Field trial with tactical bubbles for mission critical communications

Main research and development interest of 5G and beyond systems are focusing on solution for populated and hot spot areas, but public safety authorities need reliable communication solutions in rural and remote areas. Tactical bubbles—ad hoc-type nonpublic communications networks built with the 3rd Generation Partnership Project-based mobile technologies—offer mission critical communications services for public safety authorities in areas with bad mobile network coverage while also providing additional capacity in hot spot areas. In this experimental study, three interconnected bubbles acting on three different frequency bands—2.3 GHz (40), 2.6 GHz (7), and 3.5 GHz (n78)—are trialed. This article provides the analysis of different factors related to performance and user experience of tactical bubbles. Both ground-level and aerial trial measurements, as well as simulations, were utilized to verify our configuration for the tactical bubbles and their fulfillment of the quality requirements. The performance and coverage of the tactical bubbles are evaluated in a trial, which represents authorities’ search operations in a rural environment with hills, forests, and swamps. The achieved coverage range of the bubbles is more than 1000 m with the unmanned aerial system-based measurements, whereas by car, the coverage is less than 600 m. The effect of obstacles (ie, buildings and hills) on the coverage area and performance of bubbles is significant, especially on car-based measurements on the ground level.