ACCESS TERMINAL HAND-OFF METHODS IN WIRELESS NETWORKS

• US 20100157941A1
• Filed: 12/23/2008
• Published: 06/24/2010
• Est. Priority Date: 12/23/2008
• Status: Active Grant

• Current Assignee: Bison Patent Licensing, LLC
• Original Assignee: Airvana Incorporated (CommScope Holding Company, Inc.)
• Inventors: Raghothaman, Balaji, Kim, Woojune
• Granted Patent: US 8,774,134 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 36/00837 Determination of triggering parameters for hand-off
• CPC Class Codes: H04W 36/00838 Resource reservation for handover
• CPC Class Codes: H04W 8/24 Transfer of terminal data

Abstract

This description relates to access terminal hand-off methods in wireless networks.

Claims

1. A method, comprising:

determining a first pathloss value at a first private access point, the first private access point being one of several private access points in a wireless communication network, the first pathloss value being an estimate of a first pathloss between the first private access point and a first access terminal, wherein determining the first pathloss value comprises determining a first received power value at the first private access point, the first received power value being associated with the first access terminal; and

sending at least one of the first pathloss value or the first received power value to a private access point server, the private access point server being configured to communicate with the several private access points and being configured to determine, using the at least one of the pathloss value or the first received power value, whether the first private access point is most likely of the several private access points to comprise an unidentified private access point, the unidentified private access point being the subject of a handoff message sent to the private access point server by a macro access point, the macro access point being in communication with a second access terminal over a connection.

2. The method of claim 1, further comprising:

in response to sending the at least one of the first pathloss value or the first received power value, and in response to the private access point server determining that the first private access point is the most likely to comprise the unidentified private access point, communicating with the second access terminal over the connection, the connection being handed off from the macro access point to the first private access point.

3. The method of claim 1, wherein the first access terminal does not comprise the second access terminal and the first private access point does not comprise the unidentified private access point.

4. The method of claim 1, wherein the first access terminal comprises the second access terminal and the first private access point comprises the unidentified private access point.

5. The method of claim 2, wherein determining the first received power value comprises:

measuring a first received power at the first private access point from the first access terminal.

6. The method of claim 2, wherein determining the first pathloss value comprises:

determining a first transmit power value at the first private access point, the first transmit power value being indicative of a first transmit power of the first access terminal.

7. The method of claim 6, wherein determining the first transmit power value comprises:

determining the first transmit power value using at least one of a second pathloss value or an equivalent thermal noise level value, the second pathloss value being an estimate of a second pathloss between the macro access point and the first access terminal.

8. The method of claim 7, wherein an estimate of a third pathloss between the macro access point and the first private access point is used as the second pathloss value.

9. The method of claim 8, wherein determining the first pathloss value further comprises:

determining the first pathloss value by dividing the first received power value by the first transmit power value to produce the first pathloss value.

10. The method of claim 5, further comprising:

determining a second received power value, the second received power value being associated with the second access terminal;

comparing the second received power value with the first received power value; and

if the second received power value is approximately equal to the first received power value, causing a message to be sent to the macro access point, the message being configured to direct the macro access point to attempt to handoff the connection to the first private access point.

11. The method of claim 10, wherein determining the second received power value and comparing the second received power value with the first received power value comprise:

determining the second received power value at at least one of the private access point server or the first private access point; and

comparing the second received power value with the first received power value at at least one of the private access point server or the first private access point.

12. The method of claim 10, further comprising:

receiving a first transmit power value, the first transmit power value being indicative of a first transmit power of the macro access point;

receiving a third received power value, the third received power value being indicative of a third received power received from the second access terminal at the macro access point; and

receiving a first pilot strength measurement value, the first pilot strength measurement value being indicative of a fourth received power received from the macro access point at the second access terminal.

13. The method of claim 12, further comprising:

receiving a second pilot strength measurement value, the second pilot strength measurement value being indicative of a fifth received power received from a second private access point at the second access terminal; and

if the second received power value is approximately equal to the first received power value, determining that the first private access point comprises the second private access point.

14. The method of claim 13, wherein the first transmit power value, the third received power value, the first pilot strength measurement value, and the second pilot strength measurement value are sent from the macro access point to the private access point server.

15. The method of claim 13, wherein determining the second received power value comprises:

determining the second received power value using at least one of the first transmit power value, the third received power value, the first pilot strength measurement value, the second pilot strength measurement value, or a second transmit power value, the second transmit power being indicative of a second transmit power of the first private access point.

16. The method of claim 15, wherein determining the second received power value comprises:

multiplying the third received power value by a first ratio and a second ratio to produce the second received power value, the first ratio comprising the first pilot strength measurement value divided by the second pilot strength measurement value, and the second ratio comprising the first transmit power value divided by the second transmit power value.

17. A private access point, comprising:

a memory, the memory configured to store instructions for execution; and

one or more processing devices configured to execute the instructions, the instructions for causing the one or more processing devices to;

determine a first pathloss value at the private access point, the private access point being one of several private access points in a wireless communication network, the first pathloss value being an estimate of a first pathloss between the first private access point and a first access terminal, wherein determining the first pathloss value comprises determining a first received power value at the first private access point, the first received power value being associated with the first access terminal; and

send at least one of the first pathloss value or the first received power value to a private access point server, the private access point server being configured to communicate with the one or more private access points and being configured to determine, using the at least one of the pathloss value or the first received power value, whether the first private access point is most likely of the one or more private access points to comprise an unidentified private access point, the unidentified private access point being the subject of a handoff message sent to the private access point server by a macro access point, the macro access point being in communication with a second access terminal over a connection.

18. The private access point of claim 17, wherein the instructions comprise instructions for causing the one or more processing devices to:

in response to sending the at least one of the first pathloss value or the first received power value, and in response to the private access point server determining that the first private access point is the most likely to comprise the unidentified private access point, communicate with the second access terminal over the connection, the connection being handed off from the macro access point to the first private access point.

19. One or more machine-readable media storing executable instructions, the one or more computer-readable media being tangible media, the instructions for causing one or more processing devices to:

determine a first pathloss value at the private access point, the private access point being one of several private access points in a wireless communication network, the first pathloss value being an estimate of a first pathloss between the first private access point and a first access terminal, wherein determining the first pathloss value comprises determining a first received power value at the first private access point, the first received power value being associated with the first access terminal; and

send at least one of the first pathloss value or the first received power value to a private access point server, the private access point server being configured to communicate with the one or more private access points and being configured to determine, using the at least one of the pathloss value or the first received power value, whether the first private access point is most likely of the one or more private access points to comprise an unidentified private access point, the unidentified private access point being the subject of a handoff message sent to the private access point server by a macro access point, the macro access point being in communication with a second access terminal over a connection.

20. The one or more machine-readable media of claim 19, wherein the instructions comprise instructions for causing one or more processing devices to:

in response to sending the at least one of the first pathloss value or the first received power value, and in response to the private access point server determining that the first private access point is the most likely to comprise the unidentified private access point, communicate with the second access terminal over the connection, the connection being handed off from the macro access point to the first private access point.

21. A method, comprising:

receiving a handoff message from a macro access point at a private access point server, the private access point server being in communication with one or more private access points in a wireless communication network, the macro access point being in communication with a first access terminal over a connection, the macro access point sending the handoff message to the private access point server responsively to the first access terminal sending a first pilot strength measurement value to the macro access point, the first pilot strength measurement value being indicative of a first received power received from an unidentified private access point of the one or more private access points at the first access terminal, the handoff message comprising information about the unidentified private access point to assist the private access point server in identifying the unidentified private access point;

requesting one or more pathloss values from a subset of private access points of the one or more private access points, wherein for each private access point of the subset, a respective pathloss value of the one or more pathloss values is an estimate of a respective pathloss between the private access point and a respective access terminal in a vicinity of the private access point;

determining, using the one or more pathloss values, a selected private access point of the subset, the selected private access point being the most likely to comprise the unidentified private access point; and

sending a response to the handoff message that identifies the selected private access point to the macro access point so that the macro access point can attempt to handoff the connection to the selected private access point.

22. The method of claim 21, wherein sending the response to the handoff message further comprises:

sending a response to the handoff message if a first pathloss value of the one or more pathloss values exceeds a threshold, the first pathloss value being associated with the selected private access point.

23. The method of claim 22, wherein the handoff message comprises a handoff preparation request, the handoff preparation request comprising an IS-41 message.

24. The method of claim 23, wherein the IS-41 message comprises at least one of a FacDir2 message or a HandoffMeasurement Request2 message.