You're the Network: Keeping Smartphones Connected When Systems Go DownSeptember 2014
Topics: Mobile Technologies, Network Security, Network Protocols
When natural disaster strikes—knocking out power and disabling cell towers—most cell phones are little more than expensive bricks. But what if people could use smartphones to create an off-grid way for private citizens and first responders to communicate? Likewise, how might smartphone technology serve as a low-cost communication tool for members of the armed forces in remote locales, where communication infrastructures are sketchy or nonexistent?
A MITRE research team set out to answer these kinds of questions when it created Smartphone Ad Hoc Networking (SPAN). SPAN is an application and operating system modification that enables smartphones to continue connecting with one another when the usual infrastructures are unavailable.
"Whenever there is no Wi-Fi access or available cell tower, all SPAN-equipped phones would automatically switch into ad-hoc mode, forming what's known as a peer-to-peer mesh network," explains project lead Jeff Robble. "SPAN automatically connects all equipped users within range—about 800 feet."
Using Relay Points to Communicate Farther
Even better, it allows data to securely travel across a daisy chain of peers in the network to—you guessed it—span great distances. "SPAN allows you to communicate with people who are farther away simply because there are relay points between you and whoever it is you want to communicate with," Robble says.
Without cell towers, SPAN-equipped phones can be used as walkie-talkies, to send text messages, or to share photos over the network. If one SPAN user's cellular service provider restores towers, that user's smartphone becomes an Internet gateway for all others in the mesh network. SPAN can also take advantage of long-distance radio equipment.
"By hooking a phone into a radio using a USB cable, all phones in the mesh become able to communicate over the radio network," Robble explains. Communication equipment aboard unmanned aerial vehicles could become part of the mesh network as well.
One Idea, Many Applications
The research team studied a variety of events that destroy or limit communications systems, such as Hurricane Katrina and the tornadoes that hit Moore, Oklahoma, which took down both cell towers and power and telephone lines. The team created a prototype system that would have great utility in all these situations—for example, filling the need for a backup communications system between the time a disaster strikes and the time FEMA arrives on the scene.
"Using SPAN, first responders and local volunteers could communicate with one another without relying on traditional network infrastructure," Robble says. "They would be able to create situation reports and share them directly with one another over the mesh to create a common operational picture while out in the field."
In military operations, the same would be true. SPAN would provide a means for military personnel to share information such as the location of friendly forces, unexploded ordnance, or enemy activity. A SPAN-equipped phone could also store data collected over the mesh, and a courier could take the phone from the incident area back to a command and control center. Following a data transfer, the process would be reversed. Military staff could load the phone with new tasking orders and updated information relevant to the mission. The phone would then be couriered back to the field and disseminated via SPAN to the troops in the field.
Smartphones Need SPAN to Connect Off-Grid
"Compared to land mobile radios and specialized communications equipment, smartphones are relatively inexpensive—and they're ubiquitous," Robble says. "But they need to be equipped with SPAN in advance to work off-grid. Our end goal is to integrate SPAN into common off-the-shelf smartphones so that it's available at low cost to first responders and the military and to everyday people if and when disaster strikes.
To that end, MITRE has made parts of SPAN available through open source and is working with government and industry to transition this innovative technology to the nation to support critical infrastructure protection.
In May, the team presented its work at the Joint Interagency Field Experimentation (JIFX) event at Camp Roberts, California. JIFX brought together first responders and members of the armed forces for testing and policy discussions of technological innovations designed to support disaster relief, emergency response, and military operations.
"JIFX attendees saw a lot of possibilities for the technology," Robble reports, "and we're hoping their support will help move us closer to our goal."
—by Marlis McCollum