1. A mobile communication device, comprising: a positioning unit, configured to provide position information of the mobile communication device; and a processing unit, configured to detect an approach to a first geofence according to a plurality of contexts associated with the mobile communication device, turn off the positioning unit when not detecting the approach to the first geofence, and turn on the positioning unit when detecting the approach to the first geofence, wherein the contexts comprise at least one cellular context and at least one personal context, and the processing unit is further configured to prioritize at least one of the cellular context and the personal context over the other contexts, for detecting the approach to the first geofence.
1. A mobile communication device, comprising: a positioning unit, configured to provide position information of the mobile communication device; and a processing unit, configured to detect an approach to a first geofence according to a plurality of contexts associated with the mobile communication device, turn off the positioning unit when not detecting the approach to the first geofence, and turn on the positioning unit when detecting the approach to the first geofence, wherein the contexts comprise at least one cellular context and at least one personal context, and the processing unit is further configured to prioritize at least one of the cellular context and the personal context over the other contexts, for detecting the approach to the first geofence. 5. The mobile communication device of claim 1 , wherein the cellular context comprises at least one of the following: an identity of a cell which the mobile communication device is currently camped on; and an identity of a Public Land Mobile Network (PLMN) to which the cell belongs.