Parent and PHY Selection in Slot Bonding IEEE 802.15.4e TSCH Networks

Abstract

While IEEE 802.15.4e Time-Slotted Channel Hopping (TSCH) networks should be equipped to deal with the hard wireless challenges of industrial environments, the sensor networks are often still limited by the characteristics of the used physical (PHY) layer. Therefore, the TSCH community has recently started shifting research efforts to the support of multiple PHY layers, to overcome this limitation. On the one hand, integrating such multi-PHY support implies dealing with the PHY characteristics to fit the resource allocation in the TSCH schedule, and on the other hand, defining policies on how to select the appropriate PHY for each network link. As such, first a heuristic is proposed that is a step towards a distributed PHY and parent selection mechanism for slot bonding multi-PHY TSCH sensor networks. Additionally, a proposal on how this heuristic can be implemented in the IPv6 over the TSCH mode of IEEE 802.15.4e (6TiSCH) protocol stack and its Routing Protocol for Low-power and Lossy network (RPL) layer is also presented. Slot bonding allows the creation of different-sized bonded slots with a duration adapted to the data rate of each chosen PHY. Afterwards, a TSCH slot bonding implementation is proposed in the latest version of the Contiki-NG Industrial Internet of Things (IIoT) operating system. Subsequently, via extensive simulation results, and by deploying the slot bonding implementation on a real sensor node testbed, it is shown that the computationally efficient parent and PHY selection mechanism approximates the packet delivery ratio (PDR) results of a near-optimal, but computationally complex, centralized scheduler.

Experimental evaluation of multi-PHY 6TiSCH networks

“…Moreover, nodes have needed to re-synchronize continuously. Therefore, this issue calls for the implementation of novel parent selection mechanisms and different slot sizes as proposed in [47]. The observed network behavior during this measurement campaign indicates the importance of proper node positioning and careful selection of network parameters.…”

Beacon Success Rate versus Gateway Density in Sub-GHz Sensor Networks

“…The paper also addresses challenges in energy consumption and security. The paper in [15] addresses challenges in TSCH networks in industrial environments, proposing a distributed PHY and parent selection heuristic for slot bonding multi-PHY TSCH sensor networks. The paper in [16] introduces g6TiSCH (IPv6 over the TSCH mode of IEEE 802.15.4e).…”