军事通信网抗毁性能的神经网络方法研究

可靠性和时延性能是衡量军事通信网抗毁性能的两个重要指标。在研究通信网节点间的链路的可靠性和时延性能后，提出综合考虑可靠性和时延性能的代价函数，借助自组织竞争人工神经网络对其进行分析和仿真。     

电力计量主站通信网最大可靠性路径选择方法

为保证电力计量主站通信网平稳运行，提出基于蚁群算法的通信网最大可靠性路径选择方法。使用网络邻接矩阵算法推算全部节点间最短路径长度与数量，提取抽象化的通信网邻接矩阵，创建通信网可靠性评估模型；计算信息传输时延，将最大可靠性与最低传输时延当作路径选择的双重目标，初始化路径选择参数；凭借蚁群算法的自组织特征更新信息素，实现高精度、最大可靠性路径选择任务。实验结果表明，所提方法可有效优化电力计量主站通信网络带宽，提高网络吞吐率，为计量数据高效率传输提供借鉴与帮助。     

一种竞争型的临近空间通信网多址接入协议仿真

为实现移动终端对临近空间物理链路资源的有效共享,提出将基于竞争机制的载波侦听型多址接入协议(CSMA)应用到临近空间通信网中,并采用理论推导和OPNET建模仿真的方法对其吞吐量和时延性能进行了分析.仿真结果表明,在常规的用户数量下,CSMA协议能够保证较大的吞吐量和较低的端到端时延,可以很好地应用于临近空间通信网.     

基于场景对比的电力通信网仿真平台设计

针对电力通信网设计初期如何简单验证拓扑结构的合理性与可靠性及如何预测后期因拓扑或业务变化对网络性能的影响,该文提出一种基于场景对比的通信网性能分析方法并实现了某电力公司通信网仿真平台。实验证明,该仿真平台对验证拓扑结构的合理性与可靠性及预测拓扑结构或业务变化对网络性能的影响等方面均有良好效果,能为电网设计和管理人员提供通信网从设计、建立到维护整个阶段的分析预测手段。     

水声通信网中一种低时延低开销路由算法

水声通信网在军事、环境、能源、自然灾害预防和处理等方面均具有巨大的应用潜力。针对当前水声通信网背景噪声大及传播速度慢,从而导致控制开销大和平均时延大的问题,提出了旨在改善水声网整体性能的NHMLDR算法。该算法采用了时延代价度量的RREQ和去除HELLO消息的新机制。仿真结果表明,与HCR算法相比,NHMLDR算法使系统的归一化控制开销最大降低约40.88%;分组平均端到端时延减小约8.93%~51.88%;数据分组丢失率降低约0.01%~0.3%;网络吞吐量提升了约10.1%~23.7%。因此,NHMLDR算法明显改善了系统的整体性能。     

关于通信网可靠性的研究进展

在通信网的设计和维护过程中,网络可靠性是一项重要的性能指标,目前这一课题已逐步引起人们的高度重视。本文综述了迄今为止在通信网可靠性研究领域里所取得的成果,在叙述过程中将重点介绍网络可靠性的测度及其数学模型,基本上不涉及网络算法。文章把通信网可靠性的研究成果归纳为四类:1.网络的抗毀性——可靠性的确定测度;2.网络的生存性——基于网络连通性的可靠性测度;3.网络的有效性——基于网络业务性能的可靠性测度;4.网络部件工作在多模式状态的可靠性测度。同时,本文提出了一个通信网可靠性的定义,以澄清目前在这个问题上的混乱,进而归纳了影响网络可靠性的因素,给出了分析通信网可靠性的一般方法,探讨了今后通信网可靠性的研究方向。     

基于业务临近度的电力通信网脆弱性分析

电力通信网脆弱性分析对确保电力系统安全运行和加强电网健壮性具有重要意义。以网络端到端时延理论为基础,建立基于业务临近度的电力通信网的脆弱性分析和评估模型。通过分析电力通信网的运行情况和业务分布,估算出端对端的传输时延、业务临近度和相邻节点的业务临近度相关性,建立业务链和节点的脆弱性分析模型。以IEEE-30节点系统为例进行仿真,完成对通信网络的脆弱性分析。对节点和业务链进行脆弱性排序,结果表明节点时延、业务分布和节点相关度三者与电力通信网的脆弱性密切相关。     

面向智能配用电网络的电力无线专网技术分析

智能配用电网络的一个很重要的构成部分就是其配用电通信网。配用电通信网具有较大的覆盖范围、分散的信号等特点,可以弥补光纤通信的不足,以建构完善的配用电网络。因此我们需要设计出性能良好地电力无线通信系统。本文主要从满足智能配用电需求出发,详细分析了通信网对带宽、时延和安全的需求,并针对现状提出了新的电力无线宽带解决策略。     

基于NS-2的组播技术教学实验设计

本文针对"计算机通信网"课程实验教学的特点,利用NS-2网络仿真软件设计了一个组播性能分析实验,给出了组播性能分析实验的网络仿真模型、网络仿真脚本文件的编写方法。该实验采用与单播技术对比的方式,从吞吐量、分组时延和时延抖动等方面分析了仿真结果。通过编写仿真程序和分析实验数据,帮助学生掌握网络通信协议,培养学生的创新能力。     

基于OPNET的军事通信网网络性能仿真

为了在高技术条件下的局部战争中把握战场的主动权,充分发挥军事通信网的保障作用,文章基于OPNET仿真平台,对军事通信网进行了建模、实现了对军事通信网相关网络性能的仿真。通过对仿真数据分析。对网络的实时性、可靠性、稳定性等性能进行了评估,从而对军事通信网的设计及使用提供技术上的参考。     

基于NS-3的声电协同网络实现及路由性能分析

水下无线通信主要依靠水声通信的方式进行信息传输。但水声链路本身具有高时延和高误码率等不足,为水下应用提供低时延的通信服务是一项具有挑战性的工作。声电协同网(CRAN)旨在充分利用水面无线电链路弥补水声网络(UAN)的性能局限,提升网络的整体性能。其中,CRAN中的路由协议需要构建声、电混合路径,是声电协同网络研究中的关键问题。该文首先在网络模拟器3(NS-3)中设计并实现了声电浮标节点与CRAN协议栈,搭建了CRAN的仿真平台。随后探讨了以无线自组网按需平面距离向量路由协议(AODV)为代表的被动式路由在CRAN中的应用。该文发现,AODV协议使用的距离向量准则在CRAN中能够更多地选择高速的无线电链路进行数据转发,有效地降低了网络传输时延。最后,通过仿真对AODV与其他协议的性能进行了对比、分析。结果表明,CRAN在投递率、传输时延、网络吞吐量、能效和路由响应速度方面对比水声通信网有较大提升。同时,以AODV为代表的被动路由协议,相比于以优化链路状态路由协议(OLSR)为代表的主动路由协议更适用于CRAN。     

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.     

有线无线融合的卫星时间敏感网络流调度研究

随着空间通信任务日趋复杂化,尤其是对时间敏感的需求不断提升,一方面要求星内系统的高带宽、可靠性和实时性;另一方面星间无线链路也应具备低时延和高可靠性.但由于卫星内部有线链路与星间无线链路差异大,业务数据经过有线和无线链路联合传输时,容易引发节点拥塞,而无法保障时敏业务的时延有界需求.为了提升数据在空间网络传输的实时性,...     

三层卫星光网络链路性能分析

分析了三层卫星光网络的链路类型、时延和网络稳定性等参数，结果表明与单层卫星光网络比较，三层卫星光网络吞吐量大、鲁棒性强。同时由于其结构复杂导致网络中链路负载加重、路由表计算量和阻塞概率增大。这为今后卫星光通信组网技术研究和空间光通信协议的拟定提供了参考。     

An energy efficient and QoS aware routing protocol for wireless sensor and actuator networks

Wireless sensor and actuator networks are composed of sensor and actuator nodes interconnected via wireless links. The actuators are responsible for taking prompt decisions and react accordingly to the data gathered by sensor nodes. In order to ensure efficient actions in such networks, we propose a new routing protocol that provides QoS in terms of delay and energy consumption. The network is organized in clusters supervised by CHs (Cluster-Heads), elected according to important metrics, namely the energy capability, the riches of connectivity, which is used to select the CH with high node density, and the accessibility degree regarding all the actuators. The latter metric is the distance in number of hops of sensor nodes relative to the actuator nodes. This metric enhances more the network reliability by reducing the communication delay when alerting the actuator nodes, and hence, reducing the energy consumption. To reach efficiently the actuator nodes, we design a delay and energy sensitive routing protocol based on-demand routing approach. Our protocol incurs less delay and is energy efficient. We perform an evaluation of our approach through simulations. The obtained results show out performance of our approach while providing effective gain in terms of communication delay and energy consumption.     

基于复合量度的电力光纤多电路配置可靠性

能源互联网的一个本质特征是通过先进的通信网络实现能源供给与消费间的双向互动。以光纤通信为基础的高可靠通信网络优化配置以满足多业务的服务质量(QoS)需求成为亟需解决的关键问题。从电力光纤传输网络的可靠性入手,并考虑电力通信业务的多QoS传输需求,设计一种基于复合量度的电路配置优化方法。有别于传统最短路配置算法,新方法在一次配置过程中同时规划m条可行配置方案,并且通过分析路径集的带宽、时延、丢包率、衰耗和成本等不同量度和光路全程可靠性,最终获得满足可靠性和传输QoS需求的光路配置方案,并给出优先选择序列。多电路优化配置将有效提升电力通信的可靠性,也可为未来多路流量分摊提供电路配置保证。通过某城区35~500 kV电力通信站网实例仿真计算,新配置方法能够一次获取4条同时满足业务多QoS需求的传输电路,实现主备电路保护。对电力光纤传输网络的规划和运行优化,提高电力通信网的资源调配能力和可靠性提供参考。     

Reliability-constrained dimensioning of transmission resources inpacket-switched networks

The author investigates the problem of dimensioning the transmission resources of a packet-switched communication network satisfying suitable reliability targets. The goal is a communication network providing a minimal transport capability in the presence of failures in network components. This goal is expressed in terms of availability functions to be satisfied by the reliability of communication links. The design procedure is based on the routing of each communication link on more than one transmission path, so that the availability of small shares of the communication link capacity can be increased. An analytic evaluation of the availability figures considered during the design phase is provided and the tools developed are used to compute an end-to-end reliability figure, which also takes into account the amount of user traffic     

Reliability optimization of computer-communication networks

The evaluation of the reliability of a given computer communication network is a NP-hard problem. Hence, the problem of assigning reliabilities to links of a fixed computer communication network topology to optimize the system reliability is also NP-hard. A heuristic method is developed to assign links to a given topology so that the system reliability of the network is near optimal. The method provides a way to assign reliability measures to the links of a network to increase overall reliability. It is based on the principle that the most reliable link should be assigned to the most vulnerable edge. The method computes an importance order for the edges of the network and uses the order to assign link reliabilities. If there are fewer than six links in a network, it can be shown that the method gives optimal assignment     

军用通信网系统可靠性分析与评估

军用通信网系统可靠性的综合性参数指标,由于受到工程试验的环境限制,多不具备可测性。例如:网络全功能、主要功能和最低功能的可用度,网络在70%、50%、30%失效(被毁)条件下的业务传输成功率,平均时延等。为此,基于分布式仿真环境,给出了军用通信网"故障关联"、"拓扑关联"、"有效性关联"的系统可靠性综合分析与评估方法。该方法结合系统可靠性工程试验,可实现对军用通信网系统可靠性进行综合分析与评估。     

Optimal Design of Mixed-Media Packet-Switching Networks: Routing and Capacity Assignment

This paper considers a mixed-media packet-switched computer communication network which consists of a low-delay terrestrial store-and-forward subnet combined with a low-cost high-bandwidth satellite subnet. We show how to route traffic via ground and/or satellite links by means of static, deterministic procedures and assign capacities to channels subject to a given linear cost such that the network average delay is minimized. Two operational schemes for this network model are investigated: one is a scheme in which the satellite channel is used as a slotted ALOHA channel; the other is a new multiaccess scheme we propose in which whenever a channel collision occurs, retransmission of the involved packets will route through ground links to their destinations. The performance of both schemes is evaluated and compared in terms of cost and average packet delay tradeoffs for some examples. The results offer guidelines for the design and optimal utilization of mixed-media networks.