WO2024130597A1

WO2024130597A1 - Indication method of multicast session deactivation and apparatus

Info

Publication number: WO2024130597A1
Application number: PCT/CN2022/140747
Authority: WO
Inventors: Xin Zhang
Original assignee: Shenzhen Tcl New Technology Co., Ltd.
Priority date: 2022-12-21
Filing date: 2022-12-21
Publication date: 2024-06-27

Abstract

An indication method of multicast session deactivation performed by a user equipment (UE) includes if the UE is in a radio resource control (RRC) inactive state and is configured to receive a multicast session in the RRC inactive state, the UE is notified through a group paging when the multicast session is deactivated.

Description

INDICATION METHOD OF MULTICAST SESSION DEACTIVATION AND APPARATUS

BACKGROUND OF DISCLOSURE

1. Field of the Disclosure

The present disclosure relates to the field of wireless communication systems such as multicast/broadcast service (MBS) systems, and more particularly, to indication methods of multicast session deactivation and apparatuses.

2. Description of the Related Art

To enable resource-efficient delivery of multicast/broadcast services, 3GPP has developed NR broadcast/multicast in Rel-17 according to a work item (WID) , aiming to enable general MBS services over 5GS. The use cases identified that could benefit from this feature include public safety and mission critical, V2X applications, IPTV, live video, software delivery over wireless and IoT applications, etc. Two delivery modes have been agreed for Rel-17 MBS with delivery mode 1 (only for multicast) capable of addressing higher QoS services and delivery mode 2 (only for broadcast) focusing on lower QoS services. Given that Rel-17 MBS already provide the basic function to support MBS services, the general main goal for Rel-18 should be to enable better deployment of MBS, such as improvement of resource efficiency and capacity based on Rel-17 MBS.

In Rel-17, RAN only specifies multicast for UEs in RRC_CONNECTED state, which may not fully fulfil the requirements of, e.g., mission critical services, especially for cells with a large number of UEs according to TR 23.774. Also, to always keep UEs in RRC_CONNECTED state is not power efficient. It is therefore important to support multicast for UEs in RRC_INACTIVE.

In LTE SC-PTM, SC-PTM Stop Indication MAC CE was introduced to notify that the UE stops monitoring the PDCCH for a G-RNTI, whereby the MAC CE is multiplexed with SC-MTCH associated with the G-RNTI. This light-weight signaling could work under the restriction of one-to-one mapping between TMGI and G-RNTI. On the other hand, NR MBS allows many-to-one mapping between TMGI and G-RNTI, so the MAC CE, if introduced, needs to indicate the TMGI (s) which is deactivated. Since the MAC CE is sent together with MTCH, it’s expected to minimize the delay between the reception of last multicast data and the stop of MTCH monitoring.

Therefore, there is a need for indication methods of multicast session deactivation and apparatuses.

SUMMARY

An object of the present disclosure is to propose indication methods of multicast session deactivation and apparatuses, which can deal with the issue how the multicast session deactivation is notified to a UE in an RRC inactive state.

In a first aspect of the present disclosure, an indication method of multicast session deactivation performed by a user equipment (UE) includes if the UE is in a radio resource control (RRC) inactive state and is configured to receive a multicast session in the RRC inactive state, the UE is notified through a group paging when the multicast session is deactivated.

In a second aspect of the present disclosure, a user equipment (UE) comprises a memory, a transceiver, and a processor coupled to the memory and the transceiver. The processor is configured to perform the above method.

In a third aspect of the present disclosure, a non-transitory machine-readable storage medium has stored thereon instructions that, when executed by a computer, cause the computer to perform the above method.

In a fourth aspect of the present disclosure, a chip includes a processor, configured to call and run a computer program stored in a memory, to cause a device in which the chip is installed to execute the above method.

In a fifth aspect of the present disclosure, a computer readable storage medium, in which a computer program is stored, causes a computer to execute the above method.

In a sixth aspect of the present disclosure, a computer program product includes a computer program, and the computer program causes a computer to execute the above method.

In a seventh aspect of the present disclosure, a computer program causes a computer to execute the above method.

BRIEF DESCRIPTION OF DRAWINGS

In order to illustrate the embodiments of the present disclosure or related art more clearly, the following figures will be described in the embodiments are briefly introduced. It is obvious that the drawings are merely some embodiments of the present disclosure, a person having ordinary skill in this field can obtain other figures according to these figures without paying the premise.

FIG. 1 is a block diagram of one or more user equipments (UEs) and a base station (e.g., gNB) of communication in a communication network system according to an embodiment of the present disclosure.

FIG. 2 is a flowchart illustrating an indication method of multicast session deactivation performed by a user equipment (UE) according to an embodiment of the present disclosure.

FIG. 3 is a flowchart illustrating an indication method of multicast session deactivation according to an embodiment of the present disclosure.

FIG. 4 is a block diagram of a system for wireless communication according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure are described in detail with the technical matters, structural features, achieved objects, and effects with reference to the accompanying drawings as follows. Specifically, the terminologies in the embodiments of the present disclosure are merely for describing the purpose of the certain embodiment, but not to limit the disclosure.

In some embodiments of this disclosure, we are going to deal with the issue how a multicast session deactivation is notified to a UE in an RRC inactive state.

FIG. 1 illustrates that, in some embodiments, one or more user equipments (UEs) 10 and a base station (e.g., gNB) 20 for communication in a communication network system 40 according to an embodiment of the present disclosure are provided. The communication network system 40 includes the one or more UEs 10 and the base station 20. The one or more UEs 10 may include a memory 12, a transceiver 13, and a processor 11 coupled to the memory 12 and the transceiver 13. The base station 20 may include a memory 22, a transceiver 23, and a processor 21 coupled to the memory 22 and the transceiver 23. The

processor

11 or 21 may be configured to implement proposed functions, procedures and/or methods described in this description. Layers of radio interface protocol may be implemented in the

processor

11 or 21. The

memory

12 or 22 is operatively coupled with the

processor

11 or 21 and stores a variety of information to operate the

processor

11 or 21. The

transceiver

13 or 23 is operatively coupled with the

processor

11 or 21, and the

transceiver

13 or 23 transmits and/or receives a radio signal.

The

processor

11 or 21 may include application-specific integrated circuit (ASIC) , other chipset, logic circuit and/or data processing device. The

memory

12 or 22 may include read-only memory (ROM) , random access memory (RAM) , flash memory, memory card, storage medium and/or other storage device. The

transceiver

13 or 23 may include baseband circuitry to process radio frequency signals. When the embodiments are implemented in software, the techniques described herein can be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The modules can be stored in the

memory

12 or 22 and executed by the

processor

11 or 21. The

memory

12 or 22 can be implemented within the

processor

11 or 21 or external to the

processor

11 or 21 in which case those can be communicatively coupled to the

processor

11 or 21 via various means as is known in the art. Further, in some embodiments, the processor 11 is configured to perform the following methods.

FIG. 2 is a flowchart illustrating an indication method 200 of multicast session deactivation performed by a user equipment (UE) according to an embodiment of the present disclosure. In some embodiments, the method 200 includes: a step 202, if the UE is in a radio resource control (RRC) inactive state and is configured to receive a multicast session in the RRC inactive state, the UE is notified through a group paging when the multicast session is deactivated.

In some embodiments, the group paging comprises a paging message, an information element (IE) in the paging message, a short message indicator, or a short message used for indication of a multicast session deactivation. In some embodiments, the paging message and the IE in the paging message are used for the indication of the multicast session deactivation, and the UE is configured to receive a multicast service in the RRC inactive state to monitor a paging radio network temporary identifier (P-RNTI) for the paging message. In some embodiments, when the P-RNTI is detected by the UE, the UE receives and decodes the paging message. In some embodiments, when the UE receives and decodes the paging message successfully, the UE determines if the paging message is used for the multicast session deactivation and for which UEs and multicast session.

In some embodiments, the short message indicator or the short message is transmitted by a downlink control information (DCI) format 1_0 with a cyclic redundancy check (CRC) scrambled by a P-RNTI. In some embodiments, when the short message indicator is used for the indication of the multicast session deactivation, the short message indicator comprises 2 bits used for the indication of the multicast session deactivation. In some embodiments, 00 value of a bit field in the short message indicator is used for the indication of the multicast session deactivation, 01 value of a bit field in the short message indicator is used for unicast paging only, 10 value of a bit field in the short message indicator is used for short message only, and 11 value of a bit field in the short message indicator is used for unicast paging and short message. In some embodiments, the short message comprises 8 bits used for the indication of the multicast session deactivation. In some embodiments, if only a scheduling information for paging is carried, a bit field of the short message is reserved. In some embodiments, the IE is added in the paging message to indicate which multicast session is deactivated.

In some embodiments, when the short message is used for the indication of the multicast session deactivation, 00 value of a bit field in the short message indicator stays to be reserved, UE behaviors for 01 value, 10 value, and/or 11 value of bit fields in the short message indicator are changed. In some embodiments, bits of the short message are used for a decision of whether a paging is for the multicast session deactivation, and the UE is configured to decode a physical downlink shared channel (PDSCH) . In some embodiments, the IE is added in the paging message to indicate which multicast session is deactivated. In some embodiments, the UE behaviors for 01 value of the bit field in the short message indicator are changed, 2 bits of short message are used for the indication of the multicast session deactivation. In some embodiments, the UE behaviors for 10 value of the bit field in the short message indicator are changed, 1 bit of short message is used for the indication of the multicast session deactivation. In some embodiments, the UE behaviors for 11 value of the bit field in the short message indicator are changed, 2 bits of short message are used for the indication of the multicast session deactivation.

FIG. 3 is a flowchart illustrating an indication method of multicast session deactivation according to an embodiment of the present disclosure. FIG. 3 illustrates that, in some embodiments, if the UE is in a radio resource control (RRC) inactive state and is configured to receive a multicast session in the RRC inactive state, the UE is notified through a group paging by a network when the multicast session is deactivated.

In some embodiments, the group paging from the network to the UE comprises a paging message, an information element (IE) in the paging message, a short message indicator, or a short message used for indication of a multicast session deactivation. In some embodiments, the paging message and the IE in the paging message from the network to the UE are used for the indication of the multicast session deactivation, and the UE is configured to receive a multicast service in the RRC inactive state to monitor a paging radio network temporary identifier (P-RNTI) for the paging message. In some embodiments, when the P-RNTI is detected by the UE, the UE receives and decodes the paging message. In some embodiments, when the UE receives and decodes the paging message successfully, the UE determines if the paging message is used for the multicast session deactivation and for which UEs and multicast session.

In some embodiments, the short message indicator or the short message from the network to the UE is transmitted by a downlink control information (DCI) format 1_0 with a cyclic redundancy check (CRC) scrambled by a P-RNTI. In some embodiments, when the short message indicator is used for the indication of the multicast session deactivation, the short message indicator comprises 2 bits used for the indication of the multicast session deactivation. In some embodiments, 00 value of a bit field in the short message indicator is used for the indication of the multicast session deactivation, 01 value of a bit field in the short message indicator is used for unicast paging only, 10 value of a bit field in the short message indicator is used for short message only, and 11 value of a bit field in the short message indicator is used for unicast paging and short message. In some embodiments, the short message comprises 8 bits used for the indication of the multicast session deactivation. In some embodiments, if only a scheduling information for paging is carried, a bit field of the short message is reserved. In some embodiments, the IE is added in the paging message to indicate which multicast session is deactivated.

Overall solution in some embodiments of the present disclosure include that: Group paging is used to notify UEs in inactive state when multicast session is deactivated. In solution 1, legacy group paging is used, and a new IE is added in paging message for indication of multicast session deactivation. In solution 2, short message indicator is used for indication of multicast session deactivation. In solution 3, short message is used for indication of multicast session deactivation.

Embodiments

Embodiment 1: Legacy group paging is used, and new IE is added in paging message for indication of multicast session deactivation.

UEs receiving multicast services in inactive state monitor P-RNTI for possible Paging message. When P-RNTI is detected, UEs will receive and decode paging message.

When UEs receive and decode the paging message successfully, UEs can find out if this Paging message is for multicast session deactivation and for which UEs and multicast session (new IEs are added) .

During this stage which is P-RNTI is detected, and paging message has not been decoded successfully, UEs are not ware what the paging message is used for, and the paging message is for which UEs. When UEs receive and decode the paging message successfully, UEs will find out what the paging message is used for and what UEs gNB would like to perform paging.

We can see from ASN. 1 how paging message is working and why this new solution can solve the issue.

Paging message

For the existing Paging message, we can see from the above ASN. 1 and have the following observations.

If UE receive PagingUE-Identity (including whatever NG-5G-S-TMSI or I-RNTI-Value) , UE is aware this paging is legacy unicast paging for itself, and UE will initiate RACH procedure to go to connected state to receive unicast services.

If UE receive TMGI which UE is interested, UE is aware this paging is paging for multicast session activation, and UE will initiate RACH procedure to go to connected state to receive multicast services. (This is R17 procedure which multicast can only be received in connected state. )

Paging cause indicates whether the Paging message is originated due to IMS voice. If this field is present, it implies that the corresponding paging entry is for IMS voice. If upper layers indicate the support of paging cause and if this field is not present but pagingRecordList-v1700 is present, it implies that the corresponding paging entry is for a service other than IMS voice. Otherwise, paging cause is undetermined.

Therefore, for R18 multicast session deactivation, we can have the following IE as an example.

Paging message

New IE or value of Pagingcause can be added to let UEs know what purpose this paging for. The above is an example, and another types of new IE could be like the following.

Paging message

Embodiment 2: Short message indicator is used for indication of multicast session deactivation.

DCI format1_0 scrambled by P-RNTI

DCI format1_0 scrambled by P-RNTI can used for either indication of scheduling information for Paging msg, or sending short msg, or both.

Excerption from TS 38.212 Table 7.3.1.2.1-1

The following information is transmitted by means of the DCI format 1_0 with CRC scrambled by P-RNTI:

Short Messages Indicator –2 bits according to Table 7.3.1.2.1-1.

Short Messages –8 bits, according to Clause 6.5 of [9, TS38.331] . If only the scheduling information for Paging is carried, this bit field is reserved.

Frequency domain resource assignment

bits. If only the short message is carried, this bit field is reserved.

is the size of CORESET 0.

Time domain resource assignment –4 bits as defined in Clause 5.1.2.1 of [6, TS38.214] . If only the short message is carried, this bit field is reserved.

VRB-to-PRB mapping –1 bit according to Table 7.3.1.2.2-5. If only the short message is carried, this bit field is reserved.

Modulation and coding scheme –5 bits as defined in Clause 5.1.3 of [6, TS38.214] , using Table 5.1.3.1-1. If only the short message is carried, this bit field is reserved.

TB scaling –2 bits as defined in Clause 5.1.3.2 of [6, TS38.214] . If only the short message is carried, this bit field is reserved.

Reserved bits –8 bits for operation in a cell with shared spectrum channel access; or otherwise, 6 bits.

Existing short message indicator filed in the DCI format (see TS 38.212 Table 7.3.1.2.1-1) is as following.

Table 7.3.1.2.1-1: Short Message indicator

Table 6.5-1: Short Messages

By summarizing the above spec, we have the following table:

Therefore, we can have the following solution 2: Short message indicator is used for indication of multicast session deactivation.

“00” in short msg indicator is used for indication Multicast session deactivation, “01” /” 10” /” 11” stay the same as before.

New IE is added in paging message to indicate which Multicast session is deactivated.

For the first step: “00” means the paging message in the scheduled PDSCH only contains multicast session deactivation notification. The UE behaviors who receive “00” short msg indicator would be:

UEs receiving multicast session: decode PDSCH with P-RNTI.

Other UEs: Don’t decode PDSCH for paging

For the second step: new IE can be added to indicate which Multicast session is deactivated.

Paging message

Embodiment 3: Short message is used for indication of multicast session deactivation.

“00” in short msg indicator stay to be reserved, change the UE behaviors for “01” /” 10” /” 11” and don’t decide whether UE should decode PDSCH at the moment.

use short msg bits for the decision of whether this paging is for multicast session deactivation and UE should decode PDSCH.

Example 1: change UE behaviors for short msg indicator of “01” and use 2 bits of short msg.

Example 2: change UE behaviors for short msg indicator of “10” and use 1 bit of short msg.

Example 3: change UE behaviors for short msg indicator of “11” and use 2 bits of short msg

Another aspect related to some embodiments of this disclosure is how to ensure this indication is for R18 UEs only. The following solutions are disclosed.

Solution 1: Define and specify NW/BS behaviors. NW/BS and UE can reach consensus that NW/BS will send R18 specific signaling to R18 UEs during some procedures, such as registration procedure.

Solution 2: Notify UEs that the signaling is R18 signaling via broadcast message (e.g, . SIB) or dedicated signaling.

FIG. 4 is a block diagram of an example system 700 for wireless communication according to an embodiment of the present disclosure. Embodiments described herein may be implemented into the system using any suitably configured hardware and/or software. FIG. 4 illustrates the system 700 including a radio frequency (RF) circuitry 710, a baseband circuitry 720, an application circuitry 730, a memory/storage 740, a display 750, a camera 760, a sensor 770, and an input/output (I/O) interface 780, coupled with each other at least as illustrated. The application circuitry 730 may include a circuitry such as, but not limited to, one or more single-core or multi-core processors. The processors may include any combination of general-purpose processors and dedicated processors, such as graphics processors, application processors. The processors may be coupled with the memory/storage and configured to execute instructions stored in the memory/storage to enable various applications and/or operating systems running on the system.

While the present disclosure has been described in connection with what is considered the most practical and preferred embodiments, it is understood that the present disclosure is not limited to the disclosed embodiments but is intended to cover various arrangements made without departing from the scope of the broadest interpretation of the appended claims.

Claims

An indication method of multicast session deactivation performed by a user equipment (UE) , comprising:

if the UE is in a radio resource control (RRC) inactive state and is configured to receive a multicast session in the RRC inactive state, the UE is notified through a group paging when the multicast session is deactivated.
The method according to claim 1, wherein the group paging comprises a paging message, an information element (IE) in the paging message, a short message indicator, or a short message used for indication of a multicast session deactivation.
The method according to claim 2, wherein the paging message and the IE in the paging message are used for the indication of the multicast session deactivation, and the UE is configured to receive a multicast service in the RRC inactive state to monitor a paging radio network temporary identifier (P-RNTI) for the paging message.
The method according to claim 3, wherein when the P-RNTI is detected by the UE, the UE receives and decodes the paging message.
The method according to claim 4, wherein when the UE receives and decodes the paging message successfully, the UE determines if the paging message is used for the multicast session deactivation and for which UEs and multicast session.
The method according to claim 2, wherein the short message indicator or the short message is transmitted by a downlink control information (DCI) format 1_0 with a cyclic redundancy check (CRC) scrambled by a P-RNTI.
The method according to any one of claims 2 to 6, wherein when the short message indicator is used for the indication of the multicast session deactivation, the short message indicator comprises 2 bits used for the indication of the multicast session deactivation.
The method according to claim 7, wherein 00 value of a bit field in the short message indicator is used for the indication of the multicast session deactivation, 01 value of a bit field in the short message indicator is used for unicast paging only, 10 value of a bit field in the short message indicator is used for short message only, and 11 value of a bit field in the short message indicator is used for unicast paging and short message.
The method according to claim 8, wherein the short message comprises 8 bits used for the indication of the multicast session deactivation.
The method according to claim 9, wherein if only a scheduling information for paging is carried, a bit field of the short message is reserved.
The method according to any one of claims 7 to 10, wherein the IE is added in the paging message to indicate which multicast session is deactivated.
The method according to any one of claims 2 to 6, wherein when the short message is used for the indication of the multicast session deactivation, 00 value of a bit field in the short message indicator stays to be reserved, UE behaviors for 01 value, 10 value, and/or 11 value of bit fields in the short message indicator are changed.
The method according to claim 12, wherein bits of the short message are used for a decision of whether a paging is for the multicast session deactivation, and the UE is configured to decode a physical downlink shared channel (PDSCH) .
The method according to claim 12 or 13, wherein the IE is added in the paging message to indicate which multicast session is deactivated.
The method according to ant one of claims 12 to 14, wherein the UE behaviors for 01 value of the bit field in the short message indicator are changed, 2 bits of short message are used for the indication of the multicast session deactivation.
The method according to ant one of claims 12 to 14, wherein the UE behaviors for 10 value of the bit field in the short message indicator are changed, 1 bit of short message is used for the indication of the multicast session deactivation.
The method according to ant one of claims 12 to 14, wherein the UE behaviors for 11 value of the bit field in the short message indicator are changed, 2 bits of short message are used for the indication of the multicast session deactivation.
A user equipment, comprising:

a memory;

a transceiver; and

a processor coupled to the memory and the transceiver;

wherein the processor is configured to execute the method of any one of claims 1 to 17.
A non-transitory machine-readable storage medium having stored thereon instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 17.
A chip, comprising:

a processor, configured to call and run a computer program stored in a memory, to cause a device in which the chip is installed to execute the method of any one of claims 1 to 17.
A computer readable storage medium, in which a computer program is stored, wherein the computer program causes a computer to execute the method of any one of claims 1 to 17.
A computer program product, comprising a computer program, wherein the computer program causes a computer to execute the method of any one of claims 1 to 17.
A computer program, wherein the computer program causes a computer to execute the method of any one of claims 1 to 17.