Distribution of Fingerprints for 802.11-based Positioning Systems

While indoor positioning systems based on 802.11 and fingerprinting work pretty well, it is unknown how to dis-tribute large amounts of fingerprint data to mobile devices. Even worse, many mobile devices are restricted in terms of memory capabilites. We identified three classes of mo-bile devices representing different levels of storage capa-bilities. For each of these classes, we present a distribu-tion approach for fingerprint data: the Union of Access Points (UAP), the Strongest Access Point (SAP), and the Intersection of Access Points (IAP) algorithm. These ap-proaches utilize the 802.11 network to download only a sub-set of the fingerprint data to a mobile device. The subset covers the area close to the actual position of the mobile device in such a way that position estimates can be com-puted. The size of the subset is different for each of the three algorithms.