Wireless industrial networks require reliable and deterministic communication. Determinism implies that there must be a guarantee that each data packet will be delivered within a bounded delay. Moreover, it must ensure that the potential congestion or interference will not impact the predictable properties of the network. In 2016, IEEE 802.15.4 time-slotted channel hopping (TSCH) emerged as an alternative medium access control to the industrial standards such as WirelessHART and ISA100.11a. However, TSCH is based on traditional collision detection and retransmission, and cannot guarantee reliable delivery within a given time. This paper proposes LeapFrog Collaboration (LFC) to provide deterministic and reliable communication over a routing protocol (RPL) based network. LFC is a novel multipath routing algorithm that takes advantage of route diversity by duplicating the data flow onto an alternate path. Simulations and analytical results demonstrate that LFC significantly outperforms the single-path retransmission-based approach of RPL + TSCH and the state-of-the-art LinkPeek solution.

Context: Internet of Things (IoT) systems are increasingly deployed in the real world, but their security lags behind the state of the art of non-IoT systems. Moving Target Defense (MTD) is a cyberdefense paradigm, successfully implemented in conventional systems, that could improve IoT security. Objective: Identify and synthesize existing MTD techniques for IoT and validate the feasibility of MTD as a cybersecurity paradigm suitable for IoT systems. Method: We use a systematic literature review method to search and analyze existing MTD for IoT techniques up to July 2020. We evaluated the existing techniques in terms of security foundations and real-world deployability using the evidence they provide. We define and use entropy-related metrics to categorize them. This is the first MTD survey to use Shannon’s entropy metric empirically. Results: Thirty-two distinct MTD for IoT techniques exist: 54% are Network-layer-based, 50% present strong evidence about their real-world deployment, and 64% have weak security foundations. Conclusion: MTD for IoT is a feasible cyberdefense approach. A variety of proposals exist, with evidence about their implementation and evaluation. Nevertheless, the MTD for IoT state of the art is still immature: the security foundations of most existing proposals are weak. Novel techniques should prioritize providing convincing security foundations and real-world deployment evidence.

LoRa networks enable long range communications for Internet of Things (IoT) applications. The current LoRa technology provides a wide range of communication settings whereas many combination settings are orthogonal and, thus, they can be successfully decoded at the gateway when the signals are transmitted simultaneously. Previous simulation results showed that the LoRa network capacity can be improved when multiple communication parameters are applied. In this paper, we model a LoRa network consisting of nodes with different communication settings in terms of bandwidth and spreading factor. We compute the average success probability per configuration as a function of density taking into account both intra and inter-spreading factor collisions. We, also, formulate and solve an optimization problem to maximize the node capacity for a given deployment area and frequency by optimizing the number of nodes having different spreading factor configurations. We present numerical results and we show that solutions close to the optimal can increase the maximum number of nodes by more than 700% compared to case where equal number of users per spreading factor are considered.

The Industrial Internet of Things (IIoT) is expected to be a key enabler for the Industry 4.0. However, networked control automation often requires high reliability and a bounded latency to react properly. Thus, modern wireless protocols for industrial networks, such as IEEE 802.15.4-2015 Time Slotted Channel Hopping (TSCH), rely on a strict schedule of the transmissions to avoid collisions and to make the end-to-end traffic deterministic. Unfortunately, guaranteeing a bounded end-to-end latency is particularly challenging since transmissions have to be temporally chained. Even worse, potential degradation of the link quality may result in reconstructing the whole TSCH schedule along the path. In this article, we propose the Low-latency Distributed Scheduling Function (LDSF) that relies on the organization of the slotframe in smaller parts, called blocks. Each transmitter selects the right set of blocks, depending on its hop distance from the border router, so that retransmission opportunities are automatically scheduled. To save energy, a node can still turn off its radio as soon as its packet is correctly acknowledged. Our mathematical analysis as well as our simulation evaluation show the efficiency of the proposed LDSF algorithm compared to three state-of-the-art scheduling functions, the Minimal Scheduling Function (MSF), Low Latency Scheduling Function (LLSF) and Stratum.

Verification of theoretical analysis is a vital step in the development of an application or a protocol for wireless networks. Most proposals are evaluated through mathematical analysis followed by either simulation or experimental validation campaigns. In this article, we analyze a large set of statistics in articles published (674 papers in total) in the top representative ad hoc and wireless sensor networks related conferences (i.e., ACM/ IEEE IPSN, ACM MobiCom, ACM MobiHoc, and ACM SenSys) during the period 2008-2013. We focus on the evaluation methodologies provided by researchers. More specifically, our goal is to explore the role of simulators and testbeds in the theoretical analysis of a model throughout the protocol development procedure. We show that there is a tendency for more and more researchers to rely on custom or open testbeds in order to evaluate the performance of their proposals. Simulators indeed fail to reproduce actual environmental conditions of deployed systems. Experimentation with real hardware allows our research community to mind the gaps between simulation and real deployment. Still, as the experimental apFproach through custom testbeds results in a low reproducibility level (i.e., 16.5 percent), we investigate to what extent such performance evaluation methods will be able to bridge those gaps. We finally discuss experimental testbeds and their potential to replace simulators as the cornerstone of performance evaluation procedures.