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 distribute 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 mobile devices representing different levels of storage capabilities. For each of these classes, we present a distribution approach for fingerprint data: the Union of Access Points (UAP), the Strongest Access Point (SAP), and the Intersection of Access Points (IAP) algorithm. These approaches utilize the 802.11 network to download only a subset 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 computed. The size of the subset is different for each of the three algorithms.