Techniques for accessing a wireless communication system with tune-away capability

• US 20060176870A1
• Filed: 11/16/2005
• Published: 08/10/2006
• Est. Priority Date: 02/03/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Rezaiifar, Ramin, Joshi, Abhay Arvind, Turner, Simon
• Granted Patent: US 7,848,305 B2
• Time in Patent Office: Days
• US Class Current: 370/345
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04W 74/00 Wireless channel access
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

To access a first communication system, a terminal determines a transmission time for an access probe, an expected response time from the system, and a protected time interval based on the transmission time and/or expected response time. The terminal determines a starting time for sending the access probe such that the protected time interval does not overlap a tune-away interval in which the terminal is to monitor anther frequency/air-interface. This starting time may be set initially to the end of a prior access probe plus a pseudo-random wait duration and may be advanced forward or moved backward in time, if needed, by a time duration selected such that the protected time interval does not overlap the tune-away interval.

Claims

1. An apparatus comprising:

a controller configured to

determine a protected time interval when an access request can be sent to a first communication system,

determine a starting time for sending the access request such that the protected time interval does not overlap a tune-away interval, and

initiate sending the access request to the first communication system at the starting time.

2. The apparatus of claim 1, further comprising:

a receiver, wherein the protected time interval is a time interval in which the receiver is tuned to the first communication system, and

wherein the tune-away interval is a time interval in which the receiver is tuned away from the first communication system.

3. The apparatus of claim 1, wherein the controller is further configured to

determine an expected response time for an acknowledgment from first communication system for the access request, and

determine the protected time interval based on the expected response time.

4. The apparatus of claim 1, wherein the controller is further configured to

determine a transmission time for the access request,

determine the protected time interval further based on the transmission time.

5. The apparatus of claim 1, wherein the controller is further configured to

determine an initial time for sending the access request, and

set the starting time to the initial time plus or minus a zero or non-zero time duration selected such that transmission of the access request at the starting time results in the protected time interval not overlapping the tune-away interval.

6. The apparatus of claim 5, wherein the controller is further configured to determine a pseudo-random wait duration and to set the initial time to the end of a prior access request plus the pseudo-random wait duration.

7. The apparatus of claim 1, wherein the controller is further configured to initialize the starting time to the end of a prior access request, to determine a pseudo-random wait duration, to advance the starting time by the pseudo-random wait duration, and to repeat determining a pseudo-random wait duration and advancing the starting time until transmission of the access request at the starting time results in the protected time interval not overlapping the tune-away interval.

8. The apparatus of claim 2, wherein the controller is further configured to direct the receiver to tune to a second communication system prior to the tune-away interval and to direct the receiver to tune back to the first communication system after the tune-away interval.

9. The apparatus of claim 8, wherein the controller is further configured to receive a paging channel from the second communication system during the tune-away interval.

10. The apparatus of claim 1, wherein the tune-away interval corresponds to an assigned paging slot for a second communication system.

11. The apparatus of claim 1, wherein the tune-away interval corresponds to a pilot transmission or a signaling transmission from a second communication system.

12. The apparatus of claim 1, wherein the tune-away interval corresponds to a measurement interval for a second communication system.

13. A method comprising:

determining a protected time interval for an access request to be sent to a first communication system, the protected time interval being a time interval in which a receiver is tuned to the first communication system;

determining a starting time for sending the access request such that the protected time interval does not overlap a tune-away interval, the tune-away interval being a time interval in which the receiver is tuned away from the first communication system; and

sending the access request to the first communication system at the starting time.

14. The method of claim 13, wherein the determining the protected time interval for the access request comprises

determining a transmission time for the access request,

determining an expected response time for an acknowledgment from the first communication system for the access request, and

determining the protected time interval based on at least one of the transmission time and the expected response time.

15. The method of claim 13, wherein the determining the starting time for sending the access request comprises

determining a pseudo-random wait duration,

setting the starting time to the end of a prior access request plus the pseudo-random wait duration, and

adjusting the starting time either forward or backward in time, if needed, by a time duration selected such that transmission of the access request at the adjusted starting time results in the protected time interval not overlapping the tune-away interval.

16. The method of claim 13, further comprising:

tuning the receiver to a second communication system prior to the tune-away interval;

receiving a paging channel from the second communication system; and

tuning the receiver back to the first communication system after the tune-away interval.

17. An apparatus comprising:

means for determining a protected time interval for an access request to be sent to a first communication system, the protected time interval being a time interval in which a receiver is tuned to the first communication system;

means for determining a starting time for sending the access request such that the protected time interval does not overlap a tune-away interval, the tune-away interval being a time interval in which the receiver is tuned away from the first communication system; and

means for sending the access request to the first communication system at the starting time.

18. The apparatus of claim 17, wherein the means for determining the protected time interval for the access request comprises

means for determining a transmission time for the access request,

means for determining an expected response time for an acknowledgment from the first communication system for the access request, and

means for determining the protected time interval based on the transmission time and the expected response time.

19. The apparatus of claim 17, wherein the means for determining the starting time for sending the access request comprises

means for determining a pseudo-random wait duration,

means for setting the starting time to the end of a prior access request plus the pseudo-random wait duration, and

means for adjusting the starting time either forward or backward in time, if needed, by a time duration selected such that transmission of the access request at the adjusted starting time results in the protected time interval not overlapping the tune-away interval.

20. The apparatus of claim 17, further comprising:

means for tuning the receiver to a second communication system prior to the tune-away interval;

means for receiving a paging channel from the second communication system; and

means for tuning the receiver back to the first communication system after the tune-away interval.

21. An article comprising a machine-readable media including machine-executable instructions to cause a processor in a wireless device to:

determine a protected time interval for an access request to be sent to a first communication system, the protected time interval being a time interval in which a receiver is tuned to the first communication system;

determine a starting time for sending the access request such that the protected time interval does not overlap a tune-away interval, the tune-away interval being a time interval in which the receiver is tuned away from the first communication system; and

direct transmission of the access request to the first communication system at the starting time.

22. The article of claim 21, and further for storing instructions operable to determine a transmission time for the access request;

determine an expected response time for an acknowledgment from the first communication system for the access request; and

determine the protected time interval based on the transmission time and the expected response time.

23. The article of claim 21, and further for storing instructions operable to determine a pseudo-random wait duration;

set the starting time to the end of a prior access request plus the pseudo-random wait duration; and

adjust the starting time either forward or backward in time, if needed, by a time duration selected such that transmission of the access request at the adjusted starting time results in the protected time interval not overlapping the tune-away interval.

24. The article of claim 21, and further for storing instructions operable to

direct the receiver to tune a second communication system prior to the tune-away interval;

direct reception of a paging channel from the second communication system; and

direct the receiver to tune back to the first communication system after the tune-away interval.

25. A method of performing system access, comprising:

determining a protected time interval for an access request to be sent to a data only communication system, the protected time interval being a time interval in which a receiver is tuned to the data only system;

determining a starting access channel cycle for sending the access request such that the protected time interval does not overlap a tune-away interval, the tune-away interval being a time interval in which the receiver is tuned to a data and voice communication system; and

sending the access request to the data only system at the starting access channel cycle.

26. The method of claim 25, wherein the determining the protected time interval for the access request comprises

determining a transmission time for the access request,

determining an expected response time for an acknowledgment from the data only system for the access request, and

setting the protected time interval based on the transmission time and the expected response time.

27. The method of claim 25, wherein the determining the starting access channel cycle for sending the access request comprises

determining a pseudo-random wait duration,

setting the starting access channel cycle to a first access channel cycle located immediately after the end of a prior access request plus the pseudo-random wait duration, and

selecting a second access channel cycle as the starting access channel cycle if transmission of the access request at the first access channel cycle results in the protected time interval overlapping the tune-away interval.

28. The method of claim 27, wherein the second access channel cycle is after the first access channel cycle.

29. The method of claim 25, further comprising:

tuning the receiver to the data and voice system prior to the tune-away interval;

receiving a paging channel from the data and voice system; and

tuning the receiver back to the data only system after the tune-away interval.