On the complexity and manageability of Internet infrastructure

The ever increasing complexity of the Internet has made it impossible to effectively manage the Internet infrastructure. In this paper, we argue that the increased complexity was due to the “random accidents” introduced throughout the evolution of the Internet, such as ad-hoc based routing, cross-layer optimizations. These ad-hoc events increased the vulnerability and degraded the manageability of Internet. We also propose a new framework for network design and deployment, termed “assurable communication networks (ACNs)” that places the manageability in the center in network architecture. We suggest that rigorous mathematical model be developed for the measurement on the impact of manageability and accountability.     

多层优化蚁群算法的移动机器人路径规划研究

针对地图环境建模以及蚁群算法存在的问题,提出了一种移动机器人路径规划的多层优化方法.首先对U型陷阱栅格区域进行凸化处理,避免前期搜索混乱;设计新的状态转移规则,解决常规蚁群规划的路径过于紧贴障碍物的问题;改进距离启发式函数,有效提高算法收敛速度;设计平滑启发函数,增加蚂蚁局部探索时直行的机率,提升初始路径平滑性;提出按...     

基于拥塞感知的ASON路由算法

针对网络中瞬间涌现的大量并发数据流导致网络拥塞的问题,提出了一种改进的拥塞感知路由算法。该算法可实时根据节点和邻居节点到目的节点的路径长度及拥塞状况选择路径,以自动交换光网络(Automatically Switched Optical Network, ASON)网数据包拥塞指标为链路代价值,根据网络实际的信息包传输状况,对各节点链路进行加权计算。该算法能够动态感知网络拥塞状态,是一种可自适应调节的路由算法。仿真实验表明,相比传统最短路径路由算法,所提算法能够有效提高ASON网动态选路的合理性及传输网数据的传输效率,优化网络资源利用率。     

无线传感器网络中LEPS路由协议性能分析

LEPS是无线传感器网络中的多跳路由协议.它建立1个以汇聚节点为根节点的树型拓扑结构.节点向自己的父节点发送数据,并沿最短路径传送到汇聚节点.利用TinyOS的仿真软件TOSSIM对LEPS协议进行了研究,统计了控制包发送间隔取不同值时网络的路由建立时间、控制开销和数据包发送时延,分析了控制包的发送间隔对该协议性能的影...     

Energy‐aware congestion control scheme in opportunistic networks

In opportunistic networks, a congestion phenomenon may occur if the remaining buffer of a node cannot accept any arrival message. Energy is consumed by dropping the messages stored in the buffer to provide space for new messages. In order to reduce and balance the energy consumption of nodes during congestion in opportunistic networks, a novel congestion control scheme is proposed. Nodes dynamically update their residual energy level and query the residual energy level of their neighbors in current local environment and adjust their threshold ratio using the learning automata principle while moving around. Nodes will only receive messages whose remaining TTL (time to live) proportion of initial TTL is larger than the threshold ratio when congestion occurs. Simulation results show that the Epidemic routing protocol with the proposed congestion control scheme can efficiently reduce and balance energy consumption among nodes. Also, the routing performances such as delivery ratio, overhead ratio, and deliver latency are improved. Furthermore, the network lifetime is obviously improved since much more energy is left. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

跳点优化蚁群算法的移动机器人路径规划

传统的蚁群算法（ACA）在路径规划中难以克服路径次优及收敛慢等问题。针对这些问题，提出一种跳点优化蚁群算法（JPOACA）。通过引入跳点搜索（JPS）算法价值函数，筛选出低成本的邻域节点，然后运用ACA的多邻域性扩展JPS算法的邻域，扩大JPOACA的视野，增加低成本邻域数量，在低成本的JPS算法邻域内设计夹角启发信息函数和步长启发信息函数，提高算法的路径寻优能力，最后采用在跳点处补充信息素，最优路径的跳点处额外增加信息素的信息素补充方式，提高融合算法的收敛速度。仿真结果表明，JPOACA规划出的路径光滑更好性，且收敛速度、对复杂地形的适应能力均有显著提升。     

基于负载感知和伪流言机制的高稳定性路由协议

通过建立无人机自组网可以有效满足无人机集群作战的组网通信需求,但相较于传统移动自组网,无人机自组网具有节点移动速度更快,网络拓扑高度动态变化的显著特征.针对链路频繁断开带来网络性能下降严重的问题,提出了一种基于负载感知和伪流言机制的高稳定性路由协议.网络拥塞和节点移动性是影响路径稳定性的两个主要因素.针对网络拥塞问题,提出了基于节点负载预测的伪流言受限洪泛机制,在发起路由请求过程中,通过动态调整节点转发概率,均衡了网络负载的同时降低了控制开销.针对无人机节点的高移动性特征,基于接收到分组信号功率强度,提出了链路稳定性的联合度量指标.仿真结果表明,与AODV协议及其他改进型协议相比,该协议有效减少了网络的控制开销,提高了分组投递率,降低了平均端到端时延,显著改善网络性能,增强了数据传输的实时性和可靠性.     

基于关键节点备份的多路径可靠路由协议

为了提高无线传感器网络中数据传输的可靠性,设计了一种基于关键节点备份的多路径可靠路由协议（BK-MR-RP）.首先,采用侦听机制来获取邻居节点的路由信息,通过对链路质量和路径相关因子的综合评估选择一条或多条备用路径;其次,针对相关度较高的网络找出路径关键节点,采用节点备份技术对路径关键节点进行备份,以此提高数据传输的可靠性;最后,提出在数据包中添加多个附加位的方式来指示源节点选取的数据包发送的路径.仿真结果表明,随着网络中节点数目的增加,BK-MRRP协议使数据传输的成功率提高5％～10％,传输延迟降低10％ ～ 25％.     

基于自适应蚁群算法的AGV路径规划优化

针对传统蚁群算法在AGV路径规划中存在拐点数目较多，运行能耗较高等问题，提出一种改进的自适应蚁群算法。首先采用自适应参数调整方法，在迭代过程中不断调整信息素浓度和启发式信息的相对重要性，以增强蚂蚁搜索的目的性；其次引入多目标路径性能评价指标，在路径长度的单一指标基础上引入路径风险指标和拐点数目，以实现AGV路径规划的全局综合优化；然后提出一种奖惩机制更新信息素增量，针对不同程度评价指标的路径提供不同的信息素更新规则，避免算法陷入早熟；最后引入准均匀三次B样条平滑策略，进一步优化最优解。在20×20和30×30不同复杂程度的环境下进行仿真实验，本文改进算法相比传统蚁群算法在转弯次数上减少了113%～382%，在收敛速度上提升了798%～879%，验证了本文改进算法的有效性、可行性和优越性。     

基于最小路径选择度的电力通信网络路由优化策略研究

针对电力通信业务对服务质量和可靠性的要求越来越高,在软件定义网络的基础上提出了一种基于最小路径选择度的电力通信网络路由优化策略.将基于图形卷积网络的链路带宽占用率预测模型的预测结果与三角模算子相结合得到路径选择度,作为电力业务传输路径选择的依据,实现了电力通信网链路资源的动态分配.通过仿真与传统的路由优化策略进行丢包率...     

基于短距无线的低压用户停电事件突发上报拥塞规避机制研究

低压用户侧停电事件的精准分析依赖于表计设备停电上报的实时性与可靠性。文章介绍了一种适用于多用户停电事件突发上报的自组网微功率无线拥塞规避机制。该机制运行于自组网子网代理协调器媒介访问控制协议之上,在电能表停电事件报文上传初期设置等待期,充分接收电能表及其他子网内设备停电事件报文,并在等待期后通过比特映射方式将接收的停电事件统一上报给集中器;该机制的等待期参数设置能够充分适应突发报文所需的媒介竞争时间,从而降低了报文的丢包率和等待时延;通过仿真分析可知,提出的拥塞机制可以有效提高系统本地通信网数据传输的时效性和可靠性。     

Research on network failure handling technology based on deflection routing

A new deflection routing scheme is proposed to overcome the drawback of existing deflection routing scheme that cannot handle node failure and suffer from routing loops. A new algorithm for computing the backup shortest path tree (SPT) is proposed and a set of procedures are defined for utilizing the backup SPT in case of node or link failure. The failure can be handled swiftly and the backup routes are guaranteed to be loop-free. Experimental results show that the backup routes calculated by proposed scheme are close to the optimal routes by totally re-computing. __________ Translated from Journal of Beijing University of Posts and Telecommunications, 2007, 30(6): 1–4 [译自: 北京邮电大学学报]     

A controllable multi‐replica routing approach for opportunistic networks

Opportunistic networks take full advantage of opportunistic encounters among nodes to transfer packets. According to the characteristics of the limited energy of nodes and the frequent link variation in opportunistic networks, we introduce a novel routing metric that comprehensively takes into consideration the energy consumption of nodes, the probability of relay nodes meeting their destination, the time‐to‐live of the packet, and the approximate number of packet copies. Based on this metric, we propose a controllable multi‐replica routing approach in which a single‐branch diffusion strategy is applied to achieve the goal of dynamically controlling the number of replicas of packets. Our simulation results show that the proposed approach can avoid excessive load on individual nodes, guarantee the energy fairness among nodes, prolong the network lifetime, and effectively improve the delivery ratio of packets. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于改进拉格朗日松弛算法的电力通信网络负载均衡优化策略研究

针对传统电力通信网络路由策略存在的负载分布不均和丢包率较高等问题,基于软件定义网络,提出了一种基于改进拉格朗日松弛算法的电力通信网络QoS路由策略。以链路时延、可用带宽和丢包率为约束建立路由模型,并采用改进的拉格朗日松弛算法进行路径选择。通过仿真与传统路由方法进行对比,验证了该方法的可行性。结果表明,与传统路由策略相比,该方法能够规划出符合QoS要求的路径,负载分布更加均衡,有效降低了业务丢包率,丢包率由45%降低到0.1%,具有一定的实用价值。     

一种面向FANET的改进OLSR协议

路由协议对于无人机自组织网络（FANET）的服务质量（QoS）具有重要意义。FANET中节点的高速移动会带来网络拓扑剧烈变化,这一特性会加剧链路中断,从而导致网络QoS显著降低。本文提出一种基于链路质量的低路由开销协议（LQLR_OLSR）,针对FANET中多点中继（MPR）集进行优化,减少冗余的MPR节点,并修改基于期望传输计数（ETX）,使其作为路由度量,融合正向传输成功率、反向传输成功率、链路分组大小和链路带宽四个特征,实现路由多径自适应。通过OPNET仿真结果表明,FANET环境下LQLR_OLSR在平均吞吐量、发包成功率、路由开销和平均端到端时延性能方面明显优于Global_OP_OLSR和OLSR。     

认知Ad-hoc无线网络的跨层结构设计

认知ad-hoc无线网络中,提出了一种新的跨层设计方案.文章建立了认知无线网络中传统OSI 7层模型中的物理层、数据链路层及网络层的数学模型,并根据各层的数学模型特点设计了新的通信节点结构.通过提出有效信道容量的概念,实现了物理层/数据链路层/网络层的3层跨层设计,并在此基础上提出了多目标推理与决策过程新的程序设计流程图,最后使用遗传算法进行多目标优化并决策出最终的通信参数.仿真结果表明,提出的3层跨层设计的数据包投递率与系统吞吐量明显优于传统分层设计结构及双层跨层结构设计方案,即能够实现通信系统准确度及通信效率的提高.     

A cross-layer adaptive transmission scheme over correlated fading channels

Conventional adaptive transmission schemes perform poorly in wireless correlated slow-fading channels. A cross-layer adaptive transmission scheme combined with selective repeat automatic repeat request (SR-ARQ) is proposed. We apply a multi-state Markov system model for analyzing the performance of systems and optimizing the selection of modulation levels and packet sizes in correlated fading channels, which is also described by a finite-state Markov chain. A general closed-form expression of the average throughput for our suggested scheme is presented. Numerical results show that our adaptive scheme combined with SR-ARQ can obtain good performance in correlated fading channels. Translated from Journal on Communications, 2006, 45(1): 35–41 [译自: 通信学报]     

一种分布式车联网路由恢复方法

针对移动自组网路由协议在用于车联网时路由恢复延迟长、效果差的问题,提出了一种独立于具体路由协议的路由恢复方法。主要用于高速公路无基站情况下车与车之间的通信。能在通信路径断开后快速恢复并保证恢复后的通信路径有较高的可靠性。仿真实验表明,算法有效地降低了路由恢复延迟和开销,提高了路由修复成功率和路径生存时间。     

Conserving energy in wireless sensor networks

Routing in sensor networks is an area of research, with a still-limited but rapidly growing set of research results. Although many of these routing techniques look promising, there are still many challenges that need to be solved. Another interesting issue for routing protocols is node mobility. Most of the current protocols assume that the sensor nodes and the base station are stationary. However, there might be situations such as battle environments where the base station and possibly the sensors need to be mobile. In such cases, the frequent update of the position of the command node and the sensor nodes and the propagation of that information through the network may excessively drain the energy of nodes. New routing algorithms are needed in order to handle the overhead of mobility and topology changes in such energy-constrained environment.     

Adaptive routing algorithm for network load balancing

This paper introduces a routing algorithm which distributes the network traffic for each feasible route based on the reinforcement learning scheme. The aim of this algorithm is to reduce the transfer delay caused by congestion of the network. Most routing algorithms based on the reinforcement learning scheme could not avoid forwarding traffic toward the source of data packets. This property creates transfer loops and a lot of packet loss. In particular, the transfer loop may cause change in the order of packets, and also retransmit on the TCP connection. Thus, we employ a method that estimates the lower boundary of the probability for valid route to the destination, and this lower boundary can be used to reject the routes which cause the transfer loop. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.