3rd Party Geolocation Messaging: A Positioning Enabler Middleware for Realizing Context-Aware Polling

Next generation Location-based Services (LBSs) are coined by a proactive user-interaction as well as a crossreferencing target relationship. In a proactive user-interaction, a service continuously keeps track of a user's locations and performs arbitrary actions upon entry or exit of a certain region. A cross-referencing target relationship implies that the LBS user and the target are not identical, which is the case, for instance, when a 3rd party subscribes for certain location events on behalf of the tracked user, i.e. in a Location-based Advertising scenario. In order to efficiently realize sophisticated proactive, cross-referencing LBSs, a number of challenges need to be surmounted. Unfortunately, existing research within this respect is still rudimentary and a huge potential still remains untapped. Proactive LBSs involve continuous background tracking to know the location whereabouts of a user as well as process it in order to detect useful information in the vicinity. However, this results in severe battery drainage, hence shaping the main barrier for the realization of such services. Moreover, continuously tracking a user's location raises major privacy concerns, especially in case of cross-referencing LBSs. In this paper, we present the Positioning Enabler service middleware platform which provides a set of functionalities and APIs for enabling battery-efficient background tracking of single and multi-targets in a proactive manner, enabling the realization of sophisticated LBSs based on continuous background tracking and geofencing. Furthermore, it supports 3rd party Geolocation Messaging while implementing certain location privacy measures for not invading user's privacy. The service middleware is used in the implementation of a Context-aware Polling mobile application for smart cities, FlashPoll.