A taxonomy and evaluation for developing 802.11‐based wireless mesh network testbeds

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92433/1/dac1299.pd

Internet connection method for mobile ad hoc wireless networks

In recent years, wireless networks with Internet services have become more and more popular. Technologies which integrate Internet and wireless networks have extended traditional Internet applications into a more flexible and dynamic environment. This research work investigates the technology that supports the connection between a Mobile Ad Hoc Wireless Network (MANET) and the Internet, which enables the current wireless Internet technologies to provide a ubiquitous wireless life style. With detailed analysis of the existing wireless Internet technologies and MANETs regarding their features and applications, the demand and lack of research work for an application to provide Internet connection to MANET is indicated. The primary difficulty for MANET and Internet connection is that the dynamic features of MANET do not suit the traditional connection methods used in infrastructure wireless networks. This thesis introduces new concept of the 'Gateway Awareness' (GAW) to the wireless devices in the MANET. GAW is a new routing protocol designed by the author of this thesis, at the University of Warwick. Based on GAW, an inclusive definition for the connection method, which supports the Internet connection and keeps the independency of routing in MANET, is addressed. Unlike other research work, this method supports the MANET and Internet communication in both directions. Furthermore, it explores possible ways of using the Internet as an extension for wireless communications. The GAW routing method is developed from destination sequenced distance vector (DSDV) routing protocol. However, it defines a layer of wireless nodes (known as GAWNs) with exclusive functions for the Internet connection task. The layer of GAWNs brings a new set of route update and route selection method. Simulations show that the GAW routing method provides quality Internet connection performance in different scenarios compared with other methods. In particular, the connection is completed with minimum effect on the independent MANET while the routing efficiency and accuracy is guaranteed

Mobile Ad-Hoc Networks

Being infrastructure-less and without central administration control, wireless ad-hoc networking is playing a more and more important role in extending the coverage of traditional wireless infrastructure (cellular networks, wireless LAN, etc). This book includes state-of-the-art techniques and solutions for wireless ad-hoc networks. It focuses on the following topics in ad-hoc networks: quality-of-service and video communication, routing protocol and cross-layer design. A few interesting problems about security and delay-tolerant networks are also discussed. This book is targeted to provide network engineers and researchers with design guidelines for large scale wireless ad hoc networks

Improving the Performance of Wireless LANs

This book quantifies the key factors of WLAN performance and describes methods for improvement. It provides theoretical background and empirical results for the optimum planning and deployment of indoor WLAN systems, explaining the fundamentals while supplying guidelines for design, modeling, and performance evaluation. It discusses environmental effects on WLAN systems, protocol redesign for routing and MAC, and traffic distribution; examines emerging and future network technologies; and includes radio propagation and site measurements, simulations for various network design scenarios, numerous illustrations, practical examples, and learning aids

Internet connection method for mobile ad hoc wireless networks

In recent years, wireless networks with Internet services have become more and more popular. Technologies which integrate Internet and wireless networks have extended traditional Internet applications into a more flexible and dynamic environment. This research work investigates the technology that supports the connection between a Mobile Ad Hoc Wireless Network (MANET) and the Internet, which enables the current wireless Internet technologies to provide a ubiquitous wireless life style. With detailed analysis of the existing wireless Internet technologies and MANETs regarding their features and applications, the demand and lack of research work for an application to provide Internet connection to MANET is indicated. The primary difficulty for MANET and Internet connection is that the dynamic features of MANET do not suit the traditional connection methods used in infrastructure wireless networks. This thesis introduces new concept of the 'Gateway Awareness' (GAW) to the wireless devices in the MANET. GAW is a new routing protocol designed by the author of this thesis, at the University of Warwick. Based on GAW, an inclusive definition for the connection method, which supports the Internet connection and keeps the independency of routing in MANET, is addressed. Unlike other research work, this method supports the MANET and Internet communication in both directions. Furthermore, it explores possible ways of using the Internet as an extension for wireless communications. The GAW routing method is developed from destination sequenced distance vector (DSDV) routing protocol. However, it defines a layer of wireless nodes (known as GAWNs) with exclusive functions for the Internet connection task. The layer of GAWNs brings a new set of route update and route selection method. Simulations show that the GAW routing method provides quality Internet connection performance in different scenarios compared with other methods. In particular, the connection is completed with minimum effect on the independent MANET while the routing efficiency and accuracy is guaranteed.EThOS - Electronic Theses Online ServiceUniversities UKUniversity of WarwickGBUnited Kingdo

Wireless Multi Hop Access Networks and Protocols

As more and more applications and services in our society now depend on the Internet, it is important that dynamically deployed wireless multi hop networks are able to gain access to the Internet and other infrastructure networks and services. This thesis proposes and evaluates solutions for providing multi hop Internet Access. It investigates how ad hoc networks can be combined with wireless and mesh networks in order to create wireless multi hop access networks. When several access points to the Internet are available, and the mobile node roams to a new access point, the node has to make a decision when and how to change its point of attachment. The thesis describes how to consider the rapid fluctuations of the wireless medium, how to handle the fact that other nodes on the path to the access point are also mobile which results in frequent link and route breaks, and the impact the change of attachment has on already existing connections. Medium access and routing protocols have been developed that consider both the long term and the short term variations of a mobile wireless network. The long term variations consider the fact that as nodes are mobile, links will frequently break and new links appear and thus the network topology map is constantly redrawn. The short term variations consider the rapid fluctuations of the wireless channel caused by mobility and multi path propagation deviations. In order to achieve diversity forwarding, protocols are presented which consider the network topology and the state of the wireless channel when decisions about forwarding need to be made. The medium access protocols are able to perform multi dimensional fast link adaptation on a per packet level with forwarding considerations. This i ncludes power, rate, code and channel adaptation. This will enable the type of performance improvements that are of significant importance for the success of multi hop wireless networks

Secure Neighbor Discovery and Ranging in Wireless Networks

This thesis addresses the security of two fundamental elements of wireless networking: neighbor discovery and ranging. Neighbor discovery consists in discovering devices available for direct communication or in physical proximity. Ranging, or distance bounding, consists in measuring the distance between devices, or providing an upper bound on this distance. Both elements serve as building blocks for a variety of services and applications, notably routing, physical access control, tracking and localization. However, the open nature of wireless networks makes it easy to abuse neighbor discovery and ranging, and thereby compromise overlying services and applications. To prevent this, numerous works proposed protocols that secure these building blocks. But two aspects crucial for the security of such protocols have received relatively little attention: formal verification and attacks on the physical-communication-layer. They are precisely the focus of this thesis. In the first part of the thesis, we contribute a formal analysis of secure communication neighbor discovery protocols. We build a formal model that captures salient characteristics of wireless systems such as node location, message propagation time and link variability, and we provide a specification of secure communication neighbor discovery. Then, we derive an impossibility result for a general class of protocols we term "time-based protocols", stating that no such protocol can provide secure communication neighbor discovery. We also identify the conditions under which the impossibility result is lifted. We then prove that specific protocols in the time-based class (under additional conditions) and specific protocols in a class we term "time- and location-based protocols," satisfy the neighbor discovery specification. We reinforce these results by mechanizing the model and the proofs in the theorem prover Isabelle. In the second part of the thesis, we explore physical-communication-layer attacks that can seemingly decrease the message arrival time without modifying its content. Thus, they can circumvent time-based neighbor discovery protocols and distance bounding protocols. (Indeed, they violate the assumptions necessary to prove protocol correctness in the first part of the thesis.) We focus on Impulse Radio Ultra-Wideband, a physical layer technology particularly well suited for implementing distance bounding, thanks to its ability to perform accurate indoor ranging. First, we adapt physical layer attacks reported in prior work to IEEE 802.15.4a, the de facto standard for Impulse Radio, and evaluate their performance. We show that an adversary can achieve a distance-decrease of up to hundreds of meters with an arbitrarily high probability of success, with only a minor cost in terms of transmission power (few dB). Next, we demonstrate a new attack vector that disrupts time-of-arrival estimation algorithms, in particular those designed to be precise. The distance-decrease achievable by this attack vector is in the order of the channel spread (order of 10 meters in indoor environments). This attack vector can be used in previously reported physical layer attacks, but it also creates a new type of external attack based on malicious interference. We demonstrate that variants of the malicious interference attack are much easier to mount than the previously reported external attack. We also provide design guidelines for modulation schemes and devise receiver algorithms that mitigate physical layer attacks. These countermeasures allow the system designer to trade off security, ranging precision and cost in terms of transmission power and packet length