Acquiring a signal parameter for a neighboring access point

• US 8,861,383 B2
• Filed: 01/19/2010
• Issued: 10/14/2014
• Est. Priority Date: 01/19/2010
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Pandey, Santosh, Thomson, Allan, Hart, Brian, Girimaji, Jagdish
• Primary Examiner(s): Rinehart, Mark
• Assistant Examiner(s): HOPKINS, MATTHEW A
• Application Number:
  US12/689,840
• Publication Number:
  US 20110176434A1
• Time in Patent Office: 1,729 Days
• Field of Search: 370/252, 370/331
• US Class Current: 370/252
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In an example embodiment, a wireless device is configured to associate with a first access point on a first frequency. The wireless device listens for a predefined frame, which may be sent by neighboring access points or other wireless devices. When the wireless device receives a signal comprising a predefined frame, the wireless device acquires a parameter, such as signal strength, for the signal. The wireless device sends the parameter for the signal to the first access point.

Claims

1. An apparatus, comprising:

a wireless transceiver;

control logic communicatively coupled with the wireless transceiver, the control logic being configured to communicate with a plurality of associated wireless devices via the wireless transceiver;

wherein the control logic is configured to establish a communication link with a first associated wireless device;

wherein the control logic is configured to receive coordinated schedule data representative of a scheduled transmission time of transmission of one or more wireless signals by a second associated wireless device, wherein the first and second associated wireless devices coordinate a transmission schedule comprising the scheduled transmission time;

wherein the control logic is configured to selectively transition the apparatus between a power save mode and an active mode, wherein the apparatus in the power save mode is unable to receive selected wireless signals and wherein in the active mode the apparatus is able to receive the selected wireless signals;

wherein the control logic transitions the apparatus to the active mode in accordance with the received coordinated schedule data of the second associated wireless device;

wherein, in the active mode, the wireless transceiver receives a signal from the second associated wireless device at the scheduled transmission time wherein the control logic is configured to determine whether a selected packet contained in the signal received from the second associated wireless device is a predetermined packet;

wherein the control logic is configured to determine, responsive to determining the selected packet contained in the signal received from the second associated wireless device is the predetermined packet, a parameter of the signal received via the wireless transceiver from a second wireless device; and

wherein the control logic is configured to send data representative of the parameter to the first wireless device via the wireless transceiver.

2. The apparatus according to claim 1, wherein the first wireless device is a first access point operating on a first frequency;

wherein the wireless transceiver communicates with the first access point on the first frequency; and

wherein the second wireless device is a second access point configured to communicate primarily on a second frequency, and is further configured to send the signal on the first frequency.

3. The apparatus according to claim 1, wherein the parameter comprises a received signal strength indication.

4. The apparatus according to claim 1, wherein the parameter comprises a time of arrival.

5. The apparatus according to claim 1, wherein the parameter comprises an angle of arrival.

6. The apparatus according to claim 1, wherein the control logic is further configured to determine an identifier of a source of the signal.

7. The apparatus according to claim 6, wherein the control logic is further configured to send data representative of the identifier with the data representative of the parameter.

8. The apparatus according to claim 7, wherein the identifier comprises a selected one of a group consisting of a Medium Access Control address, a timestamp, and a sequence number.

9. The apparatus according to claim 1, wherein the predetermined packet is a fake beacon.

10. The apparatus according to claim 1, wherein the predetermined packet is a predefined management frame.

11. The apparatus according to claim 1, wherein the control logic receives a list of identifiers for wireless devices from the first wireless device for determining whether a signal received via the wireless transceiver is a predetermined signal.

12. The apparatus according to claim 11 wherein the control logic is configured to switch the wireless transceiver to the second channel and listen for wireless devices operating on the second channel;

wherein the control logic is configured to record identifiers for wireless devices detected operating on the second channel; and

wherein the control logic is further configured to switch the wireless transceiver to the first channel; and

wherein the control logic determines that a signal received from the second wireless device is a predetermined signal based on matching an identifier recorded on the second channel to the second wireless device.

13. The apparatus according to claim 12, wherein the control logic periodically switches the wireless transceiver to the second channel.

14. The apparatus according to claim 1, wherein the control logic is configured to switch the wireless transceiver to the second channel and listen for beacons from access points operating on the second channel;

wherein the control logic is configured to record identifiers for access points detected operating on the second channel; and

wherein the control logic is further configured to switch the wireless transceiver to the first channel; and

wherein the control logic determines that a signal received from the second wireless device having an identifier matching an identifier for an access point recorded on the second channel is a predetermined signal.

15. The apparatus according to claim 14, wherein:

the control logic is configured to determine a parameter of the signal received from the second wireless device; and

,

the control logic is configured to send data representative of the parameter of the signal received from the second wireless device to the first wireless device via the wireless transceiver.

16. The apparatus according to claim 1, wherein:

the control logic is configured to receive via the transceiver from the first associated wireless device data representative of an end of a signal transmission time period; and

wherein the control logic is configured to selectively transition the apparatus from the active mode to the power save mode responsive to receiving the data representative of the end of a signal transmission time period.

17. A method, comprising:

associating with a first access point;

receiving coordinated schedule data representative of a scheduled transmission time of transmission of one or more wireless signals by a second access point, wherein the first and second access points coordinate a transmission schedule comprising the scheduled transmission time;

selectively transitioning, in accordance with the schedule data of the second access point, from a power save mode wherein signals are unable to be received to an active mode wherein signals are able to be received;

in the active mode, receiving at the scheduled transmission time a signal from the second access point in accordance with the schedule data;

determining whether a selected packet contained in the signal is a predefined packet;

acquiring a parameter for the signal responsive to determining the selected packet is the predefined packet; and

sending the parameter for the signal to the first access point.

18. The method set forth in claim 17, further comprising determining an identifier for the second access point;

and

sending the parameter further comprises sending the identifier.

19. The method set forth in claim 18, wherein the identifier is a Medium Access Control address.

20. The method set forth in claim 17, wherein the parameter is a received signal strength indication.

21. The method set forth in claim 17, wherein

the receiving the signal from the second access point comprises receiving the signal from the second access point exclusively at the scheduled transmission time in accordance with the schedule data.

22. A non-transitory computer readable medium, the non-transitory computer readable medium having instructions encoded thereon instructions for

execution, and when executed operable to:

associate with a first access point;

receiving coordinated schedule data representative of a scheduled transmission time of transmission of one or more wireless signals by a second access point, wherein the first and second access points coordinate a transmission schedule comprising the scheduled transmission time;

selectively transition, in accordance with the schedule data of the second access point, from a power save mode wherein signals are unable to be received to an active mode wherein signals are able to be received;

in the active mode, receive at the scheduled transmission time a signal from the second access point in accordance with the schedule data;

determining whether a packet contained in the signal indicates that the signal is a predefined signal;

acquire a parameter for the signal responsive to determining the packet contained in the signal indicates that the signal is the predefined signal;

acquire a Medium Access Control (MAC) address for a source of the signal; and

sending the MAC address and the parameter for the signal to the first access point.

23. The non-transitory computer readable medium according to claim 22, and when executed further operable to:

receive the signal from the second access point exclusively at the scheduled transmission time in accordance with the schedule data.