Power management method of and apparatus for use in a wireless local area network (LAN)

• US 20020016151A1
• Filed: 08/23/2001
• Published: 02/07/2002
• Est. Priority Date: 10/03/1997
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Romans, Christopher Gwyn
• Granted Patent: US 6,665,520 B2
• Time in Patent Office: Days
• US Class Current: 455/13.4
• CPC Class Codes: H04L 41/00 Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 52/28 using user profile, e.g. mobile speed, priority or network state, e.g. standby, idle or non transmission
• CPC Class Codes: H04W 52/288 taking into account the usage mode, e.g. hands-free, data transmission, telephone
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In a wireless network containing battery powered stations, one station is designated as a control point (CP). Each of the remaining stations has two operating modes: an active mode in which it receives and transmits messages, and an inactive or sleep mode which incurs reduced power consumption. The Control Point periodically transmits a beacon signal, and each station switches to its active mode to receive at least some of these beacon signals. A beacon signal may indicate that data is available for transmission to a particular station (from another station), in which case that particular station then broadcasts a message to indicate that it is awake and can receive messages. A beacon signal also indicates whether a broadcast period is in progress, and time to elapse until a next possible broadcast period will commence; if the Control Point has previously received and stored any broadcast messages it will re-broadcast them during the next following broadcast period and the remaining stations will react by remaining in active mode for the duration of that period.

Claims

1. A method of operating a wireless network containing a plurality of stations, one station being designated as a control station and the remaining stations having an active state and an inactive state which incurs lower power consumption than the active state, wherein:

the control station periodically transmits a beacon signal;

each remaining station periodically enters its active state to receive the beacon signal; and

if there are data for a remaining station to receive, that station transmits a status signal to indicate to other remaining stations that it is active and able to receive data.

2. The method of claim 1, wherein the control station incorporates into its beacon signal an indication of the identity of each remaining station for which there are data to be received by that station.

3. The method of claim 1, wherein each remaining station returns to its inactive state when it has not received or transmitted any data during an interval of predetermined duration.

4. The method of claim 1, wherein each remaining station periodically enters its active state to receive every beacon signal.

5. A method of operating a wireless network containing a plurality of stations, one station being designated as a control station and the remaining stations having an active state and an inactive state which incurs lower power consumption than the active state, wherein:

the control station periodically transmits a beacon signal containing a flag value indicating whether a broadcast period is in progress and a count value indicating time to elapse until commencement of a next possible broadcast period;

each remaining station periodically enters its active state to receive the beacon signal;

each remaining station remains in its active state if the broadcast flag value indicates a broadcast period is in progress, and otherwise returns to its inactive state; and

the control station stores broadcast messages transmitted by any remaining station outside a broadcast period, and broadcasts such stored messages during a subsequent broadcast period.

6. The method of claim 5, wherein each remaining station periodically enters its active state to receive every beacon signal.