Background scanning method for WLAN client devices

摘要

Background scan for 802.11 client devices allows them to keep most of its components in low power mode when certain criteria are not met. A method for changing dynamically those criteria according to the air data traffic conditions is described in the present invention. This increases the time the system remains in sleep mode and consequently improves the standby current consumption to portable 802.11 enabled media.

主权项

1. A method for an unconnected device to perform Wireless Local Area Network (WLAN) background scanning, comprising steps of:
(a) setting tpo, a duration the unconnected device is in sleep mode with power consumption PO; (b) scanning for one or more possible local WLAN Access Points (APs); (c) when either a packet or higher energy is detected during the scanning of step (b), changing scanning parameters comprising decreasing the tpo, widening bandwidth of one or more receiver filters, if previously scanning is in passive mode, switching to active mode, if previously scanning is in active mode, changing transmit power, and changing response expiration time, and continuing scanning using the changed scanning parameters; and (d) when neither a packet nor higher energy are detected during the scanning of step (b), entering sleep mode for the duration tpo, and, at the end of the duration tpo, returning to step (b), and, if neither a packet nor higher energy are detected during a subsequent scanning of step (b), entering sleep mode for the duration tpo without changing the duration tpo.