  MAC layer protocol design in a WSN is crucial due to the limitations on
processing capacities and power of wireless sensors. The latest version of the
IEEE 802.15.4, referenced to as IEEE 802.15.4e, was released by IEEE and
outlines the mechanism of the Time Slotted Channel Hopping (TSCH). Hence,
6TiSCH working group has released a distributed algorithm for neighbour nodes
to agree on a communication pattern driven by a minimal scheduling function. A
slotframe contains a specific number of time slots, which are scheduled based
on the application requirements and the routing topology. Sensors nodes use the
schedule to determine when to transmit or to receive data. However, IEEE
802.15.4e TSCH does not address the specifics on planning time slot scheduling.
In this paper, we propose a distributed Enhanced Minimal Scheduling Function
(EMSF) based on the minimal scheduling function, which is compliant with
802.15.4e TSCH. In this vein, we introduce a distributed algorithm based on a
Poisson process to predict the following schedule requirements. Consequently,
the negotiation operations between pairs of nodes to agree about the schedule
will be reduced. As a result, EMSF decreases the exchanged overhead, the
end-to-end latency and the packet queue length significantly. Preliminary
simulation results have confirmed that EMSF outperforms the 802.15.4e TSCH MSF
scheduling algorithm.
