The increase of the digitalization taking place in various industrial domains is leading developers towards the design and implementation of more and more complex networked control systems (NCS) supported by Wireless Sensor Networks (WSN). This naturally raises new challenges for the current WSN technology, namely in what concerns improved guarantees of technical aspects such as real-time communications together with safe and secure transmissions. Notably, in what concerns security aspects, several cryptographic protocols have been proposed. Since the design of these protocols is usually error-prone, security breaches can still be exposed and MALICIOUSly exploited unless they are rigorously analyzed and verified. In this paper we formally verify, using ProVerif, three cryptographic protocols used in WSN, regarding the security properties of secrecy and authenticity. The security analysis performed in this paper is more robust than the ones performed in related work. Our contributions involve analyzing protocols that were modeled considering an unbounded number of participants and actions, and also the use of a hierarchical system to classify the authenticity results. Our verification shows that the three analyzed protocols guarantee secrecy, but can only provide authenticity in specific scenarios.

The use of Wireless Sensor Networks (WSNs) is considerably increasing, mainly due to their inherent low cost and wide range of applications. The formation of a WSN is driven by a request-based procedure that associates sensor nodes to a PAN (Personal Area Network) coordinator. In the IEEE 802.15.4 standard, the communication exchanges between a node willing to join the network and the PAN coordinator follows a CSMA/CA protocol. In this paper, we propose a set of specific improvements for the enhancement of the nodes joining procedure. The goal is to reduce the time spent in the association process, minimizing the time spent to deploy the network. A simulation assessment of the proposed set of improvements was performed using the OMNeT++/Castalia simulator, comparing their usage with the default mechanism defined by the IEEE 802.15.4 standard. The achieved results demonstrate that an adequate definition of the parameters of the CSMA/CA protocol significantly reduces the duration of the association procedure.

Many Wireless Sensor Network (WSN) applications operate autonomously in unreliable or inaccessible environments, precluding maintenance or human intervention. Redundant deployment schemes are usually considered in this scenario, making the network resilient to failure and environmental changes. Furthermore, sleep-scheduling techniques can also be applied, enabling redundant nodes to turn off their radios, while active nodes perform monitoring services. This paper investigates the behavior of the (m, k)-Gur Game approach. The main goal of the (m, k)-Gur Game is to provide an uniform network coverage for monitoring applications, with autonomic nodes performing a self-regulated choice between sending message to a base station or sleep until the next period. The proposal was evaluated using the OMNeT++ simulator tool under the MiXiM framework. Preliminary results shows that the (m, k)-Gur Game outperforms the traditional GurGame approach in terms of QoS provision and network coverage.

The use of cooperative diversity techniques and network coding concepts are promising solutions to improve the communication reliability in industrial Wireless Sensor Networks (WSNs). In this paper, we propose the NetCoDer scheme to address this problem, whose design is based in these concepts. The effectiveness of the NetCoDer scheme is evaluated through both an experimental setup with real WSN nodes and a simulation assessment, comparing its performance against state-of-the-art TDMA-based retransmission techniques.

This paper describes RBESP, a dual stack protocol designed as part of the communication infrastructure of a short-range Unmanned Aerial Vehicle (UAV). It aims at providing a reliable communication between the UAV and its base station and a best effort communication between the UAV and a WSN. RBESP targets two distinct communication requirements using the same communication transceiver. The other end of the communication link can be heterogeneous devices transmitting with the IEEE 802.15.4 standard, which is also used in the UAV transceiver. The paper details the software layers that implement both the reliable communication with the base station and the best-effort communication with the WSN nodes. Two different scenarios were implemented in order to allow RBESP evaluation. The first scenario consists of the UAV node communicating with spatially distributed sensors on the ground. In the second scenario, the UAV node delivers the collected data to the base station. Both communication scenarios are very different in terms of connection time and volume of transmitted data. Obtained results are presented and discussed along the paper.

Achieving RF connectivity is a critical issue in any wireless application. This is particularly challenging in mobile applications, as links are up and down many times. In such scenarios, where nodes keep on moving, it would be interesting for them to have knowledge of their remaining RF connectivity time. Such information can be used, for instance, to improve existing network protocols. The current paper addresses this problem by presenting the so-called Oriented Birth-Death (O-BD). The proposed solution is a modified version of the existing Birth-Death (BD) prediction model. We introduce in this work the notion of orientation to represent a tendency in the link future state. In other words, it considers if the link tends to increase or decrease the signal strength to make the prediction. Thereby a considerable prediction improvement is obtained, as shown in the evaluation performed. The proposed solution is well suited for mobile wireless sensor networks, whose nodes have low computational power and should be energy harvesting.

This paper presents a new routing protocol named RACE (network conditions Aware geographical forwarding protocol for real-time applications in mobile wireless sensor networks) that was developed to address the challenges found while using WSNs in a running competition scenario: QoS, mobility, and high workload. RACE aims to provide QoS requirements to the application layer by giving priority to real-time messages and also by handling network congestions. Routing is performed node-by-node, where each node calculates a score to choose the best node to forward the message. The main feature of our protocol is to also consider network conditions for calculating the score. Our simulation experiments show that RACE presents excellent performance in respect to message delivery ratio (up to 95%) and deadline miss ratio (7% in the worst case). For instance, we compared RACE with a well known protocol and observed that it outperformed this protocol in both metrics.