Distributed PID-Based Scheduling for 6TiSCH Networks

Industrial low-power networks are becoming the nexus of operational technologies and the Internet thanks to the standardization of networking layer interfaces. One of the main promoters of this shift is the IETF 6TiSCH WG, which addresses network management and IP integration of time synchronized channel hopping (TSCH) networks as those developed by the IEEE802.15.4 TG. The 6TiSCH WG is defining the operational interface and mechanism by which the network schedule can be distributed amongst the devices in the network. This operational sublayer, called 6top, supports distributed scheduling and enables implementers to define the scheduling policy, only standardizing the distribution mechanism. This letter proposes a novel distributed scheduling policy based on the well-known industrial control paradigm referred as proportional, integral, and derivative (PID) control. The proposed technique is completely decentralized, enabling each node to determine the number of cells to schedule to one another, according to its traffic demand. The mechanism is reactive to sudden or bursty traffic patterns, while staying conservative in over-provisioning cells.