WI-FI SCAN SCHEDULING AND POWER ADAPTATION FOR LOW-POWER INDOOR LOCATION

• US 20160219408A1
• Filed: 12/20/2013
• Published: 07/28/2016
• Est. Priority Date: 12/20/2013
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Yang, Lei, Xu, Hongtao, Yang, Xue
• Granted Patent: US 9,877,158 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01S 2205/02 Indoor
• CPC Class Codes: G01S 5/02521 using a radio-map
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 52/0241 where no transmission is received, e.g. out of range of the transmitter
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: H04W 52/0248 dependent on the time of the day, e.g. according to expected transmission activity
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Embodiments of a mobile station and method for Wi-Fi scan scheduling and power adaption for low-power indoor location are generally described herein. In some embodiments, the mobile station may identify channels, beacon timing and rough signal strength levels of nearby access points (APs) from at least one of a previous full-channel scan or a Wi-Fi fingerprint database and may configure receiver sensitivity based on the rough signal strength levels for receipt of subsequent beacons. The mobile station may wake-up from a low-power state to receive beacons for the nearby access points on the identified channels at times based on the identified beacon timing. The received signal strength indicators (RSSIs) levels of the received beacons may be used for location determination.

Claims

1. A method performed by a mobile station (STA) for determining access points for use for location references, the method comprising:

ranking channels, based on a number of access points detected on each channel;

identifying a group of the access points operating on a particular set of the ranked channels;

determining timing and channel predictions for beacons from each of the identified access points of the group;

waking from a low-power state to receive the beacons on predicted channels at predicted times based on the timing and channel predictions;

updating received signal strength indicators (RSSIs) for each access point, based on signal strengths of the beacons; and

updating an indoor location based on the RSSIs and known locations of the access points in the group.

2. The method of claim 1 further comprising, prior to ranking the channels, identifying channels, beacon timing and rough signal strength levels of nearby access points from a previous full-channel scan.

3. The method of claim 2 further comprising, prior to ranking the channels, identifying channels, beacon timing and rough signal strength levels of nearby access points from a Wi-Fi fingerprint database.

4. The method of claim 1 further comprising:

entering an indoor sensing mode;

performing a full Wi-Fi active scan after entering the indoor sensing mode to detect the access point on the channels for use in ranking the channels, and

performing a separate Wi-Fi scan for location sensing, the scan comprising an active Wi-Fi scan on the ranked channels.

5. The method of claim 4 further comprising refraining from performing a full scan until after the mobile station moves a predetermined distance or a number of the AP are no longer available.

6. The method of claim 4 wherein the mobile station and the access points operate in accordance with an IEEE 802.11 standard.

7. A method performed by a mobile station (STA) for determining access points for use for location references, the method comprising:

identifying channels, beacon timing and rough signal strength levels of nearby access points (APs) from at least one of a previous full-channel scan or a Wi-Fi fingerprint database;

configuring receiver sensitivity based on the rough signal strength levels for receipt of subsequent beacons;

waking-up from a low-power state to receive beacons for the nearby access points on the identified channels at times based on the identified beacon timing; and

using received signal strength indicators (RSSIs) levels of the received beacons for location determination.

8. The method of claim 7 further comprising:

ranking the identified channels, based on the number of access points detected on each channel; and

identifying a group of access points operating on a particular set of ranked channels.

9. The method of claim 8 further comprising updating an indoor location based on the RSSIs and known locations of the access points in the group.

10. A mobile station (STA) configured for determining access points for use for location references, the STA comprising processing circuitry and a transceiver arranged to:

identify channels, beacon timing and rough signal strength levels of nearby access points (APs) from at least one of a previous full-channel scan or a Wi-Fi fingerprint database;

configure receiver sensitivity based on the rough signal strength levels for receipt of subsequent beacons;

wake-up from a low-power state to receive beacons for the nearby access points on the identified channels at times based on the identified beacon timing; and

use received signal strength indicators (RSSIs) levels of the received beacons for location determination.

11. The mobile station of claim 10 wherein the processing circuitry is further arranged to:

rank the identified channels, based on the number of access points detected on each channel; and

identify a group of access points operating on a particular set of ranked channels.

12. The mobile station of claim 11 wherein the processing circuitry is further arranged to update a location of the access points and update an indoor location based on the RSSIs and known locations of the access points in the group.

13. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors of a mobile station to perform operations for determining access points for use for location references, the operations comprising:

ranking channels, based on a number of access points detected on each channel;

identifying a group of the access points operating on a particular set of the ranked channels;

determining timing and channel predictions for beacons from each of the identified access points of the group;

waking from a low-power state to receive the beacons on predicted channels at predicted times based on the timing and channel predictions;

updating received signal strength indicators (RSSIs) for each access point, based on signal strengths of the beacons; and

updating an indoor location based on the RSSIs and known locations of the access points in the group.

14. The non-transitory computer-readable storage medium of claim 13 wherein the operations further comprise, prior to ranking the channels, identifying channels, beacon timing and rough signal strength levels of nearby access points from a previous full-channel scan.

15. The non-transitory computer-readable storage medium of claim 13 wherein the operations further comprise, prior to ranking the channels, identifying channels, beacon timing and rough signal strength levels of nearby access points from a Wi-Fi fingerprint database.

16. A mobile station (STA) configured for determining access points for use for location references, the STA comprising one or more antennas, processing circuitry and a transceiver arranged to:

identify, using the one or more antennas, channels, beacon timing and rough signal strength levels of nearby access points (APs) from at least one of a previous full-channel scan or a Wi-Fi fingerprint database;

configure receiver sensitivity based on the rough signal strength levels for receipt of subsequent beacons;

wake-up from a low-power state to receive beacons for the nearby access points on the identified channels at times based on the identified beacon timing; and

use received signal strength indicators (RSSIs) levels of the received beacons for location determination.

17. The mobile station of claim 16 wherein the processing circuitry is further arranged to:

rank the identified channels, based on the number of access points detected on each channel; and

identify a group of access points operating on a particular set of ranked channels.