Method and system for performing a handoff in a wireless communication system, such as a hard handoff

• US 20040029534A1
• Filed: 08/04/2003
• Published: 02/12/2004
• Est. Priority Date: 02/13/1998
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Odenwalder, Joseph P.
• Granted Patent: US 7,242,935 B2
• Time in Patent Office: Days
• US Class Current: 455/67.11
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects
• CPC Class Codes: H04W 36/0072 of resource information of target access point
• CPC Class Codes: H04W 36/0088 Scheduling hand-off measurements
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point
• CPC Class Codes: H04W 52/12 Outer and inner loops

Abstract

A method for minimizing search time and disruption of current service on an originating frequency during a frequency search excursion to a target frequency as part of an inter-frequency hard handoff between cells on different RF CDMA channels. Disruption of service on the current frequency during the frequency search excursion to the target frequency is minimized by increasing the amount of power allocated to other symbols of two consecutive frames impacted by the search excursion as a function of the search excursion time. The mobile station tunes to a target frequency and collects chip samples, which are stored in a memory buffer. The mobile station returns to the originating frequency to process the collected samples.

Claims

1. An apparatus comprising:

a quality measurement circuit; and

a power control processor configured to tune a receiver to a first frequency during an initial portion of a first frame, to tune the receiver on a second frequency during a search excursion period, wherein the search excursion period begins during the first frame and continues through an initial portion of a second frame, wherein the second frame follows immediately after the first frame, to direct the quality measurement circuit to measure measuring at least one signal attribute on the second frequency during the search excursion period, and to tune the receiver on the first frequency during a remaining portion of the second frame.

2. The apparatus of claim 1 wherein the power control processor is further configured to direct a mobile transmission module to increase an amount of power allocated to symbols transmitted on the first frequency during the initial portion of the first frame.

3. The apparatus of claim 1 wherein the power control processor is further configured to direct a mobile transmission module to increase an amount of power allocated to symbols transmitted on the first frequency during the remaining portion of the second frame.

4. The apparatus of claim 1 wherein the power control processor is further configured to direct a mobile transmission module to increase an amount of power allocated to symbols transmitted on the first frequency during the initial portion of the first frame and on the first frequency during the remaining portion of the second frame.

5. The apparatus of claim 1 wherein the power control processor is further configured to generate a report indicative of a measurement of the at least one signal attribute.

6. The apparatus of claim 5 wherein the power control processor is further configured to provide the report to a mobile transmission module to be wirelessly transmitted on the first frequency.

7. A method for measuring signal strength in a wireless communication system comprising:

operating a receiver on a first frequency during an initial portion of a first frame;

operating the receiver on a second frequency during a search excursion period, wherein the search excursion period begins during the first frame and continues through an initial portion of a second frame, wherein the second frame follows immediately after the first frame;

measuring at least one signal attribute on the second frequency during the search excursion period; and

operating the receiver on the first frequency during a remaining portion of the second frame.

8. The method of claim 7 further comprising increasing an amount of power allocated to symbols transmitted on the first frequency during the initial portion of the first frame.

9. The method of claim 7 further comprising increasing an amount of power allocated to symbols transmitted on the first frequency during the remaining portion of the second frame.

10. The method of claim 7 further comprising:

increasing an amount of power allocated to symbols transmitted on the first frequency during the initial portion of the first frame; and

increasing an amount of power allocated to symbols transmitted on the first frequency during the remaining portion of the second frame.

11. The method of claim 7 further comprising generating a report indicative of a measurement of the at least one signal attribute.

12. The method of claim 11 further comprising transmitting the report on the first frequency.

13. An apparatus for measuring signal strength in a wireless communication system comprising:

means for operating a receiver on a first frequency during an initial portion of a first frame;

means for operating the receiver on a second frequency during a search excursion period, wherein the search excursion period begins during the first frame and continues through an initial portion of a second frame, wherein the second frame follows immediately after the first frame;

means for measuring at least one signal attribute on the second frequency during the search excursion period; and

means for operating the receiver on the first frequency during a remaining portion of the second frame.

14. The apparatus of claim 13 further comprising means for increasing an amount of power allocated to symbols transmitted on the first frequency during the initial portion of the first frame.

15. The apparatus of claim 13 further comprising means for increasing an amount of power allocated to symbols transmitted on the first frequency during the remaining portion of the second frame.

16. The apparatus of claim 13 further comprising:

means for increasing an amount of power allocated to symbols transmitted on the first frequency during the initial portion of the first frame; and

means for increasing an amount of power allocated to symbols transmitted on the first frequency during the remaining portion of the second frame.

17. The apparatus of claim 13 further comprising means for generating a report indicative of a measurement of the at least one signal attribute.

18. The apparatus of claim 17 further comprising means for transmitting the report on the first frequency.