LocURa4IoT Platform

Head : Adrien VAN DEN BOSSCHE

LocURa4IoT (Localization and UWB-Based Ranging testbed for the Internet of Things) [1] is a testbed platform dedicated to the study and analysis of the performance of Ranging networks and protocols [2] and fine synchronization [3]. It also addresses the problem of locating radio nodes in indoor environments, mainly by measuring the radio time of flight as a distance measurement method [4]. Initially designed for the study of networks based on an Ultra-Wide Band physical layer (IEEE 802.15.4z), it now also allows to address the problem of heterogeneity of physical layers, by implementing three physical layers on all nodes: UWB, Bluetooth Low Energy (BLE) and LoRa.

As with all network testbed platforms, the primary target is the research and industrial community who wish to benchmark the performance of wireless network technologies, as well as the associated protocols and algorithms. Because of its structure and its deployment in various experimental sites, LocURa4IoT also allows us to target usage studies that are of interest beyond the Networks and Protocols community and open the door to multidisciplinary initiatives. Thus, for example, in 2019, LocURa4IoT has made it possible to study the problem of semantic localization in collaboration with researchers in HMI (IRIT/ELIPSE) and linguists (LERASS) [5] as part of the PEPS/CNRS IDEALI1-DSP project.

Positioning of the platform in relation to existing platforms (local and national)

To our knowledge, the LocURa4IoT platform is quite unique. Although there are many testbed platforms in France and in Europe (FIT/IoT-lab, SmartSantander, Log-a-Tec, etc.), few of them address the issue of indoor localization by radio time-of-flight, from the point of view of networks and protocols. This can be explained by the fact that most of the existing platforms are based on IEEE 802.5.4/Zigbee technology (such as FIT/IoT-lab); on the other hand, the teams working on UWB generally have a signal processing approach. This assertion was recently confirmed by INRIA, which proposed that the LocURa4IoT platform be attached to the FIT/IoT-lab network, given the originality of having UWB technology on LocURa4IoT. The platform is a candidate for this attachment and the rapprochement with OSIRIM, in the framework of the SILECS project, also in request of labeling at IRIT.

Technical and organizational description, utilization rate

The LocURa4IoT platform was created in 2016 (based on a first “OpenWiNo” testbed deployed in 2014). It is now composed of about 50 nodes (50 embedded systems) equipped with an MCU, several wireless network interfaces (UWB, BLE and LoRa) and a local debugger. During an experiment, the nodes execute a scenario using one or more radio interfaces. A central server manages the reprogramming, startup and shutdown, and classical debugging functions by relying on a supervisory network. The existence of this wired network allows the monitoring of experiments without disturbing the wireless medium. The consoles of the nodes go back up on an MQTT bus that is cleverly configured to isolate or gather the consoles of the nodes participating in the experiment, whose progress is controlled by a central server. An online IDE simplifies the remote use of the platform.

To address the problem of locating the wireless nodes, all the nodes have a position known to the nearest centimeter (by laser measurements). If most of the nodes are fixed, some are mobile (because they are placed on 2m and 7m rails) and can be controlled in the experiment.

The LocURa4IoT platform is deployed in an indoor environment on the campus of the IUT in Blagnac. Three deployments are operational, for three complementary environments: an office area (1st floor of IUT building C, 300m²), an apartment-type area (smart house, 120m²) and an anechoic chamber (20m²). The office type environment allows experiments in a simple and stable environment, with good repeatability properties (especially at night, without human activity and with closed doors); the smart house environment allows an environment closer to an ecological situation, with strong human interactions possible [5]; the anechoic chamber allows to be totally isolated from the outside, on the electromagnetic level. The first two environments offer a wide variety of wall types (brick, plaster, metal, wood…), an important criterion for indoor localization experiments, where the non-line of sight (NLOS) is an important issue.

Currently, the platform is heavily used by the researchers of the RMESS team (6 researchers). Collaborations are also underway on the HMI part (semantic localization, context adaptation) with the ELIPSE team (2 researchers). Beyond IRIT, collaborations are underway with the S4M team of LAAS-CNRS and the FEMTO laboratory (recurrent remote use) in Montbéliard. Its use varies according to the needs of the teams, an experiment can last several hours or even several days. We consider that it is currently used at 15-20% of its capacity. Translated with www.DeepL.com/Translator (free version)

References
[1] Adrien Van Den Bossche, Rejane Dalce, Nicolas Gonzalez, Thierry Val. LocURa: A New Localisation and UWB- Based Ranging Testbed for the Internet of Things. IEEE International Conference on Indoor Positioning and Indoor Navigation (IPIN 2018), Nantes, France, 24/09/2018-27/09/2018, IEEExplore digital library, septembre 2018.

[2] François Despaux Rossi, Katia Jaffres-Runser, Adrien van den Bossche, Thierry Val. Accurate and Platform- agnostic Time-of-flight Estimation in Ultra-Wide Band. IEEE International Conference on Personal, Indoor and Mobile Radio Communications (PIMRC 2016), Valencia, Spain, 04/09/16-07/09/16, IEEExplore digital library, septembre 2016

[3] Oana Andreea Hotescu, Katia Jaffres-Runser, Adrien van den Bossche, Thierry Val. Synchronizing Tiny Sensors with SISP: a Convergence Study. ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWIM 2017), Miami Beach, USA, 21/11/2017-25/11/2017, ACM, novembre 2017

[4] François Despaux, Adrien Van den Bossche, Katia Jaffres-Runser, Thierry Val. N-TWR: An Accurate Time-of- flight-based N-ary Ranging Protocol for Ultra-Wide Band. Ad Hoc Networks Journal, Elsevier, Vol. in Press N. doi.org/10.1016/j.adhoc.2018.0, juillet 2018

[5] Réjane Dalcé, Antonio Serpa, Thierry Val, Frédéric Vella, Adrien van den Bossche, Nadine Vigouroux, Vidéo de démonstration du projet IDEALI1-DSP. Vidéo en ligne.