Peer-to-Peer Alert Systems – Part I

by Stuart Ridgway, Original Music for Film and Television

This is the first 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.

Mother Nature often provides terrific insight when looking for inspiration and innovation. The invention of VELCRO is a perfect example. When we search for improvements to alert dissemination, we need look no further than the 22,000 species of ants that traverse our planet.

The first lesson we can learn is that ants rely on more than one method for notifying each other of new sources of food or imminent threats. As we look more closely at our own systems it may help to examine alerting methods where ants are more successful than we are. The second lesson we can learn is that ants require no more infrastructure than what they already have on their bodies–a very efficient use of resources.

Multiple Methods of Alerting

Primarily ants use three methods for updating and alerting each other: touch, sound, and pheromones. First, ants send tactile signals by touching one another’s bodies with their antennae and forelegs. Our first forays into shared alerts fall under this method. We proactively get in proximity with each other by talking to our families and banging on our neighbors’ doors. This is immediately effective, but it takes a lot of effort to notify the whole town this way.

Second, ants use sound and vibrations to transmit alerts farther and wider. They produce high-pitched chirps known as stridulations by rubbing together specialized body parts on the abdomen called files and scrapers. We too have our own versions of this one-to-many alerting using the Commercial Mobile Alert Service (CMAS), Emergency Alert Service (CMAS), and older alert systems such as sirens. These systems are even more effective than touch or proximity alerting but they are not perfect. If you’re not tuned in to one of them, you may not get the message.

Finally, ants secrete pheromones, chemical messages detected by other ants through sense organs or the antennae, that convey many types of valuable information. When an ant receives a message it can immediately share that message with its peers by emitting pheromones that they too can share.

We have just begun realizing the power behind this kind of peer-to-peer connectivity. Social media is one example of how peer relationships can facilitate the exchange of detailed and relevant information among a specific subset of the population, but it’s not the only one. There are several more examples of peer-to-peer implementations in development, or currently in place, that can help inform how we might make improvements to our alerting capabilities.

Two Types of Peer-to-Peer Networks

Before examining different examples, it helps to look at two different types of peer-to-peer networks. Regardless of the devices or technology used, peer-to-peer implementations can be constructed as mesh networks, star networks, or a combination of the two.

In a mesh network, all devices that have some kind of peer relationship (more on this later), 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.

Illustration of a mesh network

In a star network, devices gather information from a central node that is recognized as the master. A device can leave a network, join a new network with a new central node, and start receiving new information. In this case, a device does not have to rely on a single central node to get information – it gets it from the most efficient source.

Illustration of a star network

A combination of these two types can be quite powerful. A device can receive information from a central node and share that information with its peers if they don’t have it as well. This can help keep information timely and authoritative.

Benefits to Peer-to-Peer Networks

Peer-to-peer networks have four notable characteristics that can unquestionably benefit alerts and warnings systems.

  1. First, peer-to-peer networks can still function when infrastructure fails. If one carrier’s tower is down in an area and other carrier sends a CMAS alert to that same area, recipients of the alert can share it with peers in their networks who should have received the alert.
  2. Second, peer relationships do not have to be based on proximity. They can be created based on someone’s current context – think of a college reunion where I’ll be meeting a group of friends I haven’t seen in a while. We’ll be converging on one location so any alert for that area is relevant to all of us, however we can get it. Peer relationships can also be created based on social relations. If I have set up my device to “listen” for alerts relevant to where my all my family lives and one of them is in danger, I can learn about it quickly.
  3. Third, peer-to-peer networks are almost infrastructure free. All I need is a Bluetooth, Ultra Wide Band (UWB), Near Field Communication (NFC) or Wi-Fi technology built into my mobile device and I can start connecting with my peers. Regardless of how they are connected with their peers, we can all create a mesh network almost instantly. Imagine being at a sporting event with 60,000 of your closest friends. Chances are you’re only a few degrees of separation from anyone in the stadium. There are tremendous opportunities for using this kind of connectivity to share information. Star networks do require minimal infrastructure, but are much more efficient than a traditional radio or broadcast system. Instead of a lattice of broadcast towers, star peer-to-peer networks merely use a Wi-Fi base station, another mobile device, or something similarly small-scale as the central node.
  4. Finally, peer-to-peer networking enables savvy developers to create innovative uses for alerts. Were FEMA to provide developers with open access to IPAWS, developers could integrate authoritative alerts directly into their existing peer-to-peer software. For example, if I am trapped in traffic and I look to my Traffic Alert app for an update, not only could the developer provide me with the relevant IPAWS alerts but I could then share them with others around me.

Peer Networks Offer Countless Possibilities

Ants use pheromones to convey many types of information such as kin recognition, mating status, warnings, new food sources, and the delineation of territorial boundaries. Similarly, as developers continue to expand upon the ways our mobile devices can communicate with each other, the kinds of information and the way we can efficiently share it will also expand. Necessity will drive much of the development in this new frontier. Whether it is vehicle safety or the ability to make the most of the resources shared by your collective peers, peer networks can offer countless possibilities for public safety.

Part II of this series will cover some of the current and new technologies that rely on peer networks to share information including vehicle to vehicle, and legal torrenting technologies. I hope some interesting ideas for improving public safety will emerge from these examples.

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