A Robust Approach to TDMA Synchronization in Aerial Networks

Area of Science:

• Robotics and Automation
• Network Engineering
• Distributed Systems

Background:

• Live remote inspection of large structures using Unmanned Aerial Vehicles (UAVs) offers advantages over manual methods.
• Current inter-vehicle networking for UAVs often relies on Time-Division Multiple Access (TDMA), which demands precise synchronization.
• Existing TDMA synchronization methods can be complex and lack flexibility in ad-hoc aerial network scenarios.

Purpose of the Study:

• To propose a delay-tolerant synchronization approach for UAV networks.
• To enable fully-distributed, ad-hoc aerial network formation without a global clock.
• To evaluate alternative synchronization methods for their impact on network performance.

Main Methods:

• Developed a delay-tolerant synchronization technique for TDMA slot ordering over COTS WiFi.
• Implemented a fully-distributed approach without reliance on a global clock.
• Evaluated multiple synchronization alternatives in a concrete aerial network testbed.

Main Results:

• The proposed synchronization approach successfully converges to the correct TDMA slot order.
• Analysis revealed trade-offs between synchronization alternatives concerning slot overlap, throughput, and packet delivery.
• Identified significant delays attributed to protocol stack and WiFi interface buffering.

Conclusions:

• The developed delay-tolerant synchronization method enhances the flexibility of ad-hoc aerial networks.
• The findings provide crucial insights into network performance trade-offs for UAV communication.
• Understanding buffering delays is essential for optimizing real-time remote inspection systems using UAVs.