A cluster-based trust-aware routing protocol for mobile ad hoc networks

Routing protocols are the binding force in mobile ad hoc network (MANETs) since they facilitate communication beyond the wireless transmission range of the nodes. However, the infrastructure-less, pervasive, and distributed nature of MANETs renders them vulnerable to security threats. In this paper, we propose a novel cluster-based trust-aware routing protocol (CBTRP) for MANETs to protect forwarded packets from intermediary malicious nodes. The proposed protocol organizes the network into one-hop disjoint clusters then elects the most qualified and trustworthy nodes to play the role of cluster-heads that are responsible for handling all the routing activities. The proposed CBTRP continuously ensures the trustworthiness of cluster-heads by replacing them as soon as they become malicious and can dynamically update the packet path to avoid malicious routes. We have implemented and simulated the proposed protocol then evaluated its performance compared to the clustered based routing protocol (CBRP) as well as the 2ACK approach. Comparisons and analysis have shown the effectiveness of our proposed scheme.     

基于双信道的一种ad hoc网络路由策略

利用多个信道接口来改善ad hoc网络信道容量。即一个信道周期性的广播节点状态信息分组来维护全网所有节点的状态信息，而另一个信道利用此信息采用最短路径搜寻算法来获得到目的节点的路由并完成数据传输。这样充分结合了表驱动路由方法和按需式路由方法的优点。另外，信息维护与数据分组分别在两个信道内同时进行，避免了信息维护对数据分组传输的影响，提高了网络性能。     

Optimal tradeoffs for location-based routing in large-scale ad hoc networks

Existing location-based routing protocols are not versatile enough for a large-scale ad hoc environment to simultaneously meet all of the requirements of scalability, bandwidth efficiency, energy efficiency, and quality-of-service routing. To remedy this deficiency, we propose an optimal tradeoff approach that: 1) constructs a hybrid routing protocol by combining well-known location-update schemes (i.e., proactive location updates within nodes' local regions and a distributed location service), and 2) derives its optimal configuration, in terms of location-update thresholds (both distance and time-based), to minimize the overall routing overhead. We also build a route-discovery scheme based on an Internet-like architecture, i.e., first querying the location of a destination, then applying a series of local-region routing until finding a complete route by aggregating the thus-found partial routes. To find the optimal thresholds for the hybrid protocol, we derive the costs associated with both location updates and route discovery as a function of location-update thresholds, assuming a random mobility model and a general distribution for route request arrivals. The problem of minimizing the total cost is then cast into a distributed optimization problem. We first prove that the total cost is a convex function of the thresholds, and then derive the optimal thresholds. Finally, we show, via simulation, that our analysis results indeed capture the real behavior.     

Position-based routing in ad hoc networks

The availability of small, inexpensive low-power GPS receivers and techniques for finding relative coordinates based on signal strengths, and the need for the design of power-efficient and scalable networks provided justification for applying position-based routing methods in ad hoc networks. A number of such algorithms were developed previously. This tutorial will concentrate on schemes that are loop-free, localized, and follow a single-path strategy, which are desirable characteristics for scalable routing protocols. Routing protocols have two modes: greedy mode (when the forwarding node is able to advance the message toward the destination) and recovery mode (applied until return to greedy mode is possible). We discuss them separately. Methods also differ in metrics used (hop count, power, cost, congestion, etc.), and in past traffic memorization at nodes (memoryless or memorizing past traffic). Salient properties to be emphasized in this review are guaranteed delivery, scalability, and robustness     

A cluster based mobility prediction scheme for ad hoc networks

The ad hoc networks are completely autonomous wireless networks where all the users are mobile. These networks do not work on any infrastructure and the mobiles communicate either directly or via other nodes of the network by establishing routes. These routes are prone to frequent ruptures because of nodes mobility. If the future movement of the mobile can be predicted in a precise way, the resources reservation can be made before be asked, which enables the network to provide a better QoS. In this aim, we propose a virtual dynamic topology, which on one hand, will organize the network as well as possible and decreases the impact of mobility, and on the other hand, is oriented user mobility prediction. Our prediction scheme uses the evidence theory of Dempster–Shafer in order to predict the future position of the mobile by basing itself on relevant criteria. These ones are related to mobility and network operation optimisation. The proposed scheme is flexible and can be extended to a general framework. To show the relevance of our scheme, we combine it with a routing protocol. Then, we implemented the prediction-oriented topology and the prediction scheme which performs on it. We implemented also a mobility prediction based routing protocol. Simulations are made according to a set of elaborate scenarios.     

A routing protocol based on node density for ad hoc networks

Ad hoc networks are a type of mobile network that functions without any fixed infrastructure. One of the weaknesses of ad hoc networks is that a route used between a source and a destination is likely to break during communication. To solve this problem, one approach consists of selecting routes whose nodes have the most stable behavior. Another strategy aims at improving the route repair procedure. This paper proposes a method for improving the success rate of local route repairs in mobile ad hoc networks. This method is based on the density of the nodes in the neighborhood of a route and on the availability of nodes in this neighborhood. Theoretical computation and simulation results show that the data packet loss rate decreased significantly compared to other methods which are well-documented in the literature. In addition, the time required to complete a local route repair following a failure was significantly reduced.     

Authenticated routing for ad hoc networks

Initial work in ad hoc routing has considered only the problem of providing efficient mechanisms for finding paths in very dynamic networks, without considering security. Because of this, there are a number of attacks that can be used to manipulate the routing in an ad hoc network. In this paper, we describe these threats, specifically showing their effects on ad hoc on-demand distance vector and dynamic source routing. Our protocol, named authenticated routing for ad hoc networks (ARAN), uses public-key cryptographic mechanisms to defeat all identified attacks. We detail how ARAN can secure routing in environments where nodes are authorized to participate but untrusted to cooperate, as well as environments where participants do not need to be authorized to participate. Through both simulation and experimentation with our publicly available implementation, we characterize and evaluate ARAN and show that it is able to effectively and efficiently discover secure routes within an ad hoc network.     

Active routing for ad hoc networks

Ad hoc networks are wireless multihop networks whose highly volatile topology makes the design and operation of a standard routing protocol hard. With an active networking approach, one can define and deploy routing logic at runtime in order to adapt to special circumstances and requirements. We have implemented several active ad hoc routing protocols that configure the forwarding behavior of mobile nodes, allowing data packets to be efficiently routed between any two nodes of the wireless network. Isolating a simple forwarding layer in terms of both implementation and performance enables us to stream delay-sensitive audio data over the ad hoc network. In the control plane, active packets permanently monitor the connectivity and setup, and modify the routing state     

采用方向性天线的ad hoc网络路由协议研究

为了降低方向性天线扫描路由发现的开销和代价,有效利用方向性天线的高空间复用度和高传输能力,提出一种采用方向性天线的ad hoc网络位置信息辅助的按需距离矢量路由协议DLAODV,协议以按需方式获取网络节点的位置信息,结合泛洪、受限泛洪、路由压缩、位置信息修正的贪婪转发策略以及分区桥接策略,充分利用方向性天线优势,有效提高路由发现效率,路由区分维护策略有效降低了路由维护开销.仿真结果显示,DLAODV能够使得网络获得高吞吐率、低时延和开销性能,相比采用全向天线的AODV协议性能获得了明显提升.     

QoS routing in ad hoc wireless networks

The emergence of nomadic applications have generated much interest in wireless network infrastructures that support real-time communications. We propose a bandwidth routing protocol for quality-of-service (QoS) support in a multihop mobile network. The QoS routing feature is important for a mobile network to interconnect wired networks with QoS support (e.g., ATM, Internet, etc.). The QoS routing protocol can also work in a stand-alone multihop mobile network for real-time applications. This QoS routing protocol contains end-to-end bandwidth calculation and bandwidth allocation. Under such a routing protocol, the source (or the ATM gateway) is informed of the bandwidth and QoS available to any destination in the mobile network. This knowledge enables the establishment of QoS connections within the mobile network and the efficient support of real-time applications. In addition, it enables more efficient call admission control. In the case of ATM interconnection, the bandwidth information can be used to carry out intelligent handoff between ATM gateways and/or to extend the ATM virtual circuit (VC) service to the mobile network with possible renegotiation of QoS parameters at the gateway. We examine the system performance in various QoS traffic flows and mobility environments via simulation. Simulation results suggest distinct performance advantages of our protocol that calculates the bandwidth information. It is particularly useful in call admission control. Furthermore, “standby” routing enhances the performance in the mobile environment. Simulation experiments show this improvement     

感知无线电ad hoc网络基于干扰的路由

感知无线电技术作为一种新兴技术,通过时间和空间维度上的频谱空洞的利用能很好地提高频谱利用率。感知无线电的路由不同于传统的路由度量,因为次用户从时间和空间上都不能对主用户造成干扰。在感知无线电ad hoc网络环境下,选取了干扰作为路由的度量,并将干扰分为系统内干扰(次用户自身之间的干扰)和系统间干扰(次用户对主用户的干扰)。在已有的ad hoc网络干扰路由协议的基础上对干扰权重做出改进,并提出新的基于系统间路由干扰(对主用户干扰最小化)和基于联合系统内和系统间干扰的路由协议。仿真结果表明,该干扰模型符合感知无线电移动ad hoc网络的特性。     

Distributed quality-of-service routing in ad hoc networks

In an ad hoc network, all communication is done over wireless media, typically by radio through the air, without the help of wired base stations. Since direct communication is allowed only between adjacent nodes, distant nodes communicate over multiple hops. The quality-of-service (QoS) routing in an ad hoc network is difficult because the network topology may change constantly, and the available state information for routing is inherently imprecise. In this paper, we propose a distributed QoS routing scheme that selects a network path with sufficient resources to satisfy a certain delay (or bandwidth) requirement in a dynamic multihop mobile environment. The proposed algorithms work with imprecise state information. Multiple paths are searched in parallel to find the most qualified one. Fault-tolerance techniques are brought in for the maintenance of the routing paths when the nodes move, join, or leave the network. Our algorithms consider not only the QoS requirement, but also the cost optimality of the routing path to improve the overall network performance. Extensive simulations show that high call admission ratio and low-cost paths are achieved with modest routing overhead. The algorithms can tolerate a high degree of information imprecision     

Information-directed routing in ad hoc sensor networks

In a sensor network, data routing is tightly coupled to the needs of a sensing task, and hence the application semantics. This paper introduces the novel idea of information-directed routing, in which routing is formulated as a joint optimization of data transport and information aggregation. The routing objective is to minimize communication cost, while maximizing information gain, differing from routing considerations for more general ad hoc networks. The paper uses the concrete problem of locating and tracking possibly moving signal sources as an example of information generation process, and considers two common information extraction patterns in a sensor network: routing a user query from an arbitrary entry node to the vicinity of signal sources and back, or to a prespecified exit node, maximizing information accumulated along the path. We derive information constraints from realistic signal models, and present several routing algorithms that find near-optimal solutions for the joint optimization problem. Simulation results have demonstrated that information-directed routing is a significant improvement over a previously reported greedy algorithm, as measured by sensing quality such as localization and tracking accuracy and communication quality such as success rate in routing around sensor holes.     

Lattice routing: A 4D routing scheme for multiradio multichannel ad hoc networks

An efficient channel assignment strategy ensures capacity maximization in a multiradio, multichannel ad hoc network. Existing mechanisms either use a static channel assignment or a centralized process intensive system that assigns channels to individual nodes. These are not effective in a dynamic environment with multiple flows that are active at different time instants. The protocol proposed in this work (Lattice routing) manages channels of the radios for the different nodes in the network using information about current channel conditions and adapts itself to varying traffic patterns in order to efficiently use the multiple channels. Further the protocol uses multipathing, a key mechanism that is found to alleviate bottlenecks present in single path routes in such an environment. Results indicate that Lattice routing consistently outperforms it closest competitor ((MCR) Kyasanur and Vaidya (2006) [1]) across a large number of experiments.     

Optimal rate allocation for energy-efficient multipath routing in wireless ad hoc networks

In this paper, we address the problem of energy efficiency in wireless ad hoc networks. We consider an ad hoc network comprising a set of sources, communicating with their destinations using multiple routes. Each source is associated with a utility function which increases with the total traffic flowing over the available source-destination routes. The network lifetime is defined as the time until the first node in the network runs out of energy. We formulate the problem as one of maximizing the sum of the source utilities subject to a required constraint on the network lifetime. We present a primal formulation of the problem, which uses penalty functions to take into account the system constraints, and we introduce a new methodology for solving the problem. The proposed approach leads to a flow control algorithm, which provides the optimal source rates and can be easily implemented in a distributed manner. When compared with the minimum transmission energy routing scheme, the proposed algorithm gives significantly higher source rates for the same network lifetime guarantee.     

Improving routing performance in wireless ad hoc networks using cross-layer interactions

This article presents a combined layer two and three control loop, which allows prediction of link breakage in wireless ad hoc networks. The method monitors the physical layer transmission mode on layer two and exploits the gained knowledge at layer three. The mechanism bases on link adaptation, which is used in IEEE 802.11a WLAN to select the transmission mode according to the link quality. The process of link adaptation contains information that is useful to predict link stability and link lifetime. After introducing the IEEE 802.11a Medium Access Control (MAC) and PHY layer, we present insight to the IEEE 802.11a link adaptation behaviour in multi-hop ad hoc networks. The link adaptation algorithm presented here is derived from Auto Rate Fallback (ARF) algorithm. We survey the performance gain of two newly developed route adaptation approaches exploding the prediction results. One approach is Early Route ReArrangement (ERRA) that starts a route reconstruction procedure before link breakage. Hence, an alternative route is available before connectivity is lost. Early Route Update (ERU) is a complementing approach that enhances this process, by communications among routing nodes surrounding the breaking link. The delay caused by route reconstruction can be significantly reduced if prediction and either of our new route discovery processes is used.     

NonStop: continuous multimedia streaming in wireless ad hoc networks with node mobility

Guaranteeing continuous streaming of multimedia data from service providers to the users is a challenging task in wireless ad hoc networks, particularly when node mobility is considered. The topological dynamics introduced by node mobility are further exacerbated by the natural grouping behavior of mobile users, which leads to frequent network partitioning. Network partitioning poses significant challenges to the provisioning of continuous multimedia streaming services in wireless ad hoc networks, since the partitioning disconnects many mobile users from the centralized streaming service. In this paper, we propose NonStop, a collection of novel middleware-based run-time algorithms that ensures the continuous availability of such multimedia streaming services, while minimizing the overhead involved. The network-wide continuous streaming coverage is achieved by partition prediction and service replication on the streaming sources and assisted by distributed selection of streaming sources on regular mobile nodes and users. The proposed algorithms are validated by extensive results from performance evaluations.     

Information for routing in energy-constrained ad hoc networks

In wireless ad hoc networks consisting of battery-limited nodes, communication protocols must be energy-aware to prevent early network failure due to radios exhausting their energy supplies. Incorporating current estimates of battery levels into routing metrics has been shown to reduce the demand on radios with little remaining energy and allow them to participate in the network longer. In addition to knowledge of current battery levels, estimates of how quickly radios are consuming energy may also be helpful in extending network lifetime. We present a family of routing metrics that incorporate a radio’s rate of energy consumption. Simulation results show that the proposed family of metrics performs well under a variety of traffic models and network topologies.     

Ad hoc网络中带宽保证路由协议

研究ad hoc网络中无线链路存在邻近链路干扰及隐藏终端和暴露终端问题，提出新的带宽预留模型及带宽保证路由协议(BGRP)，旨在按需探测符合带宽需要的路由路径并预留可靠的带宽资源。理论分析证明，BGRP探测的路由路径能满足带宽需要，而且预留的带宽资源准确有效。仿真结果表明，就有效带宽而言，BGRP较INSIGNIA和BGSR算法有效，而且消息复杂性较小，具有良好的网络扩展性。