, we propose to combine the fingerprint and speaker verification decisions using a functional link network. This is to circumvent the nontrivial trial-and-error and iterative training effort as seen in backpropagation neural networks which cannot guarantee global optimal solutions. In many data fusion applications, as individual classifiers to be combined would have attained a certain level of classification accuracy, the proposed functional link network can be used to combine these classifiers by taking their outputs as the inputs to the network. The proposed network is first applied to a pattern recognition problem to illustrate its approximation capability. The network is then used to combine the fingerprint and speaker verification decisions with much improved receiver operating characteristics performance as compared to several decision fusion methods from the literature.     

Optical Network Management and Its Performance Evaluation for Both Future Cost Planning and Triple Play Solutions

This paper has presented the wavelength division multiplexing technology is being extensively deployed on point to point links within transport networks in the Egypt. Our suggested Trans-Egypt Network which uses optical cross connects to route lightpaths through the network are referred to as wavelength routing networks. The average setup time, average link utilization, traffic load, blocking probability, network costs, and network throughput with triple play solutions and achievable link utilization for multi math routing in the presence and absence of wavelength conversions are the major interesting parameters in the design of network topology under different routing and wavelength assignment such as first fit, random, least used and most used in order to upgrade network performance and its transmission efficiency.     

Off-line permutation embedding and scheduling in multiplexedoptical networks with regular topologies

There are two basic approaches for establishing a connection in a reconfigurable switched optical network, whose links are multipiexed with virtual channels (e.g., wavelengths or time slots). One is called path multiplexing (PM), in which the same virtual channel has to be used on each link along a path, and the other is link multiplexing (LM), in which different virtual channels may be used. We focus on the problem of off-line permutation embedding and scheduling as a part of the comparative study of the multiplexing approaches. Specifically, we determine the minimum number of virtual channels per link needed for a given network to be rearrangeably nonblocking in PM and LM, respectively. We also examine the schedule length of a permutation in PM and LM when the network is blocking as a result of having an insufficient number of virtual channels per link. We found that PM and LM are equally effective in linear arrays, and LM is slightly more effective than PM in rings, meshes (grids), tori, and hypercubes