Multicast service receiving method, multicast service transmission method and related equipment

Abstract

The invention provides a multicast service receiving method. The method is performed by a user equipment (UE) in a network, comprising receiving a multicast service according to a first point-to-multipoint PTM configuration configured by a dedicated signaling; when the UE is kept in the inactive state, configuring a second PTM configuration for multicast service through a broadcast mode; and continuing to receive the multicast service in the inactive state according to the second PTM configuration. According to the method, PTM configuration can be provided for the UE in the inactive state so as to realize multicast service transmission in the inactive state.

Description

Technical Field

[0001] The present invention relates to wireless communication technology, and more specifically, to a multicast service receiving method, a multicast service transmission method, and related equipment such as user equipment (UE) and a base station (BS) (e.g., gNB). Background Art

[0002] Communication systems and networks have evolved into broadband and mobile systems. In the cellular wireless communication system developed by the Third Generation Partnership Project (3GPP). In the cellular wireless communication system, the user equipment (UE) is connected to the radio access network (RAN) via a radio link. The RAN includes a set of base stations (BS) and an interface to the core network (CN), the former providing a radio link with the UE in the cell covered by the base station, and the latter providing overall network control. The RAN and CN each perform their own functions related to the entire network. The Third Generation Partnership Project developed the Long Term Evolution (LTE) system, the Evolved Universal Mobile Telecommunications System Radio Access Network (E-UTRAN), for mobile access networks, in which one or more macro base stations are supported by base stations called eNodeB or eNB (evolved NodeB). LTE is further evolving towards the so-called 5G or NR (New Radio) system, in which one or more cells are supported by base stations called next generation NodeB base stations (gNB).

[0003] In LTE, if the UE is inactive for a period of time, the network can command the UE to enter the RRC_IDLE state to reduce the power consumption of the UE. Whenever the UE needs to perform certain activities, the UE needs to transition from the RRC_IDLE state to the RRC_CONNECTED state. Since small amounts of data must be sent very frequently in current mobile communication applications, frequent idle-connected-idle transitions increase network signaling load and latency. Therefore, 5G NR defines a new state called RRC_INACTIVE to reduce the network signaling load and latency involved in transitioning to the RRC_CONNECTED state. In NR, when the RRC connection is established, the UE is in the RRC_CONNECTED state, and when the RRC connection is suspended, the UE is in the RRC_INACTIVE state. Otherwise, the UE is in the RRC_IDLE state, that is, the RRC connection is not established. The RRC_INACTIVE and RRC_IDLE states can be called energy-saving states. More specifically, in the RRC_Inactive state, the UE AccessStratum (AS) context is stored on the UE and the network side in order to maintain the core network connection (i.e., the UE remains in the Connection Management (CM)-connection) and release the Radio Access Network (RAN) connection. The network can reach the inactive UE via RAN or CN paging messages.

[0004] To enable resource-efficient multicast / broadcast services (MBS) delivery, 3GPP developed NR broadcast / multicast in 3GPP Rel-17, aiming to enable universal MBS services over the 5G System (5GS). Identified use cases that may benefit from this capability include public safety and mission-critical, V2X applications, IPTV, real-time video, software delivery for wireless and IoT applications, etc. Two delivery modes have been agreed for 3GPP Release-17 on MBS, where delivery mode 1 (for multicast only) is able to handle higher QoS services and delivery mode 2 (for broadcast only) focuses on lower QoS services. Given that 3GPP Release-17 on MBS already provides basic functionality to support MBS services, the main goal of 3GPP in Release-18 should be to enable better deployment of MBS, such as improving resource efficiency and capacity based on 3GPP Release-17 on MBS.

[0005] In 3GPP Release 17, the Radio Access Network (RAN) specifies multicast only for UEs in the RRC_CONNECTED state, which cannot fully meet the requirements of mission-critical services, etc., especially for cells with a large number of UEs. In addition, it is not energy-efficient to always keep the UE in the RRC_CONNECTED state. Therefore, it is very important to support multicast for UEs in RRC_INACTIVE.

[0006] At the RANP#94 meeting, the R18 WID was approved to further enhance the NR multicast / broadcast functionality based on 3GPP Release 17 for MBS. The goal of 3GPP in Release 18 is to specify that UEs support multicast reception in the RRC_INACTIVE state. One of the most important issues to be addressed is the Point-To-Multipoint (PTM) configuration of UEs receiving multicast in the RRC_INACTIVE state.

[0007] Figure 1 The present invention is a flow chart of PTM configuration transmission of a UE receiving a multicast service in a connected mode according to the prior art. Figure 1 , explains how to configure a UE with a PTM configuration and receive multicast services based on the PTM configuration. For a UE in the idle state, when a multicast session starts, the gNB sends an MCCH change notification to the UE. The UE then enters the connected state to receive the multicast configuration transmitted through dedicated signaling. Finally, the UE maintains the connected state to receive the multicast service. That is, for a UE interested in receiving multicast services in the connected state, the UE will transition from the power saving state to the connected state to receive the associated PTM configuration through dedicated signaling.

[0008] Figure 2 The present invention is a flow chart of PTM configuration transmission of a UE receiving broadcast services in idle / inactive / connected mode in the prior art. Figure 2, explains how to configure a UE using a PTM configuration and receive broadcast services based on the PTM configuration. When reading the System Information Block 1 (SIB1), a UE interested in receiving broadcast services identifies the scheduling information of SIB20. SIB20 contains the information required to obtain the multicast control channel configuration associated with the transmission of the multicast traffic channel (MTCH) for broadcast data. Then, in the MCCH, the UE can further look up the configuration of the MTCH that carries the broadcast. Finally, after the UE receives the scheduling information including the G-RNTI of the MTCH by decoding the MCCH, it can receive the MTCH in idle / inactive / connected state. That is, for UEs interested in receiving broadcast services in idle / inactive / connected mode, the UE will remain in idle / inactive / connected mode to receive the associated PTM configuration configured using SIB and MCCH.

[0009] Regarding the PTM configuration of UEs receiving multicast services in an inactive state, the 3GPP meeting has reached the following agreement:

[0010] Option 1: Dedicated signaling

[0011] Option 2: SIB+MCCH based solution

[0012] However, for option 1, when the PTM configuration of a UE in RRC_INACTIVE state is updated, a large number of UEs initiating random access will cause network congestion, which runs counter to the main purpose of introducing PTM configuration in RRC_INACTIVE. In addition, this may increase the payload of the RRCRelease message.

[0013] For option 2, the UE still needs an indication or condition to decide whether it can receive multicast in the RRC_CONNECTED state. It should be noted that it may be inevitable for UEs to receive multicast in RRC_CONNECTED, so solutions like SIB+MCCH may introduce some redundancy. The SIB+MCCH approach can only provide general configurations, not UE-specific configurations, so in a sense, it may lead to QoS impairment.

[0014] Therefore, it is necessary to develop a mechanism to solve the above problems. Summary of the invention

[0015] The object of the present invention is to provide a multicast service receiving method, a multicast service transmission method and related equipment for providing PTM configuration for UE in an inactive state, so as to realize multicast service transmission in an inactive state.

[0016] In a first aspect, an embodiment of the present invention provides a method for receiving a multicast service, which is performed by a user equipment UE in a network, and the method includes: receiving a multicast service according to a point-to-multipoint PTM configuration configured by dedicated signaling; when the UE remains in an inactive state, a second PTM configuration for the multicast service is configured by broadcasting; and continuing to receive the multicast service in an inactive state according to the second PTM configuration.

[0017] In a second aspect, an embodiment of the present invention provides a method for receiving a multicast service, which is performed by a user equipment UE in a network, and the method includes: receiving a multicast service according to a first PTM configuration configured using a broadcast method; when the UE remains in an inactive state, a second PTM configuration is configured for the multicast service through a broadcast method or through dedicated signaling; and continuing to receive the multicast service in an inactive state according to the second PTM configuration.

[0018] In a third aspect, an embodiment of the present invention provides a multicast service transmission method, which is executed by a base station BS in a network, and the method includes: transmitting a multicast service to a user equipment UE to receive the multicast service according to a first point-to-multipoint PTM configuration configured by dedicated signaling; when the UE remains in an inactive state, configuring the UE with a second PTM configuration for the multicast service by broadcasting; and continuing to transmit the multicast service so that the UE receives the multicast service in an inactive state according to the second PTM configuration.

[0019] In a fourth aspect, an embodiment of the present invention provides a multicast service transmission method, which is executed by a base station BS in a network, and the method includes: sending a multicast service to a user equipment UE to receive the multicast service according to a first PTM configuration configured using a broadcast method; when the UE remains in an inactive state, configuring the UE with a second PTM configuration for the multicast service via a broadcast method or via dedicated signaling; and continuing to transmit the multicast service so that the UE receives the multicast service in an inactive state according to the second PTM configuration.

[0020] In a fifth aspect, an embodiment of the present invention provides a UE, comprising a processor and a transmitter, wherein the processor is configured to call and run program instructions stored in a memory to cooperate with the transmitter to execute any one of the methods of the first or second aspect.

[0021] In a sixth aspect, an embodiment of the present invention provides a BS, comprising a processor and a transmitter, wherein the processor is configured to call and run program instructions stored in a memory to cooperate with the transmitter to execute any method in the third or fourth aspect.

[0022] In a seventh aspect, an embodiment of the present invention provides a computer-readable storage medium for storing a computer program, enabling a computer to execute the method of any one of the first to fourth aspects.

[0023] In an eighth aspect, an embodiment of the present invention provides a computer program product, comprising computer program instructions enabling the execution of the method of any one of the first to fourth aspects.

[0024] In a ninth aspect, an embodiment of the present invention provides a computer program which, when run on a computer, enables the computer to execute the method of any one of the first to fourth aspects.

[0025] The non-transitory computer readable medium may include at least one of the following group: a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an EPROM, an electrically erasable programmable read-only memory, and a flash memory. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 FIG. 4 is a flow chart showing a PTM configuration transmission flow of a UE receiving a multicast service in a connected mode according to the prior art.

[0028] Figure 2 A flow chart of PTM configuration transmission of a UE receiving broadcast services in idle / inactive / connected mode according to the prior art is shown.

[0029] Figure 3 A block diagram of an embodiment of the present invention is shown.

[0031] Figure 4 A flow chart of a method for receiving a multicast service according to a first embodiment of the present invention is shown.

[0032] Figure 5 FIG. 1 is a flow chart showing a multicast service transmission flow in which a PTM configuration is configured through dedicated signaling in the first case.

[0033] Figure 6 FIG. 4 is a flow chart showing the multicast service transmission flow of configuring PTM through dedicated signaling in the second case.

[0034] Figure 7 Draw Figure 5A flowchart of a multicast service receiving method applied in the first scenario is shown.

[0035] Figure 8 Draw Figure 6 The flowchart of the multicast service receiving method used in the second scenario is shown.

[0036] Fig. 9 A flow chart of a method for receiving a multicast service according to a second embodiment of the present invention is shown.

[0037] Fig.10 A flow chart of multicast service transmission using SIB and MCCH to configure PTM configuration in the first case is shown.

[0038] Fig.11 A flow chart of multicast service transmission using SIB and MCCH to configure PTM configuration in the second case is shown.

[0039] Fig.12 Draw on Fig.10 A flowchart of a multicast service receiving method applied in the first scenario is shown.

[0040] Fig.13 Draw on Fig.11 The flowchart of the multicast service receiving method used in the second scenario is shown. DETAILED DESCRIPTION

[0041] The embodiments of the present invention describe technical matters, structural features, implementation purposes and effects in detail with reference to the accompanying drawings. Specifically, the terms in the embodiments of the present invention are only used for the purpose of describing specific embodiments, rather than limiting the disclosure.

[0042] like Figure 3 As shown, in some embodiments, a communication network system 30 of an embodiment of the present invention provides one or more user equipments (UEs) 10 and a base station (e.g., gNB or eNB) 20 for performing wireless communication. The communication network system 30 includes one or more UEs 10 and a base station 20. 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 the proposed functions, processes, and / or methods described in the present invention. The layers of the radio interface protocol may be implemented in the processor 11 or 21. The memory 12 or 22 works with the processor 11 or 21 and stores various information to operate the processor 11 or 21. The transceiver 13 or 23 works with the processor 11 or 21, and the transceiver 13 or 23 sends and / or receives radio signals.

[0043] The processor 11 or 21 may include an application specific integrated circuit (ASIC), other chipsets, logic circuits and / or data processing devices. The memory 12 or 22 may include a read-only memory (ROM), a random access memory (RAM), flash memory, a memory card, a storage medium and / or other storage devices. The transceiver 13 or 23 may include a baseband circuit for processing radio frequency signals. When the embodiment is implemented in software, the technology described in the present invention may be implemented by a module (e.g., a process, a function, etc.) that performs the functions described in the present invention. The module may be stored in the memory 12 or 22 and executed by the processor 11 or 21. The memory 12 or 22 may be integrated inside the processor 11 or 21, or may be implemented outside the processor 11 or 21, in which case they may be communicatively coupled with the processor 11 or 21 in various ways known in the art.

[0044] Figure 4 FIG. 1 is a flowchart of a multicast service receiving method 100 according to a first embodiment of the present invention. Figure 3 and Figure 4 , method 100 includes the following contents.

[0045] In step 110, a user equipment (UE) receives a multicast service from a base station (BS) according to a first PTM configuration configured by the BS. The first PTM configuration is configured by dedicated signaling. For example, the dedicated signaling is a radio resource control (RRC) signaling. In one embodiment, the first PTM configuration may be carried in a radio resource control (RRC) message. The UE receives the RRC message when it is in a connected state (e.g., RRC_CONNECTED) and is configured according to the first PTM configuration. The UE may receive the multicast service when it is in a connected state or an inactive state (e.g., RRC_INACTIVE) according to the first PTM configuration. In another embodiment, the first PTM configuration may be carried in an RRC release message (e.g., RRCRelease), and when the connected state is converted to an inactive state, the UE configures the PTM configuration by receiving the RRC release message. The UE may receive the multicast service when it is in an inactive state according to the first PTM configuration.

[0046] In step 120, when the UE remains in an inactive state, a second PTM configuration of the multicast service is configured for the UE in a broadcast manner. Figure 2As shown, the broadcast mode includes a method of configuring the second PTM configuration through a system information block (SIB) and an MBS control channel (MCCH). That is, if the PTM configuration (i.e., the defined first PTM configuration) is previously configured to the UE through dedicated signaling, when the UE enters or remains in an inactive state and is interested in receiving a multicast service when in the inactive state, the PTM configuration (i.e., the defined second PTM configuration) is configured for the UE through a broadcast mode.

[0047] In one embodiment, the second PTM configuration is configured to the UE in the inactive state only when the first PTM configuration needs to be changed. That is, the second PTM configuration is configured to the UE in the inactive state by broadcasting only when the first PTM configuration based on which the UE receives the multicast service changes. In another embodiment, once the UE enters the inactive state, the second PTM configuration is configured regardless of whether the first PTM configuration needs to be changed. That is, regardless of whether the first PTM configuration based on which the UE receives the multicast service changes, as long as the UE is converted to the inactive state, the second PTM configuration is configured to the UE in the inactive state by broadcasting.

[0048] If the updated PTM configuration (i.e., the defined second PTM configuration) is configured as an inactive state only when the PTM configuration changes (i.e., the defined first PTM configuration), the UE may receive a notification of the PTM configuration change and then receive the updated PTM configuration. Specifically, the UE receives an MBS control channel (MCCH) change notification transmitted from the BS when in an inactive state, and the MCCH change notification indicates a PTM configuration change. For example, the MCCH change notification may include two bits, one of which is used to notify the UE to start the multicast part, and the other bit is used to notify the UE that the configuration of the ongoing multicast part has changed or is about to change. Then, after receiving the notification of the PTM configuration change, the UE receives the changed or updated PTM configuration through the MCCH, and applies the changed or updated PTM configuration to subsequent multicast service transmissions. In this step, after receiving the notification of the PTM configuration change, the UE will receive the changed PTM configuration from the BS. The changed PTM configuration may be an incremental or complete configuration relative to the PTM configuration, that is, the changed PTM configuration itself is different compared to the PTM configuration, or the changed PTM configuration is a completely new PTM configuration even though some contents of the configuration may be the same as the PTM configuration. The changed or updated PTM configuration is then applied and the UE may receive subsequent multicast service transmissions in the inactive state.

[0049] like Figure 2As shown, if the new PTM configuration (ie, the defined second PTM configuration) is configured as the inactive state immediately after the UE switches to the inactive state, a broadcasting method using SIB and MCCH may be adopted to configure the UE with the new PTM configuration.

[0050] In step 130, the UE continues to receive the multicast service in an inactive state using the second PTM configuration configured in step 120. In this step, the multicast service received in step 110 continues to be received in step 130. The difference is that the multicast service received in step 130 is based on the second PTM configuration configured in a broadcast manner, while the multicast service received in step 110 is based on the first PTM configuration configured by dedicated signaling. Since the continuous reception of the multicast service can be seamless, it will not be perceived by the user.

[0051] Using this method, the UE can use the PTM configuration in the inactive state without having to receive the PTM configuration after switching from the inactive state to the connected state, thereby avoiding network congestion and reducing the load of the RRC release message.

[0052] In some embodiments, the method may also include: configuring according to the first PTM configuration through the dedicated signaling when in a connected state; receiving the multicast service when in the connected state according to the first PTM configuration; and transitioning from the connected state to the inactive state, wherein the multicast service received in the connected state according to the first PTM configuration continues to be received in the inactive state.

[0053] In some embodiments, the method may further include: upon receiving an RRC release message carrying the first PTM configuration, converting from the connected state to the inactive state, wherein the first PTM configuration is used to receive a multicast service in the inactive state.

[0054] 3GPP R2-119 discusses the solution for supporting multicast service reception of inactive UE. In the following two cases, it is assumed that the UE already has a valid PTM configuration.

[0055] The first case: the UE has been receiving multicast in the CONNECTED state, and it enters the INACTIVE state and continues the multicast reception.

[0056] The second situation: the UE has joined the multicast session and is directed to an inactive (INACTIVE) state, and the UE starts to receive the multicast session.

[0057] See also Figure 4 The flowchart of the multicast service receiving method is shown in FIG. Figure 5 and Figure 6 The above two situations are further described in detail.

[0058] Figure 5 It is a flow chart of multicast service transmission with PTM configuration configured through dedicated signaling in the first case. For the first case, the UE receives the multicast session in the connected state, where the PTM configuration is configured through dedicated signaling, but due to the increase in the number of UEs or traffic, some UEs need to be transferred to the inactive state, but continue to receive the multicast session.

[0059] Figure 6 is a flow chart of multicast service transmission with PTM configuration configured via dedicated signaling in the second case. For the second case, the UE has joined a multicast session in which the PTM configuration is configured via dedicated signaling and is in an inactive state, but due to the activation of the multicast session, some or all of the UEs can remain in an inactive state (i.e., without having to go to a connected state) and can receive the multicast session.

[0060] For the first and second cases, when updating the PTM configuration of the UE in RRC_INACTIVE, the dedicated signaling can cause a large number of UEs to initiate random access, which may cause network congestion, which runs counter to the main purpose of introducing PTM configuration in RRC_INACTIVE. In addition, this may increase the payload of the RRC release message. To address this problem, we introduce the following solution.

[0061] Figure 7 yes Figure 5 The flowchart of the multicast service receiving method applied in the first case is shown. Figure 7 , the UE already has a valid PTM configuration in the connected state (step 1) and starts receiving multicast services from the gNB in ​​the connected state according to the PTM configuration (step 2). The PTM configuration can be configured by dedicated signaling (e.g., RRC signaling). After receiving the RRC message from the gNB (step 3), the UE transitions from the connected state to the inactive state. The UE continues to receive multicast services from the gNB in ​​the inactive state according to the PTM configuration configured in the connected state (step 4). In the inactive state, the UE receives an MCCH change notification from the gNB indicating that the PTM configuration has changed (step 5). After receiving the notification of the PTM configuration change, the UE receives a changed or updated PTM configuration from the gNB (step 6), which is a partial new configuration or a complete configuration relative to the PTM configuration. The UE continues to receive multicast services in the inactive state according to the changed or updated PTM configuration (step 7).

[0062] Figure 8 yes Figure 6The flowchart of the multicast service receiving method used in the second case is shown. Figure 8 , the UE transitions from the connected state to the inactive state upon receiving the RRC release message from the gNB. The RRC release message carries the PTM configuration for the UE to receive multicast services based on it (step 1). When the UE is in the inactive state, the UE starts receiving multicast services from the gNB according to the PTM configuration carried in the RRC release message (step 2). In the inactive state, the UE receives an MCCH change notification from the gNB indicating that the PTM configuration has changed (step 3). After receiving the notification of the PTM configuration change, the UE receives the changed or updated PTM configuration from the gNB (step 4), which is an incremental or complete configuration relative to the PTM configuration. The UE continues to receive multicast services in the inactive state according to the changed or updated PTM configuration (step 5).

[0063] Since the UE receives the PTM configuration change and the indication of the changed or updated PTM configuration through the MCCH without transitioning from an inactive state to a connected state to receive the changed or updated PTM configuration, network congestion is avoided and the payload of the RRC release message is reduced.

[0064] Fig. 9 FIG. 2 is a flow chart of a multicast service receiving method 200 according to a second embodiment of the present invention. Figure 3 See also Fig. 9 , method 200 includes the following contents.

[0065] In step 210, a user equipment (UE) receives a multicast service from a base station (BS) according to a first PTM configuration configured by the BS. The first PTM configuration is configured using a broadcast method (e.g., using a system information block (SIB) and an MBS control channel (MCCH)). Specifically, the UE reads the broadcast system information block 1 (SIB1) and identifies the scheduling information of SIB20, which contains the information required to obtain the multicast control channel configuration. In the MCCH, the UE can further find the first PTM configuration for receiving the multicast service. In one embodiment, when the UE maintains a connected state (e.g., RRC_CONNECTED), the UE configures the first PTM configuration through the SIB and the MCCH. The UE can receive the multicast service in the connected state according to the first PTM configuration. In another embodiment, when the UE maintains an inactive state (e.g., RRC_INACTIVE), the UE configures the first PTM configuration through the SIB and the MCCH. The UE can receive the multicast service according to the first PTM configuration in the inactive state.

[0066] In step 220, when the UE remains in an inactive state, the UE is configured with a second PTM configuration for the multicast service through a broadcast method or through dedicated signaling. The broadcast method includes a method of configuring the second PTM configuration through SIB and MCCH, such as Figure 2 As shown. The dedicated signaling may be a radio resource control (RRC) signaling. Figure 1 As shown, the UE can be converted from the inactive state to the connected state to receive a radio resource control (RRC) message, the second PTM configuration is carried in the RRC message, and the UE configures the second PTM configuration by receiving the RRC message after converting to the connected state. That is, if the PTM configuration (i.e., the defined first PTM configuration) is previously configured to the UE by broadcasting, when the UE enters or remains in the inactive state and is interested in receiving a multicast service in the inactive state, the UE will configure the PTM configuration (i.e., the defined second PTM configuration) by broadcasting or dedicated signaling.

[0067] There are two situations to consider. If the second PTM configuration is a PTM configuration common to all UEs, the second PTM configuration will be configured to all UEs in an inactive state by broadcasting. That is, when the PTM configuration to be configured is in an inactive state, the PTM configuration is configured to all UEs in an inactive state by broadcasting. If the second PTM configuration is a UE-specific PTM configuration, the second PTM configuration will be configured to one or more UEs in an inactive state by dedicated signaling. That is, when the PTM configuration to be configured in an inactive state is a configuration specific to one or more UEs, the PTM configuration will be configured to one or more UEs in an inactive state by dedicated signaling.

[0068] If the PTM configuration to be configured as an inactive state (ie, the second PTM configuration) is a common PTM configuration, a broadcasting method using SIB and MCCH may be adopted, such as Figure 2 More specifically, the UE may receive a notification of a first PTM configuration change through an MCCH change notification, and receive a second PTM configuration in an inactive state through an MCCH after receiving the MCCH change notification.

[0069] If the PTM configuration to be configured as the inactive state (i.e., the second PTM configuration) is a UE-specific PTM configuration, the UE may receive a reception indication of the UE-specific PTM configuration, more specifically, the BS may page the UE to receive the UE-specific PTM configuration, and the indication of receiving the UE-specific PTM configuration may be carried in the paging message. An indication bit may be added / introduced in the paging message. For example, the indication bit may be added to a P-RNTI-scrambled short message. Compared with the first PTM configuration in step 210, the UE-specific PTM configuration is a UE-specific configuration, which is a common configuration for all UEs. After receiving the indication, the UE receives the UE-specific PTM configuration. Specifically, according to the indication, the UE transitions from the inactive state to the connected state to receive the UE-specific PTM configuration in the connected state. Since the UE transitions to the connected state to receive the UE-specific PTM configuration, the UE-specific PTM configuration may be carried in the RRC message. Since the UE-specific PTM configuration is configured through such dedicated signaling, it is a configuration specific to one or more UEs. In contrast, the first PTM configuration in step 210 is configured via SIB and MCCH (i.e., broadcast mode), and is a common configuration for all UEs. The UE-specific PTM configuration may be an incremental or complete configuration relative to the first PTM configuration, that is, the UE-specific PTM configuration itself is different from the first PTM configuration, or the UE-specific PTM configuration is a completely new PTM configuration, even though some contents of the configuration may be the same as the first PTM configuration.

[0070] In step 230, upon receiving the second PTM configuration, the UE transitions from a connected state to an inactive state to receive subsequent multicast service transmissions in the inactive state. The second PTM configuration is used to receive subsequent multicast service transmissions in the inactive state. The UE continues to receive multicast services using the second PTM configuration in the inactive state. In this step, the multicast service received in step 210 will continue to be received in step 230. The difference is that the multicast service received in step 230 is based on the second PTM configuration (which may be a general PTM configuration or a UE-specific PTM configuration), while the multicast service received in step 210 is based on the first PTM configuration (i.e., a general configuration configured by broadcasting). The continuation of multicast service reception may be seamless without being perceived by the user.

[0071] Using this method, the UE can receive the second PTM configuration via broadcast or dedicated signaling, depending on whether the PTM configuration is a general configuration or UE-specific. In the inactive state, the UE-specific PTM configuration can be provided to the UE without compromising QoS.

[0072] In some embodiments, the method may also include: configuring the first PTM configuration in the connected state using the broadcast mode; receiving the multicast service in the connected state according to the first PTM configuration; and transitioning from the connected state to the inactive state, wherein the multicast service received in the connected state according to the first PTM configuration will continue to be received in the inactive state.

[0073] In some embodiments, before step 110, the method may further include: configuring a first PTM configuration in an inactive state in a broadcast manner, wherein the first PTM configuration is used to receive a multicast service in an inactive state.

[0074] 3GPP R2-119 discusses the solution for supporting multicast service reception of inactive UE. The following two cases are used as a benchmark, assuming that the UE already has a valid PTM configuration.

[0075] The first case: the UE has been receiving multicast in CONNECTED, and it enters INACTIVE and continues multicast reception.

[0076] The second case: the UE has joined the multicast session and is directed to INACTIVE, and the UE starts to receive the multicast session.

[0077] Fig. 9 The multicast service receiving method shown in the flowchart will be combined with Fig.10 and Fig.11 The above two situations described in detail are further described.

[0078] Fig.10 This is a flow chart of multicast service transmission using SIB and MCCH to configure PTM configuration in the first case. Fig.10 For the first case, the UE is receiving a multicast session in CONNECTED and configured with PTM via SIB and MCCH, but due to, for example, an increase in the number of UEs in the cell or the traffic, some UEs need to be moved to INACTIVE, but still continue with the multicast session reception.

[0079] Fig.11 This is a flow chart of multicast service transmission using SIB and MCCH to configure PTM configuration in the second case. Fig.11 ,For the second case, the UE has joined the multicast session configured by PTM configured through SIB and MCCH and is in an inactive state, but due to the activation of the multicast session, some or all UEs can remain in the inactive state (i.e., without going to CONNECTED) and be able to receive the multicast session.

[0080] For the first and second cases, due to the broadcasting method (SIB and MCCH), only general configuration can be provided, but no UE-specific configuration can be provided, so in a sense, its QoS may be affected. To address this problem, we introduce the following solution.

[0081] Fig.12 is Fig.10 The flowchart of the multicast service receiving method applied in the first scenario is shown. Fig.12 , the UE already has a valid PTM configuration in the connected state (step 1) and starts receiving multicast services from the gNB in ​​the connected state according to the PTM configuration (step 2). The PTM configuration can be configured using SIB and MCCH (i.e. broadcast mode). Upon receiving an RRC message from the gNB (step 3), the UE transitions from the connected state to the inactive state. The UE continues to receive multicast services from the gNB in ​​the inactive state according to the PTM configuration configured in the connected state (step 4). In the inactive state, the UE receives a paging message with an indication to receive the UE-specific PTM configuration and the indication also implicitly or explicitly instructs the UE to transition from the inactive state to the connected state to receive the UE-specific PTM configuration (step 5). To transition to the connected state, the UE sends an RRC Resume Request / RRC Resume Request 1 to the gNB (step 6), and in response to the request, the gNB sends an RRC Resume message to the UE (step 7). If the state transition is successful, the UE feeds back an RRC Resume Complete message to the gNB and changes to the connected state (step 8). After transitioning to the connected state, the UE receives the UE-specific PTM configuration carried in the RRC message from the gNB via dedicated signaling (step 9). The UE-specific PTM configuration is an incremental or complete configuration relative to the PTM configuration. After receiving the UE-specific PTM configuration, the UE transitions back to the inactive state when it receives the RRC release message (step 10). The UE continues to receive the multicast service in the inactive state according to the UE-specific PTM configuration (step 11).

[0082] Fig.13 Draw Fig.11 The flowchart of the multicast service receiving method used in the second scenario is shown. Fig.13, while the UE remains in the inactive state, the PTM configuration is configured for the UE through SIB and MCCH (i.e., broadcast mode) (step 1). The UE starts receiving multicast services from the gNB in ​​the inactive state according to the PTM configuration (step 2). In the inactive state, the UE receives a paging message with an indication to receive the UE-specific PTM configuration, which also implicitly or explicitly instructs the UE to transition from the inactive state to the connected state to receive the UE-specific PTM configuration (step 3). In order to transition to the connected state, the UE sends an RRC Resume Request / RRC Resume Request 1 to the gNB (step 4), and in response to the request, the gNB sends an RRC Resume message to the UE (step 5). If the state transition is successful, the UE feeds back an RRC Resume Complete message to the gNB and changes to the connected state (step 6). After transitioning to the connected state, the UE receives the UE-specific PTM configuration carried in the RRC message from the gNB through dedicated signaling (step 7). The UE-specific PTM configuration is an incremental or complete configuration relative to the PTM configuration. After receiving the UE-specific PTM configuration, the UE switches back to the inactive state upon receiving the RRC release message (step 8). The UE continues to receive the multicast service in the inactive state according to the UE-specific PTM configuration (step 9).

[0083] Since the UE receives the UE-specific PTM configuration through dedicated signaling in addition to the common PTM configuration configured through SIB and MCCH, the UE-specific PTM configuration can be provided to the UE without degrading QoS.

[0084] The beneficial effects of some embodiments are as follows: 1. Solve the problems in the prior art 2. Provide PTM configuration for UE in an inactive state to achieve multicast service transmission in an inactive state. 3. Provide good communication performance. Some embodiments of the present invention are used by 5G-NR chipset suppliers, V2X communication system development suppliers, automobile manufacturers (including cars, trains, trucks, buses, bicycles, motorcycles, helmets, etc.), drones (drones), smartphone manufacturers, public safety communication equipment, AR / VR equipment manufacturers for games, conferences / seminars, and educational purposes. Some embodiments of the present invention are a combination of "techniques / processes" that can be adopted in 3GPP specifications to create a final product. Some embodiments of the present invention can be used in 5G NR unlicensed frequency band communications. Some embodiments of the present invention propose technical mechanisms.

[0085] The embodiment of the present invention further provides a computer-readable storage medium for storing a computer program. The computer-readable storage medium enables a computer to execute the corresponding process implemented by the UE / BS in each method of the embodiment of the present invention. For the sake of brevity, the present invention will not repeat the details.

[0086] The embodiment of the present invention further provides a computer program product, including computer program instructions. The computer program product enables a computer to execute the corresponding process implemented by the UE / BS in each method of the embodiment of the present invention. For the sake of brevity, the present invention will not repeat the details.

[0087] The embodiment of the present invention further provides a computer program. The computer program enables a computer to execute the corresponding process implemented by the UE / BS in each method of the embodiment of the present invention. For the sake of brevity, the present invention will not repeat the details.

[0088] Although not shown in detail, any device or apparatus forming part of the network may include at least a processor, a storage unit and a communication interface, wherein the processor unit, the storage unit and the communication interface are configured to perform the method of any aspect of the present invention.

[0089] Those skilled in the art will appreciate that, in conjunction with the embodiments described in the embodiments disclosed in this specification, the units and algorithm steps may be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the functions described for each specific application, but it should not be considered that the implementation is beyond the scope of this application.

[0090] Furthermore, although individually listed, several methods, components or method steps may be implemented by a single unit or processor. Furthermore, although individual features may be included in different claims, these may advantageously be combined together, and the inclusion in different claims does not imply that a combination of features is not feasible and / or advantageous. Furthermore, the inclusion of a feature in a certain category of claims does not imply a limitation to that category but rather indicates that the feature is equally applicable to other claim categories where appropriate.

[0091] Furthermore, the order of features in the claims does not imply any specific order in which the features must be performed and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. Rather, the steps may be performed in any suitable order. Furthermore, singular references do not exclude a plurality. Thus references to 'a', 'single', 'first', 'second' etc do not exclude a plurality.

[0092] While the present invention has been described in connection with what is considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiment but is intended to cover various arrangements made without departing from the broadest interpretation of the appended claims.

Claims

1. A method for receiving a multicast service, performed by a user equipment UE in a network, the method comprising: receiving a multicast service according to a first point-to-multipoint PTM configuration configured through dedicated signaling; When the UE remains in an inactive state, a second PTM configuration configured for the multicast service in a broadcast manner; and According to the second PTM configuration, the multicast service continues to be received in an inactive state.

2. The method according to claim 1, characterized in that The dedicated signaling is radio resource control RRC signaling.

3. The method according to claim 1, characterized in that The broadcasting method includes configuring the second PTM configuration through a system information block SIB and a multicast / broadcast service MBS control channel MCCH.

4. The method according to claim 1, characterized in that When the first PTM configuration needs to be changed, the second PTM configuration is configured.

5. The method according to claim 4, characterized in that When the UE remains in an inactive state, the step of configuring a second PTM configuration for the multicast service by broadcasting includes: receiving notification of a first PTM configuration change via an MCCH change notification; and After receiving the MCCH change notification, receiving the second PTM configuration through the MCCH in the inactive state.

6. The method according to claim 5, characterized in that The second PTM configuration is a newly added configuration or a complete configuration relative to the first PTM configuration.

7. The method according to claim 1, characterized in that When the UE enters the inactive state, regardless of whether the first PTM configuration needs to be changed, the UE is configured with the second PTM configuration.

8. The method according to claim 1, characterized in that It also includes: When in a connected state, the first PTM configuration is configured through the dedicated signaling; receiving the multicast service when in the connected state according to the first PTM configuration; and The connected state is transitioned to the inactive state, wherein the multicast service received in the connected state continues to be received in the inactive state according to the first PTM configuration.

9. The method according to claim 1, characterized in that: It also includes: When an RRC release message carrying the first PTM configuration is received, the connected state is converted to the inactive state, wherein the first PTM configuration is used to receive a multicast service in the inactive state.

10. A method for receiving a multicast service, performed by a user equipment UE in a network, the method comprising: receiving a multicast service according to a first point-to-multipoint PTM configuration configured using a broadcast mode; When the UE remains in an inactive state, a second PTM configuration for the multicast service is configured by broadcasting or by dedicated signaling; and According to the second PTM configuration, the multicast service continues to be received in the inactive state.

11. The method according to claim 10, characterized in that The dedicated signaling is radio resource control RRC signaling.

12. The method according to claim 10, characterized in that The broadcasting mode includes a method of configuring the first PTM configuration or the second PTM configuration through a system information block SIB and a multicast / broadcast service MBS control channel MCCH.

13. The method according to claim 10, characterized in that When the second PTM configuration is a PTM configuration common to all UEs, the second PTM configuration is configured through the broadcasting method.

14. The method according to claim 13, characterized in that The step of configuring with the second PTM configuration comprises: receiving notification of a first PTM configuration change via an MCCH change notification; and After receiving the MCCH change notification, receiving the second PTM configuration through the MCCH in the inactive state.

15. The method according to claim 10, characterized in that When the second PTM configuration is a PTM configuration specific to the UE, the second PTM configuration is configured through the dedicated signaling.

16. The method according to claim 15, characterized in that The step of configuring with the second PTM configuration comprises: receiving an indication of the second PTM configuration in the inactive state; and After receiving the indication, the inactive state is switched to the connected state, so as to receive the second PTM configuration in the connected state.

17. The method according to claim 16, characterized in that Also includes: After receiving the second PTM configuration, the connected state is switched to the inactive state, and the multicast service is continued to be received according to the second PTM configuration in the inactive state.

18. The method according to claim 16, characterized in that The indication of receiving the second PTM configuration is carried in a paging message.

19. The method according to claim 16, characterized in that The second PTM configuration is carried in an RRC message.

20. The method according to claim 16, characterized in that The second PTM configuration is a newly added configuration or a complete configuration relative to the first PTM configuration.

21. The method according to claim 10, characterized in that Also includes: configuring the first PTM configuration in the connected state using the broadcast method; receiving the multicast service in the connected state according to the first PTM configuration; and The connection state is switched to the inactive state, wherein the multicast service received in the connection state according to the first PTM configuration continues to be received in the inactive state.

22. The method according to claim 10, characterized in that Also includes: A first PTM configuration is configured in the inactive state by using a broadcasting method, wherein the first PTM configuration is used to receive a multicast service in the inactive state.

23. A multicast service transmission method, performed by a base station BS in a network, the method comprising: Transmitting a multicast service to a user equipment UE according to a first point-to-multipoint PTM configuration configured through dedicated signaling so that the UE receives the multicast service; When the UE remains in an inactive state, configuring a second PTM configuration for the UE in a broadcast manner for a multicast service; as well as According to the second PTM configuration, the multicast service continues to be transmitted in an inactive state.

24. The method according to claim 23, characterized in that The dedicated signaling is radio resource control RRC signaling.

25. The method according to claim 23, characterized in that The broadcasting method includes configuring the second PTM configuration through a system information block SIB and a multicast / broadcast service MBS control channel MCCH.

26. The method according to claim 23, characterized in that When the first PTM configuration needs to be changed, the second PTM configuration is configured.

27. The method according to claim 26, characterized in that When the UE remains in an inactive state, the step of configuring a second PTM configuration for the UE in a broadcast manner for a multicast service includes: Notifying the UE to change the first PTM configuration through an MCCH change notification; and After transmitting the MCCH change notification, transmitting the second PTM configuration to the UE in the inactive state via the MCCH.

28. The method according to claim 27, characterized in that The second PTM configuration is a newly added configuration or a complete configuration relative to the first PTM configuration.

29. The method according to claim 23, characterized in that When the UE enters the inactive state, regardless of whether the first PTM configuration needs to be changed, the UE is configured with the second PTM configuration.

30. The method according to claim 23, characterized in that Also includes: When the UE is in a connected state, configuring the UE according to the first PTM configuration through the dedicated signaling; and The multicast service is transmitted to the UE so that the UE receives the multicast service according to the first PTM configuration in the connected state, wherein the multicast service received and transmitted by the UE in the connected state according to the first PTM configuration can continue to be transmitted to the UE in the inactive state.

31. The method of claim 23, further comprising: An RRC release message is sent to the UE so that the UE switches from the connected state to the inactive state, wherein the RRC release message carries a first PTM configuration, and the first PTM configuration is used for the UE to receive a multicast service in the inactive state.

32. A multicast service transmission method, performed by a base station BS in a network, the method comprising: Transmitting a multicast service for a user equipment UE to receive the multicast service according to a first point-to-multipoint PTM configuration configured in a broadcast manner; When the UE remains in an inactive state, configuring the UE for a second PTM configuration for a multicast service by broadcasting or by dedicated signaling; and According to the second PTM configuration, the multicast service continues to be transmitted in an inactive state.

33. The method according to claim 32, characterized in that The dedicated signaling is radio resource control RRC signaling.

34. The method according to claim 32, characterized in that The broadcasting method includes configuring the first PTM configuration or the second PTM configuration through a system information block SIB and a multicast / broadcast service MBS control channel MCCH.

35. The method according to claim 32, characterized in that When the second PTM configuration is a PTM configuration common to all UEs, the second PTM configuration is configured through the broadcasting method.

36. The method according to claim 35, characterized in that The step of configuring the UE using the second PTM configuration comprises: Notifying the UE to change the first PTM configuration through an MCCH change notification; and After transmitting the MCCH change notification, transmitting the second PTM configuration to the UE in the inactive state via the MCCH.

37. The method according to claim 32, characterized in that When the second PTM configuration is a PTM configuration specific to the UE, the second PTM configuration is configured through the dedicated signaling.

38. The method according to claim 37, characterized in that The step of configuring the UE for a second PTM configuration for a multicast service comprises: sending an indication to the UE to instruct the UE to receive the second PTM configuration in an inactive state; and When transmitting the indication, the second PTM configuration is transmitted to the UE in the connected state.

39. The method of claim 38, further comprising: When transmitting the second PTM configuration, an RRC release message is transmitted to cause the UE to switch from the connected state to the inactive state, so as to continue to receive the multicast service in the inactive state according to the second PTM configuration.

40. The method according to claim 38, characterized in that The indication of receiving the second PTM configuration is carried in a paging message.

41. The method according to claim 38, characterized in that The second PTM configuration is carried in an RRC message.

42. The method according to claim 38, characterized in that The second PTM configuration is a newly added configuration or a complete configuration relative to the first PTM configuration.

43. The method according to claim 32, characterized in that Also includes: Configuring the UE in a connected state to the first PTM configuration by broadcasting; and transmitting a multicast service to the UE according to the first PTM configuration so that the UE receives the multicast service in the connected state, According to the first PTM configuration, the multicast service received and transmitted by the UE in the connected state can continue to be transmitted to the UE in the inactive state.

44. The method according to claim 32, characterized in that Also includes: The UE in the inactive state is configured as the first PTM configuration in a broadcast manner, wherein the first PTM configuration is used for the UE in the inactive state to receive a multicast service.

45. A user equipment comprising a processor and a transmitter, wherein: The processor is configured to call and run program instructions stored in the memory to cooperate with the transmitter to perform the method according to any one of claims 1 to 9.

46. ​​A user equipment comprising a processor and a transmitter, wherein: The processor is configured to call and execute program instructions stored in the memory to cooperate with the transmitter to perform the method of any one of claims 10 to 22.

47. A base station comprising a processor and a transmitter, wherein: The processor is configured to call and execute program instructions stored in the memory to cooperate with the transmitter to perform the method of any one of claims 23 to 31.

48. A base station comprising a processor and a transmitter, wherein: The processor is configured to call and run program instructions stored in the memory to cooperate with the transmitter to perform the method of any one of claims 32 to 44.

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