Two of the more frustrating aspects of living in a modern, information society and the constant need to “have internet access” everywhere, all the time are finding a strong, and stable signal to provide access and the power drain to your device that results from the constant searching for and connecting to an accessible signal. One emerging technology that is working hard to resolve these two issues is known as passive Wi-Fi, or as it is more informally known, “backscattering” (Harris, 2016).
Passive Wi-Fi refers to a technology that is being developed at the University of Washington that is working on using existing Wi-Fi technology to become more than simply a means to download and upload content (Kellogg et al, n.d.). In current Wi-Fi technology, the internet data stream enters into a network via a router. The router then transforms that data stream into a radio signal encoded with the data and broadcasts it out for devices to receive. In other words, the router needed a transmitter, receiver and encoding chip (The Economist, 2016). In order for a device, such as our smartphone, to access the internet through Wi-Fi, it needs to communicate with the router. It does this first finding the router’s signal, decoding it, and sending back its own signal confirmation. Accordingly, it also needs a transmitter, receiver, and encoding chip. The problem is that because there are usually many devices trying to access the router, there are a large number of radio signals passing back and forth. Researcher refers to as “noise” (Harris, 2016). As a result, devices are constantly working to differentiate the router’s signal from the signal of another nearby smartphone. That is to say, there is a constant effort to discern a clear signal from the noise. As a consequence, the device us constantly using power. In addition, to many signal transmissions decrease the available signal strength of the router.
With passive Wi-Fi, three changes occur. First, there is just one signal broadcast by the router. However rather than a device picking of the signal and transmitting another signal back, the simply decode the signal and reflect the signal elsewhere (Kellogg et al. n.d.). That is to say, there is no noise just one voice of the router. All devices can hear that voice and, in essence, repeat it to any other nearby device (Kellogg et al, n.d). The benefit is that there is no need for the device to constant be looking for the signal. This means that power consumption can be drastically decreased. Second, because each device, in essence become its own mini-router through its reflection or “backscattering” of the original signal, the signal strength as a whole becomes more powerful and more stable (Jeeva, 2016). The signal can become more efficient by allowing more devices the ability to reflect the signal. Lastly, and perhaps most importantly, a passive Wi-Fi device can also transform the ambient energy of any radio signals being broadcast to power itself (Kellogg et al, n.d). For instance, the signals emanating from a TV, radio, or other device can be used to provide energy for the passive Wi-Fi device.
In short, passive Wi-Fi was the potential to fundamentally transform how we access the internet, how we communicate with one another, and how we maintain access. In addition, it might also prove significant in the effort to construction a more energy efficient society.
References
Harris, M. (2016, Fe. 24). Power from the air. Retrieved from https://www.technologyreview.com/s/600773/10-breakthrough-technologies-2016-power-from-the-air/
Jeeva Wireless. (2016). About. Retrieved from http://www.jeevawireless.com/about/
Kellogg, B., Talla, V., Gollakota, S. & Smith, J.R. (n.d.). Passive Wi-Fi: bridging low power to Wi-Fi transmissions. Retrieved from http://www.passivewifi.cs.washington.edu/files/passive_wifi.pdf
The Economist. (2016, Mar. 05). Powering the internet of things – passive voice. Retrieved from http://www.economist.com/news/science-and-technology/21693901-clever-way-forward-powering-internet-things-redesigning-wi-fi-may-let
