BenchLink: An SoC-Based Benchmark for Resilient Communication Links in GPS-Denied Environments
Abstract
Accurate timing and synchronization, typically enabled by GPS, are essential for modern wireless communication systems. However, many emerging applications must operate in GPS-denied environments where signals are unreliable or disrupted, resulting in oscillator drift and carrier frequency impairments. To address these challenges, we present BenchLink, a System-on-Chip (SoC)-based benchmark for resilient communication links that functions without GPS and supports adaptive pilot density and modulation. Unlike traditional General Purpose Processor (GPP)-based software-defined radios (e.g. USRPs), the SoC-based design allows for more precise latency control. We implement and evaluate BenchLink on Zynq UltraScale+ MPSoCs, and demonstrate its effectiveness in both ground and aerial environments. A comprehensive dataset has also been collected under various conditions. We will make both the SoC-based link design and dataset available to the wireless community. BenchLink is expected to facilitate future research on data-driven link adaptation, resilient synchronization in GPS-denied scenarios, and emerging applications that require precise latency control, such as integrated radar sensing and communication.
Summary
The paper addresses the challenge of maintaining reliable wireless communication in GPS-denied environments, where oscillator drift and carrier frequency impairments degrade performance. The authors introduce BenchLink, a System-on-Chip (SoC)-based benchmark platform designed for resilient communication links without GPS. Unlike traditional General Purpose Processor (GPP)-based software-defined radios, BenchLink leverages the low-latency capabilities of SoCs to provide precise latency control. The core innovation is a reconfigurable frame structure that supports adaptive pilot density and modulation, enabling the system to dynamically adjust to changing channel conditions and mitigate frequency offsets. The authors implemented BenchLink on Zynq UltraScale+ MPSoCs and evaluated its performance in both ground-to-ground (G2G) and air-to-air (A2A) environments. They conducted comprehensive experiments to assess the impact of residual frequency offset and goodput under various channel conditions. The experimental setup involved transmitting live video data between nodes with GPS disabled. A key part of the work is the creation of a comprehensive dataset, formatted using the Signal Metadata Format (SigMF), that includes raw data and metadata related to the experiments. This dataset, along with the SoC-based link design, is made available to the wireless research community. The results demonstrate the effectiveness of adaptive pilot density in improving communication reliability, particularly for higher-order modulation schemes in dynamic environments.
Key Insights
- •BenchLink provides a practical, deployable, and open-source SoC-based benchmark for programmable wireless communications in GPS-denied environments, filling a gap in available research tools.
- •The hardware/software co-design approach, using the Zynq UltraScale+ MPSoC, allows for FPGA-accelerated PHY processing, enabling low-latency and deterministic performance compared to GPP-based SDRs.
- •Adaptive pilot density, controlled by the parameter λp, significantly impacts goodput, especially for higher-order modulation schemes (e.g., 64QAM) in A2A scenarios where a 1200% improvement was observed when increasing pilot repetitions from one to the optimal configuration.
- •An interesting counterintuitive finding is that increasing pilot repetitions from one to two sometimes *decreases* goodput, particularly for lower-order modulation schemes (4QAM, 8QAM), because the marginal improvement in channel estimation doesn't offset the increased overhead.
- •The A2A links benefit more from adaptive pilot repetition compared to G2G links. For example, 64QAM showed a 1200% goodput increase in A2A compared to 517% in G2G when increasing pilot repetitions from one to the optimal configuration. This is attributed to the shorter channel coherence time in UAV-enabled links.
- •The dataset, comprising 18 MB of labeled data, includes raw data and SigMF-compliant metadata, facilitating reproducibility and efficient analysis by other researchers.
- •The authors acknowledge limitations such as the absence of FEC/ARQ and constraints on the testing environment.
Practical Implications
- •BenchLink can be used as a platform for developing and testing AI/ML algorithms for real-world link adaptation in GPS-denied environments, particularly for applications like UAV communication and integrated radar sensing and communication (ISAC).
- •The benchmark is beneficial for researchers and engineers working on resilient wireless communication systems, particularly those operating in challenging environments where GPS is unreliable or unavailable.
- •Practitioners can use the results to optimize pilot density and modulation schemes for specific applications and channel conditions. For instance, they can adaptively adjust λp based on estimated channel coherence time.
- •Future research can focus on integrating FEC and ARQ into BenchLink to improve goodput, expanding the dataset with larger-scale and interference-rich environments, and exploring learning-based optimization for link adaptation.