WO2024065757A1

WO2024065757A1 - Wireless communication methods for multicast/broadcast service and apparatuses

Info

Publication number: WO2024065757A1
Application number: PCT/CN2022/123470
Authority: WO
Inventors: Xin Zhang
Original assignee: Shenzhen Tcl New Technology Co., Ltd.
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2024-04-04

Abstract

Wireless communication methods for multicast/broadcast service (MBS) and apparatuses are disclosed. The method performed by a user equipment (UE) includes changing a UE preference from a connected mode reception to an inactive mode reception or from the inactive mode reception to the connected mode reception and informing a base station of a UE preference change. The method further includes performing a registration update procedure when the UE preference changes.

Description

WIRELESS COMMUNICATION METHODS FOR MULTICAST/BROADCAST SERVICE AND APPARATUSES

BACKGROUND OF DISCLOSURE

1. Field of the Disclosure

The present disclosure relates to the field of wireless communication systems, and more particularly, to wireless communication methods for multicast/broadcast service (MBS) and apparatuses, for example, particularly to an MBS system.

2. Description of the Related Art

In a 3rd generation partnership project (3GPP) cellular network, broadcast and multicast services may be transported via a transport service called multimedia broadcast/multicast service (MBMS) . A broadcast multicast service center (BM-SC) server is responsible to disseminate a media content to a group of subscribers. When a UE moves out of a network coverage, the UE may be unable to use the MBMS because uplink and downlink connections to the BM-SC server are no longer available. MBMS is a point-to-multipoint (PTM) interface specification designed to provide efficient delivery of broadcast and multicast services within 3GPP cellular networks. Examples of MBMS interface specifications include those described in universal mobile telecommunication system (UMTS) and long term evolution (LTE) communication specifications. For broadcast transmission across multiple cells, the specifications define transmission over single-frequency network configurations. Intended applications include mobile TV, news, radio broadcasting, file delivery, emergency alerts, and others. When services are broadcasted by MBMS, all cells inside a multimedia broadcast/multicast service single frequency network (MBSFN) area transmit the same MBMS service.

Users access these services and obtain the MBMS content through wireless communication devices such as cellular phones, tablets, laptops, and other devices with wireless transceivers that communicate with the base station within the communication system. The base station provides wireless service to the wireless communication devices, sometimes referred to as mobile devices or UEs, within cells. A user can access at least some multimedia services through a UE using either a point-to-point (PTP) connection or a PTM transmission. In 3GPP systems, PTP services can be provided using unicast techniques and PTM transmissions can be provided using MBMS communication, transmitted over an MBSFN or single cell point to multipoint (SC-PTM) communication. In systems operating in accordance with a revision of 3GPP long term evolution (LTE) communication specification, MBMS is provided using eMBMS. Accordingly, an MBMS service can be provided using either unicast service, MBSFN, or SC-PTM in an LTE system.

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.

Therefore, there is a need for wireless communication methods for multicast/broadcast service (MBS) and apparatuses.

SUMMARY

An object of the present disclosure is to propose wireless communication methods for multicast/broadcast service (MBS) and apparatuses.

In a first aspect of the present disclosure, a wireless communication method for multicast/broadcast service (MBS) performed by a user equipment (UE) includes changing a UE preference from a connected mode reception to an inactive mode reception or from the inactive mode reception to the connected mode reception and informing a base station of a UE preference change.

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 a wireless communication method for MBS performed by the UE according to an embodiment of the present disclosure.

FIG. 3 is a flowchart illustrating a wireless communication method for MBS according to an embodiment of the present disclosure.

FIG. 4 is a flowchart illustrating a wireless communication method for MBS according to an embodiment of the present disclosure.

FIG. 5 is a flowchart illustrating a wireless communication method for MBS according to an embodiment of the present disclosure.

FIG. 6 is a flowchart illustrating a wireless communication method for MBS according to an embodiment of the present disclosure.

FIG. 7 is a flowchart illustrating a wireless communication method for MBS according to an embodiment of the present disclosure.

FIG. 8 is a flowchart illustrating a wireless communication method for MBS according to an embodiment of the present disclosure.

FIG. 9 is a flowchart illustrating a wireless communication method for MBS according to an embodiment of the present disclosure.

FIG. 10 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 RANP#94 meeting, the following R18 WID has been approved. This work item is to further enhance the NR Multicast/Broadcast functions based on Rel-17 MBS. The objectives for Rel-18 include: 1. Specify support of multicast reception by UEs in RRC_INACTIVE state [RAN2, RAN3] . Specify PTM configuration for UEs receiving multicast in RRC_INACTIVE state [RAN2] . Study the impact of mobility and state transition for UEs receiving multicast in RRC_INACTIVE [RAN2, RAN3] . 2. Specify Uu signaling enhancements to allow a UE to use shared processing for MBS broadcast and unicast reception, i.e., including UE capability and related assistance information reporting regarding simultaneous unicast reception in RRC_CONNECTED and MBS broadcast reception from the same or different operators [RAN2] . 3. Study and if necessary, specify enhancements to improve the resource efficiency for MBS reception in RAN sharing scenarios [RAN3] .

In order to provide MBS service to more UEs in a cell, RAN could enable UEs within an MBS multicast session to receive MBS session data while in RRC Inactive state, which means that within a cell and for a same MBS multicast session, some UEs can be in inactive state and others can be in active state. It is assumed that NW can choose which UEs receive in RRC INACTIVE and which in RRC Connected and can move UEs between the states for Multicast service reception, just like the agreement RANs has made as following. It is assumed the network can choose which UEs receive in RRC INACTIVE and which in RRC Connected and can move UEs between the states for Multicast service reception. On the other side, RAN2 has also made, it is up to gNB to decide whether a multicast session may be received by UE (s) in INACTIVE. FFS what information gNB may be provided to form such decision (related to SA2 discussion) . As mentioned above, UEs RRC state receiving multicast services may be influenced by two aspects. One is whether a multicast session may be received by UE (s) in INACTIVE. The other one is NW choose which UEs receive in RRC INACTIVE state and which in RRC Connected state. Herein we refer “transmission mode” to describe UEs RRC state receiving multicast, implying both of the two aspects mentioned above. Both of the aspects are determined by gNB, which means the transmission mode is determined by gNB. However, gNB might be provided some sustenance information for making such decision, whatever the assistant information is from 5GC side, UE side or both sides. Several solutions about what assist information and how UE could provide to gNB to assist gNB to determine the transmission mode have been discussed. In this disclosure we focus on one of the solutions, which is the assistance information is provided by UEs to gNB by performing registration procedure. The issue we are going to deal with is what might initial UE’s preference (one of the assist information UE provides to gNB) change, and while UE’s preference changes, what procedure should be performed.

In some embodiments of the present disclosure, we focus on one of the solutions, which is an assistance information is provided by UEs to gNB by performing a registration procedure. The issue we are going to deal with is what might initial UE’s preference (one of the assist information UE provides to gNB) change, and while UE’s preference changes, what procedure should be performed.

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.

In some embodiments, the processor 11 is configured to change a UE preference from a connected mode reception to an inactive mode reception or from the inactive mode reception to the connected mode reception, and the transceiver 13 is configured to inform the base station 20 of a UE preference change.

FIG. 2 is a flowchart illustrating a wireless communication method 200 for multicast/broadcast service (MBS) performed by a user equipment (UE) according to an embodiment of the present disclosure. In some embodiments, the wireless communication method 200 for MBS performed by the UE includes: a step 202, changing a UE preference from a connected mode reception to an inactive mode reception or from the inactive mode reception to the connected mode reception, and a step 204, informing a base station of a UE preference change.

In some embodiments, before the UE preference changes, the UE receives a multicast MBS data in a connected state or in an inactive state. In some embodiments, the UE preference changes due to a power level change. In some embodiments, the UE preference change is one of assistance information provided by the UE to the base station. In some embodiments, the method further comprises receiving a radio resource control (RRC) release message from the base station after the UE preference changes, wherein the UE is switched from the connected state to the inactive state based on the RRC release message. In some embodiments, the UE continues receiving the multicast MBS data in the inactive state after the UE preference changes.

In some embodiments, the method further comprises receiving information from the base station after the UE preference changes, wherein the UE is switched from the inactive state to the connected state based on the information. In some embodiments, the UE continues receiving the multicast MBS data in the connected state after the UE preference changes. In some embodiments, the method further comprises performing a registration update procedure when the UE preference changes.

In details, in some examples, the method further includes receiving a radio resource control (RRC) release message from the base station after changing the UE preference from the connected mode reception to the inactive mode reception, wherein the UE is switched from the connected state to the inactive state based on the RRC release message. In some examples, after changing the UE preference from the connected mode reception to the inactive mode reception, the UE continues receiving the multicast MBS data in the inactive state. In some examples, after changing the UE preference from the inactive mode reception to the connected mode reception, the UE continues receiving the multicast MBS data in the inactive state after the UE preference changes. In details, in some examples, the method further includes receiving information from the base station after changing the UE preference from the inactive mode reception to the connected mode reception, wherein the UE is switched from the inactive state to the connected state based on the information. In some examples, after changing the UE preference from the connected mode reception to the inactive mode reception, the UE continues receiving the multicast MBS data in the connected state. In some examples, after changing the UE preference from the connected mode reception to the inactive mode reception, the UE continues receiving the multicast MBS data in the connected state after the UE preference changes.

In some embodiments, the registration update procedure comprises a periodic registration update procedure or a mobility registration update procedure. In some embodiments, in the periodic registration update procedure, the UE sends a registration request and the UE preference change to the base station, and UE receives a registration accept from an access and mobility management function (AMF) . In some embodiments, a condition for triggering the periodic registration update procedure is an expiration of a related timer.

In some embodiments, in the mobility registration update procedure, the UE sends a registration request and the UE preference change to the base station, and UE receives a registration accept from an AMF. In some embodiments, the UE preference change is one of triggers to trigger the registration update procedure.

FIG. 3 to FIG. 9 illustrate examples regarding the UE preference changes for transmission mode determination according to an embodiment of the present disclosure. Two parts are included in some embodiments of this disclosure. Part 1 is what might initiate the UE preference change. Part 2 is while the UE preference changes, what procedure should be performed.

UE preference change:

One of the reasons that might initiate UE preference change is power change. While UE owns enough battery and meanwhile would like to ensure high reliability, UE would prefer to be in connected state to receive multicast service. However, while UE is consuming battery and has no enough power to support connected state reception, UE might change the preference and inform gNB.

While UE is originally receiving multicast services in connected state and then informs gNB of the preference change, the gNB may determine to switch to inactive state or still stay in connected state. The procedure can be illustrated in FIG. 3 (gNB determines to go to inactive state) and FIG. 4 (gNB determines to still stay in connected state) .

While UE is originally receiving multicast services in inactive state and then informs gNB of the preference change, the gNB may determine to switch to connected state or still stay in inactive state. The procedure can be illustrated in FIG. 5 (gNB determines to go to connected state) and FIFG. 6 (gNB determines to still stay in inactive state) .

The procedure can be as follows:

(1) UE receives multicast MBS data in connected state.

(2) UE preference changes due to e.g., power level change (no enough power) .

(3) UE informs gNB of the change (UE preference change is one of assistance information provided by UE to gNB) .

(4) gNB determines to move UE in multicast MBS session to inactive state based on the assistance information.

(5) gNB releases the RRC connection by sending RRCrelese message and moves UE to inactive state.

(6) UE continues receiving multicast MBS data in inactive state.

The procedure can be as follows:

(1) UE receives multicast MBS data in inactive state.

(2) UE preference changes due to e.g. power level change (got enough power again) .

(3) UE informs gNB of the change (UE’s preference change is one of assistance information provided by UE to gNB) .

(4) gNB determines to move UE in multicast MBS session to connected state based on the assistance information.

(5) gNB informs related UEs to connected state.

(6) UE switches to connected state to continue receiving multicast MBS data in connected state.

Based on the indication from upper layers:

Another preference based on the indication from upper layers can also be used to inform the network that UE wants to receive the multicast service in inactive mode.

The procedure as illustrated in FIG. 3 to FIG. 6 provides steps on that: how UE informs gNB of the preference change and how gNB informs UE to be switched to connected state, while UE is originally in inactive state.

In some examples, we assume that the UE registration procedure is used by UEs to transmit the assistance information to gNB. The Registration type indicates if the UE wants to perform an Initial Registration (i.e. the UE is in RM-DEREGISTERED state) , a mobility registration update (i.e., the UE is in RM-REGISTERED state and initiates a Registration procedure due to mobility or due to the UE needs to update its capabilities or protocol parameters, or to request a change of the set of network slices it is allowed to use) , a periodic registration update (i.e., the UE is in RM-REGISTERED state and initiates a Registration procedure due to the Periodic Registration Update timer expiry) , an emergency registration (i.e. the UE is in limited service state) , a Disaster Roaming Initial Registration, or a Disaster Roaming Mobility Registration Update.

While the UE preference changes, UE can perform registration update procedure to inform gNB of UE’s preference change. We can consider two solutions. The first solution is UE performs traditional registration update procedure including both Mobility Registration Update procedure and Periodic Registration Update procedure, and add UE’s preference change related information in the steps UE sends to gNB as illustrated in the above embodiments. The other solution is UE preference change is one of the triggers to trigger Registration update procedure.

UE performs Periodic Registration Update procedure:

FIG. 7 illustrates that in some embodiments, the UE performs a periodic registration update procedure as the following steps:

(1) UE sends registration request to gNB, and UE’s preference changes related information, such as an indication which indicates UE’s preference change.

(2) gNB performs AMF selection.

(3) gNB sends Registration Request to AMF.

(4) AMF sends UE Registration Accept to UE.

The condition that triggers Periodic Registration Update procedure is that the related timer expires.

UE performs Mobility Registration Update procedure:

FIG. 8 illustrates that in some embodiments, the UE performs a mobility registration update procedure as the following steps:

(2) gNB performs AMF selection.

(3) gNB sends Registration Request to new AMF.

(4) New AMF sends UE Context Transfer to acquire UE Context.

(5) Old AMF transfers UE Context to New AMF and responds UE Context Transfer.

(6) New AMF sends Registration Complete to old AMF.

(7) New AMF sends UE Registration Accept to UE.

In some examples, the UE preference change is one of the triggers to trigger Registration update procedure.

FIG. 9 illustrates that in some embodiments, the UE performs a procedure as the following steps:

(1) UE receives multicast MBS data in inactive/connected state.

(2) UE’s preference changes due to e.g., power level change.

(3) UE triggers registration update procedure.

In summary, in some embodiments of this disclosure, we focus on one of the solutions, which is the assistance information is provided by UEs to gNB by performing registration procedure. The issue we are going to deal with is what might initial UE’s preference (one of the assist information UE provides to gNB) change, and while UE’s preference changes, what procedure should be performed. This is a new requirement introduced in R18 MBS and no such requirements before.

FIG. 10 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. 10 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

A wireless communication method for multicast/broadcast service (MBS) performed by a user equipment (UE) , comprising:

changing a UE preference from a connected mode reception to an inactive mode reception or from the inactive mode reception to the connected mode reception; and

informing a base station of a UE preference change.
The method according to claim 1, wherein before the UE preference changes, the UE receives a multicast MBS data in a connected state or in an inactive state.
The method according to claim 1 or 2, wherein the UE preference changes due to a power level change.
The method according to any one of claims 1 to 3, wherein the UE preference change is one of assistance information provided by the UE to the base station.
The method according to any one of claims 2 to 4, further comprising receiving a radio resource control (RRC) release message from the base station after the UE preference changes, wherein the UE is switched from the connected state to the inactive state based on the RRC release message.
The method according to claim 5, wherein comprising receiving the RRC release message from the base station is after changing the UE preference from the connected mode reception to the inactive mode reception, wherein the UE is switched from the connected state to the inactive state based on the RRC release message.
The method according to any one of claims 2 to 6, wherein the UE continues receiving the multicast MBS data in the inactive state after the UE preference changes.
The method according to claim 7, wherein after changing the UE preference from the connected mode reception to the inactive mode reception, the UE continues receiving the multicast MBS data in the inactive state.
The method according to any one of claims 2 to 8, wherein after changing the UE preference from the inactive mode reception to the connected mode reception, the UE continues receiving the multicast MBS data in the inactive state after the UE preference changes.
The method according to any one of claims 2 to 9, further comprising receiving information from the base station after the UE preference changes, wherein the UE is switched from the inactive state to the connected state based on the information.
The method according to claim 10, wherein receiving the information from the base station is after changing the UE preference from the inactive mode reception to the connected mode reception, wherein the UE is switched from the inactive state to the connected state based on the information.
The method according to any one of claims 2 to 11, wherein the UE continues receiving the multicast MBS data in the connected state after the UE preference changes.
The method according to claim 12, wherein after changing the UE preference from the connected mode reception to the inactive mode reception, the UE continues receiving the multicast MBS data in the connected state after the UE preference changes.
The method according to any one of claims 1 to 13, further comprising performing a registration update procedure when the UE preference changes.
The method according to claim 14, wherein the registration update procedure comprises a periodic registration update procedure or a mobility registration update procedure.
The method according to claim 15, wherein in the periodic registration update procedure, the UE sends a registration request and the UE preference change to the base station, and UE receives a registration accept from an access and mobility management function (AMF) .
The method according to claim 16, wherein a condition for triggering the periodic registration update procedure is an expiration of a related timer.
The method according to claim 15, wherein in the mobility registration update procedure, the UE sends a registration request and the UE preference change to the base station, and UE receives a registration accept from an AMF.
The method according to any one of claims 14 to 18, wherein the UE preference change is one of triggers to trigger the registration update procedure.
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 19.
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 19.
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 19.
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 19.
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 19.
A computer program, wherein the computer program causes a computer to execute the method of any one of claims 1 to 19.