Highly dynamic and mobile applications, such as vehicular networks, require stable connectivity, which is often challenging to achieve. Network densification is a key approach to address this issue and can be achieved cost-effectively through mobile base stations and wireless relaying. However, existing solutions rely on rigid and complex architectures that hinder deployment in dynamic scenarios. The recently standardized Wireless Access Backhaul (WAB) architecture represents a key evolution, enabling flexible and modular wireless relay networks with native support for mobility and multi-technology wireless backhaul. This paper presents the first experimental realization of a multi-band WAB testbed, combining an FR2 backhaul and an FR1 access link using open-source software and commercial off-the-shelf components. The proposed framework validates end-to-end WAB operation under mobility and demonstrates the extension of FR2 coverage while maintaining compatibility with legacy FR1 user equipment. Experimental campaigns in vehicular and outdoor-to-indoor scenarios confirm that WAB effectively mitigates FR2 limitations, particularly in uplink and Non-Line-of-Sight conditions. These results highlight WAB as a practical and scalable approach for vehicular and next-generation wireless networks.

翻译：高动态与移动性应用（如车载网络）需要稳定的连接性，但这往往难以实现。网络密集化是解决该问题的关键途径，而通过移动基站与无线中继可低成本达成此目标。然而，现有方案依赖僵化复杂的架构，难以适应动态场景部署。最新标准化的无线接入回传（WAB）架构代表了关键演进方向，它支持灵活模块化的无线中继网络，并原生支持移动性与多技术无线回传。本文首次实现了多频段WAB测试平台，结合开源软件与商用现成组件，将FR2回传链路与FR1接入链路集成于一体。所提框架验证了移动场景下的端到端WAB运行，并展示了在保持与传统FR1用户设备兼容的同时扩展FR2覆盖范围的能力。车载与室外-室内场景的实验表明，WAB有效缓解了FR2在上行链路与非视距条件下的局限性。这些结果凸显了WAB作为车载网络及下一代无线网络实用可扩展方案的潜力。