Reducing idle power consumption in a networked battery operated device

• US 7,230,933 B2
• Filed: 04/17/2002
• Issued: 06/12/2007
• Est. Priority Date: 04/17/2002
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Sinclair, Michael J., Bahl, Paramvir, Shih, Eugene
• Primary Examiner(s): Levitan; Dmitry
• Application Number:
  US10/124,737
• Publication Number:
  US 20030198196A1
• Time in Patent Office: 1,882 Days
• Field of Search: 370309-313, 455/403, 455/421, 455/515, 455/522, 455572-574
• US Class Current: 370/311
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode

Abstract

An improved method and system for reducing the power consumption of computing devices capable of communicating over a wireless network allows longer device operation and/or the use of smaller batteries. The wireless computing device supports a low power channel for receiving control signals during idle periods of operation. When the computing device is idle, the device is configured to power down all of its components with the exception of the circuitry required to power the low power channel. As such, the channel is maintained in an active state for receiving signals during both idle and non-idle periods, or in an embodiment, only during idle periods. When another device wishes to communicate with the wireless computing device, the low power channel passes a “wake-up” signal to the device indicating that the device be powered up from the idle mode of operation. A host RF component that is coupled to the network via a host computer generates this wake-up signal in an embodiment of the invention.

Claims

1. A method for reducing the power consumption of a wireless computing device capable of accessing a network, the method comprising:

generating a wake up signal by a host transceiver component that is communicably linked to the wireless computing device via a two-way low power channel that enables two-way exchange of control information, on the two-way low power channel, between the host transceiver component and the wireless computing device, the host transceiver component residing on a host computer that is connected to the network;

transmitting the wake up signal over the low power channel by the host transceiver;

receiving the wake up signal by the wireless computing device over the low power channel indicating that the wireless computing device is to be powered up from an idle period of operation;

activating the wireless computing device from an idle period of operation in response to the wake up signal; and

communicating by the wireless computing device over a high power channel following activation of the wireless computing device from the idle period of operation, wherein the wireless computing device does not communicate over the high power channel during the idle period of operation.

2. A method for reducing the power consumption of a wireless computing device capable of accessing a network, the method comprising:

receiving a message transmitted by a remote computing device that is communicably linked to the network, the message indicating a request by the remote computing device to communicate with the wireless computing device;

generating a wake up signal; and

transmitting the wake up signal over a two-way low power channel from a host transceiver component to a low power transceiver component residing on the wireless computing device, the low power transceiver component enabling two-way exchange of control information, over the two-way low power channel, between the host transceiver component and the wireless computing device, the wake up signal indicating that the wireless computing device is to be activated from a low power state of operation to communicate on a high power channel, wherein the wireless computing device does not communicate over the high power channel during the low power state of operation.

3. The method of claim 2 wherein the remote computing device transmits the message to the host computer prior to the transmission of a message to the wireless computing device.

4. The method of claim 3 wherein the high power channel is implemented at the wireless computing device via a network interface card.

5. A wireless network system for activating a high power communication channel operable by a wireless computing device from a low power state of operation, the system comprising:

an access point, wherein the access point is an interface to a network;

a host computer interfaced with the network through the access point, wherein the host computer is logically connected to a host transceiver communicably linkable to a plurality of wireless computing devices over a two-way low power radio channel, the host transceiver being used to transmit wake up signals over the low power radio channel to the plurality of wireless computing devices; and

at least one wireless computing device comprising a high power radio that communicates over a high power radio channel, and a low power radio that communicates control information to the access point via the two-way low power radio channel, wherein the wireless computing device does not communicate over the high power channel during the low power state of operation.

6. A power efficient hand-held device for use in a wireless network, comprising:

a high power radio component that communicates data on a primary wireless channel; and

a two-way low power radio component that transmits and receives control information on a secondary wireless channel, the low power radio component being useable for receiving signals for activating the high power radio component from a low power state of operation, wherein the wireless computing device does not communicate over the high power channel during the low power state of operation.

7. The method according to claim 6 wherein the secondary wireless channel is a low frequency channel having a carrier frequency less than that of the primary wireless channel.

8. The method according to claim 6 wherein the primary wireless channel comprises an 802.11 based communication channel.

9. An access point for interfacing a plurality of wireless devices to a network comprising;

an interface to a first wireless channel for transmitting data to and receiving data from a wireless device over the first wireless channel; and

an interface to a second wireless channel for transmitting control information to and receiving control information from a wireless device, wherein the control information includes instructions to be processed by the wireless device for activating the wireless device from a low power state of operation, and wherein the wireless computing device does not communicate over the first wireless channel during the low power state of operation.

10. The access point according to claim 9, wherein the interface to the first wireless channel consumes more power to transmit a bit over the first wireless channel than the interface to the second wireless channel consumes to transmit a bit over the second wireless channel.

11. The access point according to claim 10, further comprising a network interface card comprising both the interface to the first wireless channel and the interface to the second wireless channel.

12. The access point according to claim 10, wherein the first wireless channel has a carrier frequency that differs from a carrier frequency of the second wireless channel.

13. An operating system embodied in a computer-readable medium in the form of computer-readable instructions for performing a method comprising:

interfacing a computing device to a first wireless communication channel for transmitting and receiving data over a network; and

interfacing the computing device to a second wireless communication channel for transmitting and receiving control information over a network, wherein the control information comprises instructions to be processed by the computing device for activating the computing device from a low power state of operation, and wherein the wireless computing device does not communicate over the first wireless channel during the low power state of operation.

14. The operating system of claim 13 further comprising activating the computing device from a low power state of operation in response to the processing of the control information.

15. The operating system according to claim 14, wherein the first wireless communication channel uses a higher power wireless signal than the wireless signal used by the second wireless communication channel.