IEEE 802.15.4e: a Survey

Several studies have highlighted that the IEEE 802.15.4 standard presents a number of limitations such as low reliability, unbounded packet delays and no protection against interference/fading, that prevent its adoption in applications with stringent requirements in terms of reliability and latency. Recently, the IEEE has released the 802.15.4e amendment that introduces a number of enhancements/modifications to the MAC layer of the original standard in order to overcome such limitations. In this paper we provide a clear and structured overview of all the new 802.15.4e mechanisms. After a general introduction to the 802.15.4e standard, we describe the details of the main 802.15.4e MAC behavior modes, namely Time Slotted Channel Hopping (TSCH), Deterministic and Synchronous Multi-channel Extension (DSME), and Low Latency Deterministic Network (LLDN). For each of them, we provide a detailed description and highlight the main features and possible application domains. Also, we survey the current literature and summarize open research issues

A Case for Time Slotted Channel Hopping for ICN in the IoT

Recent proposals to simplify the operation of the IoT include the use of Information Centric Networking (ICN) paradigms. While this is promising, several challenges remain. In this paper, our core contributions (a) leverage ICN communication patterns to dynamically optimize the use of TSCH (Time Slotted Channel Hopping), a wireless link layer technology increasingly popular in the IoT, and (b) make IoT-style routing adaptive to names, resources, and traffic patterns throughout the network--both without cross-layering. Through a series of experiments on the FIT IoT-LAB interconnecting typical IoT hardware, we find that our approach is fully robust against wireless interference, and almost halves the energy consumed for transmission when compared to CSMA. Most importantly, our adaptive scheduling prevents the time-slotted MAC layer from sacrificing throughput and delay

Standardized low-power wireless communication technologies for distributed sensing applications

Recent standardization efforts on low-power wireless communication technologies, including time-slotted channel hopping (TSCH) and DASH7 Alliance Mode (D7AM), are starting to change industrial sensing applications, enabling networks to scale up to thousands of nodes whilst achieving high reliability. Past technologies, such as ZigBee, rooted in IEEE 802.15.4, and ISO 18000-7, rooted in frame-slotted ALOHA (FSA), are based on contention medium access control (MAC) layers and have very poor performance in dense networks, thus preventing the Internet of Things (IoT) paradigm from really taking off. Industrial sensing applications, such as those being deployed in oil refineries, have stringent requirements on data reliability and are being built using new standards. Despite the benefits of these new technologies, industrial shifts are not happening due to the enormous technology development and adoption costs and the fact that new standards are not well-known and completely understood. In this article, we provide a deep analysis of TSCH and D7AM, outlining operational and implementation details with the aim of facilitating the adoption of these technologies to sensor application developers.Peer ReviewedPostprint (published version

TSCH Multiflow Scheduling with QoS Guarantees: A Comparison of SDN with Common Schedulers

[EN] Industrial Wireless Sensor Networks (IWSN) are becoming increasingly popular in production environments due to their ease of deployment, low cost and energy efficiency. However, the complexity and accuracy demanded by these environments requires that IWSN implement quality of service mechanisms that allow them to operate with high determinism. For this reason, the IEEE 802.15.4e standard incorporates the Time Slotted Channel Hopping (TSCH) protocol which reduces interference and increases the reliability of transmissions. This standard does not specify how time resources are allocated in TSCH scheduling, leading to multiple scheduling solutions. Schedulers can be classified as autonomous, distributed and centralised. The first two have prevailed over the centralised ones because they do not require high signalling, along with the advantages of ease of deployment and high performance. However, the increased QoS requirements and the diversity of traffic flows that circulate through the network in today's Industry 4.0 environment require strict, dynamic control to guarantee parameters such as delay, packet loss and deadline, independently for each flow. That cannot always be achieved with distributed or autonomous schedulers. For this reason, it is necessary to use centralised protocols with a disruptive approach, such as Software Defined Networks (SDN). In these, not only is the control of the MAC layer centralised, but all the decisions of the nodes that make up the network are configured by the controller based on a global vision of the topology and resources, which allows optimal decisions to be made. In this work, a comparative analysis is made through simulation and a testbed of the different schedulers to demonstrate the benefits of a fully centralized approach such as SDN. The results obtained show that with SDN it is possible to simplify the management of multiple flows, without the problems of centralised schedulers. SDN maintains the Packet Delivery Ratio (PDR) levels of other distributed solutions, but in addition, it achieves greater determinism with bounded end-to-end delays and Deadline Satisfaction Ratio (DSR) at the cost of increased power consumption.This work has been supported by DAIS (https://dais-project.eu/) which has received funding from the ECSEL Joint Undertaking (JU) under grant agreement No 101007273. The JU receives support from the European Union's Horizon 2020 research and innovation programme and Sweden, Spain, Portugal, Belgium, Germany, Slovenia, Czech Republic, Netherlands, Denmark, Norway and Turkey. It has also been funded by Generalitat Valenciana through the "Instituto Valenciano de Competitividad Empresarial-IVACE". Furthermore, has been supported by the MCyU (Spanish Ministry of Science and Universities) under the project ATLAS (PGC2018-094151-B-I00), which is partially funded by AEI, FEDER and EU.Orozco-Santos, F.; Sempere Paya, VM.; Silvestre-Blanes, J.; Albero Albero, T. (2022). TSCH Multiflow Scheduling with QoS Guarantees: A Comparison of SDN with Common Schedulers. Applied Sciences. 12(1):1-19. https://doi.org/10.3390/app1201011911912

Performance Analysis of IEEE 802.15.4 Bootstrap Process

The IEEE 802.15.4 is a popular standard used in wireless sensor networks (WSNs) and the Internet of Things (IoT) applications. In these networks, devices are organized into groups formally known as personal area networks (PAN) which require a bootstrap procedure to become operational. Bootstrap plays a key role in the initialization and maintenance of these networks. For this reason, this work presents our implementation and performance analysis for the ns-3 network simulator. Specifically, this bootstrap implementation includes the support of three types of scanning mechanisms (energy scan, passive scan, and active scan) and the complete classic association mechanism described by the standard. Both of these mechanisms can be used independently by higher layers protocols to support network initialization, network joining, and maintenance tasks. Performance evaluation is conducted in total network association time and packet overhead terms. Our source code is documented and publicly available in the latest ns-3 official release

Exploração de Covert Channels de Rede sobre comunicações IEEE 802.15.4

The advancements in information and communication technology in the past decades have been converging into a new communication paradigm in which everything is expected to be interconnected with the heightened pervasiveness and ubiquity of the Internet of Things (IoT) paradigm. As these technologies mature, they are increasingly finding its way into more sensitive domains, such as Medical and Industrial IoT, in which safety and cyber-security are paramount. While the number of deployed IoT devices continues to increase annually, up to tens of billions of connected devices, IoT devices continue to present severe cyber-security vulnerabilities, which are worsened by challenges such as scalability, heterogeneity, and their often scarce computing capacity. Network covert channels are increasingly being used to support malware with stealthy behaviours, aiming at exfiltrating data or to orchestrate nodes of a botnet in a cloaked fashion. Nevertheless, the attention to this problem regarding underlying and pervasive IoT protocols such as the IEEE 802.15.4 has been scarce. Therefore, in this Thesis, we aim at analysing the performance and feasibility of such covertchannel implementations upon the IEEE 802.15.4 protocol to support the development of new mechanisms and add-ons that can effectively contribute to improve the current state of-art of IoT systems which rely on such, or similar underlying communication technologies.Os avanços nas tecnologias de informação e comunicação nas últimas décadas têm convergido num novo paradigma de comunicação, onde se espera que todos os intervenientes estejam interconectados pela ubiquidade do paradigma da Internet of Things (Internet das Coisas). Com a maturação destas tecnologias, elas têm-se vindo a infiltrar em domínios cada vez mais sensíveis, como nas aplicações médicas e industriais, onde a confiabilidade da informação e cyber-segurança são um fator crítico. Num contexto onde o número de dispositivos IoT continua a aumentar anualmente, já na ordem das dezenas de biliões de dispositivos interconectados, estes continuam, contudo, a apresentar severas vulnerabilidades no campo da cyber-segurança, sendo que os desafios como a escalabilidade, heterogeneidade e, na maioria das vezes, a sua baixa capacidade de processamento, tornam ainda mais complexa a sua resolução de forma permanente. Os covert channels de rede são cada vez mais um meio de suporte a malwares que apresentam comportamentos furtivos, almejando a extração de informação sensível ou a orquestração de nós de uma botnet de uma forma camuflada. Contudo, a atenção dada a este problema em protocolos de rede IoT abrangentes como o IEEE 802.15.4, tem sido escassa. Portanto, nesta tese, pretende-se elaborar uma análise da performance e da viabilidade da implementação de covert channels em modelos de rede onde figura o protocolo IEEE 802.15.4 de forma a suportar o desenvolvimento de novos mecanismos e complementos que podem efetivamente contribuir para melhorar a ciber-segurança de sistemas IoT que dependem do suporte destas tecnologias de comunicação