AQUILA: A QUIC-Based Link Architecture for Resilient Long-Range UAV Communication

TL;DR

AQUILA addresses the conflicting requirements of high-bandwidth video and ultra-low-latency C2 in BVLOS UAVs operating over cellular networks. It introduces a unified QUIC-based transport that multiplexes MAVLink C2 on reliable streams and video on unreliable datagrams, coupled with a UAV-adapted SCReAM-FPV congestion control and a strict priority scheduler to prevent HOL blocking. A 0-RTT handover mechanism with a WireGuard overlay minimizes control blackout, while telemetry headroom reservation protects C2 under bandwidth stress. Experimental results show AQUILA outperforms TCP- and UDP-based approaches in C2 latency, video QoE, and resilience, validating its potential for robust BVLOS operations. The work also discusses trade-offs and limitations, including security implications of 0-RTT and areas for future enhancement such as adaptive CC and multipath QUIC.

Abstract

The proliferation of autonomous Unmanned Aerial Vehicles (UAVs) in Beyond Visual Line of Sight (BVLOS) applications is critically dependent on resilient, high-bandwidth, and low-latency communication links. Existing solutions face critical limitations: TCP's head-of-line blocking stalls time-sensitive data, UDP lacks reliability and congestion control, and cellular networks designed for terrestrial users degrade severely for aerial platforms. This paper introduces AQUILA, a cross-layer communication architecture built on QUIC to address these challenges. AQUILA contributes three key innovations: (1) a unified transport layer using QUIC's reliable streams for MAVLink Command and Control (C2) and unreliable datagrams for video, eliminating head-of-line blocking under unified congestion control; (2) a priority scheduling mechanism that structurally ensures C2 latency remains bounded and independent of video traffic intensity; (3) a UAV-adapted congestion control algorithm extending SCReAM with altitude-adaptive delay targeting and telemetry headroom reservation. AQUILA further implements 0-RTT connection resumption to minimize handover blackouts with application-layer replay protection, deployed over an IP-native architecture enabling global operation. Experimental validation demonstrates that AQUILA significantly outperforms TCP- and UDP-based approaches in C2 latency, video quality, and link resilience under realistic conditions, providing a robust foundation for autonomous BVLOS missions.

Figures (10)

• Figure 1: Impact of Aerial Mobility on Link Stability. Field measurements illustrating the correlation between UAV velocity and sharp degradations in SNR, RSRP and RSRQ. Unlike terrestrial links, the aerial channel exhibits extreme volatility due to side-lobe connectivity and inter-cell interference, fundamental limitations of cellular networks at altitude as identified in 3GPP TR 36.777 3gpp_tr36777.
• Figure 2: Experimental testbed
• Figure 3: Onboard Hardware Configuration
• Figure 4: Cross-Layer Data Flow and Scheduling
• Figure 5: C2 Latency Stability Comparison under Dynamic Network Conditions. The plot illustrates the logarithmic latency ($\log_{10}$) of C2 packets relative to a 100ms baseline over time. TCP (purple) exhibits exponential latency growth due to retransmissions and Head-of-Line blocking when the network is congested. In contrast, AQUILA (green) maintains a bounded latency profile near the baseline, empirically validating the priority scheduling mechanism's ability to decouple C2 telemetry from background video traffic intensity. Error bars represent the standard deviation across 5 experimental trials.