Emergency Communication in case of an Outage
Wifi-Direct as an emergency solution?
It seems that the scenario of an electricity and internet outage became a realistic scenario for the upcoming Swiss winter 1. How would an emergency communication with the people in your workplace or neighborhood look like when the internet and telephone lines are out? Would such a scenario mean the come-back of radio-based solutions such as walkie-talkies? In my latest blog, I am discussing a rather unknown and imperfect technology called Wi-Fi Direct that could however be a cheap and easy alternative that everyone with an Android mobile phone could use in such a situation.
During my time as an intern in Albania in 2008, electricity-shortages occurred on a weekly basis. It happened usually in the morning at work, as the steel-works and industries were requiring a lot of power then. It was thus less the romantic picture of a blackout at night with candle light. The workplace was equipped with auxiliary diesel-generators that jumped in surprisingly well: The computers back then rarely went black.
Today we are very dependent on electricity and the internet. If the electricity and therewith the internet would have an outage, then communication would be abruptly stopped. The normal telephone lines would not work 2, the mobile communication transmitters would be without energy, and the landline routing servers would also be out 3 .
There is of course no need to paint a black picture of such a case. And while it might be exaggerated to go full-scale “prepper”, it would be nevertheless wise to think such a case through and to be prepared with at least a minimum plan.
Very likely the first reaction is physical communication and gatherings at the workplaces and on the streets or hallways in case of your neighborhood. However, communication in such an emergency situation is nevertheless necessary: I guess that not all the elevators have an auxiliary power-supply yet and there are people needing assistance. Coordination might be in some cases required beyond an oral distance.
Walkie-talkies or other radio equipment can in such cases work on batteries, if a company plans to invest early in such equipment. But there is also a cheaper and easier, although quite imperfect alternative: Not many people know that mobile phones can also communicate directly among themselves without routers or antennas in between. It is called Wi-Fi Direct ® 4, which is an open standard and enables communication between devices that is over ten times faster than bluetooth. The technology is currently almost only used for fast file transfers and for sending documents to printers.
As shown in the following picture, it was not difficult to make a simple app that can transmit messages between devices 5. The devices make peer-to-peer connections without needing to specify the server and client roles, and it can be extended to as many peers as available in range.
Picture from own simple chat app over WiFi-Direct technology
The technology has two larger downsides, which is likely why the technology is so unknown in the first place. First, it is restricted to the distance of its internal Wi-Fi antenna – usually 100 meters in the open space minus connectivity-loss by obstacles such as walls, floors etc. Nevertheless, I think that one should keep in mind a broadcasting possibility that would work like a human chain: if many devices are used, they can re-transmit messages so that larger peer-to-peer networks get established in such a situation.
Extend the range by broadcasting through the participants. Picture by Stefan Schweihofer from Pixabay
A second downside is that Apple, a large manufacturer of mobile devices, did not include the technology and instead uses an own proprietary wireless ad hoc service for sending files between Apple devices (iPhone, Macs etc.). The fact that Apple does not use the open Wi-Fi Direct standard makes it impossible to send and receive messages from and to other operating systems such as Android or Windows.
Nevertheless, if you think in case of an emergency, a cheap and easy solution for quick communication around you (without radio equipment) could be useful. The installation of an app (in non-outage times of course) would suffice for that.
There might be other interesting use-cases of such a technology. One would be in the case of communicating anonymously with other people around you. For example in countries where you get arrested when publicly displaying an empty protest sign 6 , or in countries where the entire internet connectivity is taken offline by the regime7. In such cases, apps like Telegram might not be reliable anymore. The technology, used together with “MAC randomization” that is now installed in every Android device, could be used as a means of communication in places such as the metro or public squares.
What do you think about this technology? Would such a technology be of use? Send me a message or comment on social media.
Based on a great tutorial by Sarthi Technologies, see https://www.youtube.com/watch?v=nw627o-8Fok&list=PLFh8wpMiEi88SIJ-PnJjDxktry4lgBtN3 ↩︎