Microsoft develops sound based NFC

by: Robert TriggsAugust 16, 2013

Microsoft Research recently unveiled its latest invention for mobile devices, a peer to peer acoustic file transfer protocol which allows devices to send and receive information over the air. Now that might not sound particularly new or innovative, but what’s most impressive about this technology is that is doesn’t require any additional hardware, like a Bluetooth transmitter for example. It works using the standard microphone and speaker configuration found in very mobile phone.

This technology works by transmitting a series of encoded sounds, in the 1KHz of bandwidth between 6-7KHz, through the speaker of once device, which is then picked up by a nearby microphone and decoded to reveal the information. Any phone can be used as a transmitter or receiver, after installing Microsoft’s software known as Dhwani.

Ok, so this isn’t really NFC in the strictly technical sense, but it will do some of the same things over the same sort of range, allowing for around 10cm between the two devices.

dhwani acoustic peer to peer

Sadly though, the technology is currently a little on the slow side, peaking at data speeds of around 2.4 kilobits per second. It’s unclear how much can be done about this lack of speed, due to the protocols self-jamming, the need to differentiate from environmental noises, and restrictions on output power. To put that speed into perspective, it’s around 20 times slower than an old dial up modem, so don’t expect to be exchanging video files between handsets with this.

However, this is still perfectly suitable for sending contact information between devices, transferring notes, or linking other devices to a web address. The technology also has built-in jamming and scrambling capabilities, so it could also be used for mobile payments. It’s worth noting that this technology was developed by a research team in India, where not as many mobile devices are equipped with NFC or Bluetooth technologies. So expect this to probably find adoption in developing markets, rather than in more developed economies where other forms of short range communication are more commonplace.

  • Sidd

    I just read the document in details, seems quite promising. Anyone’s interested can have a look at

    • End in sight

      Will I be able to hear the noises from the transferring? I mean, is it in that frequency of my ear? (I am too lazy to read all that scientific paper, sorry.)

      • vosg

        Yes, it will use audible noise. It has to, or the receiving microphone wouldn’t detect it.

  • vosg

    Given the very limited bandwidth of smartphone speakers, this technology will be a huge fail. But yeah it’s Microsoft, so..

  • Br

    vosg, I think you miss the point of this technology and how technologies are adopted. With normal NFC you have to get everyone to agree on hardware standards, you have to get the hardware on phones, you need google and apple and samsung agree. All of those are huge road blocks. But everyone’s smartphone, computer, tablet, even dumb phone has a speaker and a microphone, no hardware needed. Now you can have services like swipe to pay from visa et. al. create a sound standard and anyone can build the app to make it work. 90%+ of new technology introduction is how easy and cheap it is to adapt. Remember most people couldn’t careless about the hardware behind NFC, you put your phone next to something and it works, that’s all that maters. You have Wifi, Bluetooth, LTE, USB to transfer large data.