METHOD FOR RANGING TO A STATION IN POWER SAVING MODE

摘要

A network based positioning NBP system (100) is disclosed that allows any of its access points APs (400) to initiate ranging operations with a station device STA (200), regardless of whether the STA (200) is in power save mode and regardless of whether a particular AP (400) is currently associated with the STA. For example, to initiate ranging operations with the STA (200) from a non-associated AP, the non- associated AP obtains the TSF timer of the associated AP (610), and then uses the obtained TSF timer to derive the associated AP's beacon transmission schedule (612) and thereby determine when the STA's corresponding wake-up periods occur (612). Thereafter, the non-associated AP can initiate ranging operations with the STA during the STA wake-up periods (614), thereby ensuring that probes sent from the non-associated AP will arrive at the STA while the STA is awake from power save mode.