The multi-copy diversity for routing in sparse vehicular ad hoc networks

The need for routing based on store-and-carry forwarding has been motivated in sparse vehicular ad hoc networks (VANETs), since the traditional end-to-end unicast routing is infeasible due to the network disconnection problem. In store-and-carry based routing, the end-to-end message delivery delay is dominated by the store-and-carry procedure rather than the wireless transmission. Therefore, the end-to-end delay in such sparse VANETs can be further reduced by replicating multiple copies of the message to other nodes when possible, i.e., multi-copy routing, to increase the chance of finally finding the destination, which we call this gain as multi-copy diversity. In this paper, we present an analytic framework to evaluate the performance of routing by assessing the multi-copy diversity gain in sparse VANETs. By using this model, we first derive an upper and lower-bound of end-to-end routing delay in sparse VANETs. Our analytic results show that a high level of multi-copy diversity gain is achieved when the network is partially connected, which is in contrast to the conventional expectation that multi-copy routing performs better in severely disconnected networks. Second, we propose a new adaptive multi-copy VANET routing scheme called AMR by exploiting these analytic results. AMR adapts to the local network connectivity and increases the level of multi-copy diversity at significantly reduced routing overhead compared to the well known epidemic routing. We validate the accuracy of our analytic model and the performance of AMR via simulation studies.     

Fuzzy Logic Based Distance and Energy-Aware Routing Protocol in Delay-Tolerant Mobile Sensor Networks

In challenged networks such as Wireless Sensor Networks, limitations such as nodes mobility, short radio range and sparse network density can prevent communications among nodes. Consequently, it can result in long delays in exchanging messages among nodes. Designing Delay-Tolerant Networks is considered to be an approach for dealing with lengthy breakdown of communication between nodes. Using multi-replica methods seems rational for these networks. However, a majority of these methods inject a large amount of replications of a message in the network so as to enhance message delivery probability which consequently leads to the loss of energy and reduction of network efficiency. Two major issues should be considered to achieve data delivery in such challenging networking environments: a routing strategy for the network and a buffer management policy. This study proposes a new routing protocol called Fuzzy-Logic based Distance and Energy Aware Routing protocol (FLDEAR) in delay tolerant mobile sensor network. A FLDEAR is a distance and energy aware protocol that reduces the number of message replications and uses two fuzzy inference systems in routing and buffer management. The results of conducted simulations indicated that this routing algorithm can be used for enhancing data packet delivery ratios and reducing data transmission overhead than several current Delay-Tolerant Mobile Sensor Networks routing protocols.     

基于LSTM模型的动态转发路由协议

文中将容忍延迟网络(Delay Tolerant Network,DTN)应用于船舶通信,提出了一种基于长短时记忆网络(Long Short-Term Memory,LSTM)模型的动态转发路由协议LSTM-DRA(Dynamic Distri-bution Routing Algorithm Based on LST...     

基于网络编码的机会网络高效路由算法

针对采用Epidemic机制的机会网络路由算法在数据分组传送阶段存在通信冗余的问题,提出了一种基于网络编码的高效路由算法--NCBER(network-coding-based epidemic routing）。NCBER在传送数据分组的过程中使用主动异或网络编码和多播,并取消了 Request（请求）控制分组,从而减少数据分组的转发次数和控制分组数量,降低网络开销,缩短分组传输时延。理论分析和仿真结果表明,NCBER 算法在网络开销和数据分组端到端时延性能方面优于经典的Epidemic路由算法及其改进算法MRRMR（message redundancy removal of multi-copy routing）,并且使数据传送成功率保持在100%。     

Integrated Social and QoS Trust-Based Routing in Delay Tolerant Networks

We propose and analyze a class of integrated social and quality of service (QoS) trust-based routing protocols in mobile ad-hoc delay tolerant networks. The underlying idea is to incorporate trust evaluation in the routing protocol, considering not only QoS trust properties but also social trust properties to evaluate other nodes encountered. We prove that our protocol is resilient against bad-mouthing, good-mouthing and whitewashing attacks performed by malicious nodes. By utilizing a stochastic Petri net model describing a delay tolerant network consisting of heterogeneous mobile nodes with vastly different social and networking behaviors, we analyze the performance characteristics of trust-based routing protocols in terms of message delivery ratio, message delay, and message overhead against connectivity-based, epidemic and PROPHET routing protocols. The results indicate that our trust-based routing protocols outperform PROPHET and can approach the ideal performance obtainable by epidemic routing in delivery ratio and message delay, without incurring high message overhead. Further, integrated social and QoS trust-based protocols can effectively trade off message delay for a significant gain in message delivery ratio and message overhead over traditional connectivity-based routing protocols.     

Enhanced fuzzy logic‐based spray and wait routing protocol for delay tolerant networks

Delay tolerant networks are a class of ad hoc networks that enable data delivery even in the absence of end‐to‐end connectivity between nodes, which is the basic assumption for routing in ad hoc networks. Nodes in these networks work on store‐carry and forward paradigm. In addition, such networks make use of message replication as a strategy to increase the possibility of messages reaching their destination. As contact opportunities are usually of short duration, it is important to prioritize scheduling of messages. Message replication may also lead to buffer congestion. Hence, buffer management is an important issue that greatly affects the performance of routing protocols in delay tolerant networks. In this paper, Spray and Wait routing protocol, which is a popular controlled replication‐based protocol for delay tolerant networks, has been enhanced using a new fuzzy‐based buffer management strategy Enhanced Fuzzy Spray and Wait Routing, with the aim to achieve increased delivery ratio and reduced overhead ratio. It aggregates three important message properties namely number of replicas of a message, its size, and remaining time‐to‐live, using fuzzy logic to determine the message priority, which denotes its importance with respect to other messages stored in a node's buffer. It then intelligently selects messages to schedule when a contact opportunity occurs. Because determination of number of replicas of a message in the network is a difficult task, a new method for estimation of the same has been proposed. Simulation results show improved performance of enhanced fuzzy spray and wait routing in terms of delivery ratio and resource consumption. Copyright © 2014 John Wiley & Sons, Ltd.     

一种增加时限和延迟的AODV协议改进方法

AODV协议是目前比较成熟的应用于移动自组网(MANET)中的一种反应式路由协议,其缺点主要是协议开销比较大,运动情况下路由优化性能不理想。利用为RREQ消息设置时限和为中间节点根据自身队长设置回复RREP消息延迟的方法,提出了一种改进的AODV协议(AODV-DL),有效地提高了网络的投包率和路由优化性能,降低了网络的协议开销。提出了将路由优化性能作为协议的一项新的评价标准。描述了其实现策略,并给出了NS2下的仿真结果。     

机会网络中基于种子喷雾的自适应路由协议

 针对喷雾路由自适应能力不强的问题,提出了一种基于种子喷雾的多副本自适应路由协议ASSR.ASSR在源节点计算种子数量和代价预测,利用少量的种子节点进行喷雾,最大程度地减少副本冗余,降低路由代价,由具备最新网络知识的中间转发节点进行喷雾决策,适用于网络环境动态变化的机会网络.仿真实验表明,ASSR在同类协议中具有最低的路由代价,同时具备较强的自适应能力,是一种有效、实用的时延约束机会路由协议.     

Generic prediction assisted single-copy routing in underwater delay tolerant sensor networks

One challenge in delay tolerant networks (DTNs) is efficient routing, as the lack of contemporaneous end-to-end paths makes conventional routing schemes inapplicable. Although many DTN routing protocols have been proposed, they often have two limitations: many protocols are not mobility cognizant, so they only suit specific mobility models and become inefficient when the environment changes; some protocols employ multi-copy replication to accommodate mobility diversity for increased delivery probability or reduced delay, but they usually do not perform well in resource constrained networks. Due to the unique characteristics of underwater sensor networks (UWSNs), efficient DTN routing becomes even more challenging. In this paper, we propose a generic prediction assisted single-copy routing (PASR) scheme that can be instantiated for different mobility models. PASR first collects a short-duration trace with network connectivity information and employs an effective off-line greedy algorithm to characterize the underlying network mobility patterns, depict the features of best routing paths and provide guidance on how to use historical information. Then it instantiates prediction assisted single-copy online routing protocols based on the guidance. As a result, the instantiated protocols are energy efficient and cognizant of the underlying mobility patterns. We demonstrate the advantages of PASR in underwater sensor networks with various mobility models.     

机会网络中基于摆渡节点与簇节点相互协作的路由机制

机会网络是一种不需要在源节点和目的节点之间存在完整路径,利用节点移动带来的相遇机会实现网络通信的延迟容忍自组织网络,它以“存储-携带-处理-转发”的模式进行.为实现互不相交簇间的信息传输,本文设计了一种带阈值的簇移动模型CMMT,并提出了一种基于摆渡（Ferry）节点与簇节点协作的路由算法（CBSW）.该算法减少了冗余的通信和存储开销,以及在Spray阶段簇节点没有遇到目的节点或摆渡节点,进入Wait阶段携带消息的节点采用直接分发方式只向目的节点传输等问题.仿真实验表明,CBSW算法能够增加传输成功率,减少网络开销和传输延迟.     

Cluster Based Routing Protocol for Mobile Nodes in Wireless Sensor Network

Mobility of sensor nodes in wireless sensor network (WSN) has posed new challenges particularly in packet delivery ratio and energy consumption. Some real applications impose combined environments of fixed and mobile sensor nodes in the same network, while others demand a complete mobile sensors environment. Packet loss that occurs due to mobility of the sensor nodes is one of the main challenges which comes in parallel with energy consumption. In this paper, we use cross layer design between medium access control (MAC) and network layers to overcome these challenges. Thus, a cluster based routing protocol for mobile sensor nodes (CBR-Mobile) is proposed. The CBR-Mobile is mobility and traffic adaptive protocol. The timeslots assigned to the mobile sensor nodes that had moved out of the cluster or have not data to send will be reassigned to incoming sensor nodes within the cluster region. The protocol introduces two simple databases to achieve the mobility and traffic adaptively. The proposed protocol sends data to cluster heads in an efficient manner based on received signal strength. In CBR-Mobile protocol, cluster based routing collaborates with hybrid MAC protocol to support mobility of sensor nodes. Schedule timeslots are used to send the data message while the contention timeslots are used to send join registration messages. The performance of proposed CBR-Mobile protocol is evaluated using MATLAB and was observed that the proposed protocol improves the packet delivery ratio, energy consumption, delay and fairness in mobility environment compared to LEACH-Mobile and AODV protocols.     

MTAODV:一种新的高速公路场景下VANET路由协议

在高速公路场景中,针对车辆间通信特性,在AODV的基础上提出了一种基于应用消息类型的改进路由协议(MTAODV).其核心思想是在路由建立过程中充分考虑VANET中应用消息的类型,从而减小路由请求洪泛范围,降低网络开销.仿真实验结果表明,与AODV协议相比,MTAODV协议能够有效地提高分组递交率,降低了路由开销,改善了分组时延和抖动.     

Congestion Control Performance of R-DSDV Protocol in Multihop Wireless Ad Hoc Networks

Ad hoc wireless networks are composed of mobile nodes communicating through wireless links, without any fixed backbone infrastructure. Frequent topology changes due to node mobility make routing in such dynamic networks a challenging problem. Moreover, successful message routing implies every mobile node is potentially capable of acting as a router, thus supporting store-and-forward mechanisms. However, resource limitations on these nodes also require a control on congestion due to message forwarding. In this paper, we consider our recently proposed randomized version of the well-known Destination-Sequenced Distance Vector (DSDV) routing protocol, referred to as R-DSDV, and validate its performance through extensive simulation experiments. Our results demonstrate that a probabilistic control on message traffic based on local tuning of protocol parameters is feasible, and that R-DSDV outperforms the basic DSDV protocol by significantly reducing the average queue size associated with each mobile node and hence the average packet delay.     

Threshold based locking routing strategy for delay tolerant network

Delay tolerance network probabilistic routing protocols forward message to a node by observing its predictability value to meet the message destination. However, it is vital to predict the ability of node to carry the transmitted message. For instance, the traffic confluence on the high probable nodes can produce congestion that results in the drop of previously stored messages. These drops diminish the delivery ratio because the dropped message lost its opportunity to be delivered. Since, there exist multiple copies of each message; therefore, the same node invariably receives the dropped messages from other parts of the network and causes the highest number of transmissions. Additionally, the replication from source node continues on the high probable peers even the previous copies were transmitted on the better predictable neighbors than the current. In this paper, we have proposed a novel routing method called as the adaptive threshold based locking method that maintains the contemporary status of the node based on its activity in the network. We have used the adaptive status measuring metrics such as transmit factor, drop factor and hop away count. Moreover, a threshold based locking method has been introduced to control the diffusion of messages. We have performed the comparison of existing and proposed routing methods with real time mobility traces. The proposed strategy has bolstered the delivery ratio and minimizes hop count, end-to-end delay and number of transmission.     

DFEMD: Delay Tolerant Fast Emergency Message Dissemination Routing Protocol

In vehicular ad-hoc network, vehicles are move very speedy thus their topology is changing frequently and intermittent connectivity occur often. The intermittent connectivity network (delay and disruption-tolerant network) resulting is end to end path is absent. In this intermittent network connectivity areas, during emergency event occurs, emergency rescue message (Example: Fire, Accident, etc.,) are sent to a rescue team is most necessary. Due to these constraints, general ad hoc protocol approaches is not suitable and, as a result, alternative protocol must be deliberated. This leads to the make a specific protocol mechanisms able to deliver both fast and trustworthiness in-order delivery emergency message needed. Thus we introduce the DFEMDR protocol, it follow the vehicular delay tolerant network (VDTN) common technique store carry-forward method and message replicas. This paper describes an efficient Delay tolerant Fast Emergency Message Dissemination Routing Protocol, called DFEMD routing protocol. This protocol enables in VDTN, the source node broadcast an emergency message to all available node in its communication range. The source node allocates a message replicas and message time to live to the neighbour nodes (forwarded node) based on that node has credence value. Credence value is calculated to all nodes based on two values; the first value is visited level estimation, it is calculated based on the number of nodes previously visited by the node. The second value is Destination Reaches Level Estimation (DLE); it is calculated based on the number of times the node successfully delivered the message to the destination. Finally, each node credence value is calculated, from this visited level and destination reaches level estimation values. Finally, the trust authority received emergency messages and evaluate the trustworthiness of message based on message reputation value or message confidence value.

     

Extension of Delay Tolerant Network’s Routing Protocols for Preventing Excessive Utilization of Resources

The routing algorithms of DTN have the inbuilt storage management scheme such as Hop based TTL (Spray and Wait) or passive cure (Potential-based Entropy Adaptive Routing PEAR). There has been a significant amount of work in the past regarding buffer management policies. In this paper, we have proposed a new message deletion policy for multi-copy routing schemes. In this scheme, message delivery information is communicated to the other nodes in the network for removing useless bundles from the network, which prevents the nodes from the buffer overflow problem and avoid transfer of useless message replicas thus relaxing the resources of the nodes. We evaluate our proposed method by simulating network, on four major DTNs routing algorithms: Epidemic, Spray and Wait, ProPHET and MaxProp. The simulation results clearly show significant improvement in the value of delivery probability and the overhead ratio for an Epidemic, Spray and Wait, and Prophet routing protocols.     

RPB-MD: Providing robust message dissemination for vehicular ad hoc networks

To improve traffic safety and efficiency, it is vital to reliably send traffic-related messages to vehicles in the targeted region in vehicular ad hoc networks (VANETs). In this paper, we propose a novel scheme, relative position based message dissemination (RPB-MD), to reliably and efficiently disseminate messages to the vehicles in the zone-of-relevance. Firstly, the relative position based (RPB) addressing model is proposed to effectively define the intended receivers in the zone-of-relevance. To ensure high message delivery ratio and low delivery delay, directional greedy broadcast routing (DGBR) is introduced to make a group of candidate nodes hold the message for high reliability. Moreover, to guarantee efficiency, the protocol time parameters are designed adaptively according to the message attributes and local vehicular traffic density. The protocol feasibility is analyzed to illustrate the robustness and reliability of RPB-MD. Simulation results show that RPB-MD, compared with representative existing schemes, achieves high delivery ratio, limited overhead, reasonable delay and high network reachability under different vehicular traffic density and data sending rate.     

A delay‐bounded routing protocol for vehicular ad hoc networks with traffic lights

In vehicular ad hoc networks, vehicles may use a routing protocol to inform emergent events, for example, car accidents or traffic jams. Hence, many of the researchers are focused on minimizing the end‐to‐end delay of the routing protocol. However, some applications, for example, email or ftp, are not time critical, and radio spectrum is a limited resource. Hence, delay‐bounded routing protocol, whose goal is to deliver messages to the destination within user‐defined delay and minimize the usage of radio, has become an important issue. The delay‐bounded routing protocols deliver message to the destination by the hybrid of data muling (carried by the vehicle) and forwarding (transmitted through radio). When the available time is enough, the message will be delivered by muling; otherwise, it will be delivered by forwarding. However, in an urban area, there are many traffic lights, which may greatly affect the performance of the delay‐bounded routing protocols. Existing works do not consider the effect of traffic lights, and hence, it may adopt an improper delivery strategy and thus wastes much available time. To improve previous works, we propose a novel delay‐bounded routing protocol, which has considered the effect of traffic lights. Whenever a vehicle passes an intersection, it will gather the information of the traffic light and traffic load of the next road section, and thus, it can make a more accurate prediction and adopt a more proper strategy to deliver message. Simulation results show that the proposed protocol can make a better usage of the available time and uses less radio resource to deliver the message in time. Copyright © 2013 John Wiley & Sons, Ltd.     

An evaluation of routing in vehicular networks using analytic hierarchy process

This paper presents a comprehensive study of the performance of routing protocols in distributed vehicular networks. We propose a novel and efficient routing protocol, namely cross‐layer, weighted, position‐based routing, which considers link quality, mobility and utilisation of nodes in a cross layer manner to make effective position‐based forwarding decisions. An analytic hierarchy process approach is utilised to combine multiple decision criteria into a single weighting function and to perform a comparative evaluation of the effects of aforementioned criteria on forwarding decisions. Comprehensive simulations are performed in realistic representative urban scenarios with synthetic and real traffic. Insights on the effect of different communication and mobility parameters are obtained. The results demonstrate that the proposed protocol outperforms existing routing protocols for vehicular ad hoc networks, including European Telecommunications Standards Institute (ETSI's) proposed greedy routing protocol, greedy traffic aware routing protocol and advanced greedy forwarding in terms of combined packet delivery ratio, end‐to‐end delay and overhead. Copyright © 2015 John Wiley & Sons, Ltd.     

移动自组织网络预测分簇算法的路由协议

针对移动自组织网络中传统分簇算法存在稳定性低、网络开销大的问题,在WCA分簇算法的基础上,提出一种带有预测机制的EWCA-MP(Efficient on-demand Weighted Clustering Algorithm using Mobility Prediction)分簇算法,该算法在簇头选择时充分考虑节点间的链路保持时间,在簇维护阶段引入模糊逻辑的概念,对Hello消息包的广播周期进行优化。并将其应用于CBRP中,提出了一种ECBRP-MP(Efficient Cluster Based Routing Protocol using Mobility Prediction)移动预测的分簇路由协议。仿真结果表明,EWCA-MP算法在簇头数目、单位时间内节点转移次数和统治集更新次数明显减少,ECBRP-MP路由协议在路由开销、分组投递率的性能得到优化。