Method and device for performing cell reselection by terminal

• US 10,531,348 B2
• Filed: 08/23/2016
• Issued: 01/07/2020
• Est. Priority Date: 08/30/2015
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Sangwon, Lee, Youngdae
• Primary Examiner(s): Roberts, Brian S
• Assistant Examiner(s): Decker, Cassandra L
• Application Number:
  US15/755,512
• Publication Number:
  US 20180270723A1
• Time in Patent Office: 1,232 Days
• Field of Search: None
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 36/0007 for multicast or broadcast services, e.g. MBMS multicast or broadcast application services H04W4/06; resource management for broadcast services H04W72/30; connection management for selective distribution or broadcast H04W76/40
• CPC Class Codes: H04W 36/00835 Determination of neighbour cell lists
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/20 Selecting an access point

Abstract

Provided are a method for performing cell reselection by a terminal in a wireless communication system and a device for supporting same. The terminal detects a single-cell point-to-multipoint (SCPTM) cell of interest, calculates the ranking of the SCPTM cell of interest, and performs cell reselection on the basis of the calculated ranking. The ranking of the SCPTM cell of interest can be calculated by means of applying a cell-specific priority (CSP).

Claims

1. A method of performing cell reselection, by a user equipment (UE), in a wireless communication system, the method comprising:

receiving system information including a first offset, a second offset and a third offset;

calculating a ranking for a single-cell point-to-multipoint (SCPTM) cell based on the first offset, the second offset and the third offset; and

performing the cell reselection based on the calculated ranking,

wherein the first offset is an offset applied to the SCPTM cell according to whether a frequency to which the SCPTM cell belongs is an inter-frequency or an intra-frequency of a serving cell that the UE is camping on,

wherein the second offset is an offset applied temporarily to the SCPTM cell, and

wherein the third offset is an offset only applied to the SCPTM cell.

2. The method of claim 1, wherein the SCPTM cell is a cell which provides Multimedia Broadcast/Multicast Service (MBMS) service via SCPTM transmission.

3. The method of claim 1, wherein the SCPTM cell belongs to a SCPTM frequency.

4. The method of claim 1, wherein the SCPTM cell is a neighboring cell other than the serving cell.

5. The method of claim 1, wherein the second offset is not applied to a non-SCPTM cell.

6. The method of claim 1, wherein the third offset for the SCPTM cell is a cell specific priority (CSP).

7. The method of claim 1, further comprising:

receiving Multimedia Broadcast/Multicast Service (MBMS) service via the SCPTM cell, if the cell reselection is performed to the SCPTM cell.

8. The method of claim 7, wherein if the calculated ranking for the SCPTM cell is highest among neighboring cells, the cell reselection is performed to the SCPTM cell.

9. The method of claim 7, further comprising:

if the UE determines that the SCPTM cell exists near the UE, performing, by the UE, measurement on a SCPTM frequency to which the SCPTM cell belongs.

10. The method of claim 1, wherein the ranking for the SCPTM cell is defined by:

R=Qmeas−

Qoffset−

Qoffsettemp+CSP,

where R is a ranking for the SCPTM cell, Qmeas is Reference Signal Received Power (RSRP) measurement quantity used in cell reselection, Qoffset is the first offset, Qoffsettemp is the second offset, and CSP is the third offset.

11. The method of claim 1, further comprising:

calculating, by the UE, a ranking for a non-SCPTM cell,

wherein the ranking for the non-SCPTM cell is calculated without at least one of the first offset, the second offset or the third offset.

12. The method of claim 1, further comprising:

calculating, by the UE, a ranking for a non-SCPTM cell using an offset for the non-SCPTM cell,

wherein a value of the offset for the non-SCPTM cell is zero.

13. The method of claim 1, further comprising:

performing, by the UE, measurement on a SCPTM frequency to which the SCPTM cell belongs; and

detecting, by the UE, the SCPTM cell on the SCPTM frequency.

14. The method of claim 1, wherein the UE is receiving or interested to receive Multimedia Broadcast/Multicast Service (MBMS) service.

15. The method of claim 1, further comprising:

determining, by the UE, whether the SCPTM cell exists near the UE based on the system information.

16. The method of claim 15, wherein the system information further includes a mapping relation between a cell ID and a service area identity (SAI) and at least one of the first offset, the second offset or the third offset corresponding to the cell ID.

17. The method of claim 15, wherein the system information further includes a mapping relation between a cell ID and a temporary mobile group identifier (TMGI) and at least one of the first offset, the second offset or the third offset corresponding to the cell ID.

18. A user equipment (UE) performing cell reselection in a wireless communication system, the UE comprising:

a memory;

a transceiver; and

a processor, connected with the memory and the transceiver, that;

controls the transceiver to receive system information including a first offset, a second offset and a third offset;

calculates a ranking for a single-cell point-to-multipoint (SCPTM) cell based on the first offset, the second offset and the third offset; and

performs the cell reselection based on the calculated ranking,

wherein the first offset is an offset applied to the SCPTM cell according to whether a frequency to which the SCPTM cell belongs is an inter-frequency or an intra-frequency of a serving cell that the UE is camping on,

wherein the second offset is an offset applied temporarily to the SCPTM cell, and

wherein the third offset is an offset only applied to the SCPTM cell.