WSNs中基于转发区域调整的能效地理路由

针对无线传感网络(WSNs)的数据传输问题,提出基于转发区域调整的能效地理位置路由(FAEG)。FAEG限定了数据包的转发区域,构建候选转发节点集,并从节点集中选择权重大的节点传递数据包;通过节点剩余能量和离目的节点距离信息计算节点权重,使剩余能量大和离目的节点近的节点具有优先传递数据包的资格,提高了路由稳定性。节点遭遇路由空洞时,则调整转发区域,在更广范围内选择传输数据包的节点。仿真结果表明,提出的FAEG降低了能耗,并提高了数据包传递率。     

改进遗传算法在QoS组播路由选择中的研究

QoS组播路由的选择问题本质是从源节点至目的节点间找到满足QoS要求的传输路径,尽管现在有许多文献利用遗传算法对组播路由问题做了研究,但其组播路由费用都比较大,执行时间过长,并且编码难度都比较大,优化效率低。针对这些问题,文中提出了一种改进的遗传算法,该算法综合考虑了带宽约束、时延约束、时延抖动约束、丢包率约束以及路由费用等度量指标,在传统遗传算法的基础上,设计了一种基于应用层业务的自适度函数,改进了染色体编码方式,并且设计了自适应交叉函数与自适应变异函数等多种优化函数。通过仿真结果表明,该改进的遗传算法很大程度上降低了QoS组播路由的费用和执行时间,并且能快速地找到最优QoS组播路径。     

一种适用于异步无线传感器网络的机会路由机制

无线传感器网络通常使用低占空比的异步睡眠调度来降低节点能耗。由于发送节点在接收节点醒来后才能向其发送数据,这将引入额外的等待时延。在最近的一些任播路由机制中,发送节点动态地选择最先醒来的候选节点转发数据,以最小化等待时延。但是,由于从最先醒来的候选节点到基站的时延可能并不低,任播路由机制并不一定能最小化端到端总时延。为此,提出了一种适用于异步无线传感器网络的机会路由机制,将路由决策建模为强马尔科夫过程,并根据最优停止理论推导出该过程一种简化的停止规则。仿真结果表明,节点到基站的最大端到端时延仅为基于地理位置的机会路由的68.5%。     

一种基于带宽和时延约束的分布式组播路由算法

针对已有分布式组播路由算法在寻找QoS路由时的低成功率问题,本文提出了一种新的基于带宽和时延约束的分布式组播路由算法-QDMR(QoS-based Distributed Multicast Routing).在为新组播成员搜索连接到组播树的可行路径时,QDMR算法使用RBMF(Reverse Best Metric Forwarding)转发算法代替RPF(Reverse Path Forwarding)转发算法,从而优先搜索满足带宽和时延约束要求的路径,然后才考虑代价的优化.模拟分析表明,QDMR提高了路由搜索的成功率,并且降低了协议开销.     

无线网络编码增益感知的低时延路由协议

降低无线网络数据包传递时延对实时应用有重要的意义.该文提出了一种编码增益的计算方法和编码图的简化方法,并基于此提出了编码增益感知的路由协议CGAR(Coding Gain Aware Routing).CGAR利用网络编码增益和无线链路的期望传输次数ETX(Expected Transmission Count)计算传递一个来自新流的数据包所需要的时间,并以此为选路度量,旨在降低数据传递时延.仿真试验表明,CGAR的时延优于COPE和DCAR协议.     

基于4G辅助的车载网地理路由算法

针对车载网(VANETs)城市场景的路由问题,提出基于4G网络的长期演进(LTE)和VANETs混合结构的地理路由LTE-GR。LTE-GR路由充分利用LTE高峰速率和低时延特性,辅助VANETs间的数据传输。基站e Node B收集路段信息,计算路段稳定值,并与门限值进行比较,若小于门限值,则利用e Node B转发数据包;否则,就引用贪婪转发地理路由传输数据包。仿真结果表明,相比于同类路由,提出的LTE-GR路由能有效地提高数据包传输率、端到端传输时延性能。     

面向VANETs城市环境的基于道路连通路由协议

路由协议是车联网VANETs的研究焦点,特别是在城市环境中,复杂路况给VANETs的路由提出挑战。为此,提出面向VANETs城市环境基于道路连通的路由RCR协议。考虑道路是静态的,建立以道路连通为基础的路由协议。RCR协议先利用数字地图知识将道路划分为不同路段,再依据车辆的位置选择网关,建立包含路段信息的路由表,最后,采用反应式路由策略建立路由。仿真结果表明,提出的RCR协议降低了端到端传输时延、提高了数据包的传递率,与GYTAR协议相比,RCR协议的端到端传输时延下降了32%。     

无线Mesh网络中转发节点的选择算法

稳定路由是无线Mesh网络(WMNs)的重要性能指标,不稳定路由会引起数据包丢失率和高的传输时延。为此,提出基于熵函数的节点稳定路由(ESR)协议。ESR利用熵函数估计节点稳定度。具体而言,ESR协议收集链路质量,并计算链路稳定值,再依据稳定值估计节点熵。同时,将熵信息载入路由表,并与邻居节点交互。一旦接收此消息,节点就存储于路由表,然后选择具有最大熵的节点作为下一跳节点。实验数据表明,与基于干扰和信道切换(MIC)、基于期望传输次数(ETX)和基于加强学习的连通网关的最佳路径(RLBDR)路由协议相比,提出的ESR协议在吞吐量、时延和数据包丢失率方面均具有较好的性能。     

MANETs中基于节点移动度的虚连接的路由

由于移动自组织网络MANETs中节点的快速移动,使得维持源节点与目的节点间的通信路径成为一项挑战性工作。节点的高速移动导致通信链路频繁断裂。为此,提出基于节点移动度的虚连接的路由(MDVRP)。虚路由为一条动态的逻辑路由,其由一系列的特定地理区域构成。每个区域内的节点依据自己的移动度设置转发数据包的定时器,移动度越小,具有优先转发数据包权。MDVRP通过虚路由策略,在源节点与目的节点间建立了多条传输路通,每个节点能独立选取下一跳转发节点,并利用节点移动度,择优选取转发数据包下一跳节点,从而提高链路的稳定性。仿真结果表明,提出的路由协议在端到端传输时延、路由开销以及数据包传输率性能均得到提高。     

基于SDN的链式快速转发网络模型研究

针对当前网络中降低数据包传输时延的机制复杂且在数据包的匹配过程中存在较高的处理时延,提出了基于软件定义网络(SDN)架构的虚拟链式快速通道路由模式(Chain-Like Hyperchannel Routing Mode,CHRN),在将不同优先级的数据流映射到不同的虚拟传输网络上的同时,时延敏感型数据将采用不查表的快速转发方式来降低数据包的处理时延.实验证明,这种方式在不影响普通数据包传输的条件下,有效提高了时延敏感型数据的传输效率.     

A New Dynamic Energy Efficient Latency Improving Protocol for Wireless Sensor Networks

In delay sensitive applications of wireless sensor network, it is required to monitor the situation continuously with the sensors. The continuous operation and processing delay, may contribute latency in data communication. This results in more energy consumption of the sensor nodes. It is difficult to replace the battery of a sensor node, after the deployment in the network. The efficient energy management and low latency are the important issues in delay sensitive applications as they affect the life of network. There are some limitations in existing routing protocols as they are particularly designed either for energy efficiency or minimum latency. This paper presents the new protocol to overcome some drawbacks of the existing protocols. A concept of distance metric based routing is explored for shortest routing path selection. This helps to reduce the overhead of the network traffic, which results in improvement of energy efficiency and latency. The simulation results are compared with standard ‘AODV’ routing protocol. It is observed that, this ‘Dynamic Energy Efficient and Latency Improving Protocol’ will be very much suitable for wireless sensor networks in industrial control applications.     

An Energy-Aware Routing Protocol for Mobile Ad Hoc Networks Based on Route Energy Comprehensive Index

The design of energy-aware routing protocols has always been an important issue for mobile ad hoc networks (MANETs), because reducing the network energy consumption and increasing the network lifetime are the two main objectives for MANETs. Hence, this paper proposes an energy-aware routing protocol that simultaneously meets above two objectives. It first presents Route Energy Comprehensive Index (RECI) as the new routing metric, then chooses the path with both minimum hops and maximum RECI value as the route in route discovery phase, and finally takes some measures to protect the source nodes and the sink nodes from being overused when their energies are low so as to prolong the life of the corresponding data flow. Simulation results show that the proposed protocol can significantly reduce the energy consumption and extend the network lifetime while improve the average end-to-end delay compared with other protocols.     

A scheme for solving Anycast scalability in IPv6

The existing designs for providing Anycast services are either to confine Anycast groups to a preconfigured topological region or to distribute Anycast groups globally across the whole Internet. The latter causes routing tables to grow proportionally to the number of global Anycast groups in the entire Internet and both of the above designs restrict and hinder the application and development of Anycast services. A new kind of Anycast communication scheme is proposed in this paper. This scheme adopts a novel Anycast address structure which can achieve a dynamic Anycast group while allowing Anycast members to freely leave and join the Anycast group without geographical restriction and it effectively solves the expanding explosion of the Anycast routing table. In addition, this scheme can evenly disperse Anycast request messages from clients across the Anycast servers of one Anycast group, thus achieving load balance. This paper analyzes the communication scheme in depth and discusses its feasibility and validity. The experimental data in IPv6 simulation demonstrate that the TRT (Total Response Time) of one Anycast service (e.g., file downloading) acquired through this communication scheme is shorter by 15% than that through the existing Anycast communication scheme. Copyright © 2007 John Wiley & Sons, Ltd.     

A technique to improve network lifetime in mobile ad hoc networks

Energy is an important issue in mobile ad hoc networks (MANETs), and different energy‐aware routing mechanisms have been proposed to minimize the energy consumption in MANETs. Most of the energy‐aware routing schemes reported in the literature have considered only the residual battery capacity as the cost metric in computing a path. In this paper, we have proposed, an energy‐aware routing technique which considers the following parameters: (i) a cost metric, which is a function of residual battery power and energy consumption rate of participating nodes in path computation; (ii) a variable transmission power technique for transmitting data packets; and (iii) To minimize the over‐utilization of participating nodes, a limit is set on the number of paths that can be established to a destination through a participating node. The proposed scheme is simulated using Qualnet 4.5 simulator, and compared with Ad hoc On‐Demand Distance Vector (AODV) and Lifetime Enhancement Routing (LER). We observed that the proposed scheme performs better in terms of network lifetime and energy consumption. Copyright © 2014 John Wiley & Sons, Ltd.     

Energy‐aware geographic routing in wireless sensor networks with anchor nodes

Energy efficiency has become an important design consideration in geographic routing protocols for wireless sensor networks because the sensor nodes are energy constrained and battery recharging is usually not feasible. However, numerous existing energy‐aware geographic routing protocols are energy‐inefficient when the detouring mode is involved in the routing. Furthermore, most of them rarely or at most implicitly take into account the energy efficiency in the advance. In this paper, we present a novel energy‐aware geographic routing (EAGR) protocol that attempts to minimize the energy consumption for end‐to‐end data delivery. EAGR adaptively uses an existing geographic routing protocol to find an anchor list based on the projection distance of nodes for guiding packet forwarding. Each node holding the message utilizes geographic information, the characteristics of energy consumption, and the metric of advanced energy cost to make forwarding decisions, and dynamically adjusts its transmission power to just reach the selected node. Simulation results demonstrate that our scheme exhibits higher energy efficiency, smaller end‐to‐end delay, and better packet delivery ratio compared to other geographic routing protocols. Copyright © 2011 John Wiley & Sons, Ltd.     

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.     

A reliable and energy‐efficient routing protocol for underwater wireless sensor networks

Recently, underwater wireless sensor networks (UWSNs) have attracted much research attention to support various applications for pollution monitoring, tsunami warnings, offshore exploration, tactical surveillance, etc. However, because of the peculiar characteristics of UWSNs, designing communication protocols for UWSNs is a challenging task. Particularly, designing a routing protocol is of the most importance for successful data transmissions between sensors and the sink. In this paper, we propose a reliable and energy‐efficient routing protocol, named R‐ERP²R (Reliable Energy‐efficient Routing Protocol based on physical distance and residual energy). The main idea behind R‐ERP²R is to utilize physical distance as a routing metric and to balance energy consumption among sensors. Furthermore, during the selection of forwarding nodes, link quality towards the forwarding nodes is also considered to provide reliability and the residual energy of the forwarding nodes to prolong network lifetime. Using the NS‐2 simulator, R‐ERP²R is compared against a well‐known routing protocol (i.e. depth‐based routing) in terms of network lifetime, energy consumption, end‐to‐end delay and delivery ratio. The simulation results proved that R‐ERP²R performs better in UWSNs.Copyright © 2012 John Wiley & Sons, Ltd.     

Analysis and discussion of Anycast scalability in IPv6

The existing designs for providing Anycast services are either to confine Anycast groups to a preconfigured topological region or to globally distribute Anycast groups across the whole Internet. The latter causes the routing tables to grow proportionally to the number of global Anycast groups in the entire Internet and both of the above designs restrict and hinder the application and development of Anycast services. In this paper a new kind of Anycast communication model is proposed on the basis of Anycast tree technology. Since this model adopts a dynamic Anycast group, allowing Anycast members to freely leave and join the Anycast group, it radically solves the existing scalability problem. In addition, this model accomplishes the distributed maintenance and transaction of Anycast service requests and information on the Anycast tree; thus it performs load balance. This paper analyzes and discusses the feasibility and validity of the communication model; the experimental data in IPv6 simulation demonstrate that the total response time of one Anycast service (e.g., file downloading) acquired through this communication model is shorter by 15% than that through the current communication model. Copyright © 2007 John Wiley & Sons, Ltd.     

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.     

A New Routing Metric for Satisfying Both Energy and Delay Constraints in Wireless Sensor Networks

Besides energy constraint, wireless sensor networks should also be able to provide bounded communication delay when they are used to support real-time applications. In this paper, a new routing metric is proposed. It takes into account both energy and delay constraints. It can be used in AODV. By mathematical analysis and simulations, we have shown the efficiency of this new routing metric.