Fast cell selection in a mobile wireless device

• US 8,301,145 B2
• Filed: 11/19/2010
• Issued: 10/30/2012
• Est. Priority Date: 06/24/2010
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Deivasigamani, Giri Prassad, Ramasamy, Venkatasubramanian, Garg, Sharad, Vasudevan, Srinivasan
• Primary Examiner(s): Patel, Nimesh
• Application Number:
  US12/950,691
• Publication Number:
  US 20110319081A1
• Time in Patent Office: 711 Days
• Field of Search: 455/436, 455/450, 455/525, 455/524, 455/63.1, 455/67.13, 370/331, 370/332, 370/333, 375/260
• US Class Current: 455/436
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 36/0055 Transmission or use of information for re-establishing the radio link
• CPC Class Codes: H04W 36/00833 Handover statistics
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/304 due to measured or perceived resources with higher communication quality
• CPC Class Codes: H04W 36/305 Handover due to radio link failure control signalling for hand-off failure H04W36/0079
• CPC Class Codes: H04W 36/324 by mobility data, e.g. speed data
• CPC Class Codes: H04W 36/36 by user or terminal equipment
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 64/003 locating network equipment

Abstract

A method and apparatus for fast cell selection by a mobile wireless device. The mobile wireless device detects when a first wireless cell fails a set of stored suitability criteria and searches for and locates a set of candidate wireless cells to associate with. The mobile wireless device measures at least one received signal metric for each candidate wireless cell in the set of candidate wireless cells. When a candidate cell in the set of candidate wireless cells is identically the first wireless cell, the mobile wireless device evaluates the suitability of the candidate wireless cell using the stored set of suitability criteria for the first wireless cell and the measured at least one received signal metric for the candidate wireless cell. The mobile wireless communication device associates with the candidate wireless cell when the candidate wireless cell meets the stored set of suitability criteria.

Claims

1. A method, comprising:

in a mobile wireless communication device,

detecting a first wireless cell in a wireless communication network associated with the mobile wireless communication device that fails at least one criterion for the first wireless cell in a set of suitability criteria stored in the mobile wireless communication device, the set of suitability criteria including at least one of received power level and received signal quality parameters broadcast in one or more system information blocks by the wireless communication network and stored in the mobile wireless communication device before detecting the first wireless cell fails the at least one criterion;

searching for and locating a set of candidate wireless cells with which to associate;

measuring at least one received signal metric for each candidate wireless cell in the set of candidate wireless cells;

determining whether a candidate wireless cell in the set of candidate wireless cells is the first wireless cell;

evaluating whether the candidate wireless cell satisfies one or more criteria for the first wireless cell in the stored set of suitability criteria in the mobile wireless communication device using the measured at least one received signal metric for the candidate wireless cell when the candidate wireless cell is the first wireless cell; and

associating the mobile wireless communication device with the candidate wireless cell when the candidate wireless cell is the first wireless cell and satisfies one or more criteria in the stored set of suitability criteria.

2. The method as recited in claim 1, wherein searching for and locating the set of candidate wireless cells includes receiving a radio frequency signal from a radio network subsystem in each candidate wireless cell identifying the candidate wireless cell.

3. The method as recited in claim 2, wherein the received signal metric used to measure each candidate wireless cell is a measure of received signal code power.

4. The method as recited in claim 2, wherein the received signal metric used to measure each candidate wireless cell is a chip energy.

5. The method as recited in claim 1, wherein

determining whether the candidate wireless cell is the first wireless cell includes estimating the candidate wireless cell'"'"'s geographic location and the first wireless cell'"'"'s geographic location.

6. The method as recited in claim 1, wherein

determining whether the candidate wireless cell is the first wireless cell includes estimating changes in geographic position of the mobile wireless communication device.

7. The method as recited in claim 1, further comprising:

when no candidate wireless cell in the set of candidate wireless cells is the first wireless cell,

receiving suitability criteria for the set of candidate wireless cells from at least one radio network subsystem in the wireless communication network, the suitability criteria including at least one cell selection or reselection parameter broadcast in one or more system information blocks by at least one radio network subsystem in the wireless communication network;

evaluating whether a cell in the set of candidate wireless cells satisfies one or more of the received suitability criteria; and

associating the mobile wireless communication device with the cell in the set of candidate wireless cells, when the cell satisfies one or more of the received suitability criteria.

8. The method as recited in claim 7, wherein the at least one radio network subsystem in the wireless communication network transmits the suitability criteria using broadcast system information block type 3 (SIB3) or block type 11 (SIB11) messages.

9. A mobile wireless communication device, the device comprising:

an application processor configured to generate and receive messages;

a transceiver connected to the application processor, the transceiver configured to transmit radio frequency signals to and receive radio frequency signals from a wireless communication network and configured to select a cell in the wireless communication network with which to connect by;

detecting a loss of radio frequency connection between the transceiver in the mobile wireless communication device and a first cell in the wireless communication network;

locating a set of candidate cells in the wireless communication network with which to connect;

determining a subset of located candidate cells that match to cell suitability criteria stored in the mobile wireless communication device, the cell suitability criteria including at least one of received power level and received signal quality parameters broadcast in one or more system information blocks by the wireless communication network;

determining whether one of the cells in the subset of located candidate cells is the first cell to which the mobile wireless device was previously connected; and

selecting the first cell to associate with the mobile wireless communication device when the first cell satisfies one or more of the stored cell suitability criteria,

wherein the cell suitability criteria are stored in the mobile wireless communication device prior to detecting the loss of radio frequency connection.

10. The mobile wireless communication device as recited in claim 9, wherein the transceiver is further configured to select the cell in the wireless communication network with which to connect by:

when none of the cells in the subset of located candidate cells is the first cell,

receiving suitability criteria from a radio network subsystem in a located candidate cell in the subset of located candidate cells;

determining whether the located candidate cell satisfies the received suitability criteria; and

associating the mobile wireless communication device with the located candidate cell when the located candidate cell satisfies the received suitability criteria.

11. The mobile wireless communication device as recited in claim 10, wherein locating the set of candidate cells in the wireless communication network with which to connect includes receiving a radio frequency signal from the radio network subsystem in each candidate wireless cell identifying the candidate wireless cell.

12. The mobile wireless communication device as recited in claim 10, wherein determining whether the located candidate cell satisfies the received suitability criteria includes measuring a received signal quality of the located candidate cell.

13. The mobile wireless communication device as recited in claim 9, wherein the application processor is configured to determine whether one of the candidate cells is the first cell to which the mobile wireless communication device was previously connected by estimating the one of the candidate cells geographic location and the first cell'"'"'s geographic location.

14. The mobile wireless communication device as recited in claim 9, wherein the application processor is further configured to determine whether the selected cell is the first cell using a measure of time elapsed after detecting the loss of radio frequency connection between the transceiver and the first cell.

15. The mobile wireless communication device as recited in claim 9, wherein the application processor is further configured to determine whether the selected cell is the first cell using a measure of a rate of displacement of the mobile wireless communication device.

16. A non-transitory computer readable medium for storing computer program code executable by a processor in a mobile wireless communication device for selecting a cell in a wireless network with which to associate comprising:

in the mobile wireless communication device,

computer program code for detecting a first cell in the wireless network associated with the mobile wireless communication device fails one or more suitability criteria stored in the mobile wireless communication device, the set of suitability criteria including at least one of received power level and received signal quality parameters broadcast in one or more system information blocks by the wireless communication network and stored in the mobile wireless communication device before detecting the first cell fails the one or more suitability criteria;

computer program code for searching for and locating a set of candidate cells with which to associate the mobile wireless communication device;

computer program code for determining whether one of the candidate cells in the set of candidate cells is the first cell to which the mobile wireless communication device was previously connected;

computer program code for evaluating whether the first cell satisfies one or more stored suitability criteria for the first wireless cell when one of the candidate cells is the first cell; and

computer program code for associating with the first cell when one of the candidate cells in the set of candidate cells is the first cell and the first cell satisfies one or more of the received suitability criteria.

17. The non-transitory computer readable medium as recited in claim 16 further comprising:

computer program code for receiving suitability criteria for the set of candidate cells from the wireless network when no candidate cell is the first cell and for evaluating whether a cell in the set of candidate cells satisfies one or more of the received suitability criteria; and

computer program code for associating with the candidate cell, when the candidate cell satisfies one or more of the received suitability criteria.

18. The non-transitory computer readable medium as recited in claim 16, wherein computer program code for locating the set of candidate cells includes receiving a radio frequency signal from the radio network subsystem in each candidate cell identifying the candidate cell.

19. The non-transitory computer readable medium as recited in claim 17, wherein computer program code for receiving suitability criteria for the set of candidate cells from the wireless network includes receiving system information messages broadcast by radio network subsystems in the candidate cells.

20. The non-transitory computer readable medium as recited in claim 19, wherein computer program code for determining whether one of the candidate cells in the set of candidate cells is the first cell includes receiving master information messages broadcast by radio network subsystems in the candidate cells.

21. The non-transitory computer readable medium as recited in claim 16, wherein computer program code for determining whether the candidate wireless cell is the first wireless cell includes estimating changes in geographic position of the mobile wireless communication device.

22. The non-transitory computer readable medium as recited in claim 16, wherein computer program code for determining whether the candidate wireless cell is the first wireless cell includes measuring time elapsed after detecting the first cell fails one or more stored suitability criteria.

23. The non-transitory computer readable medium as recited in claim 17, wherein computer program code for determining whether the candidate wireless cell is the first wireless cell includes estimating the candidate wireless cell'"'"'s geographic location and the first wireless cell'"'"'s geographic location.