Adaptive channel selection in IEEE 802.15.4 TSCH networks

2017 13th International Conference on Distributed Computing in Sensor Systems (DCOSS)

Fafoutis

Pope

et al. 2017

Self Cite

The upcoming Internet of Things (IoT) applications include real-time human activity monitoring with wearable sensors. Compared to the traditional environmental sensing with low-power wireless nodes, these new applications generate a constant stream of a much higher rate. Nevertheless, the wearable devices remain battery powered and therefore restricted to low-power wireless standards such as IEEE 802.15.4 or Bluetooth Low Energy (BLE). Our work tackles the problem of building a reliable autonomous schedule for forwarding this kind of dynamic data in IEEE 802.15.4 TSCH networks. Due to the a priori unpredictability of these data source locations, the quality of the wireless links, and the routing topology of the forwarding network, it is wasteful to reserve the number of slots required for the worst-case scenario; under conditions of high expected datarate, it is downright impossible. The solution we propose is a hybrid approach where dedicated TSCH cells and shared TSCH slots coexist in the same schedule. We show that under realistic assumptions of wireless link diversity, adding shared slots to a TSCH schedule increases the overall packet delivery rate and the fairness of the system.

Section: The Sphere Use Casementioning

confidence: 98%

Scheduling High-Rate Unpredictable Traffic in IEEE 802.15.4 TSCH Networks

2017 13th International Conference on Distributed Computing in Sensor Systems (DCOSS)

Fafoutis

Pope

et al. 2017

Self Cite

“…The purpose of the SPHERE deployments is three-fold. Firstly, a large number of IoT deployments in the wild, would allows us to understand and overcome the weakness and limitations of state-of-the-art IoT enabling technologies: for example, scheduling [6] and interference avoidance [4] in IEEE 802.15.4-2015 TSCH (time slotted, channel hopping) networks. Secondly, data collected from large-scale deployments in the wild, would enable the development of robust machine learning models that are able to operate effectively in real world situations and under missing data [14].…”

Section: Introductionmentioning

confidence: 99%

SPHERE Deployment Manager: A Tool for Deploying IoT Sensor Networks at Large Scale

Fafoutis

Ad-Hoc, Mobile, and Wireless Networks

Oikonomou

et al. 2018

Self Cite

Internet of Things (IoT) technology has the potential to revolutionise several domains of everyday life, including the healthcare sector. In order to reach its full potential, IoT technology needs to be evaluated in the real world, beyond controlled environments, such as laboratories and test-beds. SPHERE is an experimental sensing platform for healthcare in a residential environment. Unlike other similar smart home health systems, SPHERE is deployed in a large number of properties of volunteers. Based on our experiences and lessons learned from SPHERE's large-scale deployments, this paper focuses on the challenge of effectively managing the sensor installation overhead, aiming at supporting our deployment technicians with achieving a satisfactory deployment throughput. In this context, this paper presents the SPHERE Deployment Manager: an open-source tool that facilitates the deployment of bespoke IoT networks by technicians that are not experts in IoT technology. We believe that the SPHERE Deployment Manager is a tool that can accelerate future IoT research deployments of similar nature and scale.

“…Hopping blindly over all channels enables reliable operation even when a subset of the channels has poor quality. Adaptive channel blacklisting was nonetheless proposed [10] that pushes reliability and throughput further.…”

Section: Related Workmentioning

confidence: 99%

TSCH and 6TiSCH for Contiki: Challenges, Design and Evaluation

Duquennoy

2017 13th International Conference on Distributed Computing in Sensor Systems (DCOSS)

Nahas

et al. 2017

Self Cite

Abstract-Synchronized communication has recently emerged as a prime option for low-power critical applications. Solutions such as Glossy or Time Slotted Channel Hopping (TSCH) have demonstrated end-to-end reliability upwards of 99.99%. In this context, the IETF Working Group 6TiSCH is currently standardizing the mechanisms to use TSCH in low-power IPv6 scenarios. This paper identifies a number of challenges when it comes to implementing the 6TiSCH stack. It shows how these challenges can be addressed with practical solutions for locking, queuing, scheduling and other aspects.With this implementation as an enabler, we present an experimental validation and comparison with state-of-the-art MAC protocols. We conduct fine-grained energy profiling, showing the impact of link-layer security on packet transmission. We evaluate distributed time synchronization in a 340-node testbed, and demonstrate that tight synchronization (hundreds of microseconds) can be achieved at very low cost (0.3% duty cycle, 0.008% channel utilization). We finally compare TSCH against traditional MAC layers: low-power listening (LPL) and CSMA, in terms of reliability, latency and energy. We show that with proper scheduling, TSCH achieves by far the highest reliability, and outperforms LPL in both energy and latency.