A Decentralized Scheduling Algorithm for Time Synchronized Channel Hopping - (Invited Paper)

Time Synchronized Channel Hopping (TSCH) is an existing medium access control scheme which enables robust communication through channel hopping and high data rates through synchronization. It is based on a time-slotted architecture, and its correct functioning depends on a schedule which is typically computed by a central node. This paper presents, to our knowledge, the first scheduling algorithm for TSCH networks which both is distributed and which copes with a mobile nodes. Two scheduling algorithms are presented. Aloha-based scheduling allocates one frequency channel for broadcasting advertisements for new neighbors. Reservation-based scheduling augments Aloha-based scheduling with a dedicated slot for targeted advertisements based on gossip information. A mobile ad-hoc network with frequent connectivity changes is simulated, and the performance of the two proposed algorithms is assessed against the optimal case. Reservation-based scheduling performs significantly better than Aloha-based scheduling, suggesting that the improved network reactivity is worth the increased algorithmic complexity and resource consumption.