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

• US 8,170,558 B2
• Filed: 09/18/2009
• Issued: 05/01/2012
• Est. Priority Date: 02/13/1998
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Odenwalder, Joseph P.
• Primary Examiner(s): Nguyen, Duc M
• Application Number:
  US12/562,522
• Publication Number:
  US 20100046478A1
• Time in Patent Office: 956 Days
• Field of Search: 455/436, 455/442, 455/522, 455/524, 455/525, 455/62, 455/67.11, 370/331, 370/332, 370/333
• US Class Current: 455/436
• 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 receive a frequency change command, to tune to a first frequency during an initial portion of a first frame, to tune to a second frequency during a period that 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 at least one signal attribute on the second frequency during the period, and to tune the receiver on the first frequency during a remaining portion of the second frame;

wherein said power control processor is further configured to increase a target signal-to-noise level over at least a portion of at least one of the first and second frames by requesting an adjustment of the forward link power control during a time between the initial portion of the first frame and the tuning to the second frequency.

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 both the initial portion of the first frame and 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, comprising:

receiving a frequency change command;

tuning to a first frequency during an initial portion of a first frame;

tuning to a second frequency during a period that 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 period; and

tuning to the first frequency during a remaining portion of the second frame, wherein a target signal-to-noise level is increased over at least a portion of at least one of the first and second frames by requesting an adjustment of the forward link power control during a time between the initial portion of the first frame and the tuning to the second frequency.

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, comprising:

means for receiving a frequency change commend;

means for tuning to a first frequency during an initial portion of a first frame;

means for tuning to a second frequency during a period that 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 period; and

means for tuning to the first frequency during a remaining portion of the second frame, wherein a target signal-to-noise level is increased over at least a portion of at least one of the first and second frames by requesting an adjustment of the forward link power control during a time between the initial portion of the first frame and the tuning to the second frequency.

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.

19. A non-transitory computer-readable medium embodying compuetr-executalbe codes, comprising:

a first set of codes for causing a computer to receive a frequency change command;

a second set of codes for causing a computer to tune to a first frequency during an initial portion of a first frame;

a third set of codes for causing a computer to tune to a second frequency during a period that 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;

a fourth set of codes for causing a computer to measure at least one signal attribute on the second frequency during the period; and

a fifth set of codes for causing a computer to tune to the first frequency during a remaining portion of the second frame, wherein a target signal-to-noise level is increased over at least a portion of at least one of the first and second frames by requesting an adjustment of the forward link power control during a time between the initial portion of the first frame and the tuning to the second frequency.

20. The medium of claim 19 further comprising increasing an amount of power allocated to symbols transmitted on the first frequency during the initial portion of the first frame.

21. The medium of claim 19 further comprising increasing an amount of power allocated to symbols transmitted on the first frequency during the remaining portion of the second frame.

22. The medium of claim 19 further comprising:

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

p1 increasing an amount of power allocated to symbols transmitted on the first frequency during the remaining portion of the second frame.

23. The medium of claim 19 further comprising generating a report indicative of a measurement of the at least one signal attribute.

24. The medium of claim 23 further comprising transmitting the report on the first frequency.