FireChat, Communicating Completely Off the Grid
In our modern, highly connected lives, we take for granted that we should always be able to type a text message and have it instantly be delivered to its intended recipient. But we all have times when we are faced with ridiculous roaming charges, overpriced international data plans, or simply spotty coverage at the places to which we travel. That is, not to mention emergency scenarios like natural disasters, in which cellular networks might go completely offline.
According to the Business Insider article linked below, FireChat is an app that intends to solve this problem, by allowing phones with the app installed to send and receive text messages without being connected to a conventional cellular or Wi-Fi network. This works via a technology called mesh-networking, in which devices to form a peer-to-peer communication network and send messages directly to one another via their Wi-Fi antennas, entirely bypassing the conventional communication networks. The article states that data is able to be transmitted among devices within a range of 210 feet from each other. In areas with a dense enough population, this app is able to form a massive network of users in close proximity to each other, and by hopping messages from device to device, it is able to transmit messages across distances far beyond the Wi-Fi range of any particular device. This allows for people to communicate effectively in instances where the large number of people might overload the conventional cellular networks, like at big sports stadiums.
Up to this point, however, the only type of supported communication was broadcasting a message to the entire network either anonymously, or with the user’s real name. While this might be useful during a disaster situation, people might want to send private messages to one another. According to the TechCrunch article linked below, FireChat has solved this problem as well. In order to transmit messages between two separate connected components of a network, the app utilizes a technique called “store and forward”. Using this technique, a mobile device receives encrypted messages (for whom it is not the intended recipient) from its neighboring devices, and it stores them until it comes into contact with other devices later on. It then forwards the messages until each message finds its intended recipient. Now, actually finding the recipient is the challenging part. Using FireChart, “Devices run a probabilistic distributed algorithm to build a connected graph”, says Open Garden CTO Stanislav Shalunov. “This is possible when the density is above a certain threshold. This threshold is easily reached in an urban scenario and in a crowd. Once the network is established, messages get delivered in a way that balances reliability and use of resources.” To reach the ultimate recipient, FireChat’s algorithms sometimes must route the messages over the wider internet, if there is a disconnect in the graph. But despite this, both the sender and the recipient of the message may be completely disconnected from the internet. The graph theories that we studied in class directly appliy to writing such algorithms for efficient routing of information over a communication network. Using this new networking technology, people will be able to form their own communication networks completely independent of the existing infrastructure. According to co-founder and CEO of Open Garden, Micha Benoliel, “This innovation paves the way for the next evolution of the Internet: networks created by the people, for the people.”
Links:
http://www.businessinsider.com/firechat-app-lets-you-text-without-wifi-or-data-2015-8
http://techcrunch.com/2015/07/29/firechats-off-grid-messenger-gets-private-messaging/