Location based services in wireless ad hoc networks

In this dissertation, we investigate location based services in wireless ad hoc networks from four different aspects - i) location privacy in wireless sensor networks (privacy), ii) end-to-end secure communication in randomly deployed wireless sensor networks (security), iii) quality versus latency trade-off in content retrieval under ad hoc node mobility (performance) and iv) location clustering based Sybil attack detection in vehicular ad hoc networks (trust). The first contribution of this dissertation is in addressing location privacy in wireless sensor networks. We propose a non-cooperative sensor localization algorithm showing how an external entity can stealthily invade into the location privacy of sensors in a network. We then design a location privacy preserving tracking algorithm for defending against such adversarial localization attacks. Next we investigate secure end-to-end communication in randomly deployed wireless sensor networks. Here, due to lack of control on sensors\u27 locations post deployment, pre-fixing pairwise keys between sensors is not feasible especially under larger scale random deployments. Towards this premise, we propose differentiated key pre-distribution for secure end-to-end secure communication, and show how it improves existing routing algorithms. Our next contribution is in addressing quality versus latency trade-off in content retrieval under ad hoc node mobility. We propose a two-tiered architecture for efficient content retrieval in such environment. Finally we investigate Sybil attack detection in vehicular ad hoc networks. A Sybil attacker can create and use multiple counterfeit identities risking trust of a vehicular ad hoc network, and then easily escape the location of the attack avoiding detection. We propose a location based clustering of nodes leveraging vehicle platoon dispersion for detection of Sybil attacks in vehicular ad hoc networks --Abstract, page iii

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

Adaptive Middleware for Resource-Constrained Mobile Ad Hoc and Wireless Sensor Networks

Mobile ad hoc networks: MANETs) and wireless sensor networks: WSNs) are two recently-developed technologies that uniquely function without fixed infrastructure support, and sense at scales, resolutions, and durations previously not possible. While both offer great potential in many applications, developing software for these types of networks is extremely difficult, preventing their wide-spread use. Three primary challenges are: 1) the high level of dynamics within the network in terms of changing wireless links and node hardware configurations,: 2) the wide variety of hardware present in these networks, and: 3) the extremely limited computational and energy resources available. Until now, the burden of handling these issues was put on the software application developer. This dissertation presents three novel programming models and middleware systems that address these challenges: Limone, Agilla, and Servilla. Limone reliably handles high levels of dynamics within MANETs. It does this through lightweight coordination primitives that make minimal assumptions about network connectivity. Agilla enables self-adaptive WSN applications via the integration of mobile agent and tuple space programming models, which is critical given the continuously changing network. It is the first system to successfully demonstrate the feasibility of using mobile agents and tuple spaces within WSNs. Servilla addresses the challenges that arise from WSN hardware heterogeneity using principles of Service-Oriented Computing: SOC). It is the first system to successfully implement the entire SOC model within WSNs and uniquely tailors it to the WSN domain by making it energy-aware and adaptive. The efficacies of the above three systems are demonstrated through implementation, micro-benchmarks, and the evaluation of several real-world applications including Universal Remote, Fire Detection and Tracking, Structural Health Monitoring, and Medical Patient Monitoring

Location-aware mechanism for efficient video delivery over wireless mesh networks

Due to their flexibility, ease of use, low-cost and fast deployment, wireless Mesh Networks have been widely accepted as an alternative to wired network for last-mile connectivity. When used in conjunction with Peer-to-Peer data transfer solutions, many innovative applications and services such as distributed storage, resource sharing, live TV broadcasting or Video on Demand can be supported without any centralized administration. However, in order to achieve a good quality of service in such variable, error-prone and resource-constrained wireless multi-hop environments, it is important that the associated Peer-to-Peer overlay is not only aware of the availability, but also of the location and available path link quality of its peers and services. This thesis proposes a wireless location-aware Chord-based overlay mechanism for Wireless Mesh Networks (WILCO) based on a novel geographical multi-level ID mapping and an improved finger table. The proposed scheme exploits the location information of mesh routers to decrease the number of hops the overlay messages traverse in the physical topology. Analytical and simulation results demonstrate that in comparison to the original Chord, WILCO has significant benefits: it reduces the number of lookup messages, has symmetric lookup on keys in both the forward and backward direction of the Chord ring and achieves a stretch factor of O(1). On top of this location-aware overlay, a WILCO-based novel video segment seeking algorithm is proposed to make use of the multi-level WILCO ID location-awareness to locate and retrieve requested video segments from the nearest peer in order to improve video quality. An enhanced version of WILCO segment seeking algorithm (WILCO+) is proposed to mitigate the sometimes suboptimal selection of the WILCO video segment seeking algorithm by extracting coordinates from WILCO ID to enable location-awareness. Analytical and simulation results illustrate that the proposed scheme outperforms the existing state-of-the-art solutions in terms of PSNR and packet loss with different background traffic loads. While hop count is frequently strongly correlated to Quality of Service, the link quality of the underlying network will also have a strong influence on content retrieval quality. As a result, a Cross-layer Wireless Link Quality-aware Overlay peer selection mechanism (WLO) is proposed. The proposed cross-layer mechanism uses a Multiplication Selector Metric (MSM) to select the best overlay peer. The proposed MSM overcomes the two issues facing the traditional summation-based metric, namely, the difficulty of bottleneck link identification and the influence of hop count on behavior. Simulation results show that WLO outperforms the existing state-of-the-art solutions in terms of video quality at different background loads and levels of topology incompleteness. Real life emulation-based tests and subjective video quality assessments are also performed to show that the simulation results are closely matched by the real-life emulation-based results and to illustrate the significant impact of overlay peer selection on the user perceived video quality

Cognitive radio systems in LTE networks

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London.The most important fact in the mobile industry at the moment is that demand for wireless services will continue to expand in the coming years. Therefore, it is vital to find more spectrums through cognitive radios for the growing numbers of services and users. However, the spectrum reallocations, enhanced receivers, shared use, or secondary markets-will not likely, by themselves or in combination, meet the real exponential increases in demand for wireless resources. Network operators will also need to re-examine network architecture, and consider integrating the fibre and wireless networks to address this issue. This thesis involves driving fibre deeper into cognitive networks, deploying microcells connected through fibre infrastructure to the backbone LTE networks, and developing the algorithms for diverting calls between the wireless and fibre systems, introducing new coexistence models, and mobility management. This research addresses the network deployment scenarios to a microcell-aided cognitive network, specifically slicing the spectrum spatially and providing reliable coverage at either tier. The goal of this research is to propose new method of decentralized-to-distributed management techniques that overcomes the spectrum unavailability barrier overhead in ongoing and future deployments of multi-tiered cognitive network architectures. Such adjustments will propose new opportunities in cognitive radio-to-fibre systematic investment strategies. Specific contributions include: 1) Identifying the radio access technologies and radio over fibre solution for cognitive network infrastructure to increase the uplink capacity analysis in two-tier networks. 2) Coexistence of macro and microcells are studied to propose a roadmap for optimising the deployment of cognitive microcells inside LTE macrocells in the case of considering radio over fibre access systems. 3) New method for roaming mobiles moving between microcells and macrocell coverage areas is proposed for managing spectrum handover, operator database, authentication and accounting by introducing the channel assigning agent entity. The ultimate goal is to reduce unnecessary channel adaptation

A Quantitative Analysis of Performance in a Multi-Protocol Ad Hoc 802.11b-based Wireless Local Network

The popularity of the Internet and the growing demand for ubiquitous connectivity accelerate the need for viable wireless local area network (WLAN) solutions. As a consequence, increasing number of manufacturers have adopted the Institute of Electrical and Electronic Engineers (IEEE) 802.11a/b/g set of WLAN standards and produced inexpensive wireless products to expand capabilities of existing LANs. IEEE 802.11 b wireless products are widely accepted. Mobile ad hoc networks, a variant of the 802.11 standards, exist without the requirement for a wired infrastructure or host to provide routing, connectivity, and maintenance services. Because of the high variability of environments in which ad hoc networks operate, numerous routing protocols are proposed. Research indicates that these protocols are unsuited for efficient operation in multiple environments. In this investigation, the author examined the effect of multiple protocols on throughput and end-to-end delay in simulated ad hoc networks. The author selected the ad hoc on-demand distance vector (AODV) and dynamic source routing (DSR) routing protocols for this research. The outcomes from the simulations conducted indicated increased end-to-end delay and reduced packet throughput as a result of the mixed populations of the AODV and DSR ad hoc routing protocols. The results also indicated that increasing node density and velocity improved packet throughput and reduced end-to-end delay

Smart Wireless Sensor Networks

The recent development of communication and sensor technology results in the growth of a new attractive and challenging area - wireless sensor networks (WSNs). A wireless sensor network which consists of a large number of sensor nodes is deployed in environmental fields to serve various applications. Facilitated with the ability of wireless communication and intelligent computation, these nodes become smart sensors which do not only perceive ambient physical parameters but also be able to process information, cooperate with each other and self-organize into the network. These new features assist the sensor nodes as well as the network to operate more efficiently in terms of both data acquisition and energy consumption. Special purposes of the applications require design and operation of WSNs different from conventional networks such as the internet. The network design must take into account of the objectives of specific applications. The nature of deployed environment must be considered. The limited of sensor nodes� resources such as memory, computational ability, communication bandwidth and energy source are the challenges in network design. A smart wireless sensor network must be able to deal with these constraints as well as to guarantee the connectivity, coverage, reliability and security of network's operation for a maximized lifetime. This book discusses various aspects of designing such smart wireless sensor networks. Main topics includes: design methodologies, network protocols and algorithms, quality of service management, coverage optimization, time synchronization and security techniques for sensor networks

Security of Cyber-Physical Systems

Cyber-physical system (CPS) innovations, in conjunction with their sibling computational and technological advancements, have positively impacted our society, leading to the establishment of new horizons of service excellence in a variety of applicational fields. With the rapid increase in the application of CPSs in safety-critical infrastructures, their safety and security are the top priorities of next-generation designs. The extent of potential consequences of CPS insecurity is large enough to ensure that CPS security is one of the core elements of the CPS research agenda. Faults, failures, and cyber-physical attacks lead to variations in the dynamics of CPSs and cause the instability and malfunction of normal operations. This reprint discusses the existing vulnerabilities and focuses on detection, prevention, and compensation techniques to improve the security of safety-critical systems