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"Bread Crumbs" for First Responders

Laboratory: National Institute of Standards and Technology (NIST)

Technology: Smart Multi-hop Relay Communication System

Opportunity: Available in the public domain

Description: NIST has demonstrated a prototype approach to maintain two-way communications with first responders as they make their way in building fires, and mine and tunnel collapses. The system is highly automated so that it can be deployed on the fly. It features “smart” multi-hop relays or “bread crumbs” that advise first responders when to place the next device so as to extend the communications range. Assembled from off-the-shelf microprocessors and other standard hardware, the relays incorporate NIST-developed software that monitors the status of radio communication signals. The algorithms embedded in the software rapidly assess the strength of received signals so the device can automatically alert first responders to lay down the next relay before they walk out of range and lose the radio signal.

NIST developed two prototypes: one based on Mica 2 motes from Crossbow Technology and the second based on WiFi on the Gumstix platform. Both systems support text messaging; transmission of physiological status of first responders, warfighters, or other sensor data; an indoor localization capability based on RFID technology and inertial navigation; and two-way voice comm (with the WiFi version). The WiFi version may be adapted for video surveillance. Both systems continuously measure the wireless links to relays node already deployed and prompt the mobile user to deploy a new relay when one is needed.


  • By adding relay nodes in strategic locations, communications can be enhanced in uneven landscapes like mountainous ranges, disaster zones, urban areas, and underground mines.
  • Relay nodes can help to expand communications over long distances in remote areas.
  • The adaptable system is not dependent upon location or environment.
  • It greatly reduces the risk of losing contact with emergency first responders in disaster areas or soldiers in war zones.


Contact: Jack Pevenstein, Technology Partnership Office

For more details, view NIST’s listing for this technology.


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