System and methods for improving intra-frequency cell reselection on a wireless communication device in connected mode

• US 9,648,525 B2
• Filed: 10/02/2014
• Issued: 05/09/2017
• Est. Priority Date: 08/12/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Ponukumati, Dhananjaya Sarma, Kumar, Mohit, Kandlakunta, Rammohan
• Primary Examiner(s): Wang-Hurst, Kathy
• Assistant Examiner(s): HANNAN, B M M
• Application Number:
  US14/505,071
• Publication Number:
  US 20160050590A1
• Time in Patent Office: 950 Days
• Field of Search: 455436, 455434, 4554353, 455437, 455438, 455442, 455458, 455466, 4554352, 455525, 370328, 370331, 370329, 370338
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04W 36/0061 of neighbour cell information
• CPC Class Codes: H04W 36/00835 Determination of neighbour cell lists
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 8/183 Processing at user equipment or user record carrier

Abstract

Methods and devices for enabling improved cell reselection procedures on a wireless communication device with a first SIM is camped on a serving cell of a first network may include receiving a list of neighbor cells from system information that is broadcast in the serving cell, and performing signal measurements associated with the listed neighbor cells and the serving cell, and, based on the signal measurements, identifying neighbor cells that satisfy selection criteria. The wireless device may calculate ranking criteria for the serving cell and the identified neighbor cells, and determine whether an inter-frequency neighbor cell has a highest ranking criteria among all of the ranked cells. Upon determining that an intra-frequency neighbor cell has the highest ranking criteria, the wireless device may start a reselection timer and also start decoding the system information that is being broadcast in the intra-frequency neighbor cell that has the highest ranking criteria.

Claims

1. A method of improving cell reselection on a wireless communication device having at least a first subscriber identity module (SIM) associated with a radio frequency (RF) resource and a first modem stack operating in a radio resource control (RRC) connected mode, the method comprising:

detecting that the first modem stack is camped on a serving cell of a first network;

receiving a list of neighbor cells from system information broadcast in the serving cell;

performing signal measurements associated with listed neighbor cells and the serving cell;

identifying neighbor cells that satisfy selection criteria based on the signal measurements;

calculating ranking criteria for the serving cell and for the identified neighbor cells;

determining whether the calculated ranking criteria for an intra-frequency neighbor cell is a highest value among the calculated ranking criteria for the identified neighbor cells and the serving cell; and

in response to determining that the calculated ranking criteria for an intra-frequency neighbor cell is a highest value among the calculated ranking criteria for the identified neighbor cells and the serving cell, starting a non-zero reselection timer and decoding system information broadcast by the intra-frequency neighbor cell, wherein the non-zero reselection timer runs concurrently with decoding the system information.

2. The method of claim 1, further comprising:

determining whether the reselection timer has expired;

determining whether decoding the system information broadcast by the intra-frequency neighbor cell is completed in response to determining that the reselection timer has expired; and

finishing decoding the system information broadcast by the intra-frequency neighbor cell in response to determining that decoding the system information broadcast by the intra-frequency neighbor cell is not completed.

3. The method of claim 2, further comprising:

continuing decoding the system information broadcast by the intra-frequency neighbor cell in response to determining that the reselection timer has not expired.

4. The method of claim 2, further comprising:

recalculating ranking criteria for the serving cell and for the identified neighbor cells in response to determining that the reselection timer has expired; and

determining whether the recalculated ranking criteria for the intra-frequency neighbor cell has a highest value among the identified neighbor cells and the serving cell.

5. The method of claim 4, further comprising:

completing reselection to the intra-frequency neighbor cell in response to determining that the recalculated ranking criteria for the intra-frequency neighbor cell has a highest value among the identified neighbor cells and the serving cell, wherein completing reselection comprises performing a cell update procedure.

6. The method of claim 5, wherein the wireless communication device also includes a second SIM associated with the RF resource and with a second modem stack, wherein the second modem stack is provided use of the RF resource following the cell update procedure on the first modem stack.

7. The method of claim 1, further comprising:

determining whether the first modem stack is in an RRC state in which the RF resource is being used to monitor a downlink channel of the serving cell, wherein decoding the system information broadcast by the intra-frequency neighbor cell is performed concurrently with monitoring the downlink channel of the serving cell.

8. The method of claim 7, wherein determining whether the first modem stack is in an RRC state in which the RF resource is being used to monitor a downlink channel of the serving cell comprises determining whether the first modem stack is in a CELL_FACH state.

9. The method of claim 1, wherein calculating ranking criteria for the serving cell and for the identified neighbor cells is performed based on at least one of signal strength measurements and signal quality measurements.

10. The method of claim 1, wherein the non-zero reselection timer has a duration equal to a non-zero Treselection value that is received in system information broadcast on the serving cell.

11. The method of claim 10, wherein the Treselection value is greater than 500 milliseconds.

12. A wireless communication device, comprising:

a radio frequency (RF) resource configured to connect to at least a first subscriber identity module (SIM);

a processor coupled to the RF resource and configured with processor-executable instructions to;

detect when a first modem stack configured to operate in a radio resource control (RRC) connected mode is camped on a serving cell of a first network;

receive a list of neighbor cells from system information broadcast in the serving cell;

perform signal measurements associated with the listed neighbor cells and the serving cell;

identify neighbor cells that satisfy selection criteria based on the signal measurements;

calculate ranking criteria for the serving cell and for the identified neighbor cells;

determine whether the calculated ranking criteria for an intra-frequency neighbor cell is a highest value among the calculated ranking criteria for the identified neighbor cells and the serving cell; and

in response to determining that the calculated ranking criteria for an intra-frequency neighbor cell is a highest value among the calculated ranking criteria for the identified neighbor cells and the serving cell, start a non-zero reselection timer and decode system information broadcast by the intra-frequency neighbor cell, wherein the non-zero reselection timer runs concurrently with decoding the system information.

13. The wireless communication device of claim 12, wherein the processor is further configured with processor-executable instructions to:

determine whether the reselection timer has expired;

determine whether decoding the system information broadcast by the intra-frequency neighbor cell is completed in response to determining that the reselection timer has expired; and

finish decoding the system information broadcast by the intra-frequency neighbor cell in response to determining that decoding the system information broadcast by the intra-frequency neighbor cell is not completed.

14. The wireless communication device of claim 13, wherein the processor is further configured with processor-executable instructions to:

continue decoding the system information broadcast by the intra-frequency neighbor cell in response to determining that the reselection timer has not expired.

15. The wireless communication device of claim 13, wherein the processor is further configured with processor-executable instructions to:

recalculate ranking criteria for the serving cell and for the identified neighbor cells in response to determining that the reselection timer has expired; and

determine whether the recalculated ranking criteria for the intra-frequency neighbor cell has a highest value among the identified neighbor cells and the serving cell.

16. The wireless communication device of claim 15, wherein the processor is further configured with processor-executable instructions to:

complete reselection to the intra-frequency neighbor cell in response to determining that the recalculated ranking criteria for the intra-frequency neighbor cell has a highest value among the identified neighbor cells and the serving cell, wherein completing reselection comprises performing a cell update procedure.

17. The wireless communication device of claim 16, further comprising a second modem stack, wherein the wireless communication device also includes a second SIM associated with the RF resource is configured to couple with a second SIM, wherein the processor is configured with processor-executable instructions to provide the second modem stack with use of the RF resource following the cell update procedure on the first modem stack.

18. The wireless communication device of claim 12, wherein the processor is further configured with processor-executable instructions to:

determine whether the first modem stack is in an RRC state in which the RF resource is being used to monitor a downlink channel of the serving cell, wherein decoding the system information broadcast by the intra-frequency neighbor cell is performed concurrently with monitoring the downlink channel of the serving cell.

19. The wireless communication device of claim 18, wherein the processor is further configured with processor-executable instructions to determine whether the first modem stack is in an RRC state in which the RF resource is being used to monitor a downlink channel of the serving cell by determining whether the first modem stack is in a CELL_FACH state.

20. The wireless communication device of claim 12, wherein the processor is further configured with processor-executable instructions to calculate ranking criteria for the serving cell and for the identified neighbor cells based on at least one of signal strength measurements and signal quality measurements.

21. The wireless communication device of claim 12, wherein the non-zero reselection timer has a duration equal to a non-zero Treselection value that is received in system information broadcast on the serving cell.

22. The wireless communication device of claim 21, wherein the Treselection value is greater than 500 milliseconds.

23. A wireless communication device, comprising:

a radio frequency (RF) resource configured to connect to at least a first subscriber identity module (SIM);

means for detecting when a first modem stack configured to operate in a radio resource control (RRC) connected mode is camped on a serving cell of a first network;

means for receiving a list of neighbor cells from system information broadcast in the serving cell;

means for performing signal measurements associated with listed neighbor cells and the serving cell;

means for identifying neighbor cells that satisfy selection criteria based on the signal measurements;

means for calculating ranking criteria for the serving cell and for the identified neighbor cells;

means for determining whether the calculated ranking criteria for an intra-frequency neighbor cell is a highest value among the calculated ranking criteria for the identified neighbor cells and the serving cell; and

means for starting a non-zero reselection timer and decoding system information broadcast by the intra-frequency neighbor cell in response to determining that the calculated ranking criteria for an intra-frequency neighbor cell is a highest value among the calculated ranking criteria for the identified neighbor cells and the serving cell, wherein the non-zero reselection timer runs concurrently with decoding the system information.

24. A non-transitory processor-readable storage medium having stored thereon processor-executable instructions configured to cause a processor of a wireless communication device having a first SIM associated with a first radio frequency (RF) resource to perform operations comprising:

detecting that a first modem stack configured to operate in a radio resource control (RRC) connected mode is camped on a serving cell of a first network;

receiving a list of neighbor cells from system information broadcast in the serving cell;

performing signal measurements associated with listed neighbor cells and the serving cell;

identifying neighbor cells that satisfy selection criteria based on the signal measurements;

calculating ranking criteria for the serving cell and for the identified neighbor cells;

determining whether the calculated ranking criteria for an intra-frequency neighbor cell is a highest value among the calculated ranking criteria for the identified neighbor cells and the serving cell; and

in response to determining that the calculated ranking criteria for an intra-frequency neighbor cell is a highest value among the calculated ranking criteria for the identified neighbor cells and the serving cell, starting a non-zero reselection timer and decoding system information broadcast by the intra-frequency neighbor, wherein the non-zero reselection timer runs concurrently with decoding the system information.

25. The non-transitory processor-readable storage medium of claim 24, wherein the stored processor-executable instructions are configured to cause the processor of the wireless communication to perform operations further comprising:

determining whether the reselection timer has expired;

determining whether decoding the system information broadcast by the intra-frequency neighbor cell is completed in response to determining that the reselection timer has expired; and

finishing decoding the system information broadcast by the intra-frequency neighbor cell in response to determining that decoding the system information broadcast by the intra-frequency neighbor cell is not completed.

26. The non-transitory processor-readable storage medium of claim 25, wherein the stored processor-executable instructions are configured to cause the processor of the wireless communication to perform operations further comprising:

continuing decoding the system information broadcast by the intra-frequency neighbor cell in response to determining that the reselection timer has not expired.

27. The non-transitory processor-readable storage medium of claim 25, wherein the stored processor-executable instructions are configured to cause the processor of the wireless communication to perform operations further comprising:

recalculating ranking criteria for the serving cell and for the identified neighbor cells in response to determining that the reselection timer has expired; and

determining whether the recalculated ranking criteria for the intra-frequency neighbor cell has a highest value among the identified neighbor cells and the serving cell.

28. The non-transitory processor-readable storage medium of claim 27, wherein the stored processor-executable instructions are configured to cause the processor of the wireless communication to perform operations further comprising:

completing reselection to the intra-frequency neighbor cell in response to determining that the recalculated ranking criteria for the intra-frequency neighbor cell has a highest value among the identified neighbor cells and the serving cell.