Reducing RNA update procedures and improving RACH efficiency

Patent metadata

Field	Value
Publication number	US-11490306-B2
Application number	US-202016915893-A
Country	US
Kind code	B2
Filing date	Jun 29, 2020
Priority date	Jun 29, 2020
Publication date	Nov 1, 2022
Grant date	Nov 1, 2022

Abstract

Disclosed are embodiments for reducing likelihood of selecting a cell identified by a Radio Access Network (RAN) Notification Area ID (RNA ID) that is different from that identifying a last or current serving cell so as to avoid an RNA update procedure; reducing Random Access Channel (RACH) transmissions for an RNA update procedure and a mobile originated (MO) data transmission in response to a Radio Resource Control (RRC) triggered RNA update procedure; and selecting a band or beam in a multi-band/beam cellular system that improves RACH efficiency.

First claim

The invention claimed is:

1. A method, performed by a User Equipment (UE) configured to initiate a cell selection procedure or a cell reselection procedure, of avoiding selection of a cell identified by a Radio Access Network (RAN) Notification Area (RNA) identifier (RNA ID) that is different from that identifying a last or current serving cell so as to avoid an RNA update procedure, the method comprising:
before initiating the cell selection procedure or the cell reselection procedure, determining an RNA ID of the last or current serving cell based on a ran-NotificationAreainfo portion received in a Suspend Config parameter in an RRC Release message;
preferentially selecting a new cell based on the RNA ID of the last or current serving cell, the preferentially selecting comprising:
performing a first Storage List Search (SLS) procedure on a first list of candidates which belong to the same RNA as the last or current serving cell;
in response to the first SLS procedure being unsuccessful, performing a first Derived Band Search (DBS) procedure on the first list of candidates;
in response to the first DBS procedure being unsuccessful, performing a second SLS procedure on a second list of candidates which do not belong to the same RNA as the last or current serving cell; and
in response to the second SLS procedure being unsuccessful, performing a second DBS procedure on at least a portion of the second list of candidates having an RNA ID that does not match that of the last or current serving cell; and

attempting to obtain an RNA ID of the new cell based on an associated system information value tag matching that stored in an acquisition database maintained by the UE; and
in response to determining a match, reusing the RNA ID retrieved from database so as to avoid a decode of System Information from the new cell.

2. The method of claim 1 in which the determining the RNA ID comprises obtaining the RNA ID from information stored in an acquisition database maintained by the UE.

3. The method of claim 1 in which the at least a portion of the second list of candidates excludes candidates previously searched in the second SLS procedure.

4. The method of claim 1 in which the preferentially selecting further comprises determining a priority as a function of RNA ID and an absolute priority indicated in System Information or dedicated signaling priority.

5. The method of claim 1 further comprising triggering a unified Random Access Channel (RACH) procedure for a mobile originated data transfer and an RNA update.

6. The method of claim 1 further comprising reducing a System Information Block (SIB) priority of a coverage cell in RRC_Inactive state before transitioning to an RRC_Connected state in a capacity cell.

7. The method of claim 1 , further comprising receiving from a gNB a System Information Block (SIB) reselection priority for neighbor cells indicating reselection priority for RRC idle and reselection priority for RRC inactive.

8. A non-transitory machine-readable storage medium, the machine-readable storage medium including instructions that when executed by a processor of a User Equipment (UE), cause the UE to avoid selecting a cell identified by a Radio Access Network (RAN) Notification Area (RNA) identifier (RNA ID) that is different from that identifying a last or current serving cell so as to avoid an RNA update procedure in a cell selection procedure or a cell reselection procedure by configuring the UE to:
before initiation of the cell selection procedure or the cell reselection procedure, determine an RNA ID of the last or current serving cell based on a ran-NotificationAreainfo portion received in a Suspend Config parameter in an RRC Release message;
preferentially select a new cell based on the RNA ID of the last or current serving cell, the preferentially selecting comprising:
performing a first Storage List Search (SLS) procedure on a first list of candidates which belong to the same RNA as the last or current serving cell;
in response to the first SLS procedure being unsuccessful, performing a first Derived Band Search (DBS) procedure on the first list of candidates;
in response to the first DBS procedure being unsuccessful, performing a second SLS procedure on a second list of candidates which do not belong to the same RNA as the last or current serving cell; and
in response to the second SLS procedure being unsuccessful, performing a second DBS procedure on at least a portion of the second list of candidates having an RNA ID that does not match that of the last or current serving cell;

attempt to obtain an RNA ID of the new cell based on an associated system information value tag matching that stored in an acquisition database maintained by the UE; and
in response to determining a match, reuse the RNA ID retrieved from database so as to avoid a decode of System Information from the new cell.

9. The machine-readable storage medium of claim 8 in which the determining the RNA ID comprises obtain the RNA ID from information stored in an acquisition database maintained by the UE.

10. The machine-readable storage medium of claim 8 in which the at least a portion of the second list of candidates excludes candidates previously searched in the second SLS procedure.

11. The machine-readable storage medium of claim 8 in which the preferentially selecting further comprises determining a priority as a function of RNA ID and an absolute priority indicated in System Information or dedicated signaling priority.

12. The machine-readable storage medium of claim 8 in which the instructions further configure the processor to trigger a unified Random Access Channel (RACH) procedure for a mobile originated data transfer and an RNA update.

13. The machine-readable storage medium of claim 8 in which the instructions further configure the processor to reduce a System Information Block (SIB) priority of a coverage cell in RRC_Inactive state before transitioning to an RRC_Connected state in a capacity cell.

14. The machine-readable storage medium of claim 8 , in which the instructions further configure the processor to receive from a gNB a System Information Block (SIB) reselection priority for neighbor cells indicating reselection priority for RRC idle and reselection priority for RRC inactive.

Assignees

• Apple Inc

Inventors

• Venkataraman Vijay
• Dhanapal Muthukumaran
• Su Li
• Garg Sharad
• Rahim Syed A
• Sunkesala Sandeep K
• Tang Jia
• Gadde Vijay
• Dhanani Tarakkumar G
• Saad Muhammad

Classifications

• H04W76/19

  Connection re-establishment · CPC title

• H04W52/242

  taking into account path loss · CPC title

• H04W76/27

  Transitions between radio resource control [RRC] states · CPC title

• H04W72/046

  the resource being in the space domain, e.g. beams · CPC title

• H04W76/11

  Allocation or use of connection identifiers · CPC title