Optimized Scheduling Method in 6TSCH Wireless Networks
Abstract
IEEE802.15.4e-TSCH is a mode exploited by the Internet of Things. Time
Slotted Channel Hopping (TSCH) presents an upgrade to the IEEE 802.15.4 to
build a Medium Access Control (MAC) for low power and loss network
applications in IoT. This norm defines the concept of TSCH based on channel
hopping and reservation of bandwidth to achieve energy efficiency, as well as
consistent transmissions. Centralized approaches have been proposed for
planning TSCH. They have succeeded in increasing network efficiency and
reducing latency, but the scheduling length remains not reduced. However,
distributed solutions appear to be more stable in the face of change, without
creating a priori assumptions about the topology of the network or the
amount of traffic to be transmitted. A distributed scheduling allowing
neighboring nodes to decide on a coordination system operated by a minimal
scheduling feature is currently proposed by the 6TiSCH working group. This
scheduling allows sensor nodes to determine when data is to be sent or
received. However, the details of scheduling time intervals are not specified
by the TSCH-mode IEEE802.15.4e standard. In this work, we propose a
distributed Optimized Minimum Scheduling Function (OMSF) that is based
on the 802.15.4e standard TSCH mode. For this purpose, a distributed
algorithm is being implemented to predict the scheduling requirements over
the next slotframe, focused on the Poisson model and using a cluster tree
topology. As a consequence, it will reduce the negotiation operations
between the pairs of nodes in each cluster to decide on a schedule. This
prediction allowed us to deduce the number of cells needed in the next
slotframe. Clustering decreases, the overhead processing costs that produce
the prediction model. So, an energy-efficient data collection model focused
on clustering and prediction has been proposed. As a result, the energy
consumption, traffic load, latency, and queue size in the network, have been
reduced.