by Stuart Ridgway, Original Music for Film and Television

This is the second of three articles exploring peer-to-peer communications and how these technologies could impact the timeliness and relevance of emergency alerting.  These first appeared in September, 2012 on the AWARE Forum.

Last week I wrote about the basics of peer-to-peer alerting for mobile devices and how peer networks might facilitate the dissemination of alerts. In this article I provide several examples of technologies that demonstrate the first of two types of peer networks called “mesh” networks.

To recap from Part I: in a mesh network all devices that have some kind of peer relationship, talk to each other, and co-exist as equal peers. As devices move out of the network and form new ones with new peers, information is continually shared.

Peer-to-Peer Mesh Network
As devices move out of the network and form new ones with new peers, information is continually shared.

There are many existing systems using peer-to-peer networks that may be valuable to consider when improving peer-to-peer alerting. These first examples use mesh networks to share important data among peers. In the Part III of this series, I will give examples of “star” networks and finish up with examples of combined mesh/star networks.

Examples of Existing Mesh Networks

University of Michigan

The University of Michigan Transportation Research Institute has teamed up with the National Highway Traffic Safety Administration to start testing peer networks among vehicles. In August this year almost 3,000 cars, trucks and buses hit the road in the Ann Arbor area with dedicated short-range communications (DSRC) devices. These DSRCs continually transmit a “here I am” signal to the vehicles around them that trigger another vehicle’s warning system if the two get too close.

When one of the vehicles picks up a signal from another and a collision is imminent, a signal alerts the driver to take action, with the hope of turning a collision into a near miss. Clearly the more quickly that the two vehicles share their whereabouts with each other, the more time the driver has to take action.


Airmobs, an MIT Media Lab project, provides a marketplace for sharing Internet connectivity. This is particularly beneficial when one device has no available Internet connection and another device has excellent network connectivity and a full battery. Airmobs facilitates the bartering of airtime between mobile phone users: users gain airtime credit when they share their connectivity then use that credit when they themselves cannot connect.


Barclays Banks in the UK has recently upgraded its Pingit mobile money transfer service. Using their iOS, Android, or Blackberry mobile apps, Barclay customers and non-customers alike can link a UK mobile phone number with their UK bank account to send and receive money. This is the first service of its kind in Europe. Not only can a Londoner pay her tab at a participating commercial establishment using her phone, similar to Google Wallet, she can also use it to pay the 10 pounds she owes her brother.

By considering each example, developers of peer alerting networks have opportunities to learn from existing technologies to improve their own. The communication protocols that vehicle networks use to share data so quickly provide tremendous insight into ways to share alerts as fast as possible. Airmobs demonstrates that users can share connectivity with their peers using a mobile device network, which could be very important for sharing alerts if a cell carrier’s network is down. Finally, Pingit connects third-party data (bank account information) with a user’s peer network, which opens the possibility for incorporating more detailed information with an alert.

Next week I will publish Peer-to-Peer Alert Systems Part III to wrap up this series on peer-to-peer networks. My hope is that readers will be inspired to research some of these technologies and develop their own ideas for improving peer alerting.

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