Otiy: locators tracking nodes

We propose Otiy, a node-centric location service that limits the impact of location updates generate by mobile nodes in IEEE 802.11-based wireless mesh networks. Existing location services use node identifiers to determine the locator (aka anchor) that is responsible for keeping track of a node's location. Such a strategy can be inefficient because: (i) identifiers give no clue on the node's mobility and (ii) locators can be far from the destination thus increasing location updates path length and bandwidth consumption. To solve these issues, Otiy introduces a new strategy that identifies nodes to play the role of locators based on the likelihood of a destination to be close to these nodes -- i.e., locators are identified depending on the mobility pattern of nodes. Otiy relies on the cyclic mobility patterns of nodes and creates a slotted agenda composed of a set of predicted locations, defined according to the past and present patterns of mobility. Correspondent nodes fetch this agenda and use it as a reference for identifying which locator is currenty in charge for the node. Over a period of about one year, the weekly proportion of nodes having at least 50% of exact location predictions is in average about 75%. This proportion increases by 10% when nodes also consider their closeness to the locator from only what they know about the network. In this paper we focus on the analysis of the concepts behind Otiy leaving more quantitative and comparative results for future work.