METHOD AND APPARATUS FOR PERFORMING HANDOFF IN COMMUNICATIONS SYSTEMS

• US 20070123261A1
• Filed: 01/30/2007
• Published: 05/31/2007
• Est. Priority Date: 11/04/1999
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Black, Peter
• Granted Patent: US 7,580,709 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 36/304 due to measured or perceived resources with higher communication quality
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff

Abstract

A communication system including a closed loop power control system. Prior to allowing a handoff to a new base station, the subscriber station verifies that its reverse link signal is being received by the destination base station with sufficient energy. The determination is made based on the received reverse link power control commands from the base station. Moreover, a handoff may be forced when the base station providing the best forward link signal in not receiving the reverse link signal from the subscriber station with sufficient energy.

Claims

1. A method for communications, comprising:

determining if a handoff to a base station is necessary;

determining if the base station receives reverse link transmissions with sufficient energy; and

performing the handoff to the base station based on the determination.

2. The method of claim 1, wherein the determining if the base station receives reverse link transmissions with sufficient energy is based in part on a message indicating a reverse link quality received from the base station.

3. The method of claim 1, wherein the determining if the base station receives reverse link transmissions with sufficient energy is based in part on reverse link power control commands received from the base station.

4. The method of claim 1, wherein the performing the handoff further comprises prohibiting the handoff to the base station if the base station does not receive reverse link transmissions with sufficient energy.

5. The method of claim 1, wherein the performing the handoff further comprises allowing the handoff to the base station if the base station receives reverse link transmissions with sufficient energy.

6. An apparatus for communications, comprising:

means for determining if a handoff to a base station is necessary;

means for determining if the base station receives reverse link transmissions with sufficient energy; and

means for performing the handoff to the base station based on the determination.

7. The apparatus of claim 6, wherein the means determining if the base station receives reverse link transmissions with sufficient energy further comprises means for receiving a message indicating a reverse link quality from the base station.

8. The apparatus of claim 6, wherein the means for determining if the base station receives reverse link transmissions with sufficient energy further comprises means for receiving reverse link power control commands from the base station.

9. The apparatus of claim 6, wherein the means for performing the handoff further comprises means for prohibiting the handoff to the base station if the base station does not receive reverse link transmissions with sufficient energy.

10. The apparatus of claim 6, wherein the means for performing the handoff further comprises means for allowing the handoff to the base station if the base station receives reverse link transmissions with sufficient energy.

11. A computer program product, comprising:

code for determining if a handoff to a base station is necessary;

code for determining if the base station receives reverse link transmissions with sufficient energy; and

code for performing the handoff to the base station based on the determination.

12. The computer program product of claim 11, wherein the code for determining if the base station receives reverse link transmissions with sufficient energy further comprises code for receiving a message indicating a reverse link quality from the base station.

13. The computer program product of claim 11, wherein the code for determining if the base station receives reverse link transmissions with sufficient energy further comprises code for receiving reverse link power control commands from the base station.

14. The computer program product of claim 11, wherein the code for performing the handoff further comprises code for prohibiting the handoff to the base station if the base station does not receive reverse link transmissions with sufficient energy.

15. The computer program product of claim 11, wherein the code for performing the handoff further comprises code for allowing the handoff to the base station if the base station receives reverse link transmissions with sufficient energy.

16. A method for communications, comprising:

receiving a message indicating a reverse link quality from a base station; and

selecting the base station for a forward link data transmission if the reverse link quality is above a threshold based on the message.

17. A computer program product, comprising:

code for receiving a message indicating a reverse link quality from a base station; and

code for selecting the base station for a forward link data transmission if the reverse link quality is above a threshold based on the message.