Simple distributed scheduling with collision detection in TSCH networks

Abstract

The IETF IPv6 over the time synchronized channel hopping mode of IEEE 802.15.4e (6TiSCH) working group standardizes a distributed mechanism for neighbor motes to agree on a schedule to communicate, driven by a scheduling function. This letter introduces the notion of housekeeping to the schedule function, in which motes relocate cells in the schedule to build a collision-free schedule in a distribute manner. The solution, based on detecting underperforming cells and listening for unexpected packets, does not require additional signaling traffic or state. This letter shows that simple housekeeping rules introduced allow a network to contain 17% more motes and suffer from 64% fewer collision, while maintaining end-to-end reliability above 99.5% in a typical industrial environment. This solution is now being discussed for standardization at 6TiSCH.