LEO星座中基于不完全信息的路由联盟博弈策略

针对LEO卫星网络在多跳转发数据包时流量分布不均问题,提出了一种基于不完全信息的最优收益路由联盟博弈算法.各节点协同联盟邻居节点,共同确定数据报文当前最优转发路径,从而分配和平衡节点间流量负载.仿真结果表明,与最短路径卫星路由DSP或智能路由TLR相比,本文算法的平均数据传输延迟降低了18.5%,节点流量负载均衡度提高了65.6%.     

低轨卫星星座快速响应链路损毁路由算法

设计高效弹性的卫星路由算法是未来低轨(Low Earth Orbit, LEO)卫星通信技术的一个重要发展方向。为解决低轨卫星星座网络中星间链路发生故障后存在的传输中断和数据安全问题,提出了一种低轨卫星星座快速响应链路损毁路由算法(Quick-response Link Destruction Routing Algorithm for LEO Satellite Constellation, QRLDRA)。QRLDRA以星座可预测拓扑作为星间路由计算基础,增加星地回传路由设计,快速将星间链路异常回传至地面计算中心处理;引入多优先级动态队列,根据节点链路状态调整星间链路不同数据传输的优先级;综合路由计算、路由上注、链路检测等功能,完成对拓扑变化的及时响应。通过仿真实验与传统算法的比较发现,所提算法有效提高了数据端到端传输的成功率,为用户业务服务质量(Quality of Service, QoS)提供了可靠保障。     

低轨卫星星座网的切换研究

提出了一种适用于装备有星际链路的低轨卫星星座网的切换策略——最小跳数切换策略。该策略以端到端连接的跳数为基础,充分利用了低轨星座网的特点,将切换过程与路由有机地结合为一体,有效解决了不同卫星之间的切换问题。仿真结果表明,同已有的切换策略相比,该策略能够提供一定程度的QoS保障,获得较好的系统性能,如较低的传播延时和较小的切换频率,具有很好的实用价值。     

Mitigation of Packet Loss Using Data Rate Adaptation Scheme in MANETs

Node’s mobility, bursty data traffic, and dynamic nature of the network make congestion avoidance and control a challenging task in Mobile Adhoc Networks (MANETs). Congestion results in high packet loss rate, increased delays, and wastage of network resources due to re-transmissions. In this paper, we propose In-route data rate adaptation to avoid packet loss. Proposed scheme is based on the analysis of queue length of the forwarding nodes, number of data source nodes, and rate of link changes. In proposed technique, queue length of forwarding nodes is communicated periodically to the neighbor nodes using existing control messages of the underlying routing protocol. Keeping in view the queue length of forwarding nodes, number of data source nodes, and rate of link changes, initially the intermediate nodes buffer the incoming data packets upto some threshold and then, gradually shift the effect of congestion to the data source nodes. Then, the source node adapts its sending data rate to avoid congestion and to ensure reliable data communication. We have performed simulations in NS-2 simulator by varying different network metrics such as data rate, number of source nodes, and node speed. Results show that proposed technique improves network performance in terms of packet delivery ratio upto 15 %, reduction of average end-to-end delay and packet loss due to interface queue overflow upto 25 % and 14 % respectively, as compared to the static rate adaptation scheme.     

LEO multi-service routing algorithm based on multi-objective decision making

In low earth orbit(LEO) satellite networks,in view of the unbalanced link resource,it's difficult to meet differentiated quality of service(QoS) requirements and easily lead to reduce the efficiency of the whole network.A routing algorithm based on multi-objective decision making was proposed which defined LEO satellite network transmission service as the delay sensitive,sensitive bandwidth and reliability sensitive three categories.It used the eigenvector method to calculate service weights,and used the consistency ratio to determine whether it can be accepted.Based on the multi-objective decision making theory,it combined with the actual state of satellite network nodes and links and the specific requirements of the business,calculating the path that meets the QoS requirements of the service,so as to realize the LEO satellite network multi objective dynamic routing optimization.Established simulation platform based on the iridium network system simulated network delay,the uncertain characteristics like the residual bandwidth and packet error rate,route planning for the randomly generated three classes of business.The simulation results show that,the algorithm not only satisfies the QoS constrain while balancing the traffic load of the satellite link effectively,but also improves the performance on the throughput.     

Load balancing routing for single-layered satellite networks

The varying population density leads to imbalanced utilization rate of satellites. To ensure an intelligent engineering of traffic over satellite networks, a distributed routing scheme for single-layered satellite network, load balancing routing protocol based on mobile agent (LBRP-MA) is proposed. For LBRP-MA, mobile agents explore route by migrating autonomously. Upon arriving at destination, mobile agents migrate back. On each intermediate satellite, mobile agents evaluate path cost considering satellite geographical position as well as inter-satellite link (ISL) cost, and finally take ISL congestion index into account to update routing tables. Through simulations on the Courier-like constellation, the proposed approach is shown to achieve guaranteed end-to-end delay bound and decrease packet loss ratio with better throughput, which is especially suitable for data transferring in case of high traffic load. Moreover, results of the complexity analysis demonstrate that LBRP-MA can have low onboard signaling, storage and computation requirements. Furthermore, issues of LBRP-MA such as ISL congestion index and cost modification factor are discussed.     

Routing optimization based on topology control in satellite network

A new double-layer satellite network model for space networking was established and a routing algorithm based on topology control (TCRA) was proposed considering the advantages of low earth orbit and stationary earth orbit satellite networks.This model used virtual node strategy and satellite grouping idea,which regarded the coverage area of each low earth orbit satellite as a virtual node.The network took into account the influence of the polar area on the division of the satellite footprints,such that the upper management satellites can accurately acquire the topology of the lower satellites.Using the improved virtual node strategy,the time slices were superior to other network models in quantity,length and other aspects.Based on the network topology,stationary earth orbit satellites calculate routing for low earth orbit satellites,while low earth orbit satellites were responsible for forwarding data.The simulation results show that the routing algorithm is superior to other algorithms in average end-to-end delay and packet loss rate.     

无线传感器网络路由协议的设计与实现

针对传统路由协议端到端时延长、丢包率过高的现实问题,提出了一种基于贪婪转发的能量感知多路径路由协议(Greedy Forward Energy-aware Multipath Routing Protocol,GFEMRP)。GFEMRP从传感器起始结点出发,如果遇到网络黑洞则选择周边转发方式,否则将选择吞吐量大、且更接近于目的结点的结点作为下一跳结点。利用了OMNET++5.0和INET框架对包括无线自组网按需平面距离向量路由协议(Ad hoc on-demand distance vector routing protocol,AODV),动态按需无线自组织网络(Dynamic MANET On-demand,DYMO),贪婪周边无状态路由无线网络(Greedy Perimeter Stateless Routing for Wireless Networks,GPSR)和GFEMRP协议在内的四种路由协议进行了仿真和比较,实验结果表明GFEMRP协议具有良好的端到端时延、丢包率等性能。     

Content forwarding strategy based on ICN architecture in VANET

Combining VANET with ICN,a routing building and selecting strategy-SRBS based on vehicular dynamic parameters was proposed.After locating the content nodes through content discovery process,several unicast forwarding paths would be built,which reduces useless traffic compared with a flooding way.By introducing dynamic metrics and LET to routing building and selecting process,SRBS improved the link stability and reliability,which ensured the Data’s successful return.Simulation results show the scheme also improves the time tolerance of routings and makes full use of network cache and reduces delay and routing hops.     

车载Ad hoc网络基于转发能力预测的路由策略

在车载Ad hoc网络中,节点的高速移动导致全网拓扑的频繁变化,以街道为单位的路由策略更加高效。传统的研究中使用街道的静态信息或者瞬时的动态信息选择路由路径。前者忽略了车辆节点的动态分布,后者中,精确的全局动态信息获取困难且开销巨大。文章提出街道转发能力来评估街道的路由特性,并预测其持续时间。基于街道转发能力的预测,本文设计了结合静态长度和动态信息的路由策略。仿真结果表明,本策略可以显著提高路由性能。     

EOMR: An Energy-Efficient Optimal Multi-path Routing Protocol to Improve QoS in Wireless Sensor Network for IoT Applications

The wireless sensor network based IoT applications mainly suffers from end to end delay, loss of packets during transmission, reduced lifetime of sensor nodes due to loss of energy. To address these challenges, we need to design an efficient routing protocol that not only improves the network performance but also enhances the Quality of Service. In this paper, we design an energy-efficient routing protocol for wireless sensor network based IoT application having unfairness in the network with high traffic load. The proposed protocol considers three-factor to select the optimal path, i.e., lifetime, reliability, and the traffic intensity at the next-hop node. Rigorous simulation has been performed using NS-2. Also, the performance of the proposed protocol is compared with other contemporary protocols. The results show that the proposed protocol performs better concerning energy saving, packet delivery ratio, end-to-end delay, and network lifetime compared to other protocols.

     

QoS routing based on mobile agent for LEO satellite IP networks

Current quality of service (QoS) routing schemes for low earth orbit (LEO) satellites IP networks either neglect the varying population density or fail to guarantee end-to-end delay. As a remedy, QoS routing protocol based on mobile agent (QoSRP-MA) is proposed. QoSRP-MA is a source-based routing protocol. Once connection requests arrive, QoS mobile agents are dispatched from ingress satellite to explore routes, which migrate using satellite routing tables. Upon arriving in egress satellite, QoS mobile agents migrate back towards ingress satellite to reserve bandwidth. To construct satellite routing tables, load balancing routing algorithm based on mobile agent (LBRA-MA) is presented. In LBRP-MA, at regular intervals mobile agents launched on all satellites migrate autonomously to evaluate path cost and update routing tables. Moreover, path cost between source and destination is evaluated considering satellite geographical position as well as inter-satellite link (ISL) cost. Furthermore, ISL congestion index is considered to update routing table. Through simulations on a Courier-like constellation, it shows that QoSRP-MA can achieve guaranteed end-to-end delay bound with higher throughput, lower connection failing ratio and signaling overhead compared to high performance satellite routing (HPSR) scheme.     

一种基于迁移可测度的移动自组织网路由模型

 本文利用链路状态有效估测端到端路径的可达性。路由模型给出最近时间内,任意两点分组传输的迁移可测度;节点根据其邻节点的迁移可测度制定组合策略,计算组合迁移可测度,选取最优中继组合完成分组传输。仿真实验表明,该路由模型既可有效控制分组副本数目,又可获得较高的分组到达率。     

An ellipse-guided routing algorithm in wireless sensor networks

In wireless sensor networks, sensor nodes are deployed to collect data, perform calculations, and forward information to either other nodes or sink nodes. Recently, geographic routing has become extremely popular because it only requires the locations of sensor nodes and is very efficient. However, the local minimum phenomenon, which hinders greedy forwarding, is a major problem in geographic routing. This phenomenon is attributed to an area called a hole that lacks active sensors, which either prevents the packet from being forwarded to a destination node or produces a long detour path. In order to solve the hole problem, mechanisms to detect holes and determine landmark nodes have been proposed. Based on the proposed mechanisms, landmark-based routing was developed in which the source node first sends a packet to the landmark node, and the landmark node then sends the packet to the destination. However, this approach often creates a constant node sequence, causing nodes that perform routing tasks to quickly run out of energy, thus producing larger holes. In this paper, a new approach is proposed in which two virtual ellipses are created with the source, landmark, and destination nodes. Then guide the forwarding along the virtual ellipses. Furthermore, a recursive algorithm is designed to ensure a shortcut even if there are multiple holes or a hole has multiple landmarks. Thus, the proposed approach improves both geographic routing and energy efficiency routing. Simulation experiments show that the proposed approach increases the battery life of sensor nodes, lowers the end-to-end delay, and generates a short path.     

A new link lifetime estimation method for greedy and contention-based routing in mobile ad hoc networks

Greedy and contention-based forwarding schemes were proposed for mobile ad hoc networks (MANETs) to perform data routing hop-by-hop, without prior discovery of the end-to-end route to the destination. Accordingly, the neighboring node that satisfies specific criteria is selected as the next forwarder of the packet. Both schemes require the nodes participating in the selection process to be within the area that confronts the location of the destination. Therefore, the lifetime of links for such schemes is not only dependent on the transmission range, but also on the location parameters (position, speed and direction) of the sending node and the neighboring node as well as the destination. In this paper, we propose a new link lifetime prediction method for greedy and contention-based routing which can also be utilized as a new stability metric. The evaluation of the proposed method is conducted by the use of stability-based greedy routing algorithm, which selects the next hop node having the highest link stability.     

多层卫星网络链路中断容忍路由策略设计

链路中断和接续对卫星网络路由有重要影响,该文针对多层卫星网络,设计了链路中断容忍路由策略,利用非均匀时间段内卫星网络拓扑结构的可预测性进行路由表计算,采取动态的拥塞控制机制和洪泛策略,解决由于卫星运动、通信设备故障引发链路中断情况下的路由问题。仿真结果表明,该路由策略具有较高的链路利用率,能够减少动态路由计算中时延信息收集和星上路由表生成给卫星节点带来的时空开销。     

Dynamic traffic-aware routing algorithm for multi-sink wireless sensor networks

In this paper, a distributed traffic-balancing routing algorithm is proposed for multi-sink wireless sensor networks that effectively distributes traffic from sources to sinks. Each node has a gradient field that is used to decide on a neighbor node to reach a sink. The node’s gradient index contains (1) the distance cost from a source to a respective sink, and (2) traffic information from neighboring nodes. The proposed algorithm considers the traffic being faced by surrounding neighbors before forwarding packets to any sink using gradient search for routing and providing a balance between optimal paths and possible congestion on routes toward those sinks. The key objective of this work is to achieve traffic-balancing by detecting congested areas along the route and distributing packets along paths that have idle and underloaded nodes. Extensive simulations conducted to evaluate the performance of the proposed scheme indicate that it effectively reduces the overall packet delay, energy consumption and improves the packet delivery ratio under heavy traffic.     

基于限制广播域和节点剩余能量的按需路由算法研究

按需路由协议AODV的路由发现使用洪泛方式的扩散法,导致网络超负荷运行和拥塞,而且在选择转发路由时,总是选择最少跳数的路由,造成无线传感网络中节点能量不均,减少网络寿命.本文提出了AODV-DE算法,该算法引入广播域的概念,限制RREQ分组的转发范围,同时避免使用剩余能量低的节点转发数据分组,选择路由路径时选择总剩余能量最多的路径进行信息的传送.仿真结果表明,AODV-DE协议在路由开销、网络寿命和端到端的延迟这三个方面表现出了优势.     

Ant-based routing and QoS-effective data collection for mobile wireless sensor network

Mobility management in mobile wireless sensor networks (MWSNs) is a complex problem that must be taken into account. In MWSN, nodes move in and out of the network randomly. Hence, a path formed between two distant nodes is highly susceptible to changes due to unpredictable node movement. Also, due to the limited resources in WSN, the paths used for data transmission must be tested for the link quality and time consumed for data forwarding. In order to solve these issues, in this paper, an ant-based routing protocol with QoS-effective data collection mechanism is proposed. In this protocol, the link quality and link delay are estimated for each pair of nodes. Link quality is estimated in terms of packet reception rate, received signal strength indicator, and link quality index. A reliable path is chosen from the source to the destination based on the paths traversed by forward ants and backward ants. Then, if the link is found to be defective during data transmission, a link reinforcement technique is used to deliver the data packet at the destination successfully. The mobile robots collect the information with high data utility. In addition, each mobile robot is equipped with multiple antennas, and space division multiple access technique is then applied for effective data collection from multiple mobile robots. Simulation results show that the proposed routing protocol provides reliability by reducing the packet drop and end-to-end delay when compared to the existing protocols.     

车联网中基于动态传输距离的多跳稳定路由

数据传输是车联网(VANETs)实现交通安全的基础。然而,车辆的移动、信号传输的衰减以及彼此间的干扰对链路的可靠性均有影响。为此,提出基于动态传输距离的多跳稳定(DTMS)路由。DTMS路由在选择下一跳转发节点时,考虑到因衰减而导致的传输距离的变小,先估计车辆动态传输距离,再依据动态传输距离估计链路的连通时间以及距离因素,然后,计算邻居节点的权重,最后,基于节点权重值设置定时器,进而竞争产生下一跳转发节点。仿真结果表明,提出的DTMS路由有效地提高了数据包传输成功率。