Node Stability-Based Location Updating in Mobile Ad-Hoc Networks

In this paper, we consider the problem of location updating in mobile ad-hoc networks (MANETs). We propose a node stability-based location updating approach. In order to optimize the routing, most of the existing routing algorithms use some mechanism for determining a node's neighbors. This information is stored in a table called the neighbor table. The updating of the neighbor table is referred to as location updating. To evaluate our proposed algorithm, we simulated it and compared its performance with that of the performance of the conventional location updating algorithm, by considering different performance measures such as the number of collisions on the carrier, the number of acknowledgments received and the energy consumed. In our work, we obtained different types of results by varying different parameters such as the number of nodes and the terrain dimensions. The simulation results obtained show that the proposed algorithm outperforms the typical location updating algorithm used in existing routing protocols.     

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.     

应急情况下最少转发节点的传感器网络组播路由树算法

在抢险救灾等应急情况下,传感器网络的节点能量更为有限。为减少无用转发的能量消耗,利用无线信道的广播特性,根据广播子树删除思想,提出一种基于最短路由树、具有最少转发节点的组播路由树生成算法。对该算法进了证明和详细分析,并针对实际需要,给出使用范围更广泛的分布式实现方法。仿真分析说明,算法的分布式实现方法可减少ODMRP的转发节点数,大大降低数据发送次数,接收成员节点较多时尤为明显。最少转发节点的组播路由树的网络总开销最小,是延长网络生存时间的有效方法。     

A cross-layer design and ant-colony optimization based load-balancing routing protocol for ad-hoc networks

In order to periodically reassess the status of the alternate path route (APR) set and to improve the efficiency of alternate path construction existing in most current alternate path routing protocols, we present a cross-layer design and ant-colony optimization based load-balancing routing protocol for ad-hoc networks (CALRA) in this paper. In CALRA, the APR set maintained in nodes is aged and reassessed by the inherent mechanism of pheromone evaporation of ant-colony optimization algorithm, and load balance of network is achieved by ant-colony optimization combining with cross-layer synthetic optimization. The efficiency of APR set construction is improved by bidirectional and hop-by-hop routing update during routing discovery and routing maintenance process. Moreover, ants in CALRA deposit simulated pheromones as a function of multiple parameters corresponding to the information collected by each layer of each node visited, such as the distance from their source node, the congestion degree of the visited nodes, the current pheromones the nodes possess, the velocity of the nodes, and so on, and provide the information to the visiting nodes to update their pheromone tables by endowing the different parameters corresponding to different information and different weight values, which provides a new method to improve the congestion problem, the shortcut problem, the convergence rate and the heavy overheads commonly existed in existing ant-based routing protocols for ad-hoc networks. The performance of the algorithm is measured by the packet delivery rate, good-put ratio (routing overhead), and end-to-end delay. Simulation results show that CALRA performs well in decreasing the route overheads, balancing traffic load, as well as increasing the packet delivery rate, etc. Translated from Journal of ACTA Electronica Sinica, 2006, 34(7): 1199–1208 [译自: 电子学报]     

一种有效的具有负载意识的按需路由协议

移动Ad hoc网络是由一组无线移动终端构成的临时性网络,不依赖于固定的基站或现有的有线骨干网。由于网络拓扑结构动态变化的特性和网络资源的有限性,开发一种性能优越的Ad hoc网络路由协议是一项具有挑战意义的工作。在本论文中,提出了一种有效的具有负载意识的按需驱动路由方案。该方案将网络负载信息作为路由选路的主要标准。对提出的方案作了仿真,并且和Dynamic Source Routing（DSR）协议进行了比较。结果表明网络负载在总体上得到了平衡,包传递率和平均端到端时延的性能也得到了有效的改善。     

基于能量的非完全分簇路由算法

针对LEACH算法中节点能量消耗过快而容易死亡、簇头选举机制不合理及稳定周期短等问题,为提高网络稳定性,有效利用节点能量,提出了一种非完全分簇路由算法.该算法考虑节点剩余能量来选举簇头,利用基站能量充足的优势,建立非完全分簇,采用平面路由和分簇路由相结合的方式来实现数据传输,以均衡网络负载.仿真结果表明,该算法对比LE...     

基于网络划分的VANET路由构建及数据传输方法

为提高车载自组网的路由扩展性,提出了一种基于网络划分的车载自组网路由构建及数据传输方法。首先,提出了一种新的车载自组网划分算法来把网络划分为多个子网,随后,搭建和维护各子网中的头尾节点间路由,最后,所有路由的搭建和维护都基于各个子网的头尾节点间路由。该方法将链路失败的影响局限于包含该链路的子网中,并且能够多次复用子网中的路由信息。仿真表明,在网络节点数和路由数目不断增多的情况下,相对于直接在网络中应用相关路由算法,文中方法显著地减小了路由代价,提高了网络性能。仿真结果充分地说明了文中方法的有效性。     

A Radial Path Building Algorithm for Optimal Feeder Planning of Primary Distribution Networks Considering Reliability Assessment

Optimal feeder routing is an important part of general optimal distribution network planning. This article proposes a new algorithm for optimal feeder routing using an easy step-by-step, radial path building algorithm, ensuring minimization of the total system planning cost. Furthermore, reliability assessment is carried out to obtain the most reliable feeder routing to acquire less interrupted network structure with different feeder configurations. The proposed approach is also tested for optimal feeder routing with variations in the number of substations, which provides information on the trade-off between optimality and reliability of the system configuration. Moreover, the concept of principle of optimality is effectively used to make the proposed approach computationally more efficient and useful. The extensive test results reflect the potential ability of the proposed approach for optimizing the network structure in power distribution networks.     

软件定义网络的流量调度算法研究

目前,NOX、FloodLight等SDN控制器均提供了类似于传统路由器OSPF协议的最短路径转发算法,这些算法通过SDN控制器收集全局交换机静态参数从而进行路径计算,但并没有利用SDN系统的优势即获得运行时的动态信息来优化算法性能,在流量过大时传统算法容易导致网络拥堵。对SDN的路由算法进行研究,应用粒子群算法并利用SDN技术的特点对网络的负载均衡问题进行相关的优化。仿真实验表明与ECMP算法相比,提出的算法可以在一定程度提升网络的整体利用率,降低网络的时延和拥塞。     

Perfor mance of a QoS-based multiple-route ad hoc on-demand distance vector protocol for mobile ad hoc networks

This paper proposes a quality of service based multiple-route ad hoc on-demand distance vector (QoS-MRAODV) routing protocol for achieving and maintaining QoS in mobile ad hoc networks (MANETs). The QoS-MRAODV protocol supports one active QoS-based primary route and several backup routes to provide hot standby redundancy against frequent route failures that are prevalent in MANETs. Results from extensive performance simulation of the QoS-MRAODV protocol demonstrate that it is indeed a viable protocol for achieving and maintaining QoS support in MANETs, providing the additional benefits of fast route discovery time and low routing overhead without a significant increase in end-to-end packet delay.     

ASAR: An ant-based service-aware routing algorithm for multimedia sensor networks

Aimed at three basic services (event-driven, data query and stream query), the paper presents a QoS routing model for multimedia sensor networks. Moreover, based on the traditional ant-based algorithm, we propose an ant-based service-aware routing (ASAR) algorithm. The ASAR chooses suitable paths to meet diverse QoS requirements from different kinds of services, thus maximizing network utilization and improving network performance. Finally, extensive simulation is conducted to verify the effectiveness of our solution and we give a detailed discussion on the effects of different system parameters. Compared to the typical routing algorithm in sensor networks and the traditional ant-based algorithm, our ASAR algorithm has better convergence and significantly provides better QoS for multiple types of services in the multimedia sensor networks. __________ Translated from Acta Electronica Sinica, 2007, 35(4): 705–711 [译自: 电子学报]     

TCP performance over mobile ad hoc networks

TCP is a transport protocol that guarantees reliable ordered delivery of data packets over wired networks. Although it is well tuned for wired networks, TCP performs poorly in mobile ad hoc networks (MANETs). This is because TCP's implicit assumption that any packet loss is due to congestion is invalid in mobile ad hoc networks where wireless channel errors, link contention, mobility and multipath routing may significantly corrupt or disorder packet delivery. If TCP misinterprets such losses as congestion and consequently invokes congestion control procedures, it will suffer from performance degradation and unfairness. To understand TCP behaviour and improve the TCP performance over multi-hop ad hoc networks, considerable research has been carried out. As the research in this area is still active and many problems are still wide open, an in-depth and timely survey is needed. In this paper, the challenges imposed on the standard TCP in the wireless ad hoc network environment are first identified. Then some existing solutions are discussed according to their design philosophy. Finally, some suggestions regarding future research issues are presented.     

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.     

无线Mesh网络中一种新的路由判据

由于无线Mesh网络特有的性质，网络中的路由判据设计对网络整体性能起着至关重要的作用。文章介绍了无线Mesh网对路由判据的要求，分析了现有的几种路由判据，并针对现有路由判据的缺点提出了一种新的判据——链路累积干扰．通过仿真对该判据进行了验证。仿真结果说明，新的路由判据能明显改善网络性能。     

基于分级调度算法的交换机路由信息处理技术

针对交换机路由信息高效处理的需求,研究了基于分级调度算法的交换机路由信息处理技术。基于插卡式交换机接口进行系统配置,并在此基础上细化了交换机路由信息处理功能模块,以便于大规模交换机组网信息。为避免路由信息处理进程通信阻塞而导致的通信时延以最大化系统性能,提出了利用分级调度算法对交换机信息处理进程进行实时调度。另外,为计算分级调度算法的最优解以对交换机进行高效配置,利用粒子群优化算法实现分级调度函数的最优解搜索。系统测试结果显示,所提出的分级调度方案可以有效降低交换机通信时延,显著提高交换机路由信息处理能力。     

低压电力线通信网络特性模型与组网算法

由于低压电力线载波通信网络具有物理拓扑复杂和电力线信道时变的特征,在实际应用中存在着通信可靠性较低的问题。为了提高低压配电网电力线载波通信系统可靠性,在总结前人提高电力线通信可靠性的研究基础上,分析电力线通信网络的拓扑结构和组网模型,并提出组网的优化目标函数;进而提出一种基于信道状态和服务需求的电力线通信组网算法。分析了网络拓扑结构,信道特性和通信误码率、传输延时之间的关系,并提出估算方法。仿真试验结果表明,所提算法可根据信道和通信链路的动态变化以及不同的服务需求而动态地建立并优化电力线通信网络路由,保证通信网络的有效性,为后续的工程应用提供参考。     

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。     

基于AdaBoost与BP神经网络的风速预测研究

介绍了基于AdaBoost的多神经网络集成预测方法。集成方法的预测结果优于其他方法的预测结果,这一点在理论上和经验上已经得到证明。AdaBoost是适用于时间序列预测的集成方法。基于AdaBoost算法,采用多个BP神经网络训练随机生成的风速样本,再由多个训练结果生成最终的风速预测值。用该方法预测的误差低于用单一BP神经网络进行的预测,其分析和仿真结果表明了其优越性。     

Heuristic techniques for accelerating hierarchical routing on road networks

The route computation module is one of the most important functional blocks in a dynamic route guidance system. Although various algorithms exist for finding the shortest path, their performance tends to deteriorate as the network size increases. We present an efficient hierarchical routing algorithm that finds a near-optimal route and evaluate it on a large city road network. Solutions provided by the hierarchical routing algorithm are compared with the optimal solutions to analyze and quantify the loss of accuracy. We propose a novel yet simple heuristic to substantially improve the performance of the hierarchical routing algorithm with acceptable loss of accuracy. A network pruning technique has been incorporated into the algorithm to reduce the search space and the correctness of the results is evaluated. The improved hierarchical routing algorithm that incorporates the heuristic techniques has been found to be over 50 times faster than a typical shortest path algorithm.     

New dynamic routing algorithm based on MANET in the LEO/MEO satellite network

The features of low earth orbit/medium earth orbit (LEO/MEO) satellite networks routing algorithm based on inter-satellite link are analyzed and the similarities between satellite networks and mobile Ad Hoc network (MANET) are pointed out. The similar parts in MANET routing protocol are used in the satellite network for reference. A new dynamic routing algorithm based on MANET in LEO/MEO satellite networks, which fits for the LEO/MEO satellite communication system, is proposed. At the same time, the model of the algorithm is simulated and features are analyzed. It is shown that the algorithm has strong adaptability. It can give the network high autonomy, perfect function, low system overhead and great compatibility. __________ Translated from Journal on communications, 2005, 26(5): 50–62 (in Chinese)