Wi-Fi Ads

Established: July 28, 2007



Delivering Location-Based Content to Clients Over Wi-Fi Networks


Many consumers carry portable electronic devices, smartphones, personal digital assistants, or laptops that can connect to Wi-Fi networks. Location-sensitive advertisements, ads targeted to a Wi-Fi user based in part on the physical location of that user, will be an important market in the near future. We have developed two schemes for distributing location-sensitive ads to Wi-Fi devices: BeaconStuffing and Neighborcast.

BeaconStuffing fragments large messages, and embeds them in Wi-Fi beacons. This approach has three advantages:

  • We do not require information from the client device to deliver ads to the client.
  • We do not require the client to have Internet connectivity. In fact, we can deliver ads even when the client is connected to a different Wi-Fi network.
  • We can supply dynamic information to consumers in real time. For example, a restaurant can continuously advertise an expected wait time to all wireless clients in its vicinity.

In recent work, we developed a technique called Neighborcast, which enables group communication among physically nearby clients, even when the clients are on different frequency channels or connected to different Wi-Fi Access Points. We define two clients to be near if they can hear a common Wi-Fi Access Point, and construct an IP overlay spanning physically nearby clients. This technique enables retailers to send location-based advertisements/annoucements to all physically nearby clients.

Neighborcast is complimentary to BeaconStuffing. Neighborcast does not require modifications to the Access Points or the Wi-Fi drivers on the clients, and has a wider reach — content can be delivered to clients that do not even hear the retailer’s Access Point. However, compared to BeaconStuffing, it cannot deliver content to disconnected Wi-Fi clients.


The WiFiAds project is a joint collaboration between the Networking Research Group at Microsoft Research, Redmond and the Mobility, Network and Systems Group at Microsoft Research, India.