WALLSY: The UWB and SmartMesh IP enabled Wireless Ad-hoc Low-power Localization SYstem

This paper follows the implementation of a proofof-concept localization system for GNSS-denied environments. WALLSY (Wireless Ad-hoc Low-power Localization SYstem) is a portable and modular Ultra Wide-Band (UWB) and Smart Mesh IP (SMIP) hybrid. WALLSY uses UWB two way ranging (TWR) to measure distances, which are then sent via the lowpower SMIP backbone network to a central hub for calculating coordinates of tracked objects. The system is highly flexible and requires no external infrastructure or prior knowledge of the installation site. It uses a completely nomadic topology and delivers high localization accuracy with all modules being battery powered. It achieves this by using a custom time-slotting protocol which maximizes deep-sleep mode for UWB. Battery life can be further improved by activating inertial measurement unit (IMU) filtering. Visualization of tracked objects and system reconfiguration can be executed on-the-fly and are both accessible to end users through a simple graphical user interface (GUI). Results demonstrate that WALLSY can achieve more than ten times longer battery lifetime compared to competing solutions (localizing every 30 seconds). It provides 3D coordinates with an average spatial error of 60.5cm and an average standard deviation of 15cm. The system also provides support for up to 20 tags

Simulating Confidence for the Ellison-Glaeser Index

The Ellison and Glaeser (1997) index is an unbiased statistic of industrial localization. Though the expected value of the index is known, ad hoc thresholds are used to interpret the extent of localization. We improve the interpretation of the index by simulating confidence intervals that a practitioner may use for a statistical test. In the data, we find cases whose index value is above the ad hoc threshold that are not statistically significant. We find many cases below the ad hoc threshold that are statistically significant. Our simulation program is freely available and is customizable for specific applications

Mobile Codes Localization in Ad hoc Networks: a Comparative Study of Centralized and Distributed Approaches

This paper presents a new approach in the management of mobile ad hoc networks. Our alternative, based on mobile agent technology, allows the design of mobile centralized server in ad hoc network, where it is not obvious to think about a centralized management, due to the absence of any administration or fixed infrastructure in these networks. The aim of this centralized approach is to provide permanent availability of services in ad hoc networks which are characterized by a distributed management. In order to evaluate the performance of the proposed approach, we apply it to solve the problem of mobile code localization in ad hoc networks. A comparative study, based upon a simulation, of centralized and distributed localization protocols in terms of messages number exchanged and response time shows that the centralized approach in a distributed form is more interesting than a totally centralized approach.Comment: 14 Pages, IJCNC Journal 201

An Iterative Quality-Based Localization Algorithm for Ad Hoc Networks

An iterative quality-based algorithm for location discovery is presented which can be used in wireless ad hoc sensor networks. The algorithm will take the reliability of measurements into account and will produce a reliability index for every estimated location using a statistical approach. The algorithm can also work in a hybrid network with different kinds of distance measuring techniques. It will use the reliability of each of these methods in the final result. Satisfactory results can be achieved with this approach

Effect of Location Accuracy and Shadowing on the Probability of Non-Interfering Concurrent Transmissions in Cognitive Ad Hoc Networks

Cognitive radio ad hoc systems can coexist with a primary network in a scanning-free region, which can be dimensioned by location awareness. This coexistence of networks improves system throughput and increases the efficiency of radio spectrum utilization. However, the location accuracy of real positioning systems affects the right dimensioning of the concurrent transmission region. Moreover, an ad hoc connection may not be able to coexist with the primary link due to the shadowing effect. In this paper we investigate the impact of location accuracy on the concurrent transmission probability and analyze the reliability of concurrent transmissions when shadowing is taken into account. A new analytical model is proposed, which allows to estimate the resulting secure region when the localization uncertainty range is known. Computer simulations show the dependency between the location accuracy and the performance of the proposed topology, as well as the reliability of the resulting secure region

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

Secure Geographic Routing in Ad Hoc and Wireless Sensor Networks

Security in sensor networks is one of the most relevant research topics in resource constrained wireless devices and networks. Several attacks can be suffered in ad hoc and wireless sensor networks (WSN), which are highly susceptible to attacks, due to the limited resources of the nodes. In this paper, we propose innovative and lightweight localization techniques that allow for intrusion identification and isolation schemes and provide accurate location information. This information is used by our routing protocol which additionally incorporates a distributed trust model to prevent several routing attacks to the network. We finally evaluate our algorithms for accurate localization and for secure routing which have been implemented and tested in real ad hoc and wireless sensor networks

Distributed Recognition of Reference Nodes for Wireless Sensor Network Localization

All known localization techniques for wireless sensor and ad-hoc networks require certain set of reference nodes being used for position estimation. The anchor-free techniques in contrast to anchor-based do not require reference nodes called anchors to be placed in the network area before localization operation itself, but they can establish own reference coordinate system to be used for the relative position estimation. We observed that contemporary anchor-free localization algorithms achieve a low localization error, but dissipate significant energy reserves during the recognition of reference nodes used for the position estimation. Therefore, we have proposed the optimized anchor-free localization algorithm referred to as BRL (Boundary Recognition aided Localization), which achieves a low localization error and mainly reduces the communication cost of the reference nodes recognition phase. The proposed BRL algorithm was investigated throughout the extensive simulations on the database of networks with the different number of nodes and densities and was compared in terms of communication cost and localization error with the known related algorithms such as AFL and CRP. Through the extensive simulations we have observed network conditions where novel BRL algorithm excels in comparison with the state of art

An ETX based positioning system for wireless ad-hoc networks

RF-based localization has gained popularity because it offers low-cost positioning solution for ad-hoc networks. The Received Signal Strength (RSS) measured by a node has traditionally been used as a parameter to estimate location. However, RSS is not made readily available in the ad-hoc routing protocols like some other link quality indication parameter, e.g., Expected Transmission Count (ETX). ETX predicts the number of transmissions required to deliver a packet over a particular link, including retransmissions. We reveal that ETX can be shown as a proximity indicator relative to an anchor node (i.e., node with known position), and thereby, could also be utilized as a location estimation parameter similar to RSS. We implement a localization plugin for the popular ad-hoc routing protocol, Optimized Link State Routing (OLSR) based on ETX. Our analysis and experiments show favorable results