Guide to Wireless Ad Hoc Networks

Frontmatter

Chapter 1. Properties of Wireless Multihop Networks in Theory and Practice

Abstract

Simulation and testbeds are frequently used for the validation of wireless networking protocols, but several assumptions regarding node placement, wireless signal propagation, and traffic type must be made. We compare common models with the measurements made in Berlin’s and Leipzig’s free multihop wireless networks. It is shown that the properties observed in reality are different than in commonly used models: network is connected but with low average node density; it has large number of bridges and articulation points that can compromise its connectivity; and the traffic distribution over nodes is highly asymmetrical. As an illustration of the discrepancy between reality and synthetic models, we present issues of reactive route discovery process that cannot be observed in simulation that use common placement and propagation models. This chapter focuses on the understanding of limitations of simulation methodologies. It also provides general guidelines on ways of reducing the gap between simulation theory and practice of wireless multihop networks.

Bratislav Milic, Miroslaw Malek

Chapter 2. Self-Configuring, Self-Organizing, and Self-Healing Schemes in Mobile Ad Hoc Networks

Abstract

The evolution of technology, the expansion of the Internet, and the tendency of systems to become more software-dependent make computing environments and networks more complicated and less humanly controlled. In this chapter, we consider the problem of organizing a set of mobile nodes, with unique IDs, that communicate through a wireless medium, into a connected network, in order to obtain a self-configuring or self-organizing network. Additionally, we address the issue of how a reliable structure, once acquired by self-configuring, can be maintained when topological changes occur, due to node failure, node motion, or link failure, in order to obtain a self-healing network. We discuss these concepts and present a brief history of self-configuring or self-healing algorithms, respectively, for wireless mobile networks. We detail a number of representative algorithms used in practice. We then go on to address the current theoretical results on self-configuring networks for which we propose directions for future research.

Doina Bein

Chapter 3. Cooperation in Mobile Ad Hoc Networks

Abstract

Mobile ad hoc networks (MANETs) are collections of self-organizing mobile nodes with dynamic topologies and no fixed infrastructure [1, 2]. Cooperation among nodes is fundamental to the function of a MANET. However, nodes in a MANET are autonomous and independent wireless devices. Due to the lack of infrastructure, the constraints of resources at each node, and the ad hoc nature of nodes, we cannot assume that every node behaves as the protocol requires. This chapter presents a detailed study on the recent advances in stimulating cooperation in MANETs. Virtual currency systems and reputation systems are described, followed by a discussion of the directions for future research.

Jiangyi Hu, Mike Burmester

Chapter 4. Routing in Mobile Ad Hoc Networks

Abstract

A Mobile Ad Hoc Network (MANET) is built on the fly where a number of wireless mobile nodes work in cooperation without the engagement of any centralized access point or any fixed infrastructure. Two nodes in such a network can communicate in a bidirectional manner if and only if the distance between them is at most the minimum of their transmission ranges. When a node wants to communicate with a node outside its transmission range, a multi-hop routing strategy is used which involves some intermediate nodes. Because of the movements of nodes, there is a constant possibility of topology change in MANET. Considering this unique aspect of MANET, a number of routing protocols have been proposed so far. This chapter gives an overview of the past, current, and future research areas for routing in MANET. In this chapter we will learn about the following things:

• The preliminaries of mobile ad hoc network
• The challenges for routing in MANET
• Expected properties of a MANET routing protocol
• Categories of routing protocols for MANET
• Major routing protocols for MANET
• Criteria for performance comparison of the routing protocols for MANET
• Achievements and future research directions
• Expectations and reality

Al-Sakib Khan Pathan, Choong Seon Hong

Chapter 5. Multicasting in Mobile Ad Hoc Networks

Abstract

The success of wireless ad hoc networks and the increasing interest in multimedia applications explain the need of multicast protocols adapted to the wireless environment. In this chapter, we first introduce the design considerations for a multicast protocol in a wireless ad hoc network. We then present a classification of multicast protocols and another for reliable ones. Each family is illustrated by a representative example. Finally, we give some directions for the future research related to the multicast protocols: QoS (Quality of Service) support and network coding.

Pascale Minet, Anis Laouiti

Chapter 6. Broadcast in Ad Hoc Networks

Abstract

Broadcast is the process of sending a message from one node to all other nodes in an ad hoc network. It is a fundamental operation for communication in ad hoc networks as it allows for the update of network information and route discovery as well as other operations. The chapter presents a comprehensive review and analysis of existing localized solutions on broadcast, where only local knowledge is required. The techniques reviewed include optimized broadcast techniques, such as multipoint relay and dominating set-based broadcasting with fixed transmission radii, resource awareness, localized minimum energy broadcasting with adjustable transmission radii, and solutions for increasing reliability of broadcasting are also reviewed. Further, the chapter highlights the use of broadcast in route discovery and new approaches to route discovery based upon self-selecting search techniques as opposed to traditional broadcast approaches.  

Justin Lipman, Hai Liu, Ivan Stojmenovic

Chapter 7. Geographic Routing in Wireless Ad Hoc Networks

Abstract

Geographic routing has become an efficient solution for communications and information delivery in wireless ad hoc networks where the position information of nodes is available. This chapter provides a comprehensive overview of basic principles, classical techniques, as well as latest advances in geographic routing. The chapter first presents in detail the topic of geographic unicast routing, where the presentation is focused on two operation modes of geographic forwarding, that is, greedy forwarding and void handling. The chapter also briefly introduces three advanced topics in geographic routing: geographic multicast, geocast, and trajectory-based forwarding. Finally, the chapter makes some comments on the practical aspects of geographic routing for practitioners and discusses the directions for further research with a list of open issues in the area of geographic routing.

Dazhi Chen, Pramod K. Varshney

Chapter 8. Formal Verification of Routing Protocols for Wireless Ad Hoc Networks

Abstract

Routing is one of the most basic and important tasks in a collaborative computer network. Having a correct, robust, and efficient routing protocol is fundamental to any wireless network. However, a difficult problem is how to guarantee these desirable qualities. Neither simulations nor testbed implementations can ensure the quality required for these protocols. As an alternative to these methods, some researchers have successfully investigated the use of formal verification as a mean to guarantee the quality of routing protocols. Formal verification is a technique that assures a system has, or has not, a given property, based on a formal specification of the system under evaluation. This technique has proved to be a valuable tool, even contradicting some authors’ claims and informal proofs. This chapter presents the main tools, proposals, and techniques available to perform formal verification of routing algorithms for wireless ad hoc networks.

Daniel Câmara, Antonio A.F. Loureiro, Fethi Filali

Chapter 9. Mobility Management in MANETs: Exploit the Positive Impacts of Mobility

Abstract

The question of whether mobility is a blessing (Burleigh et al., IEEE Communications Magazine, 41:128–136, 2003; Capkun et al., Proc. of ACM MobiHoc, 2003) or a curse (Zhang et al., Proc. of ACM MobiHoc, 2005) to ad hoc networks has attracted a significant amount of research interest. Some researchers argue that mobility is a hurdle, as it makes the routing, naming and addressing, and location services more challenging. Some new mechanisms such as Zhang et al. (Proc. of ACM MobiHoc, 2005) have been proposed to tackle the problems caused by node mobility in MANETs. Others argue that far?from being a hurdle, mobility can be exploited to increase the system performance. Carefully designed protocols may exploit the mobility to obtain advantages in many important aspects of ad hoc networks, such as network capacity, security, and information dissemination.

This chapter surveys the impact of mobility in ad hoc networks from a wide perspective. We refrain from going into minute details of mobility, and instead?head for giving a broader picture. The goal of this chapter is to endorse new approaches to employ mobility in ad hoc networks based on the current situation and show why mobility can help in many different aspects (Cooper et?al., Proc. of IEEE MASCOTS, 2005; Camp et al., Wireless Communications and Mobile Computing, 2(5):483–502, 2002).

Feng Li, Yinying Yang, Jie Wu

Chapter 10. Mobility Models for Ad Hoc Networks

Abstract

Network simulators emerged as the most common method of evaluating the performance of large and complex networking systems. However, for systems involving mobile nodes, the movement of the mobile nodes has a significant influence on the results of the simulation. Therefore, in the past decade, a significant amount of research was devoted to develop mobility models suitable for evaluating the performance of wireless networks. Existing mobility models vary widely in their realism, from completely artificial to very realistic as well as in their statistical properties. In this chapter we provide an overview of those mobility models and their most important properties.

Mihail L. Sichitiu

Chapter 11. Models for Realistic Mobility and Radio Wave Propagation for Ad Hoc Network Simulations

Abstract

An ad hoc network is realized by mobile devices which communicate over radio. Since, experiments with real devices are very difficult, simulation is used very often. Among many other important properties that have to be defined for simulative experiments, the mobility model and the radio propagation model have to be selected carefully. Both have strong impact on the performance of mobile ad hoc networks, e.g., the performance of routing protocols changes with these models. There are many mobility and radio propagation models proposed in literature. Each of them was developed with different intentions and is not suited for every scenario. In this chapter we introduce well-known models for mobility and radio propagation, and discuss their advantages, drawbacks, and limitations in respect to the simulation of mobile ad hoc networks.

Mesut Güneş, Martin Wenig

Chapter 12. Quality of Service Support in Wireless Ad Hoc Networks

Abstract

Quality of Service is the performance level of a service offered by the network to the user. Provision of quality of service guarantees in wireless ad hoc networks is very challenging due to some inherent difficulties like node mobility, multi-hop communications, contention for channel access and lack of central coordination. In this chapter we summarise a comprehensive review of the state-of-the-art research works related to quality of service support in wireless ad hoc network and provide coordination among the research works.

Musfiq Rahman, Ashfaqur Rahman

Chapter 13. Delay Management in Wireless Ad Hoc Networks

Abstract

A good amount of research has been developed to support QoS issues in IEEE 802.11 ad hoc networks. In this chapter, we address QoS management issues through multiple layers for real-time multimedia applications. We investigate the adaptation mechanisms at middleware layer and MAC layer to dynamically adjust the service classes for applications by feedback control theory. Based on our investigation, we propose a cross-layer end-to-end delay management framework for multimedia traffic over multi-hop wireless networks.

Wenbo He, Yuan Xue, Klara Nahrstedt

Chapter 14. Address Allocation Mechanisms for Mobile Ad Hoc Networks

Abstract

A Mobile Ad hoc Network (MANET) is an independent self-organizing network, in which each node functions as an end host and a wireless relay. This form of wireless network is created by mobile nodes without any existing or fixed infrastructure. The nodes in the MANET need mutually exclusive identities before participating in any form of communication; in particular, each end host in the MANET needs to be uniquely addressed so that the packets can be relayed hop by hop and delivered ultimately to the destination. The mobility of the nodes, however, makes address allocation a challenging task in MANETs.

In the past decade, many address allocation schemes have been proposed to address these challenges. In this chapter, we will present a comprehensive survey on the state-of-the-art of address allocation in MANETs. We will also demonstrate a new address allocation protocol for MANET based on the concept of quadratic residue, which can be applied to large-scale MANETs with low communication overhead, even distribution, and low latency.

Xiaowen Chu, Jiangchuan Liu, Yi Sun

Chapter 15. Congestion Control in Wireless Ad Hoc Networks

Abstract

Multi-hop Wireless Networks (MHWNs) are anticipated to play an important role at the edge of the Internet, enabling a large number of innovative applications. The great demand for capacity from a large number of users and applications, coupled with the sparse bandwidth available on the wireless channel, place particular emphasis on effective congestion management approaches. Effective and well-studied algorithms for congestion control at the transport layer exist in wired networks. However, for a number of reasons, these approaches do not translate directly to wireless environments. In this chapter, we first describe the problem of congestion control in MHWNs, and discuss approaches for solving it. The presentation is organized into two components: (1) a review of the causes of congestion and algorithms for congestion avoidance in MHWNs at different layers of protocol stack; and (2) a review of analytical models for the rate control problem and their use for congestion control.

Vinay Kolar, Sameer Tilak, Nael Abu-Ghazaleh

Chapter 16. Security in Wireless Ad Hoc Networks

Abstract

Operating in open and shared media, wireless communication is inherently less secure than wired communication. Even worse, mobile wireless devices usually have limited resources, such as bandwidth, storage space, processing capability, and energy, which makes security enforcement hard. Compared with infrastructure-based wireless networks, security management for wireless ad hoc networks is more challenging due to unreliable communication, intermittent connection, node mobility, and dynamic topology. A complete security solution should include three components of prevention, detection, and reaction, and provides security properties of authentication, confidentiality, non-repudiation, integrity, and availability. It should be adaptive in order to trade-off service performance and security performance under resource limitation. In this chapter, we will focus on the preventive mechanism for key management and broadcast authentication with resource constraints.

Klara Nahrstedt, Wenbo He, Ying Huang

Chapter 17. Intrusion Detection in Mobile Ad Hoc Networks

Abstract

In recent years, mobile ad hoc networks (MANETs) have become a very popular research topic. By providing communications in the absence of a fixed infrastructure, MANETs are an attractive technology for many applications such as rescue operations, tactical operations, environmental monitoring, conferences, and the like. However, this flexibility introduces new security risks. Since prevention techniques are never enough, intrusion detection systems (IDSs), which monitor system activities and detect intrusions, are generally used to complement other security mechanisms.

Intrusion detection for MANETs is a complex and difficult task mainly due to the dynamic nature of MANETs, their highly constrained nodes, and the lack of central monitoring points. Conventional IDSs are not easily applied to them. New approaches need to be developed or else existing approaches need to be adapted for MANETs. This chapter outlines the issues of intrusion detection for MANETs and reviews the main solutions proposed in the literature.

Sevil Şen, John Andrew Clark

Chapter 18. Security Threats in Ad Hoc Routing Protocols

Abstract

The lack of infrastructure and centralized nodes in ad hoc networks have made nodes to depend on the cooperative nature of neighbor nodes for critical services like routing and maintenance. This unique cooperative nature of ad hoc network’s routing mechanism has spawned unprecedented security threats in the routing protocol. Attackers have the potential to directly disrupt the routing protocol communications, which is transparent in conventional wired and wireless networks. A routing attack scenario is composed of a sequence of attack behaviors, and an attack behavior is a sequence of elementary attack behaviors, which is executed in particular fashion. The chapter enumerates in detail the routing attack scenarios and their elements. Also, the chapter introduces a security threat analysis that is used to explore different attack scenarios and behaviors in ad hoc routing protocols. The observations made in the threat analysis are useful for understanding the security vulnerabilities and realizing the requisites of a security system design for ad hoc networks.

John Felix Charles Joseph, Amitabha Das, Bu-Sung Lee

Chapter 19. Trust Management in Mobile Ad Hoc Networks

Abstract

In this chapter, we present the state of the art in trust management systems in mobile ad hoc networks (MANET). First, we consider the rationale for trust management systems by demonstrating the shortcomings of secure routing protocols and incentive-based systems. We then establish the context by exploring the concepts and methodology of traditional trust management systems. In sequent, we analyze and compare recently proposed and few well-reviewed trust management based models for MANET. Finally, we present the limitations and shortcomings of these trust models, and then discuss the possible research directions toward the development of efficient trust management systems.

Venkat Balakrishnan, Vijay Varadharajan, Uday Tupakula

Chapter 20. Vehicular Ad Hoc Networks

Abstract

A vehicular ad hoc network consists of smart vehicles on the road and provides communication services among nearby vehicles or with roadside infrastructure. It is envisioned to provide numerous interesting services in the near future. This chapter first introduces the basic application scenarios of vehicular ad hoc network and its unique characteristics, and then provides a brief survey of several research issues in vehicular ad hoc networks, such as routing, data sharing, mobility models, and security.

Yu Wang, Fan Li

Chapter 21. Integration of Mobile Ad Hoc Networks into IP-Based Access Networks

Abstract

The study of mobile ad hoc networks (MANET) is commonly focused on how nodes belonging to the same network communicate by means of ad hoc routing protocols. However, when integrated into the Internet, the ad hoc routing protocols become insufficient, so additional technologies are required. In the IPv6 context, technologies such as NDP (Neighbor Discovery Protocol), which plays a fundamental role in automatically configuring the mobile nodes, were initially conceived to operate in on-link communications. This assumption is a clear restriction in multihop networks so the technologies should be adapted to these new scenarios. In order to provide a framework where these adaptations could be accomplished, several mechanisms have been proposed. All of them introduce an additional element that plays the role of the Internet Gateway. The characteristics as well as the functionalities of the Internet Gateway differ in the integration supports. In this chapter, the problems that arise in the integration of MANET into IP-based access networks, such as the Internet, will be described as well as the solutions that the research community IS analyzing.

A. Triviño Cabrera

Backmatter