Reducing WLAN power consumption on a mobile device utilizing a cellular radio interface

摘要

A system and method of reducing the WLAN power consumption and limiting battery drain of a mobile communications device is provided. The mechanism continuously monitors for changes in the WLAN and cellular signal strength and modifies the WLAN profile scanning activity accordingly. By monitoring for changes, transitions can be detected which indicate the location of the mobile device (i.e., indoor or outdoor). An increase in cellular signal strength and a decrease in WLAN signal strength indicates the user is transitioning outdoors where WLAN coverage may be limited. To reduce battery power consumption, background scanning is suspended or its frequency significantly lowered. Moving indoors is indicated by a decrease in cellular signal strength and an increase in WLAN signal strength. Background/Connectivity scanning frequency is increased to provide shorter time-to-connect to WLAN Networks for the user within the WLAN coverage area.

主权项

1. A method performed by a mobile device, the method comprising:
at a first time:
obtaining from a cellular radio subsystem incorporated in the mobile device a first cellular signal strength measurement and identifying to which first cellular signal strength category of a predefined set of cellular signal strength categories the first cellular signal strength measurement belongs; andobtaining from a wireless local area network (WLAN) radio subsystem incorporated in the mobile device a first WLAN signal strength measurement and identifying to which first WLAN signal strength category of a predefined set of WLAN signal strength categories the first WLAN signal strength measurement belongs; waiting a predefined amount of time following the first time; at a second time:
obtaining from the cellular radio subsystem a second cellular signal strength measurement and identifying to which second cellular signal strength category of the predefined set of cellular signal strength categories the second cellular signal strength measurement belongs; andobtaining from the WLAN radio subsystem a second WLAN signal strength measurement and identifying to which second WLAN signal strength category of the predefined set of WLAN signal strength categories the second WLAN signal strength measurement belongs; comparing the first cellular signal strength category to the second cellular signal strength category; comparing the first WLAN signal strength category to the second WLAN signal strength category; in the event that both (i) the first cellular signal strength category represents a stronger cellular signal strength than the second cellular signal strength category and (ii) the first WLAN signal strength category represents a weaker WLAN signal strength than the second WLAN signal strength category, determining that the obtained measurements are indicative of an outdoor-to-indoor transition of the mobile device and increasing a background scanning frequency of the WLAN radio subsystem.