As we pointed out in Sect. 3.2, a location can be associated with multiple Wi-Fi APs to increase the accuracy of indoor locationing. Specifically, an implementation issue arises in this circumstance. If a location is associated with multiple Wi-Fi APs, in location matching, we can set the criterion to be either ‘‘match any of these APs’’ or ‘‘match all of these APs’’. Using the former criterion can make location matching easier and quicker because a location match can be declared as soon as any of the APs associated with the location is sensed. In contrast to this, using the latter criterion can make location matching more accurate, because intuitively it will require the user to be physically close to the spot where he/she established this location previously in the reminder application. However, doing so can sometimes make location matching difficult if one of the APs is removed from the location.