8. A context-based geofence control method, executed by a mobile communication device comprising a positioning unit for providing position information of the mobile communication device, the context-based geofence control method comprising: detecting an approach to a first geofence according to a plurality of contexts associated with the mobile communication device; turning off the positioning unit when not detecting the approach to the first geofence; and turning 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 context-based geofence control method further comprises: prioritizing at least one of the cellular context and the personal context over the other contexts, for detecting the approach to the first geofence.
8. A context-based geofence control method, executed by a mobile communication device comprising a positioning unit for providing position information of the mobile communication device, the context-based geofence control method comprising: detecting an approach to a first geofence according to a plurality of contexts associated with the mobile communication device; turning off the positioning unit when not detecting the approach to the first geofence; and turning 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 context-based geofence control method further comprises: prioritizing at least one of the cellular context and the personal context over the other contexts, for detecting the approach to the first geofence. 9. The context-based geofence control method of claim 8 , further comprising: turning off the positioning unit when detecting that the mobile communication device has entered a second geofence according to one or more of the contexts.