Mobile robots in disaster scenarios such as tunnels, mines, or collapsed structures face communication challenges for reliable video streaming to remote control centers. Commercial fifth-generation (5G) networks provide low latency and high bandwidth, especially in urban areas, but ad hoc WiFi networks with static and robotic nodes can provide a solution to attenuation in occluded areas. This paper offers a field experiment report from a search and rescue (SAR) exercise where we tested a WiFi mesh network against commercial 5G in tunnels 184 m long, 6 m wide, and 4 m high. Two operator streamed video to the Internet through a mesh that consisted of two static nodes and two mobile nodes on unmanned ground vehicles (UGV). Latency was measured for both operators for different video resolutions, as well as for a 5G customer-premises equipment (CPE) on-board a scout-UGV. The paper discusses experimental results and lessons learned.

This work has been partially funded by the Spanish Ministerio de Ciencia, Innovación y Universidades, Gobierno de España, project PID2021-122944OB-I00, and by the Maori project (grant agreement number TSI-063000-2021-53) funded by the European Union-NextGenerationEU.