Multicast service receiving method, multicast service transmitting method and related devices

Abstract

The application provides a multicast service receiving method. The method is executed by a user equipment (UE) in a network, and comprises 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, receiving a second PTM configuration for the multicast service in a broadcast mode; and continuing to receive the multicast service in the inactive state according to the second PTM configuration. The method can provide the PTM configuration for the UE in the inactive state, so that the multicast service transmission in the inactive state is realized.

Description

Technical Field

[0001] This 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 base station (BS) (e.g., gNB). Background Technology

[0002] Communication systems and networks have evolved into broadband and mobile systems. In the cellular wireless communication systems developed under the 3rd Generation Partnership Project (3GPP), user equipment (UE) connects to the radio access network (RAN) via a radio link. The RAN comprises a set of base stations (BS) and interfaces to the core network (CN). The former provides the radio link with the UE within the cell covered by the base stations, while the latter provides overall network control. The RAN and CN each perform their respective functions relevant to the entire network. The 3GPP developed the Long Term Evolution (LTE) system, namely the Evolved Universal Mobile Telecommunications System Radio Access Network (E-UTRAN), for mobile access networks, where one or more macro base stations are supported by base stations called eNodeBs or eNBs (evolved NodeBs). LTE is further evolving towards so-called 5G or NR (New Radio) systems, where one or more cells are supported by base stations called next-generation NodeBs (gNBs).

[0003] In LTE, if a UE is inactive for a period of time, the network can command the UE to enter the RRC_IDLE state to reduce power consumption. Whenever the UE needs to perform some activity, it needs to transition from the RRC_IDLE state to the RRC_CONNECTED state. Because 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, the UE is in the RRC_CONNECTED state when an RRC connection is established, and in the RRC_INACTIVE state when an RRC connection is suspended. Otherwise, the UE is in the RRC_IDLE state, i.e., no RRC connection is established. The RRC_INACTIVE and RRC_IDLE states can be referred to as power-saving states. More specifically, in the RRC inactive state, the UE Access Stratum (AS) context is stored on both the UE and the network side to maintain the core network connection (i.e., the UE remains in Connection Management (CM) – a connection) and release the Radio Access Network (RAN) connection. The network can reach the inactive UE via RAN or CN paging messages.

[0004] To achieve resource-efficient delivery of multicast / broadcast services (MBS), 3GPP developed NR Broadcast / Multicast in 3GPP Release 17, aiming to enable universal MBS services through 5G systems (5GS). Identified use cases that may benefit from this feature include software delivery for public safety and mission-critical applications, V2X applications, IPTV, real-time video, wireless, and IoT applications. Two delivery modes have been agreed upon for MBS in 3GPP Release 17: Delivery Mode 1 (multicast only) handles higher QoS services, while Delivery Mode 2 (broadcast only) focuses on lower QoS services. Given that 3GPP Release 17 already provides the basic functionality to support MBS services, the primary goal of 3GPP Release 18 should be to achieve better MBS deployment, such as improving resource efficiency and capacity based on 3GPP Release 17's MBS specifications.

[0005] In 3GPP Release 17, the Radio Access Network (RAN) only specifies multicast for UEs in the RRC_CONNECTED state. This cannot fully meet the requirements of mission-critical services, especially for cells with a large number of UEs. Furthermore, keeping UEs in the RRC_CONNECTED state at all times is not energy efficient. Therefore, supporting UE multicast in RRC_INACTIVE is crucial.

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

[0007] Figure 1 This is a flowchart illustrating the PTM configuration transmission process for a UE receiving multicast services in connected mode based on existing technology. (Reference) Figure 1 This document explains how to configure a UE using PTM configuration and receive multicast services based on the PTM configuration. For a UE in idle state, when a multicast session starts, the gNB sends an MCCH change notification to the UE. The UE then enters connected state to receive the multicast configuration transmitted via dedicated signaling. Finally, the UE remains connected to receive multicast services. In other words, for a UE interested in receiving multicast services in connected state, the UE transitions from power-saving state to connected state to receive the associated PTM configuration via dedicated signaling.

[0008] Figure 2 This is a flowchart illustrating the PTM configuration transmission process for a UE receiving broadcast services in idle / inactive / connected modes using existing technology. (Reference) Figure 2This document explains how to configure a UE using the PTM configuration and how to receive broadcast services based on the PTM configuration. When reading System Information Block 1 (SIB1), a UE interested in receiving broadcast services will recognize the scheduling information in SIB20. SIB20 contains the information needed to obtain the multicast control channel configuration related to the multicast traffic channel (MTCH) transmission of broadcast data. Then, in the MCCH, the UE can further look up the configuration of the MTCH carrying 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 the idle / inactive / connected state. In other words, for a UE 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 using the SIB and MCCH configurations.

[0009] Regarding the PTM configuration for 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 a UE in the RRC_INACTIVE state updates its PTM configuration, a large number of UEs initiating random access can lead to network congestion, which contradicts the main purpose of introducing PTM configuration in RRC_INACTIVE. Furthermore, this may increase the payload of the RRCRelease message.

[0013] For option 2, the UE still needs an indication or condition to determine whether it can receive multicast in the RRC_CONNECTED state. It should be noted that some UEs may inevitably receive multicast in the RRC_CONNECTED state, so solutions like SIB+MCCH may introduce some redundancy. Furthermore, the SIB+MCCH method only provides general configurations and not UE-specific configurations; therefore, in a sense, it may lead to QoS degradation.

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

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

[0016] In a first aspect, embodiments of the present invention provide a multicast service reception method, executed by a user equipment (UE) in a network, the method comprising: receiving multicast services according to a point-to-multipoint (PTM) configuration configured via dedicated signaling; when the UE remains in an inactive state, receiving a second PTM configuration configured for multicast services via broadcast; and continuing to receive multicast services in an inactive state according to the second PTM configuration.

[0017] In a second aspect, embodiments of the present invention provide a multicast service reception method, executed by a user equipment (UE) in a network, the method comprising: receiving multicast services according to a first PTM configuration configured using a broadcast method; when the UE remains in an inactive state, receiving a second PTM configuration configured for multicast services via a broadcast method or via dedicated signaling; and continuing to receive multicast services in an inactive state according to the second PTM configuration.

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

[0019] In a fourth aspect, embodiments of the present invention provide a multicast service transmission method, executed by a base station (BS) in a network. 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; configuring a UE with a second PTM configuration for the multicast service via broadcast or via dedicated signaling when the UE remains in an inactive state; and continuing to transmit the multicast service so that the UE can receive the multicast service in the inactive state according to the second PTM configuration.

[0020] In a fifth aspect, embodiments of the present invention provide a UE including a processor and a transmitter, wherein the processor is configured to invoke and execute program instructions stored in a memory to cooperate with the transmitter in performing the method of either the first or second aspect.

[0021] In a sixth aspect, embodiments of the present invention provide a BS including a processor and a transmitter, wherein the processor is configured to invoke and execute program instructions stored in a memory to cooperate with the transmitter in performing the method of either the third or fourth aspect.

[0022] In a seventh aspect, embodiments of the present invention provide a computer-readable storage medium for storing a computer program that enables a computer to perform the methods of any one of the first to fourth aspects.

[0023] In an eighth aspect, embodiments of the present invention provide a computer program product, including a method for enabling computer program instructions to execute any one of the first to fourth aspects.

[0024] In a ninth aspect, embodiments of the present invention provide a computer program that, when run on a computer, enables the computer to perform the method of any one of the first to fourth aspects.

[0025] Non-transitory computer-readable media may include at least one of the following groups: hard disk, CD-ROM, optical storage device, magnetic storage device, read-only memory, programmable read-only memory, erasable programmable read-only memory, EPROM, electrically erasable programmable read-only memory, and flash memory. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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 effort.

[0027] Figure 1 This diagram illustrates the PTM configuration transmission flow of a UE receiving multicast services in connected mode using existing technology.

[0028] Figure 2 This diagram illustrates the PTM configuration transmission flow of a UE receiving broadcast services in idle / inactive / connected modes using existing technology.

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

[0030] Figure 4 A flowchart illustrating the multicast service receiving method according to the first embodiment of the present invention is shown.

[0031] Figure 5 The diagram illustrates the multicast service transmission flow of the PTM configuration via dedicated signaling in the first scenario.

[0032] Figure 6 The diagram illustrates the multicast service transmission flow for PTM configuration via dedicated signaling in the second scenario.

[0033] Figure 7 Draw Figure 5 The flowchart shows the multicast service reception method used in the first scenario.

[0034] Figure 8 Draw Figure 6 The flowchart shows the multicast service reception method used in the second scenario.

[0035] Figure 9 A flowchart illustrating a multicast service receiving method according to a second embodiment of the present invention is shown.

[0036] Figure 10 The diagram illustrates the multicast service transmission flow when using SIB and MCCH to configure PTM in the first scenario.

[0037] Figure 11 The diagram illustrates the multicast service transmission flow when using SIB and MCCH to configure PTM in the second scenario.

[0038] Figure 12 Drawn in Figure 10 The flowchart shows the multicast service reception method applied in the first scenario.

[0039] Figure 13 Drawn in Figure 11 The flowchart shows the multicast service reception method used in the second scenario. Detailed Implementation

[0040] The embodiments of the present invention are described in detail with reference to the accompanying drawings, including technical aspects, structural features, objectives, and effects. Specifically, the terminology used in the embodiments of the present invention is only used to describe the purpose of a particular embodiment and is not intended to limit the disclosure.

[0041] like Figure 3 As illustrated, in some embodiments, the communication network system 30 of this invention provides one or more user equipment (UE) 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 transceiver 13. The base station 20 may include a memory 22, a transceiver 23, and a processor 21 coupled to the memory 22 and transceiver 23. The processor 11 or 21 may be configured to implement the proposed functions, processes, and / or methods described in this invention. A layer of 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 transmits and / or receives radio signals.

[0042] Processor 11 or 21 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, and / or data processing devices. Memory 12 or 22 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices. Transceiver 13 or 23 may include baseband circuitry for processing radio frequency signals. When embodiments are implemented in software, the techniques described in this invention can be implemented by modules (e.g., procedures, functions, etc.) that perform the functions described in this invention. Modules may be stored in memory 12 or 22 and executed by processor 11 or 21. Memory 12 or 22 may be integrated inside processor 11 or 21 or implemented outside processor 11 or 21, in which case they may be communicatively coupled to processor 11 or 21 in various ways known in the art.

[0043] Figure 4 A flowchart illustrating a multicast service receiving method 100 according to a first embodiment of the present invention is shown. See also... Figure 3 and Figure 4 Method 100 includes the following.

[0044] In step 110, the User Equipment (UE) receives multicast services from the 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 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 this RRC message when in a connected state (e.g., RRC_CONNECTED) and configures itself according to the first PTM configuration. The UE can receive multicast services when 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 the UE configures the PTM configuration by receiving the RRC release message when transitioning from a connected state to an inactive state. The UE can receive multicast services when in an inactive state according to the first PTM configuration.

[0045] In step 120, when the UE remains inactive, the second PTM configuration for multicast services is configured for the UE via broadcast. For example... Figure 2As shown, the broadcast method includes configuring the second PTM configuration via the System Information Block (SIB) and the MBS Control Channel (MCCH). In other words, if the PTM configuration (i.e., the defined first PTM configuration) was previously configured to the UE via dedicated signaling, then when the UE enters or remains in an inactive state and is interested in receiving multicast services while in an inactive state, the PTM configuration (i.e., the defined second PTM configuration) is configured for the UE via broadcast.

[0046] In one embodiment, the second PTM configuration is configured to the inactive UE only when the first PTM configuration needs to be changed. That is, the second PTM configuration is only broadcast to the inactive UE when the first PTM configuration upon which the UE receives multicast services changes. In another embodiment, the second PTM configuration is configured once the UE enters an inactive state, regardless of whether the first PTM configuration needs to be changed. That is, regardless of whether the first PTM configuration upon which the UE receives multicast services changes, the second PTM configuration is broadcast to the inactive UE as soon as the UE enters an inactive state.

[0047] If the updated PTM configuration (i.e., the defined second PTM configuration) is only configured to be inactive when the PTM configuration changes (i.e., the defined first PTM configuration), the UE can 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 inactive, and the MCCH change notification indicates a PTM configuration change. For example, the MCCH change notification might contain two bits, one of which notifies the UE to initiate a multicast portion, and the other bit notifies the UE that the configuration of the ongoing multicast portion has changed or will change. Then, after receiving the PTM configuration change notification, the UE receives the changed or updated PTM configuration via the MCCH and applies the changed or updated PTM configuration to subsequent multicast service transmissions. In this step, after receiving the PTM configuration change notification, the UE receives the changed PTM configuration from the BS. The modified PTM configuration can be an incremental or complete configuration relative to the original PTM configuration. That is, the modified PTM configuration itself differs from the original PTM configuration, or the modified PTM configuration is entirely new, even if some parts of the configuration may be the same as the original PTM configuration. Then, by applying the modified or updated PTM configuration, the UE can receive subsequent multicast service transmissions while in an inactive state.

[0048] like Figure 2As shown, if the new PTM configuration (i.e. the defined second PTM configuration) is configured to be inactive immediately after the UE transitions to the inactive state, the UE can be configured using the new PTM configuration through broadcasting using SIB and MCCH.

[0049] In step 130, the UE continues to receive multicast services in the inactive state using the second PTM configuration configured in step 120. In this step, the multicast services received in step 110 will continue to be received in step 130. The difference is that the multicast services received in step 130 are based on the second PTM configuration configured via broadcast, while the multicast services received in step 110 are based on the first PTM configuration configured via dedicated signaling. Since the continuous reception of multicast services can be seamless, it will not be noticeable to the user.

[0050] Using this method, the UE can use PTM configuration in an inactive state without having to transition from an inactive state to a connected state to receive PTM configuration. This avoids network congestion and reduces the payload of RRC release messages.

[0051] In some embodiments, the method may further include: configuring via the dedicated signaling according to the first PTM configuration 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.

[0052] In some embodiments, the method may further include: upon receiving an RRC release message carrying the first PTM configuration, transitioning from the connected state to the inactive state, wherein the first PTM configuration is used to receive multicast services in the inactive state.

[0053] 3GPP Release 2-119 discusses schemes for supporting multicast service reception for inactive UEs. In the following two cases, it is assumed that the UE already has a valid PTM configuration.

[0054] The first scenario: The UE has been receiving multicast in the CONNECTED state, and it enters the INACTIVE state and continues to receive multicast.

[0055] The second scenario: The UE has joined a multicast session and has been directed to an inactive state, and the UE begins to receive multicast sessions.

[0056] Please see Figure 4 The flowchart illustrates the multicast service reception method, and is combined with... Figure 5 and Figure 6 The above two situations will be explained in further detail.

[0057] Figure 5 This is the multicast service transmission flowchart for the first scenario, configured via dedicated signaling for PTM. In the first scenario, the UE receives multicast sessions in the connected state, where PTM is configured via dedicated signaling. However, due to an increase in the number of UEs or traffic, some UEs need to be moved to an inactive state, but multicast session reception continues.

[0058] Figure 6 This is a flowchart of the multicast service transmission process configured via dedicated signaling for PTM in the second scenario. In the second scenario, the UE has joined the multicast session, where the PTM configuration is configured via dedicated signaling and is in an inactive state. However, due to the activation of the multicast session, some or all UEs can remain inactive (i.e., they do not need to switch to the connected state) and can still receive the multicast session.

[0059] For the first and second scenarios, updating the PTM configuration of a UE in RRC_INACTIVE mode can lead to network congestion due to the dedicated signaling causing a large number of UEs to initiate random access. This contradicts the main purpose of introducing PTM configuration in RRC_INACTIVE mode. Furthermore, this may increase the payload of the RRC release message. To address this issue, we introduce the following solutions.

[0060] Figure 7 yes Figure 5 The flowchart illustrates the multicast service reception method used in the first scenario. (See reference) Figure 7 The UE already has a valid PTM configuration in the connected state (step 1) and begins receiving multicast services from the gNB in ​​the connected state according to the PTM configuration (step 2). The PTM configuration can be configured via dedicated signaling (e.g., RRC signaling). After 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 an MCCH change notification from the gNB, indicating a change in the PTM configuration (step 5). After receiving the PTM configuration change notification, the UE receives the changed or updated PTM configuration from the gNB (step 6), which is either a partial addition or a complete configuration relative to the original PTM configuration. The UE continues to receive multicast services in the inactive state according to the changed or updated PTM configuration (step 7).

[0061] Figure 8 yes Figure 6The flowchart illustrates the multicast service reception method used in the second scenario. (Reference) Figure 8 Upon receiving an RRC release message from the gNB, the UE transitions from the connected state to the inactive state. The RRC release message carries the PTM configuration, allowing the UE to receive multicast services based on it (step 1). When the UE is in the inactive state, it begins 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 a change in the PTM configuration (step 3). After receiving the PTM configuration change notification, the UE receives the changed or updated PTM configuration from the gNB (step 4), which is either an incremental or complete configuration relative to the original PTM configuration. The UE continues to receive multicast services in the inactive state according to the changed or updated PTM configuration (step 5).

[0062] Since the UE receives PTM configuration changes and indications of changes or updates to the PTM configuration via the MCCH without needing to transition from an inactive state to a connected state to receive changes or updates to the PTM configuration, network congestion is avoided, and the payload of the RRC release message is reduced.

[0063] Figure 9 This is a flowchart of a multicast service receiving method 200 according to a second embodiment of the present invention. (In conjunction with...) Figure 3 See Figure 9 Method 200 includes the following.

[0064] In step 210, the User Equipment (UE) receives multicast services from the Base Station (BS) according to the 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 the 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 locate the first PTM configuration for receiving multicast services. In one embodiment, when the UE is in a connected state (e.g., RRC_CONNECTED), the UE configures the first PTM configuration via the SIB and MCCH. The UE can receive multicast services in the connected state according to the first PTM configuration. In another embodiment, when the UE is in an inactive state (e.g., RRC_INACTIVE), the UE configures the first PTM configuration via the SIB and MCCH. The UE can receive multicast services in the inactive state according to the first PTM configuration.

[0065] In step 220, when the UE remains inactive, the UE is configured with a second PTM configuration for multicast services via broadcast or dedicated signaling. The broadcast method includes a method for configuring the second PTM configuration via SIB and MCCH, such as... Figure 2 As shown. Specialized signaling can be Radio Resource Control (RRC) signaling. For example... Figure 1 As shown, a UE can transition from an inactive state to a connected state to receive Radio Resource Control (RRC) messages. The second PTM configuration is carried in the RRC message, and the UE configures the second PTM configuration by receiving the RRC message after transitioning to the connected state. In other words, if the PTM configuration (i.e., the defined first PTM configuration) was previously configured to the UE via broadcast, then when the UE enters or remains in an inactive state and is interested in receiving multicast services in an inactive state, the UE will configure the PTM configuration (i.e., the defined second PTM configuration) via broadcast or dedicated signaling.

[0066] There are two scenarios to consider. If the second PTM configuration is a common PTM configuration for all UEs, it will be broadcast to all inactive UEs. That is, when the required PTM configuration is inactive, it will be broadcast to all inactive UEs. If the second PTM configuration is UE-specific, it will be configured for one or more inactive UEs via dedicated signaling. In other words, when the PTM configuration to be configured in an inactive state is specific to one or more UEs, dedicated signaling will be used to configure it for those UEs.

[0067] If the PTM configuration to be configured as inactive (i.e., the second PTM configuration) is a common PTM configuration, then a broadcast method using SIB and MCCH can be used, such as... Figure 2 As shown, a UE with a general PTM configuration is configured. More specifically, the UE can receive a notification of a first PTM configuration change via an MCCH change notification, and after receiving the MCCH change notification, receive a second PTM configuration that is inactive via the MCCH.

[0068] If the PTM configuration to be configured as inactive (i.e., the second PTM configuration) is a UE-specific PTM configuration, the UE can receive a reception indication for the UE-specific PTM configuration. More specifically, the BS can page the UE to receive the UE-specific PTM configuration, and the indication to receive the UE-specific PTM configuration can be carried in the paging message. An indication bit can be added / introduced in the paging message. For example, the indication bit can be added to a P-RNTI scrambled short message. Compared to the first PTM configuration in step 210, the UE-specific PTM configuration is a UE-specific configuration that is a common configuration for all UEs. Upon receiving the indication, the UE receives the UE-specific PTM configuration. Specifically, according to the indication, the UE transitions from an inactive state to a 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 can be carried in the RRC message. Because the UE-specific PTM configuration is configured via 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), and it is a configuration common to all UEs. The UE-specific PTM configuration can be an incremental or complete configuration relative to the first PTM configuration. That is, the UE-specific PTM configuration itself differs from the first PTM configuration, or the UE-specific PTM configuration is a completely new PTM configuration, even if some of the configuration content may be the same as the first PTM configuration.

[0069] 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 in the inactive state using the second PTM configuration. 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 can 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 via broadcast). The continuation of multicast service reception can be seamless and imperceptible to the user.

[0070] Using this method, the UE can receive the second PTM configuration via broadcast or dedicated signaling, depending on whether the PTM configuration is general or UE-specific. In the inactive state, a UE-specific PTM configuration can be provided to the UE without compromising QoS.

[0071] In some embodiments, the method may further include: 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 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.

[0072] In some embodiments, prior to step 110, the method may further include: configuring a first PTM configuration in an inactive state using a broadcast method, wherein the first PTM configuration is used to receive multicast services in an inactive state.

[0073] 3GPP Release 2-119 discusses schemes for supporting multicast service reception for inactive UEs. The following two scenarios serve as benchmarks, assuming the UE already has a valid PTM configuration.

[0074] The first scenario: The UE is always receiving multicast in CONNECTED mode, and then it enters INACTIVE mode and continues to receive multicast.

[0075] The second scenario: The UE has joined the multicast session and has been directed to INACTIVE, and the UE begins to receive the multicast session.

[0076] Figure 9 The multicast service reception method shown in the flowchart will combine Figure 10 and Figure 11 The two situations described above are further explained in detail below.

[0077] Figure 10 This is a flowchart illustrating the multicast service transmission process using SIB and MCCH to configure PTM in the first scenario. (Reference) Figure 10 In the first scenario, the UE is receiving a multicast session in CONNECTED and configuring PTM via SIB and MCCH, but due to, for example, an increase in the number of UEs or traffic in the cell, it is necessary to move some UEs to INACTIVE, but multicast session reception continues.

[0078] Figure 11 This is a flowchart illustrating the multicast service transmission process using SIB and MCCH to configure PTM in the second scenario. (Reference) Figure 11 In the second scenario, the UE has joined a multicast session configured by PTM through SIB and MCCH and is in an inactive state. However, due to the activation of the multicast session, some or all UEs can remain inactive (i.e., without switching to CONNECTED) and be able to receive the multicast session.

[0079] For the first and second scenarios, due to the broadcast methods (SIB and MCCH), only general configurations can be provided, not UE-specific configurations. Therefore, in a sense, its QoS may be affected. To address this issue, we introduce the following solutions.

[0080] Figure 12 Is Figure 10 The flowchart illustrates the multicast service reception method used in the first scenario. (See reference.) Figure 12 The UE already has a valid PTM configuration in the connected state (step 1) and begins 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). After 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 inactive gNB 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, 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 5). To transition to the connected state, the UE sends an RRC recovery request / RRC recovery request 1 to the gNB (step 6), and in response, the gNB sends an RRC recovery message to the UE (step 7). If the state transition is successful, the UE sends an RRC recovery complete message back 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 either an incremental or complete configuration relative to the standard PTM configuration. Upon receiving the UE-specific PTM configuration, the UE transitions back to the inactive state upon receiving the RRC release message (step 10). The UE continues to receive multicast services in the inactive state according to the UE-specific PTM configuration (step 11).

[0081] Figure 13 Draw Figure 11 The flowchart illustrates the multicast service reception method used in the second scenario. Please refer to it. Figure 13When the UE remains inactive, the PTM configuration is configured for the UE via SIB and MCCH (i.e., broadcast mode) (Step 1). The UE begins receiving multicast services from the inactive gNB based on 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). To transition to the connected state, the UE sends an RRC recovery request / RRC recovery request 1 to the gNB (Step 4), and in response, the gNB sends an RRC recovery message to the UE (Step 5). If the state transition is successful, the UE sends an RRC recovery complete message back 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 via dedicated signaling (Step 7). The UE-specific PTM configuration is an incremental or complete configuration relative to the standard PTM configuration. Upon receiving the UE-specific PTM configuration, the UE transitions back to the inactive state when it receives the RRC release message (step 8). The UE continues to receive multicast services in the inactive state according to the UE-specific PTM configuration (step 9).

[0082] Since the UE receives UE-specific PTM configurations via dedicated signaling in addition to the common PTM configurations configured through SIB and MCCH, UE-specific PTM configurations can be provided to the UE without reducing QoS.

[0083] Some embodiments offer the following advantages: 1. Solving problems in the prior art; 2. Providing PTM configuration for inactive UEs to enable multicast service transmission in inactive states; 3. Providing 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, smartphone manufacturers, public safety communication equipment manufacturers, and AR / VR device manufacturers for gaming, conferences / seminars, and educational purposes. Some embodiments of the present invention are combinations of "technologies / processes" that can be adopted in 3GPP specifications to create the final product. Some embodiments of the present invention can be adopted in 5G NR unlicensed frequency band communication. Some embodiments of the present invention propose technical mechanisms.

[0084] This invention also 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 this invention. For the sake of brevity, further details are omitted.

[0085] This invention also 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 this invention. For the sake of brevity, further details are omitted.

[0086] This invention also provides a computer program. The computer program enables a computer to execute the corresponding processes implemented by the UE / BS in each method of this invention. For the sake of brevity, further details are omitted.

[0087] Although not shown in detail, any device or apparatus that forms part of the network may include at least a processor, a storage unit, and a communication interface, wherein the processor unit, storage unit, and communication interface are configured to perform any aspect of the methods of the present invention.

[0088] Those skilled in the art will recognize that, in conjunction with the embodiments described in this specification, the units and algorithm steps can 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 can use different methods to implement the functions described for each specific application, but should not consider such implementation to be beyond the scope of this application.

[0089] Furthermore, although listed separately, multiple methods, components, or method steps may be implemented by a single unit or processor. Additionally, while a single feature may be included in different claims, these features may be advantageously combined together, and inclusion in different claims does not imply that such a combination of features is infeasible and / or advantageous. Moreover, the inclusion of a feature in a claim of a particular class does not imply a limitation on that class, but rather indicates that the feature is equally applicable to other claim classes where appropriate.

[0090] Furthermore, the order of features in the claims does not imply that the features must be performed in any particular order, and in particular, the order of the steps in a method claim does not imply that the steps must be performed in that order. On the contrary, the steps can be performed in any suitable order. Moreover, singular references do not exclude plurals. Therefore, references to 'a', 'single', 'first', 'second', etc., do not exclude plurals.

[0091] While the invention has been described in conjunction with what are considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various arrangements without departing from the broadest interpretation of the appended claims.

Claims

1. A multicast service reception method, executed by a user equipment (UE) in a network, the method comprising: To receive multicast services, a first point-to-multipoint PTM configuration is configured via dedicated signaling. When the UE remains inactive, the second PTM configuration for the multicast service is configured via broadcast. The UE receives a paging message in the inactive state, wherein the paging message includes an indication bit to indicate that the UE needs to enter the connected state to receive the second PTM configuration. and According to the second PTM configuration, the multicast service continues to be received in the 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 the System Information Block (SIB) and the Multicast / Broadcast Service (MBS) Control Channel (MCCH).

4. The method according to claim 1, characterized in that, When it is necessary to change the first PTM configuration, configure the second PTM configuration.

5. The method according to claim 4, characterized in that, When the UE remains inactive, the steps for configuring the second PTM configuration for the multicast service via broadcast include: Receive notification of the first PTM configuration change via MCCH change notification; and Upon receiving the MCCH change notification, the second PTM configuration is received via the MCCH in the inactive state.

6. The method according to claim 5, characterized in that, The second PTM configuration is a new 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 via the dedicated signaling. According to the first PTM configuration, the multicast service is received while in the connected state; and The transition from the connected state to the inactive state occurs when the multicast service received in the connected state according to the first PTM configuration continues to be received in the inactive state.

9. The method according to claim 1, characterized in that, It also includes: Upon receiving an RRC release message carrying the first PTM configuration, the connection state is transitioned to the inactive state, wherein the first PTM configuration is used to receive multicast services in the inactive state.

10. A multicast service reception method, performed by a user equipment (UE) in a network, the method comprising: Based on the first point-to-multipoint PTM configuration configured using broadcast mode, receive multicast services; When the UE remains in an inactive state, it is configured with a second PTM configuration for the multicast service via broadcast or dedicated signaling. The UE receives a paging message in the inactive state, wherein the paging message includes an indication bit to indicate that the UE needs to enter a connected state to receive the second PTM configuration. and According to the second PTM configuration, the multicast service continues to be received while 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 method includes configuring the first PTM configuration or the second PTM configuration through the System Information Block (SIB) and the Multicast / Broadcast Service (MBS) Control Channel (MCCH).

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

14. The method according to claim 13, characterized in that, The steps involving the configuration of the second PTM include: Receive notification of the first PTM configuration change via MCCH change notification; and Upon receiving the MCCH change notification, the second PTM configuration is received via the MCCH in the inactive state.

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

16. The method according to claim 15, characterized in that, The steps involving the configuration of the second PTM include: Receives an instruction for the second PTM configuration in the inactive state; and Upon receiving the instruction, the system transitions from the inactive state to the connected state to receive the second PTM configuration in the connected state.

17. The method according to claim 16, characterized in that, Also includes: Upon receiving the second PTM configuration, the system transitions from the connected state to the inactive state, and continues to receive the multicast service in the inactive state according to the second PTM configuration.

18. The method according to claim 16, characterized in that, The instruction to receive the second PTM configuration is carried in the paging message.

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

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

21. The method according to claim 10, characterized in that, Also includes: The first PTM configuration is configured in the connection state using the broadcast method described above. According to the first PTM configuration, the multicast service is received in the connection state; and The transition from the connected state to the inactive state occurs when the multicast service received in the connected 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: Configure a first PTM configuration in the inactive state using a broadcast method, wherein the first PTM configuration is used to receive multicast services in the inactive state.

23. A multicast service transmission method, executed by a base station (BS) in a network, the method comprising: According to the first point-to-multipoint PTM configuration configured via dedicated signaling, multicast services are transmitted to the user equipment (UE) so that the UE can receive the multicast services; When the UE remains in an inactive state, the second PTM configuration is configured for the UE via broadcast for multicast service. When the UE is in an inactive state, it receives a paging message, wherein the paging message includes an indication bit to indicate that the UE needs to enter a connected state to receive the second PTM configuration. as well as According to the second PTM configuration, the multicast service continues to be transmitted in the 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 the System Information Block (SIB) and the Multicast / Broadcast Service (MBS) Control Channel (MCCH).

26. The method according to claim 23, characterized in that, When it is necessary to change the first PTM configuration, configure the second PTM configuration.

27. The method according to claim 26, characterized in that, When the UE remains inactive, the step of configuring the second PTM configuration for multicast service via broadcast includes: The UE is notified of the change in the first PTM configuration via MCCH change notification; and After transmitting the MCCH change notification, the second PTM configuration is transmitted 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 new 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, the UE is configured according to the first PTM configuration via the dedicated signaling; and Multicast services are transmitted to the UE so that the UE receives multicast services according to the first PTM configuration in the connected state, wherein the multicast services 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 can transition from the connected state to the inactive state, wherein the RRC release message carries a first PTM configuration, which is used by the UE to receive multicast services in the inactive state.

32. A multicast service transmission method, executed by a base station (BS) in a network, the method comprising: Based on the first point-to-multipoint PTM configuration configured using broadcast mode, multicast services are transmitted to the user equipment (UE) to receive multicast services. When the UE remains inactive, the UE is configured for multicast service using the second PTM configuration via broadcast or dedicated signaling. The UE receives a paging message in the inactive state, wherein the paging message includes an indication bit to indicate that the UE needs to enter the connected state to receive the second PTM configuration. and According to the second PTM configuration, the multicast service continues to be transmitted in the 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 the System Information Block (SIB) and the Multicast / Broadcast Service (MBS) Control Channel (MCCH).

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

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

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

38. The method according to claim 37, characterized in that, The steps for configuring the UE for a second PTM configuration for multicast services include: Send an indication to the UE to instruct it to receive the second PTM configuration in the inactive state; and When transmitting the instruction, 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 that it can continue to receive multicast services in the inactive state according to the second PTM configuration.

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

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

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

43. The method according to claim 32, characterized in that, Also includes: The UE in the connected state is configured to the first PTM configuration using a broadcast method; and According to the first PTM configuration, the multicast service is transmitted to the UE so that the UE can receive the multicast service in the connected state. Specifically, according to the first PTM configuration, multicast services 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 an inactive state is configured to use the first PTM configuration via broadcast, wherein the first PTM configuration is used for the UE to receive multicast services while in an inactive state.

45. A user equipment comprising a processor and a transmitter, wherein, The processor is configured to invoke and execute program instructions stored in memory to cooperate with the transmitter in performing the method of any one of claims 1 to 9.

46. ​​A user equipment comprising a processor and a transmitter, wherein, The processor is configured to invoke and execute program instructions stored in memory to cooperate with the transmitter in performing 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 invoke and execute program instructions stored in memory to cooperate with the transmitter in performing 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 invoke and execute program instructions stored in memory to cooperate with the transmitter in performing the method of any one of claims 32 to 44.

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