Micro aerial vehicles (MAVs) provide data such as images and videos from an aerial perspective, with data typically transferred to the ground. To establish connectivity in larger areas, a fleet of MAVs may set up an ad-hoc wireless network. Packet forwarding in aerial networks is challenged by unstable link quality and intermittent connectivity caused by MAV movement. We show that signal obstruction by the MAV frame can be alleviated by adapting the MAV platform, even for low-priced MAVs, and the aerial link can be properly characterized by its geographical distance. Based on this link characterization and making use of GPS and inertial sensors on-board of MAVs, we design and implement a motion-driven packet forwarding algorithm. The algorithm unites location-aware end-to-end routing and delay-tolerant forwarding, extended by two predictive heuristics. Given the current location, speed, and orientation of the MAVs, future locations are estimated and used to refine packet forwarding decisions. We study the forwarding algorithm in a field measurement campaign with quadcopters connected over Wi-Fi IEEE 802.11n, complemented by simulation. Our analysis confirms that the proposed algorithm masters intermittent connectivity well, but also discloses inefficiencies of location-aware forwarding. By anticipating motion, such inefficiencies can be counteracted and the forwarding performance can be improved.

Summary It is now possible to embed radio‐frequency identification tags into almost any physical device. However, issues regarding privacy remain a concern and limit their widespread use. We propose a scalable anonymous radio‐frequency identification authentication protocol using what we refer to as anonymous tickets. These tickets uniquely identify tags and are reusable. This considerably strengthens its non‐traceability and requires just search/query time, with minimal storage overhead on the back‐end system. We formally prove the protocol and compare the performance of the proposed protocol with selected works found in literature. Copyright © 2013 John Wiley & Sons, Ltd.

Search and rescue missions are entering a new era with the advent of small scale unmanned aerial vehicles (UAVs) with communication capabilities and embedded cameras. Yet, delivering high resolution images of the supervised surface to rescuers is time-critical. To help resolving this problem, we study how UAVs can take advantage of their controlled mobility to derive the optimum strategy for data transmission. Driven by real-world aerial experiments with both airplanes and quadrocopters equipped with 802.11n technology, we show that the UAV should not necessarily transmit as soon as a wireless link is established. Instead, it should wait until it reaches a suitable distance to the receiving UAV, only to transmit when the time to move to the new location and transmit is minimal. We then apply the principle of delayed gratification, where the UAV attempts to solve the tradeoff between postponing until it reaches this minimum and the impatience to deliver as much data as soon as possible, before any physical damage on-the-fly may occur. Our empirical-driven simulations demonstrate that the optimal distance of transmission greatly depends on the interplay of actual throughput, data size, UAV cruise speed, and failure rate, and that state-of-the-art UAVs can already benefit from our approach.

This work addresses communication challenges associated with computationally limited distributed embedded systems. Methods for overcoming these challenges are implemented and tested on a robotics testbed called the Distributed Flight Array (DFA). The DFA consists of distributed computational units that can be assembled at random into a wired and/or wireless mesh network. Coordinate control of the DFA such as driving and flying, which is discussed in previous work, demonstrates successful implementation of various communication tasks in a resource constrained platform.

A majority of the existing privacy-friendly RFID protocols use the output of a cryptographic hash function in place of real identity of an RFID tag to ensure anonymity and untraceability. In order to provide unique identification for the tags, these protocols assume that the hash functions are collision resistant. We show that, under this assumption on the hash functions, a substantial number of the existing protocols suffer from a traceability problem that causes differentiating a tag from another. We propose a scalable privacy-friendly RFID protocol and describe its design and implementation issues. Our protocol substitutes the hash functions used for identification with anonymous tickets, thus avoiding the aforementioned traceability problem. The anonymous tickets are reusable. They nevertheless identify the tags uniquely, at any given point in time. The query and search algorithm of our proposed protocol is of O(1) time complexity, and it imposes small storage overhead on the back- end database. We show that the protocol is scalable, and compare its storage and computational requirements to some existing protocols. We formally prove the security requirements of our protocol, and mechanically analyze some of its requirements using the model checker OFMC.