Mobile ad hoc networks allow first responders to communicate in harsh environments at a reasonable cost.
The U.S. Government and communications vendors continue their slow, but steady progress toward the goal of providing interoperable communications for first responders. They also seek ways to improvise with mobile networks when the need arises, such as when natural disasters like Hurricane Katrina take out entire network infrastructures or when the laws of physics keep radio signals from penetrating places like snaking canyons and the bowels of container ships.
Digital Internet Protocol (IP) technology offers a means of achieving connectivity on the fly and establishing interoperability by bridging separate systems digitally. One way of extending this technology’s reach is through a mobile ad hoc network (MANET). The system builds on wireless mesh network technology commonly used to link industrial sensors as well as some sensors used in “smart” homes.
A MANET is a type of self-forming network similar to stationary mesh networks. Every device—whether a notebook computer, smart phone, or wireless router—serves as a relay point. Unlike a wireless hotspot, in which devices connect to a single router like spokes to a hub, on a MANET, data can hop from wireless device to wireless device, forming a chain. With an Internet connection at just one end, the physical extent of the network is limited only by the number of devices and their individual ranges.
CoCo Communications Corp. of Seattle has applied MANET technology in a boarding-team solution developed for the U.S. Coast Guard. When a team boards a vessel, it carries with it a set of CoCo tactical mesh routers (TMR), each about the size of a soda can and weighing roughly a pound and a half. When activated, the first TMR will display a green light indicating a strong network signal from the patrol vessel.
As the boarding team proceeds into the ship, that light will eventually change from green to yellow. The team leaves that TMR in place and activates a second, which it carries forward, repeating the process as it proceeds into the ship. The chain of routers extends the MANET, keeping the team connected via encrypted voice and data communications with commanders on the patrol ship, using computers or other wireless devices with network-specific software installed, explains Jeff Meyer, CoCo’s vice president of product management.
Not only can MANET establish connectivity in hard-to-reach places, it also can come with additional hardware to help address interoperability woes, explains Luke Klein-Berndt, chief technology officer of the U.S. Department of Homeland Security’s Office of Interoperability and Compatibility. The 800 MHz, Project 25-compliant (P25) land-mobile radio (LMR) carried by the typical police officer or firefighter was intended to address the interoperability issue, but despite its cost and sophistication, it hasn’t nearly the processing capability to operate as a network (IP) device.
There is, however, an alternative means to establish interoperability. By simply plugging individual LMRs from different systems into one of CoCo’s briefcase-sized IP gates—regardless of the individual radios’ frequency bands—their systems are patched into the MANET, says Meyer. This would also work for responders carrying standard radios; they could communicate radio-to-radio or “talkaround” as part of the broader network.
The Department of Defense is betting on MANET and IP gates to both establish connectivity among its troops and solve the persistent problem of interoperability in places like Afghanistan, where there are not only countless mountain ranges and valleys but also numerous coalition forces operating on different radio networks.
The Defense Advanced Research Projects Agency (DARPA) recently tested its Mobile Ad Hoc Interoperability Network Gateway (MAINGATE) program, developed by Raytheon. But that version of the technology is expensive. One of DARPA’s requirements was that each MAINGATE switch cost $60,000 or less; however, that is still high by local law enforcement standards—it equals the cost of roughly 20 P25-compliant hand-held radios, which themselves are considered costly.
CoCo’s hardware is more affordable, according to the company. IP gateways cost roughly $15,000, software and server options total about $17,000, while each TMR runs $3,500.