OSCAR: An Optimized Scheduling Cell Allocation Algorithm for Convergecast in IEEE 802.15.4e TSCH Networks.

Area of Science:

• Computer Science
• Electrical Engineering
• Networking

Background:

• Wireless sensor networks (WSNs) face increasing data demands.
• Time Slotted Channel Hopping (TSCH) in IEEE 802.15.4-2015 mitigates latency and energy use.
• Convergecast traffic in WSNs causes congestion near the root node.

Purpose of the Study:

• Propose OSCAR, a novel autonomous scheduling algorithm for TSCH cell allocation.
• Optimize slot allocation based on node proximity to the root to address congestion.
• Enhance network performance by maximizing transmission opportunities for critical nodes.

Main Methods:

• Developed OSCAR, an algorithm building on Orchestra, for TSCH cell allocation.
• Integrated RPL routing protocol's rank to manage timeslot allocation per node.
• Implemented a mechanism to adjust radio duty cycles by reducing slots for inactive nodes.
• Evaluated OSCAR using Contiki-ng through simulations and real-world experimentation.

Main Results:

• OSCAR outperforms Orchestra in average latency and reliability.
• The algorithm effectively manages slot allocation based on node rank (proximity to root).
• Radio duty cycle is adjusted without significant increases, even under high traffic loads.

Conclusions:

• OSCAR provides an effective solution for TSCH network congestion, particularly for convergecast traffic.
• The algorithm balances transmission opportunities with energy efficiency.
• OSCAR demonstrates superior performance compared to Orchestra in key network metrics.