Apparatus and Method for High Priority Search on RRC State Change

• US 20150094067A1
• Filed: 12/09/2014
• Published: 04/02/2015
• Est. Priority Date: 05/08/2012
• Status: Active Grant

• Current Assignee: Blackberry Limited
• Original Assignee: Blackberry Limited
• Inventors: FARNSWORTH, Andrew John, MACH, Tomasz Henryk, SUZUKI, Takashi, REDDY, Giri Narayana, HOLE, David Philip
• Granted Patent: US 9,432,887 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0061 of neighbour cell information
• CPC Class Codes: H04W 36/0088 Scheduling hand-off measurements
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 76/27 Transitions between radio resource control [RRC] states

Abstract

A user equipment is provided comprising: 1) transceiver circuitry configured to operate in cells associated with at least one radio access technology (RAT) network; and 2) a controller configured to perform neighbor cell searches. The controller is further configured to determine when the user equipment enters a first RRC state from a second RRC state. In response to a determination that the user equipment entered a first RRC state from a second RRC state, the controller delays performing a cell search until the controller determines that the user equipment has received complete system information for a serving cell.

Claims

1. A user equipment comprising:

transceiver circuitry configured to operate in cells associated with at least one radio access technology (RAT) network; and

a controller configured to perform neighbor cell searches, wherein the controller is further configured to determine when the user equipment enters a first RRC state from a second RRC state and, in response to the determination, the controller delays performing a cell search until the controller determines that the user equipment has received complete system information for a serving cell.

2. The user equipment as set forth in claim 1, wherein the complete system information comprises neighbor cell information and high-priority frequency information.

3. The user equipment as set forth in claim 1, wherein the first RRC state is one of at least:

CELL_PCH, URA_PCH and IDLE

4. The user equipment as set forth in claim 1, wherein the second RRC state is one of at least CELL_FACH and CELL_DCH.

5. The user equipment as set forth in claim 1, wherein the controller is further configured to determine whether the user equipment has changed cells since a most recent search was performed.

6. The user equipment as set forth in claim 5, wherein the controller, in response to a determination that the user equipment has not changed cells since the most recent search was performed, is further configured to delay performing a cell search until the controller determines that the user equipment has received complete system information for the serving cell.

7. A method of operating a user equipment configured to operate in cells associated with at least one radio access technology (RAT) network comprising:

determining when the user equipment enters a first RRC state from a second RRC state;

in response to a determination that the user equipment has entered the first RRC state, determining whether the user equipment has received complete system information for a serving cell;

in response to a determination that the user equipment has received complete system information, performing a search for neighbor cells; and

in response to a determination that the user equipment has not received complete system information, delaying performing a cell search until the user equipment has received complete system information for the serving cell.

8. The method as set forth in claim 7, wherein the complete system information comprises neighbor cell information and high-priority frequency information.

9. The method as set forth in claim 7, wherein the first RRC state is one of at least:

CELL_PCH, URA_PCH and IDLE

10. The method as set forth in claim 7, wherein the second RRC state is one of at least CELL_FACH and CELL_DCH.

11. The method as set forth in claim 7, further comprising determining whether the user equipment has changed cells since a most recent search was performed.

12. The method as set forth in claim 11, wherein, in response to a determination that the user equipment has not changed cells since the most recent search was performed, delaying performing a cell search until the user equipment has received complete system information for the serving cell.

13. A non-transitory computer-readable medium for managing a wireless device in cells associated with at least one radio access technology (RAT), the computer-readable medium storm computer-executable instructions for causing one or more processors to performrations comprising:

performing neighbor cell searches;

determining when the user equipment enters a first RRC state from a second RRC state; and

in response to the determination, delaying performing a cell search until the processor determines that the user equipment has received complete system information for a serving cell.

14. The computer-readable medium as set forth in claim 13, wherein the complete system information comprises neighbor cell information and high-priority frequency information.

15. The computer-readable medium as set forth in claim 13, wherein the first RRC state is one of at least:

CELL_PCH, URA_PCH and IDLE

16. The computer-readable medium as set forth in claim 13, wherein the second RRC state is one of at least CELL_FACH and CELL_DCH.

17. The computer-readable medium as set forth in claim 13, wherein the computer-executable instructions are further operable to cause the one or more processors to perform an operation comprising determining whether the user equipment has changed cells since a most recent search was performed.

18. The computer-readable medium as set forth in claim 17, wherein the computer-executable instructions are further operable to cause the one or more processors, in response to a determination that the user equipment has not changed cells since the most recent search was performed, to performm delaying performing a cell search until the processor determines that the user equipment has received complete system information for the serving cell.