Asset tracking refers to tracking the movement of physical assets, either by scanning barcode tags attached to the assets or by using smart tags, like 'passive' RFID, which broadcast their location, but which have limited transmission range (typically a few meters). Longer-range "smart tags" use 'active' RFID -where a radio transmitter is powered by a battery and can transmit up to 2000 meters (6,600 feet) in optimum conditions. RFID-based Asset Tracking requires an infrastructure to be put in place before the whereabouts of tags may be ascertained. An asset tracking system can record the location and usage of the assets and generate various reports.