Date Added: Jan 2011
Many indoor localization methods are based on the association of 802.11 wireless RF signals from Wireless Access Points (WAPs) with location labels. An "Organic" RF positioning system relies on regular users, not dedicated surveyors, to build the map of RF fingerprints to location labels. However, signal variation due to device heterogeneity may degrade localization performance. The authors analyze the diversity of those signal characteristics pertinent to indoor localization - signal strength and AP detection - as measured by a variety of 802.11 devices. They first analyze signal strength diversity, and show that pairwise linear transformation alone does not solve the problem. They propose kernel estimation with a wide kernel width to reduce the difference in probability estimates.