Gunnar Forsgren

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Kista, Stockholm, Sweden

Former Ericsson / Sony Ericsson development engineer.
30 years of engineering experience in telecom and mobile.
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October 12, 2011

The Wifi beacon chips

This article advocates for how a subset of Wifi technology can be used as proximity indicators.

The functionality in Wifi access points to signal its identity as a text string (SSID) have uses in
indication proximity to a location.  It can be interesting to implement the beacon signaling subset of a Wifi circuit as a function on its own.

The beacon chip is an electronic circuit that implement the beacon function of a WiFi chip. Wifi chips are radio based network circuits found in networked devices and wireless access points (WiFi routers, etc).
Its serves to periodically transmit a piece of data over the air, an identification string on the Wifi frequency band so that this ID can be detected by a mobile phone application. Smartphones which are very popular nowadays (iPhone, Android) all have Wifi access and you can download and install applications that can scan for such SSID's in the environment. When such a beacon signal is transmitted in the area where you are located the phone application can quickly detect its presence. Such a beacon chip needs to perform only this role, where the rest of a Wifi interface chip is simply omitted. The role of the beacon in this application is unrelated to Wifi, it only uses this frequency band to radiate its identity string (SSID). The unique ID can be translated by the phone application to a fixed geographical position, meaning that when the application senses this ID it knows that the ID is transmitted by a beacon device located at that geographical position. This offers sufficient positioning accuracy for many applications. Such chips would be quite cheap to manufacture ( $1 ) and there would be a substantial demand worldwide for use in this type of positioning application. A commercial prerequisite is that they need to pass radio spectrum approval in the country where they will be deployed.
Once it has been resolved how such chips can get commercial approval to operate on Wifi frequency bands then the next job is to package them in a format where they can be powered by an energy source at hand at the location where the chip transmits. The power source can be a solar panel, an inductive pickup charger or something else. Focus on minimizing cost per beacon transmitter is important.

So why all these beacon devices ? Well by placing them at suitable intervals along a path where you want to track the geographical position (preferrably at locations where GPS satellites or A-GPS is not available such as underground) you accomplish a means of keeping track of your position along this path. This is typically locations where GPS/A-GPS do not have a reach. A major application is enabling location sensing in the subway network of a city. There are numerous applications possible that would be very popular in the subway such as tourist guides, games, navigation apps, etc. if only the app could have a sense of location. There are many cities with subways, worldwide. In addition to existing access points at a location the beacon device fills a need as enabler for positioning at coordinates where other means are missing. If you know of a supplier or potential manufacturer of such beacon chips then please inform me.
I donate this idea here since I am not in a position to embark on becoming a millionaire beacon chip entrepreneur at this moment. I just need the chips to support some cool subway apps (such as the so far little known SubTrip underground commuting entertainment app)

In the meantime it is possible to use regular Wifi-enabled microcontrollers ($50) to serve as these beacons but since full Wifi devices are relatively costly units (due to features way beyond what a beacon chip offers) they can only serve as prototyping/demo substitutes.


  1. I see the idea was out already in 2008:

  2. Hi, Gunnar!
    I was searching for a wireless beacon solution for Android and stumbled upon your post. Just curious, was there any progress with manufacturing of such wifi beacon chip?

  3. Hello the idea has not yet been taken further. Onr thing that needs investigating is to what extent a chip that is not Wifi certified (it cannot be unless it implements the whole Wifi protocol) may send out signalling that a Wifi certified chip picks up as an SSID.

  4. The words "may send out" is key; is it permitted from a radio spectrum regulation standpoint for a radio transmitter to speak a minor subset of an established protocol on the same channels as the standardized Wifi chips and sell these beacons commercially for legal use by customers ?

  5. The reason for bothering about beacon chips is that they are likely low cost to manufacture; while full Wifi chips cost some 50 dollars each and can be too costly for deploying in volume as position beacons.

  6. Bluetooth Low Energy is what solves that beacon problem and it does it big time. Two decades of Bluetooth were unable to come up with this, But now the super slow and unreliable scanning to find a Bluetooth device is no longer a limitation. A low energy BLE device can work as a beacon and BLE enabled phones can be programmed to pick up a beacon signal instantly and alert an app . So once BLE becomes commonplace in phones (so far iPhone5 and recent Android phones) there is a big boom for what I wrote about earlier. Solutions based on that technology is in intensive development out there.
    I do some exploration with beacon detection on both iOS and Android and it´s just fantastic.

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