A backup path routing for guaranteeing bandwidth in mobile ad hoc networks for multimedia applications

This paper suggests a backup path routing scheme in ad hoc networks for multimedia applications. A data path is established in an on-demand manner when there is a need to send data. A primary and a backup path are created as a result of a route control message exchange process. Each control message has additional information for guaranteeing the service quality. A backup path is configured around the primary path in multi-hop wireless networks. After detecting a failure when sending data, a repairing procedure occurs near the failed node of the primary path. The proposed scheme exploits the route request and reply information exchanged between nodes to create a backup path. Proposed backup routing scheme uses a one-hop search method, and the rerouted path length is two-hop at maximum. The service quality as measured by the error rate and delay is considered when establishing and repairing a route by making an allowance for the required bandwidth. Simulation results show that the proposed backup path routing scheme has a better data delivery ratio and an improved end-to-end data delay while guaranteeing the requested bandwidth for multimedia application.     

Triangle-based routing for mobile ad hoc networks

Routing protocols for Mobile ad hoc networks (MANETs) have been studied extensively in the past decade. Routing protocols for MANETs can be broadly classified as reactive (on-demand), proactive, hybrid and position-based. Reactive routing protocols are attractive because a route between a source and a destination is established only when it is needed. Such protocols, unlike proactive protocols, do not have high overhead for route maintenance and are especially suitable for networks in which not all nodes communicate frequently. One problem with existing reactive routing protocols is the propagation of redundant route request messages during route discovery. In this paper, we present a low-overhead reactive routing protocol which reduces propagation of redundant route request messages. We also compare its performance with the well-known reactive routing protocol AODV.     

Adaptive routing protocol for mobile ad hoc networks

Artificial immune systems (AIS) are used for solving complex optimization problems and can be applied to the detection of misbehaviors, such as a fault tolerant. We present novel techniques for the routing optimization from the perspective of the artificial immunology theory. We discussed the bioinspired protocol AntOR and analyze its new enhancements. This ACO protocol based on swarm intelligence takes into account the behavior of the ants at the time of obtaining the food. In the simulation results we compare it with the reactive protocol AODV observing how our proposal improves it according to Jitter, the delivered data packet ratio, throughput and overhead in number of packets metrics.     

A two-zone hybrid routing protocol for mobile ad hoc networks

Recently, an elegant routing protocol, the zone routing protocol (ZRP), was proposed to provide a hybrid routing framework that is locally proactive and globally reactive, with the goal of minimizing the sum of the proactive and reactive control overhead. The key idea of ZRP is that each node proactively advertises its link state over a fixed number of hops, called the zone radius. These local advertisements provide each node with an updated view of its routing zone - the collection of all nodes and links that are reachable within the zone radius. The nodes on the boundary of the routing zone are called peripheral nodes and play an important role in the reactive zone-based route discovery. The main contribution of this work is to propose a novel hybrid routing protocol - the two-zone routing protocol (TZRP) - as a nontrivial extension of ZRP. In contrast with the original ZRP where a single zone serves a dual purpose, TZRP aims to decouple the protocol's ability to adapt to traffic characteristics from its ability to adapt to mobility. In support of this goal, in TZRP each node maintains two zones: a crisp zone and a fuzzy zone. By adjusting the sizes of these two zones independently, a lower total routing control overhead can be achieved. Extensive simulation results show that TZRP is a general MANET routing framework that can balance the trade offs between various routing control overheads more effectively than ZRP in a wide range of network conditions.     

A light-weight trust-based QoS routing algorithm for ad hoc networks

In a mobile ad hoc network (MANET), the lack of a trusted infrastructure makes secure and reliable packet forwarding very challenging, especially for providing QoS guarantee for multimedia applications. In this paper, we firstly introduce the concept of trust and QoS metric estimation into establishing a trust-based QoS model. In this model, we estimate the trust degree between nodes from direct trust computation of direct observation and indirect trust computation by neighbors’ recommendations. On the other hand, due to the NP-completeness of the multi-QoS constraints problem, we only take into account link delay as the QoS constraint requirement. Then, we design a trust-based QoS routing algorithm (called TQR) from the trade-off between trust degree and link delay. At last, by using NS2 we implement this algorithm based on AODV (Ad hoc On-demand Distance Vector). We compare its performance with AODV, Watchdog-DSR and QAODV. The simulation results show that TQR scheme can prevent attacks from malicious nodes and improve the security performance of the whole network, especially in terms of packet delivery ratio, average end-to-end delay, routing packet overhead and detection ratio of malicious nodes.     

Neural networks for shortest path computation and routing incomputer networks

The application of neural networks to the optimum routing problem in packet-switched computer networks, where the goal is to minimize the network-wide average time delay, is addressed. Under appropriate assumptions, the optimum routing algorithm relies heavily on shortest path computations that have to be carried out in real time. For this purpose an efficient neural network shortest path algorithm that is an improved version of previously suggested Hopfield models is proposed. The general principles involved in the design of the proposed neural network are discussed in detail. Its computational power is demonstrated through computer simulations. One of the main features of the proposed model is that it will enable the routing algorithm to be implemented in real time and also to be adaptive to changes in link costs and network topology.     

Efficient virtual-backbone routing in mobile ad hoc networks

Since the physical topology of mobile ad hoc networks (MANETs) is generally unstable, an appealing approach is the construction of a stable and robust virtual topology or backbone. A virtual backbone can play important roles related to routing and connectivity management. In this paper, the problem of providing such a virtual backbone with low overhead is investigated. In particular, we propose an approach, called virtual grid architecture (VGA), that can be applied to both homogeneous and heterogeneous MANETs. We study the performance tradeoffs between the VGA clustering approach and an optimal clustering based on an integer linear program (ILP) formulation. Many properties of the VGA clustering approach, e.g., VGA size, route length over VGA, and clustering overhead are also studied and quantified. Analytical as well as simulation results show that average route length over VGA and VGA cardinality tend to be close to optimal. The results also show that the overhead of creating and maintaining VGA is greatly reduced, and thus the routing performance is improved significantly. To illustrate, two hierarchical routing techniques that operate on top of VGA are presented and evaluated. Performance evaluation shows that VGA clustering approach, albeit simple, is able to provide more stable (long lifetime) routes, deliver more packets, and accept more calls.     

Scalability of routing methods in ad hoc networks

In an ad hoc network each host (node) participates in routing packets. Ad hoc networks based on 802.11 WLAN technology have been the focus of several prior studies. These investigations were mainly based on simulations of scenarios involving up to 100 nodes (usually 50 nodes) and relaxed (too unrealistic) data traffic conditions. Many routing protocols in such setting offer the same performance, and many potential problems stay undetected. At the same time, an ad hoc network may not want (or be able) to limit the number of hosts involved in the network. As more nodes join an ad hoc network or the data traffic grows, the potential for collisions and contention increases, and protocols face the challenging task to route data packets without creating high administrative load. The investigation of protocol behavior in large scenarios exposes many hidden problems. The understanding of these problems helps not only in improving protocol scalability to large scenarios but also in increasing the throughput and other QoS metrics in small ones. This paper studies on the example of AODV and DSR protocols the influence of the network size (up to 550 nodes), nodes mobility, nodes density, suggested data traffic on protocols performance. In this paper we identify and analyze the reasons for poor absolute performance that both protocols demonstrate in the majority of studied scenarios. We also propose and evaluate restructured protocol stack that helps to improve the performance and scalability of any routing protocol in wireless ad hoc networks.     

Bandwidth-based routing protocols in mobile ad hoc networks

In this paper, we propose a high performance routing protocol and a long lifetime routing protocol by considering the fact that the bandwidth between two mobile nodes should be different when distances are different. In the high performance routing protocol, to reduce the number of rerouting times, we take the bandwidth issue into account to choose the path with the capability to transmit the maximum amount of data with the help of the GPS. With exchanging the moving vectors and the coordinates of two adjacent mobile nodes, the possible link lifetime of two adjacent mobile nodes can be predicted. Subsequently, a path with the maximal amount of data transmission can be found. With regard to our proposed long lifetime routing protocol, to maximize the overall network lifetime, we find a path with the maximal remaining power after data transmission. With the link bandwidth and the desired amount of data transmitted, the consumption power is computed to obtain the remaining power of a mobile node. Accordingly, we can choose the path with the maximal predicted remaining power to maximize the overall network lifetime. In the simulation, we compare our high performance routing protocol with the AODV and LAWS in terms of throughput, rerouting (path breakage), and route lifetime. With respect to power consumption, we compare our proposed power-aware routing protocol with the POAD and PAMP in terms of the overall network lifetime and the ration of survival nodes to the all nodes.     

一种新的多路径自组网路由算法

传统的单路径路由使自组网路由性能一直不能获得太大的突破。因此,设计有效的和稳定的多路径路由成为最受关注的问题。为此提出了一种新的多路径路由算法,其在路由发现阶段使用了一种新的多路径转发策略。在基于稳定性因子的基础上,该算法计算路径间海明距离并据此选择多条相似的稳定不相交多路由,从而进一步提高该路由算法的性能。模拟结果显示,与经典的多路径路由相比较,该算法是一个有效的多路径自组网路由算法。     

Gathering-based routing protocol in mobile ad hoc networks

A gathering-based routing protocol (GRP) for mobile ad hoc networks is presented. The idea is to rapidly collect network information at a source node at an expense of a small amount of control overheads. The source node can equip promising routes on the basis of the collected information, thereby continuously transmitting data packets even if the current route is disconnected. It results in achieving fast (packet) transfer delay without unduly compromising on (control) overhead performance.     

A learning automata-based fault-tolerant routing algorithm for mobile ad hoc networks

Reliable routing of packets in a Mobile Ad Hoc Network (MANET) has always been a major concern. The open medium and the susceptibility of the nodes of being fault-prone make the design of protocols for these networks a challenging task. The faults in these networks, which occur either due to the failure of nodes or due to reorganization, can eventuate to packet loss. Such losses degrade the performance of the routing protocols running on them. In this paper, we propose a routing algorithm, named as learning automata based fault-tolerant routing algorithm (LAFTRA), which is capable of routing in the presence of faulty nodes in MANETs using multipath routing. We have used the theory of Learning Automata (LA) for optimizing the selection of paths, reducing the overhead in the network, and for learning about the faulty nodes present in the network. The proposed algorithm can be juxtaposed to any existing routing protocol in a MANET. The results of simulation of our protocol using network simulator 2 (ns-2) shows the increase in packet delivery ratio and decrease in overhead compared to the existing protocols. The proposed protocol gains an edge over FTAR, E2FT by nearly 2% and by more than 10% when compared with AODV in terms of packet delivery ratio with nearly 30% faulty nodes in the network. The overhead generated by our protocol is lesser by 1% as compared to FTAR and by nearly 17% as compared to E2FT when there are nearly 30% faulty nodes.     

A stable weight-based on-demand routing protocol for mobile ad hoc networks

A mobile ad hoc network (MANET) consists of a set of mobile hosts that can communicate with each other without the assistance of base stations. In MANETs, the high mobility of mobile nodes is a major reason for link failures. In this paper, we propose a stable weight-based on-demand routing protocol (SWORP) for MANETs. The proposed scheme uses the weight-based route strategy to select a stable route in order to enhance system performance. The weight of a route is decided by three factors: the route expiration time, the error count, and the hop count. Route discovery usually first finds multiple routes from the source node to the destination node. Then the path with the largest weight value for routing is selected. Simulation results show that the proposed SWORP outperforms DSR, AODV, and AODV-RFC, especially in a high mobility environment.     

基于移动状态的车载自组织网络路由算法

传统的AODV协议应用于车载自组织网络,尽管分组投递率比较高,但在数据分组需要发送时才建立路由,网络延迟较大。而DSDV中通过周期性的路由更新机制,网络延迟小,但需维护大量不必要的路由,并且拓扑结构变化使许多路由无效,导致分组投递率非常低。为了综合满足VANET分组投递率和网络延迟的要求,将AODV和DSDV两种路由建立机制相互融合,形成混合式路由协议。首先,根据车辆节点的位置、速度和方向等移动状态周期性地选择稳定且距离适中的链路,形成网络主干并更新路由;其次,当数据分组目的节点路由不存在时,发起路由发现过程建立路由,在路由请求报文前进和路由应答报文回溯过程中求出路由过期时间。仿真实验表明,尽管路由开销有所增大,分组投递率略低于AODV,但是网络延迟显著降低。     

Improving source routing reliability in mobile ad hoc networks

In this paper, we propose a novel on-demand routing protocol called backup source routing (BSR) to establish and maintain backup routes that can be utilized after the primary path breaks. The key advantage of BSR is the reduction of the frequency of route discovery flooding, which is recognized as a major overhead in on-demand protocols. We define a new routing metric, called the route reliability, and use it to provide the basis for the backup path selection. We use a heuristic cost function to develop an analytical model and an approximation method to measure this metric. Various algorithms for our BSR protocol in the route discovery phase and route maintenance phase have been designed based on this cost function. Extensive simulations demonstrated that our routing strategy has two interesting features: 1) in less stressful situations of lower mobility, BSR has similar performance to DSR, 2) in more challenging situations of high mobility, BSR can improve the performance significantly.     

A location routing protocol based on smart antennas for ad hoc networks

Ad hoc networks are a type of mobile networks that function without any fixed infrastructure. One of the weaknesses of ad hoc networks is that route between a source and a destination is likely to break during communication. Location-based routing algorithms are promising in reducing routing overhead in ad hoc networks. Existing location-based routing algorithms employ the Global Positioning System (GPS) as their location information provider, and synchronize information network-wide. Nonetheless, these protocols have some limitations because the use of GPS is not realistic in certain circumstances. Since smart antenna is able to infer direction and ranging information between pairs of ad hoc node, the obtained local position information can be used to improve routing mechanism. This work proposes a novel Location-Enhanced On-Demand (LEOD) routing protocol which is based on smart antenna technique. The LEOD protocol utilizes local position instead of global position to discover routes and make routing decision for the ad hoc network. Theoretical computation and simulation results show that data packet loss rate decreased significantly compared to other methods well-documented in the literature. In addition, this protocol reduces the network control overheads and the power consumption. It also improves network average throughput.     

Energy efficient multicast routing in ad hoc wireless networks

In this paper, we discuss the energy efficient multicast problem in ad hoc wireless networks. Each node in the network is assumed to have a fixed level of transmission power. The problem of our concern is: given an ad hoc wireless network and a multicast request, how to find a multicast tree such that the total energy cost of the multicast tree is minimized. We first prove this problem is NP-hard and it is unlikely to have an approximation algorithm with a constant performance ratio of the number of nodes in the network. We then propose an algorithm based on the directed Steiner tree method that has a theoretically guaranteed approximation performance ratio. We also propose two efficient heuristics, node-join-tree (NJT) and tree-join-tree (TJT) algorithms. The NJT algorithm can be easily implemented in a distributed fashion. Extensive simulations have been conducted to compare with other methods and the results have shown significant improvement on energy efficiency of the proposed algorithms.     

无线自组网中一种高效的路由协议

无线自组网与传统的有线网不同,它由一些可移动的结点组成,这些结点的带宽、计算能力和能量都受到一定限制。针对这种网络,研究者们提出了按需路由协议,这些协议非常适合无线自组网这种拓扑结构,但是由于缺乏对全局拓扑和结点移动性的了解,可能达不到最优。因此提出了一种高效的路由协议ERNC,该协议基于已提出的SHORT路由协议[13],并对以前所提出的NAOR协议[14]进行了扩展,即利用网络编码技术来进一步提高路由协议的性能。最后,使用NS-2模拟器来评估ERNC的性能,结果显示ERNC在分组投递率和平均端到端时延等方面获得了比已有协议更好的性能。     

A link availability-based QoS-aware routing protocol for mobile ad hoc sensor networks

With more and more wireless devices being mobile, there is a constant challenge to provide reliable and high quality communication services among these devices. In this paper, we propose a link availability-based QoS-aware (LABQ) routing protocol for mobile ad hoc networks based on mobility prediction and link quality measurement, in addition to energy consumption estimate. The goal is to provide highly reliable and better communication links with energy-efficiency. The proposed routing algorithm has been verified by NS-2 simulations. The results have shown that LABQ outperforms existing algorithms by significantly reducing link breakages and thereby reducing the overheads in reconnection and retransmission. It also reduces the average end-to-end delay for data transfer and enhances the lifetime of nodes by making energy-efficient routing decisions.     

RIVER: A reliable inter-vehicular routing protocol for vehicular ad hoc networks

Vehicular Ad hoc NETworks (VANETs), an emerging technology, would allow vehicles on roads to form a self-organized network without the aid of a permanent infrastructure. As a prerequisite to communication in VANETs, an efficient route between communicating nodes in the network must be established, and the routing protocol must adapt to the rapidly changing topology of vehicles in motion. This is one of the goals of VANET routing protocols. In this paper, we present an efficient routing protocol for VANETs, called the Reliable Inter-VEhicular Routing (RIVER) protocol. RIVER utilizes an undirected graph that represents the surrounding street layout where the vertices of the graph are points at which streets curve or intersect, and the graph edges represent the street segments between those vertices. Unlike existing protocols, RIVER performs real-time, active traffic monitoring and uses these data and other data gathered through passive mechanisms to assign a reliability rating to each street edge. The protocol then uses these reliability ratings to select the most reliable route. Control messages are used to identify a node’s neighbors, determine the reliability of street edges, and to share street edge reliability information with other nodes.