Using Wi-Fi for client-based indoor positioning can be beneficial because in many cases existing infrastructure can be used. This could be for example Wi-Fi enabled cash register systems, routers and client hot spots. It is not even necessary that the devices are connected with the access points to determine their position, it is sufficient that the Wi-Fi function of the device is switched on. The position is being determindes using a RSSI (Received Signal Strength Indication) and the MAC address of the device. The accuracy is 5-15 meters.
Client-based Wi-Fi positioning is not possible on iOS devices
A major disadvantage of tracking with Wi-Fi is that end devices running the iOS operating system version 4.3 or higher do not support client-based (end-device-based) positioning via Wi-Fi. Relying exclusively on Wi-Fi would mean that a lot of devices are excluded. Wi-Fi as a positioning technology can make sense in cases when the operator offers his own devices to their visitors or employees. For example visitor guides in museums or smartphones for employees. If this is not the case, beacons can be a better alternative.
Server-based positioning using special hardware
The server-side localization of all end devices, regardless of the operating system, is possible with specific receiver hardware (e.g. infsoft Locator Nodes or Cisco MSE, Meraki, Xirrus).