This paper presents a measurement-based performance evaluation of two custom Smart Roadside Units (SmartRSUs) featuring different V2X antenna architectures. The first configuration integrates GNSS and communication antennas into an all-in-one rooftop module, whereas the second uses external dual ITS-G5 (IEEE 802.11p) antennas operating at 5.9~GHz and a dedicated GNSS antenna. Both systems are built upon a proprietary On-Board Unit (OBU) platform adapted for infrastructure deployment. The experimental campaign evaluates key V2X communication metrics, including coverage, received signal strength indicator (RSSI), packet loss, and end-to-end latency in both transmission (OBU-to-infrastructure) and reception (infrastructure-to-OBU) directions. To ensure objective validation, a commercial off-the-shelf V2X Roadside Unit is co-located on the same infrastructure and used as a performance benchmark, providing ground-truth reference measurements under identical environmental conditions through a controlled co-located deployment. Results highlight the impact of antenna design and placement on communication reliability and latency, revealing trade-offs between integrated and external antenna configurations in real-world deployment scenarios. The findings provide practical insights for the design and optimization of next-generation SmartRSUs in cooperative intelligent transportation systems (C-ITS).

翻译：本文对两款采用不同V2X天线架构的定制化智能路侧单元进行了基于实测的性能评估。第一种配置将全球导航卫星系统和通信天线集成至一体化车顶模块，而第二种则采用工作在5.9GHz频段的外部双路ITS-G5（IEEE 802.11p）天线及独立GNSS天线。两套系统均基于适用于基础设施部署的专有车载单元平台构建。实验研究评估了关键V2X通信指标，包括覆盖范围、接收信号强度指示、丢包率，以及传输方向（OBU至基础设施）和接收方向（基础设施至OBU）的端到端延迟。为确保客观验证，在相同基础设施上共址部署了一款商用现成V2X路侧单元作为性能基准，通过受控共址部署在相同环境条件下提供地面实况参考测量值。结果揭示了天线设计与布局对通信可靠性和延迟的影响，并展示了真实部署场景中集成式与外部天线配置之间的权衡。研究结论为下一代智能路侧单元在协作式智能交通系统中的设计与优化提供了实践指导。