Multi-Band Wireless Access-and-Backhaul (WAB) for 5G: Implementation and Experiments

The growing demand for wireless capacity and coverage has driven research into new radio architectures and higher frequency bands. The recently standardized Wireless Access Backhaul (WAB) architecture represents a key evolution, enabling cost-effective network densification through wireless relaying. 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 the feasibility of end-to-end WAB operation and demonstrates its ability to extend FR2 coverage while maintaining compatibility with legacy FR1 user equipment. Experimental campaigns conducted in vehicular and outdoor-to-indoor scenarios confirm that WAB effectively mitigates the limitations of FR2 links, particularly in uplink and Non-Line-of-Sight conditions. These results highlight WAB as a practical and scalable approach for next-generation wireless networks.