TSM™ Tactical Radios for Urban and Subterranean Environments: Experimentation Report [open pdf - 1MB]
From the Executive Summary: "The TW-400 CUB TSM™ tactical radio, developed by TrellisWare Technologies Inc., underwent Urban Operational Experimentation (OpEx) on January 26, 2017, by the U.S. Department of Homeland Security (DHS) Science and Technology Directorate (S&T) National Urban Security Technology Laboratory (NUSTL). NUSTL hosts Urban OpEx to introduce new technologies to first responders corresponding to their identified needs, and to provide feedback to technology developers--while sharing results with the national first responder community. The TW-400 CUB TSM is a handheld radio that forms an ad-hoc network with nearby radios such that each can collaboratively receive and transmit voice, data or video, allowing communications to 'hop' from radio to radio to extend communication coverage and range. This provides a potential solution to a responder-identified need for technologies that enhance the ability to communicate information from the scene of an incident that is Global Positioning System (GPS)-denied and impedes radio frequency (RF) signals (such as tunnels and underground subway systems) to colleagues and incident commanders who may or may not also be in such environments."
U.S. Department of Homeland Security: https://www.dhs.gov/