Noise Cancelling Headphones

I just want to preface this post by saying…. I’m going out on a limb here. Like way way out on a limb.

Somebody posted on Twitter the other day that they were purchasing their 4th set of noise cancelling headphones. If you don’t have a pair of these magical devices, you should stop reading this, get on your favorite purchasing website and buy some, especially if you are ever on an airplane. After you’re done buying, make sure to come back and keep reading.

Side note: Turns out that the white noise caused by airplane engines can actually increase your stress hormones and potentially cause cardiovascular issues. Who knew? http://www.onlinejacc.org/content/71/6/688

But, noise cancelling headphones got me thinking about WiFi. Signal to Noise Ratio (SNR) is something we talk about all the time. Trying to achieve that ideal SNR (ideally no less than 20 dB in a high density environment) is what we spend a lot of time doing as Wireless Engineers. So it got me thinking about how active noise cancelling headphones work and if the same idea could be applied to reducing noise in dense environments. (I told you I was out on a limb)

So essentially, active noise cancelling requires 3 things. A receiver that senses the frequency and amplitude of the noise. A CPU for making sense of the receivers input and then telling the transmitter that offers a rarefaction wave that is in line with the compression waves of the received noise. This is called “destructive interference”.

What if there was a way to have “destructive interference” that was able to detect non-WiFi RF to reduce noise in our environments? What if we had separate hardware in the environment that did only this? Would it even be possible? Would it even be able to differentiate between WiFi RF and interfering RF? Why wouldn’t this work? Anybody want to take a stab at the math?

Anybody want to join me on the limb?

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