Infrastructure-Assisted Geofencing: Proactive Location-Based Services with Thin Mobile Clients and Smart Servers

With the increasing popularity of smart phones, location-based services became a hot topic and a great number of solutions were presented over the last years. The majority of applications are based on the idea to present location-specific information in case the smartphone user asks for it. A relatively small amount of applications are dealing with geo-notifications that are intended to inform the smartphone user proactively about location-specific information in case a dedicated zone is entered or left. The technology behind proactive location-based services is called Geofencing and it is mainly implemented and executed at the mobile device. This paper presents a new approach to offload this resource intensive process of monitoring the user's location into the infrastructure. The mobile device is thereby considered to be a thin client that is mainly responsible to locate itself whereas the continuous comparison of the mobile's position with a large set of dedicated zones, called geophones, is executed within an environment with lower resource constraints. A prototypical implementation of a thin client as well as the corresponding location processing unit within the infrastructure gets introduced, discussed and evaluated under different environmental conditions.