Multicast in communication system

Abstract

A method, an apparatus, and a computer program product for multicast in a communication system are provided. A method for multicast in a communication system includes deciding to use a transmission mode of inactive state reception for a multicast session in an area, providing at least one device in the area with information indicating that the transmission mode of inactive state reception is used for the multicast session, and transmitting data in the multicast session using the transmission mode of inactive state reception.

Description

[0001] Related Applications

[0002] This patent application claims priority to UK patent application No. 2204470.5 filed on March 29, 2022, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to methods, apparatus, and computer program products for multicasting in a communication system. Background Art

[0004] Data can be transferred between communication devices (such as users or terminal devices, base stations / access points and / or other nodes). For example, communication can be provided through a communication network and one or more compatible communication devices. The communication equipment on the network side provides the access point of the system and is equipped with appropriate receiving and sending means for implementing communication. Communication can include, for example, data communication for carrying voice, video, electronic mail (email), text message, multimedia and / or content data communication, etc. Non-limiting examples of the services provided include two-way or multi-way calls, data communications, multimedia services and access to data network systems, such as the Internet. Multicast and / or broadcast can also be performed to communication devices.

[0005] In a mobile or wireless communication system, at least a portion of data communication is carried out via a wireless or radio link. Examples of wireless systems include public land mobile networks (PLMNs), satellite-based communication systems, and different wireless local networks, such as wireless local area networks (WLANs). A wider range of communication systems can be accessed through appropriate communication devices or terminals. Such equipment is generally referred to as user equipment (UE). The communication device is equipped with appropriate signal receiving and sending means for implementing communication, for example, for implementing access to a communication network or direct communication with other users. The user's communication device can receive signaling through a node (e.g., a base station) at a radio access network (RAN) and send and / or receive communications accordingly.

[0006] Communication systems and related equipment typically operate according to a given standard or specification, which specifies the functions and tasks of various entities associated with the system. Communication protocols and / or parameters for the connections are also typically defined. An example of a communication system is UTRAN (3G radio). Other examples of communication systems are the Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) and the so-called fifth generation (5G) or New Radio (NR) systems. 5G is being standardized by the 3rd Generation Partnership Project (3GPP). Different versions of 3GPP specifications are called Releases (Rel).

[0007] Data can be broadcast or multicast to multiple devices. The service provides the ability to deliver content to multiple users, and unlike unicast services, data can be sent to multiple destinations / devices simultaneously from a single source. An example of these services is the Multicast Broadcast Service (MBS) which provides point-to-multipoint communications. Summary of the invention

[0008] According to one aspect, a method is provided, comprising: determining to use a transmission mode of inactive state reception for a multicast session in an area, providing information indicating to use the transmission mode of inactive state reception for the multicast session to at least one device in the area, and sending data using the transmission mode of inactive state reception in the multicast session.

[0009] According to more specific aspects, the method may include receiving capability information indicating that at least one device supports inactive state reception of a multicast session.

[0010] The inactive state reception may include reception in at least one of a radio resource control (RRC) inactive state or a radio resource control (RRC) idle state.

[0011] The decision to use a multicast transmission mode for reception in an inactive state may be based at least in part on at least one of: the number of devices in the area that wish to receive the multicast session, the load in the area, the capabilities of the devices in the area, the radio resource control state of the devices in the multicast session in the area or in one or more notification areas including the area, the ability of devices that have joined the multicast session in the area to receive multicast data in a radio resource control inactive state, a preference of devices that have joined the multicast session in the area to use a transmission mode for reception in an inactive state or a transmission mode for reception in a connected state, a preference received from the core network to use a transmission mode for reception in an inactive state of radio resource control or a transmission mode for reception in a connected state of radio resource control, and / or information that at least one device in a connected state is also capable of receiving data based on the multicast transmission mode for reception in an inactive state.

[0012] The method may include broadcasting information using a transmission mode for inactive state reception.

[0013] The method may include sending at least one of the following: information indicating that the transmission mode received in the inactive state is used for a multicast session, information indicating that the transmission mode received in the connected state is used for a multicast session, an identifier that the transmission mode received in the inactive state is used for a multicast session, and / or information indicating that the transmission mode received in the inactive state is used for a multicast session in one or more neighboring cells.

[0014] The information of the transmission mode received using the inactive state may include an indication of whether the multicast session is inactive or active. The information of the transmission mode received using the inactive state may be provided only when the multicast session is active.

[0015] Providing the at least one device with information indicating a transmission mode using inactive state reception may include configuring the at least one device to monitor at least one point-to-multipoint control channel and to send an identifier associated with the multicast session.

[0016] Providing the at least one device with information indicating a transmission mode using inactive state reception may include configuring the at least one device to monitor a multicast control channel / multicast traffic channel (MCCH / MTCH) and to send an identifier of the MTCH for the multicast session on the MCCH.

[0017] The method may include sending information indicating a transmission mode using connected state reception, the sending including configuring at least one device for reception of the multicast session using dedicated RRC signaling.

[0018] The method may include indicating a transition between a connected state reception mode and an inactive state reception mode.The method may include sending a release message for the device to transition from the connected state to the inactive state and identifying a multicast session for inactive state reception.

[0019] According to one aspect, a method is provided that includes receiving information indicating that a transmission mode of inactive state reception is used for a multicast session in a region, and receiving data in the multicast session based on the information indicating the transmission mode of inactive state reception.

[0020] The method may include sending capability information indicating support for inactive state reception for the multicast session.

[0021] The inactive state reception may include at least one of: reception in a radio resource control (RRC) inactive state, and reception in a radio resource control (RRC) idle state.

[0022] The method may include at least one of: receiving an identifier that a transmission mode received in an inactive state is used for a multicast session, receiving information whether the multicast session is inactive or active, receiving information indicating that a transmission mode received in a connected state is used for the multicast session, and / or receiving information that a transmission mode received in an inactive state is used only when the multicast session is active.

[0023] The method may include sending a request to join a multicast session, and receiving a response including at least information regarding a successful join request, and an identification of the multicast session.

[0024] The method may include receiving data for the multicast session based on a transmission mode of inactive state reception while in a radio resource control connected state or a radio resource control inactive state.

[0025] The method may comprise monitoring at least one point-to-multipoint control channel and receiving an identifier associated with a multicast session on the monitored at least one point-to-multipoint control channel.

[0026] The method may include receiving information indicating that a transmission mode for inactive state reception is used for a multicast session in at least one or more neighboring cells, and preparing to receive data for the multicast session based on the transmission mode for inactive state reception when selecting a cell in the one or more neighboring cells or when being switched to a cell in the one or more neighboring cells.

[0027] The method may include switching between a connected state receiving mode and an inactive state receiving mode.

[0028] The method may include receiving a release message triggering a transition from a connected state reception mode to an inactive state reception mode, and identifying a multicast session for inactive state reception.

[0029] The method may include sending a request to transition from an inactive state to a connected state in response to participating in a multicast session in an inactive state, and in response to receiving information indicating that a transmission mode received in a connected state is to be used for the multicast session, or in response to not receiving information indicating that a transmission mode received in an inactive state is to be used for the multicast session.

[0030] According to one aspect, an apparatus for a radio access network node is provided, comprising at least one processor and at least one memory, the at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, enable the apparatus to at least: decide to use a transmission mode of inactive state reception for a multicast session in an area, provide information indicating that the transmission mode of inactive state reception is used for the multicast session for at least one device in the area, and send data using the transmission mode of inactive state reception in the multicast session.

[0031] The apparatus may be configured to receive capability information indicating that at least one device supports inactive state reception of a multicast session.

[0032] Inactive state reception may include reception in at least one of a radio resource control (RRC) inactive state or an RRC radio resource control (RRC) idle state. The apparatus may be configured to decide to use a multicast transmission mode for inactive state reception based at least in part on at least one of the following: the number of devices in the area that wish to receive the multicast session, the load in the area, the capabilities of the devices in the area, the radio resource control states of the devices in the multicast session in the area or in one or more notification areas including the area, the capabilities of the devices that have joined the multicast session in the area to receive multicast data in the radio resource control inactive state, the preference of the devices that have joined the multicast session in the area to use a transmission mode for reception in the inactive state or a transmission mode for reception in the connected state, the preference received from the core network to use a transmission mode for reception in the radio resource control inactive state or a transmission mode for reception in the radio resource control connected state, and / or information that at least one device in the connected state is also capable of receiving data based on the multicast transmission mode for inactive state reception.

[0033] The apparatus may be configured such that information using a transmission mode of inactive state reception is broadcasted.

[0034] The apparatus may be configured to cause at least one of the following to be sent: information indicating that a transmission mode received in an inactive state is used for a multicast session, information indicating that a transmission mode received in a connected state is used for a multicast session, an identifier of a multicast session that a transmission mode received in an inactive state is used, information indicating that a transmission mode received in an inactive state is used for a multicast session in one or more neighboring cells, information whether a multicast session is inactive or active, and / or information for configuring at least one device to monitor at least one point-to-multipoint control channel and to send an identifier associated with a multicast session.

[0035] The apparatus may be configured to send information to the at least one device indicating that a transmission mode of connected state reception is used to configure the at least one device for reception of the multicast session using dedicated RRC signaling.

[0036] The apparatus may be configured to at least one of: provide information on a transmission mode using inactive state reception only when a multicast session is active, indicate a transition between a connected state reception mode and an inactive state reception mode, and / or send a release message for a device to transition from connected state reception to inactive state reception, and identify a multicast session for inactive state reception.

[0037] According to one aspect, an apparatus for a device is provided, comprising at least one processor and at least one memory, the memory comprising computer program code, the at least one memory and the computer program code being configured, together with the at least one processor, to cause the apparatus to at least: receive information indicating that a transmission mode of inactive state reception is used for a multicast session in an area, and receive data in the multicast session based on the information indicating the transmission mode of inactive state reception.

[0038] The apparatus may be configured such that capability information indicating support for inactive state reception for a multicast session is sent.The apparatus may be configured to receive multicast data in at least one of a radio resource control (RRC) inactive state or a radio resource control (RRC) idle state.

[0039] The apparatus may be configured to at least one of: receive an identifier of a multicast session in which a transmission mode received in an inactive state is used, receive information as to whether the multicast session is inactive or active, receive information indicating that a transmission mode received in a connected state is used for the multicast session, receive information as to the use of a transmission mode received in an inactive state only when the multicast session is active, and / or send a request to join the multicast session, and receive a response including at least information about a successful request to join, and a multicast session identifier.

[0040] The apparatus may be configured to receive data of the multicast session based on a transmission mode of inactive state reception when in a radio resource control connected state or a radio resource control inactive state.

[0041] The apparatus may be configured to monitor at least one point-to-multipoint control channel and to receive an identifier associated with a multicast session on the monitored at least one point-to-multipoint control channel.

[0042] The apparatus may be configured to receive information indicating that a transmission mode for inactive state reception is used for a multicast session in at least one or more neighboring cells, and to prepare for receiving data for the multicast session based on the transmission mode for inactive state reception when selecting a cell in one or more neighboring cells or when being switched to a cell in one or more neighboring cells.

[0043] The apparatus may be configured to switch between connected state reception and inactive state reception.

[0044] The apparatus may be configured to receive a release message triggering a transition from connected state reception to inactive state reception, and identify a multicast session for inactive state reception, and / or send a request to transition from inactive state reception to connected state reception in response to participating in a multicast session in an inactive state, and in response to receiving information indicating that a transmission mode of connected state reception is to be used for the multicast session, or in response to not receiving information indicating that a transmission mode of inactive state reception is to be used for the multicast session.

[0045] The area may include a cell.

[0046] According to another aspect, a method in a network node is provided, comprising: for a cell, deciding whether to apply a transmission mode received in an RRC inactive state or a transmission mode received in an RRC connected state for a multicast session; based on the decision, sending data for the multicast session in the cell using the transmission mode received in an RRC inactive state or the transmission mode received in an RRC connected state for the multicast session; and providing information indicating that the transmission mode received in an RRC inactive state is used for the multicast session to a user equipment in the cell.

[0047] The method may also include receiving an indication of whether the served user equipment is capable of receiving multicast data in an RRC inactive state.

[0048] The method may also include receiving an indication of a served user equipment joining the multicast session.

[0049] The decision whether to apply a transmission mode received in an RRC inactive state or a transmission mode received in an RRC connected state for a multicast session in a cell may be based at least in part on at least one or more of the following criteria: the number of user devices that want to receive the multicast session in the cell; the RRC state of user equipment in the multicast session in the cell or in one or more RAN notification areas including the cell; the load in the cell; the ability of user equipment that has joined the multicast session in the cell to receive multicast data in an RRC inactive state; the preference of user equipment that has joined the multicast session in the cell to use a transmission mode received in an RRC inactive state or a transmission mode received in an RRC connected state; and the preference received from the core network to use a transmission mode received in an RRC inactive state or a transmission mode received in an RRC connected state.

[0050] In the method as described above, the user equipment in the RRC connected state or the RRC inactive state can receive the transmission mode received in the RRC inactive state.

[0051] The information received in the RRC inactive state that the transmission mode is used for the multicast session may also include an indication of whether the multicast session is active or inactive. The information received in the RRC inactive state that the transmission mode is used for the multicast session may also be provided only when the multicast session is active.

[0052] The information that the transmission mode is used for the multicast session received in the RRC inactive state may include an identifier of the multicast session.

[0053] The method may also include sending an indication of whether the transmission mode received in the RRC inactive state is used for the multicast session in one or more neighboring cells.

[0054] Providing the information that the transmission mode received in the RRC inactive state is used for the multicast session to the user equipment in the cell may include: configuring the user equipment to monitor one or more MCCH / MTCHs, and sending a multicast session identifier MTCH configuration for the multicast session in the MCCH. Alternatively, providing the information that the transmission mode received in the RRC inactive state is used for the multicast session to the user equipment in the cell may include: providing an indication that the transmission mode received in the RRC inactive state is used for the multicast session and a configuration for monitoring the MCCH / MTCH in the PDCCH-ConfigCommon, and sending the multicast session identifier in the MCCH.

[0055] The method may further include sending an indication to user equipment in the cell to use the transmission mode received in the RRC connected state. The indication sent to the user equipment in the cell to use the transmission mode received in the RRC connected state may include configuring the user equipment for reception of the multicast session using dedicated RRC signaling.

[0056] According to yet another aspect, a method for a receiver device (e.g., user equipment) is provided, comprising: receiving information that a transmission mode received in an RRC inactive state is used for a multicast session in a cell, and receiving data for the multicast session in the cell based on the transmission mode received in the RRC inactive state and based on the information of the transmission mode received in the RRC inactive state.

[0057] The method may further include sending an indication of the ability of the user equipment to receive multicast data while in the RRC inactive state.

[0058] The method may also include sending a request to join the multicast session, and receiving a response notifying the user equipment of a successful join request, and an identification of the multicast session.

[0059] The method may further include, when in the RRC connected state or the RRC inactive state, receiving data of the multicast session in the cell using a transmission mode received in the RRC inactive state.

[0060] The information received in the RRC inactive state that the transmission mode is used for the multicast session may also include an indication of whether the multicast session is active or inactive.

[0061] Only when the multicast session is active, information that the transmission mode received in the RRC inactive state is used for the multicast session may be provided.

[0062] The information that the transmission mode is used for the multicast session received in the RRC inactive state may include an identifier of the multicast session.

[0063] The method may also include receiving an indication of whether a transmission mode received in an RRC inactive state is used for a multicast session in one or more neighboring cells, and preparing to use the transmission mode to receive data for the multicast session when selecting the cell or being handed over to the cell.

[0064] The receiving of information that the transmission mode is used for the multicast session in the RRC inactive state may include receiving a configuration for monitoring one or more MCCH / MTCHs, receiving a multicast session identifier, and receiving an MTCH configuration for the multicast session in the MCCH.

[0065] The reception of information that the transmission mode received in the RRC inactive state is used for the multicast session includes: receiving an indication that the transmission mode received in the RRC inactive state is used for the multicast session and a configuration for monitoring MCCH / MTCH in PDCCH-ConfigCommon, and receiving a multicast session identifier in MCCH.

[0066] The method may also include receiving an indication to use the transmission mode received in the RRC connected state.

[0067] The reception of the indication of the transmission mode received at the user equipment in the cell using the RRC connected state may comprise receiving the configuration in dedicated RRC signalling for reception of the multicast session.

[0068] The method may further include sending a service request when an indication to use a transmission mode received in an RRC connected state is received and in an RRC idle state.

[0069] The method may further include sending a service request when no indication of using a transmission mode received in an RRC inactive state is received within a period configured in the cell, is located within a service area of ​​the multicast session, and is in an RRC inactive or RRC idle state.

[0070] Components for implementing the operations and functions disclosed herein may also be provided. The components may include appropriately configured hardware and / or software.

[0071] A computer software product embodying at least part of the functionality described herein may also be provided.According to one aspect, a computer program comprises instructions for performing at least one of the methods described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Some aspects will now be described in more detail, by way of example only, with reference to the following examples and accompanying drawings, in which:

[0073] Figure 1 An example of a system in which the present invention may be implemented is illustrated;

[0074] Figure 2 An example of a control device is shown;

[0075] Figure 3 , Figure 4 , Figure 5 and Figure 6 A flow chart illustrating an example of operations in a device and an access node is shown; and

[0076] Figures 7 to 10 is a signaling flow diagram according to some examples. DETAILED DESCRIPTION

[0077] The following description gives an exemplary description of some possibilities for implementing the present invention. Although this specification may refer to "an", "one" or "some" examples or embodiments at several locations in the text, this does not necessarily mean that each reference refers to the same example of (multiple) embodiments, or that a particular feature applies only to a single example or embodiment. Individual features of different examples and embodiments may also be combined to provide other embodiments.

[0078] A wireless communication system provides wireless communication to devices connected therein. Typically, access points (such as base stations) or other nodes of a radio access system (RAN) are provided for enabling communication. In the following, different scenarios will be described using the 3GPP 5G radio architecture as an example of an access architecture. However, the embodiments are not necessarily limited to such an architecture. Some example options for suitable systems are: Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (LTE), LTE-A (LTE Advanced), Wireless Local Area Network (WLAN or Wi-Fi), Worldwide Interoperability for Microwave Access (WiMAX), Personal Communications Service (PCS), Wideband Code Division Multiple Access (WCDMA), systems using Ultra-Wideband (UWB) technology, sensor networks, Mobile Ad Hoc Networks (MANET), Cellular Internet of Things (IoT) RAN and Internet Protocol Multimedia Subsystem (IMS) or any combination and further development thereof.

[0079] Figure 1 A schematic example of a communication system 1 including a radio access network (RAN) 2 is shown. The radio access network may include one or more radio access network nodes (RAN nodes) 11, 12 and 13. The RAN node may provide one or more cells 14. The RAN node may include any node that can send / receive radio signals (e.g., TRP, 3GPP 5G base station, such as gNB, eNB, user equipment, etc.). A large number of radio access networks may be provided in the communication system. For simplicity, only a few communication devices, RAN nodes, cells and radio access networks are shown. The radio access network may include multiple RAN nodes (e.g., base stations). The communication device 15 may be located within the service area of ​​the radio access network 2. The device 15 in the cell 14 may communicate with the RAN nodes 11-13.

[0080] Figure 1 An apparatus including a session management function 20 is shown. The session management function may include, for example, a multicast / broadcast session management function (MB-SMF). An apparatus 10 including a control function is provided between the apparatus including the session management function 20 and the RAN nodes 11, 12 and 13. The control function may be an access and mobility management function (AMF). The AMF provides an intermediate control function, and the general principle is that a multicast / broadcast session (MBS) is constructed by the multicast / broadcast session management function (MB-SMF) and remains transparent to the access and mobility management function (AMF). The AMF manages broadcast areas and registration area (RA) nodes (base stations, such as, for example, gNBs in 5G). The apparatus 10 including the AMF includes at least one processor 25 and a memory 26. The AMF may send and receive messages 16 and 17 with a user equipment, and send and receive messages 18, 19 with a RAN node. The configuration, operation and related functions of the AMF will be described in more detail later.

[0081] It is worth noting that the communication system 1 is shown only as a cloud and may include multiple other elements, which are not shown for clarity. For example, various operations and functions according to a 5G-based system may be included in a terminal or user equipment (UE), a 5G radio access network (5GRAN) or a next generation radio access network (NG-RAN), a 5G core network (5GC), one or more application functions (AF) and one or more data networks (DN). 5G-RAN may include one or more gNodeBs (gNBs) or one or more gNodeB distributed unit functions connected to one or more gNodeB centralized unit functions. 5GC may also include entities such as a network slice selection function (NSSF); a network open function; a network repository function (NRF); a policy control function (PCF); a unified data management (UDM); an application function (AF); an authentication server function (AUSF); an access and mobility management function (AMF); various session management functions (SMFs), etc.

[0082] The communication device 15 can be any suitable device suitable for wireless communication. Non-limiting examples include a mobile station (MS) (e.g., a mobile device such as a mobile phone or so-called "smart phone", etc.), a computer equipped with a wireless interface card or other wireless interface facilities (e.g., a USB dongle), a personal data assistant (PDA) or a tablet equipped with wireless communication capabilities, a machine type communication (MTC) device, an Internet of Things (IoT) type communication device, a cellular Internet of Things (CIoT) device, or any combination of these devices or similar devices. The device can be provided as part of another device. The device can receive signals via an air or radio interface via an appropriate receiving device, and can send signals via an appropriate device for sending radio signals. Communication can be carried out via multiple paths. In order to achieve MIMO type communication, a device with multiple antenna elements can be provided.

[0083] Communication devices, such as access nodes, terminal devices and network functions, are equipped with data processing means comprising at least one processor and at least one memory. Figure 2 An example of a data processing apparatus 50 comprising processor(s) 52 , 53 and one or more memories 51 is shown. Figure 2Also shown are connections between elements of the device and interfaces for connecting the data processing device to other components of the device. At least one memory may include at least one ROM and / or at least one RAM. The communication device may include other possible components for assisting in performing the tasks it is designed to perform in software and hardware, including implementing the features described herein involving multicast and / or broadcast services. At least one processor may be coupled to at least one memory. At least one processor may be configured to execute appropriate software code to implement one or more of the following aspects. The software code may be stored in at least one memory, such as in at least one ROM.

[0084] Certain aspects, configurations, and signaling related operations are described below using 3GPP terminology. More specifically, certain detailed examples of providing backward compatibility, especially for inactive or idle reception of multicast services, are discussed. Compatibility issues may arise because, for example, 3GPP Rel-17 defines procedures for multicast limited to UEs in a Radio Resource Control (RRC) connected state, while subsequent releases do not have this restriction.

[0085] Radio Resource Control (RRC) is used to control wireless communications. Traditionally, RRC provides two states, RRC_CONNECTED and RRC_IDLE. Another RRC state for inactive UEs, called RRC_INACTIVE, was introduced in 3GPP New Radio (NR) Rel-15 to supplement the RRC_CONNECTED and RRC_IDLE states, thereby providing states for streamlined signaling and energy saving support for NR services between the RRC_CONNECTED and RRC_IDLE states. Compared with the RRC_IDLE state, the RRC_INACTIVE state enables faster resumption of a previously suspended connection and the start of transmission of small or sporadic data, with low initial access delay and associated signaling overhead. This is mainly achieved by reducing the control signaling required for requesting and obtaining the resumption of a suspended RRC connection. The transition from RRC_CONNECTED to RRC_INACTIVE can be triggered by a RAN node (e.g., a gNB) using an RRCRelease message including suspension configuration information. When the UE is transitioned to RRC_INACTIVE, the UE access stratum (AS) context required for fast resumption of the suspended connection (referred to as UE inactive AS context) is maintained on both the UE side and the RAN side, and is identified by a UE identifier (e.g., an inactive radio network temporary identifier (I-RNTI)) on the network side.

[0086] Multicast Broadcast Service (MBS) is an example of a point-to-multipoint communication service where data can be sent from a single source to multiple destinations / devices simultaneously. Broadcast is the ability to deliver content to all users in an area. Broadcast content can be sent over a broadcast area. A broadcast area is a combination of one or more network access nodes (e.g., base stations and / or cells) that are capable of delivering the same content. Multicast, in turn, is a transmission directed to a group of target devices. The number and variety of mobile multicast applications are growing, and multicast traffic load is expected to increase as well. In addition to mobile user devices, multicast services can target a wide variety of devices, such as machine type communications (MTC) for the Internet of Things (IoT). Hybrid broadcast-multicast can also be provided.

[0087] According to 3GPP Rel-17, multicast is limited to UEs in radio resource control (RRC) connected mode. RAN nodes compliant with 3GPP Rel-17 will operate accordingly, and UEs served by such RAN nodes should be in RRC connected mode to receive multicast data for RAN nodes. Similarly, UEs compliant with Rel-17 only need to be able to receive in RRC connected mode. The RAN node serving the UE should operate accordingly so that the UE receives multicast data. On the other hand, RAN nodes and UEs compliant with 3GPP Rel-18 can support multicast transmission to inactive UEs. In this case, the RAN node can decide whether to apply the inactive UE mode to the multicast session or cell. The decision can be based on various factors, such as the number of UEs in the cell, the amount of data sent, etc.

[0088] The following explains how to handle the situation where the UE may need to be informed whether the transmission mode used by the RAN node is for inactive reception or whether the RAN node uses the transmission mode for connected mode reception for the cell. For example, a RAN node may advertise inactive / idle support or inactive / idle usage for a Multicast Broadcast Service (MBS) session.

[0089] Figure 3 An operational flow chart for configuring a device for at least one multicast session at a RAN node according to an example is shown. The RAN node receives capability information from a receiver device indicating that the receiver device supports inactive state reception for a multicast session at 100. The RAN node determines to apply a transmission mode of inactive state reception to transmit at least one multicast session to the receiver device at 102. The RAN node may then send information for enabling the receiver device to use the inactive mode for at least one multicast session at 104.

[0090] If the RAN node decides at 102 that the inactive reception of multicast data is not suitable for multicast transmission to the receiver devices, it may continue to multicast in connected mode.

[0091] Figure 4 A flow chart of operations at a receiver device for receiving at least one multicast session according to an example is shown. The receiver device sends capability information indicating that the receiver device supports inactive state reception of multicast sessions to a RAN node at 200. The receiver device may then receive response information from the RAN node at 202 to enable inactive state multicast reception for at least one multicast session. The receiver device is correspondingly configured at 204 for inactive state reception in an inactive multicast mode for at least one multicast session.

[0092] It should be understood that the term inactive state reception of a multicast session is intended to cover reception in a radio resource control (RRC) inactive state (eg, RRC_INACTIVE state) or an RRC idle state (eg, RRC_IDLE state).

[0093] Figure 5 Another example of operation at an access node is shown. At step 300, a decision is made to use a multicast transmission mode of inactive state reception for a multicast session in a region. At 302, information indicating that the multicast transmission mode of inactive state reception is used for at least one multicast session is provided to at least one device in the region. Then, at 304, data is sent using the multicast transmission mode of inactive state reception in at least one multicast session.

[0094] Figure 6 Another example of operations at a device for receiving multicast data is shown. In the method, information indicating that a transmission mode of inactive state reception is used for a multicast session in a region is received at 400. Then, data in the multicast session is received at 402 based on the information indicating the transmission mode of inactive state reception.

[0095] Figure 7 A signaling flow diagram according to a more detailed example of operation using 5G terminology is shown. The UE sends its capability to support multicast reception in an RRC inactive state (e.g., RRC_INACTIVE state) at message 1. The transmission may occur via the AMF to the relevant RAN node(s), see Figure 1Messages 17 and 18 in . The capability information may also be forwarded to other RAN nodes when the UE is switched. In stage 2, the RAN node may decide whether to apply a transmission mode for connected mode reception or a transmission mode for inactive mode reception to a multicast session (e.g., an MBS session) in the cell based on, for example, the number of UEs in the cell, the load in the cell or other defined area, and / or the capabilities of the relevant UEs. Other non-limiting examples of information that may form the basis for making a decision include: the number of devices in the area that wish to receive the multicast session; the radio resource control state of the devices in the multicast session in the area or in one or more notification areas including the area; the ability of devices that have joined the multicast session in the area to receive multicast data in the radio resource control inactive state; the preference of devices that have joined the multicast session in the area to use a transmission mode for reception in the radio resource control inactive state or a transmission mode for reception in the radio resource control connected state; and a preference received from the core network to use a transmission mode for reception in the radio resource control inactive state or a transmission mode for reception in the radio resource control connected state.

[0096] Then in phase 3, the inactive / idle MBS multicast transmission may broadcast an indication over the intra-cell radio channel that the transmission mode received in the RRC inactive state is applicable to the multicast session in the cell. The indication may include the ID of the multicast session.

[0097] The UE may then receive the multicast data according to the indicated mode via a transmission mode for inactive / idle mode reception or connected mode reception in step 4. The RAN node may transition the UE that has joined the multicast session and is not sending or receiving other data to an inactive state in stage 5 and perform reception of the multicast data accordingly.

[0098] According to one possibility, the broadcast message 3 applies only to multicast sessions active in the cell(s), or broadcasts the session ID only when the corresponding MBS session is active. According to another possibility, the broadcast message 3 comprises an indication whether the multicast session is active or inactive.

[0099] According to one possibility, the transmission mode also received in connected mode is adapted to broadcast the session ID in the cell and the transmission mode received indicating connected mode is adapted to broadcast the session ID in the cell.

[0100] Information related to using the inactive / idle mode reception may be sent in a point-to-multipoint control channel over the radio link.

[0101] Indicating that the transmission mode for RRC inactive mode reception is applicable to a cell or group of cells Transmission may also occur in neighboring cells to enable more seamless reception when the UE reselects another cell. To this end, the RAN node may send some or all of the above information to the neighboring node. The neighboring node may send this information and an indication of which cells it applies to.

[0102] When a UE in idle or inactive state wishing to receive multicast session data begins to be served by a RAN node, it may detect that the RAN node does not advertise the use of the inactive state reception transmission mode for multicast or that the RAN advertises the use of the connected mode reception transmission mode for the multicast session. In this case, the UE may send a service request to transition to the RRC connected state.

[0103] When a UE wishing to receive a multicast session is already in RRC connected mode, it can determine whether the inactive / idle state reception transmission mode or the connected state reception transmission mode should be applied to the multicast session based on information broadcast in the cell or another defined broadcast area.

[0104] Figure 8 An example is shown where the gNB receives the UE's multicast reception capabilities in the RRC inactive state in the UE's radio capability information. This information may be received from the AMF during UE context establishment or directly from the UE. In this example, the capability information is received in message 2b in response to a capability query 1b by the RAN node. This in turn may be triggered by an initial connection establishment request message 1a received by the RAN node from the core network (CN). Conventional session establishment messages (such as 3, 4 and 5) may then follow to exchange information such as features such as Temporary Mobile Group Identity (TMGI) and Source Specific Multicast (SSM).

[0105] The RAN node may decide in step 6 to apply the transmission mode for inactive UEs. The decision may be based, for example, on the number of UEs in the cell, on the load in the cell, and / or on the capabilities of the UE. A configuration for the transmission mode for RRC inactivity is then provided. In step 7, the UE is configured with a search space (SS) for a multicast control channel / multicast traffic channel (MCCH / MTCH) as part of the physical downlink control channel (PDCCH) ConfigCommon configuration in the RRC reconfiguration message. In step 8, upon receiving the MCCH / MTCH SS, the UE capable of multicast reception in RRC inactivity monitors the MCCH for the TMGI associated with the multicast session.

[0106] If the RAN node decides to apply the RRC inactive state transmission mode, it may send only the MCCH configured with the MTCH required for the session in step 9. If the RAN node decides to apply the RRC connected state transmission mode, it may configure the UE using UE-specific RRC signaling, where the RAN configures the MBS radio bearers.

[0107] In phase 10, data for transmission is received from the CN. The data is then multicast on the MTCH in phase 11 based on the inactive mode reception.

[0108] Fig. 9 Another example is shown in which the NG-RAN (e.g., the gNB of the NG-RAN) receives the multicast reception capabilities of the UE in the radio capabilities of the UE in the RRC inactive state from the AMF of the CN during UE context establishment, or from the UE. In accordance with the above steps 1-5, the RAN node may decide at step 6 to apply the transmission mode for the inactive UE. The decision may be based on, for example, the number of UEs in the cell, the load in the cell, and / or the capabilities of the UE, etc. Next is the configuration of the transmission mode for the RRC inactive state, and in step 7, the NG-RAN provides the UE with an explicit indication that it will apply the transmission mode for the RRC inactive state. This may be provided in the same message in which the SS for MCCH / MTCS is provided as part of the PDCCH-ConfigCommon configuration. In step 8, upon receiving the SS configuration and indication for MCCH / MTCH reception, the UE capable of multicast reception in the RRC inactive state monitors the MCCH for the TMGI associated with the multicast session. Steps 9 to 11 may be performed in accordance with the above steps.

[0109] Next reference Fig.10 The signaling flow chart of FIG. 1 explains the transition between the RRC connected state and the RRC inactive state. Fig. 9 As shown, the example starts from step 6 and continues to step 11. In the following steps, the UE changes from the connected state to the inactive state.

[0110] The RAN may decide to release the UE in step 12 so that the UE transitions to the RRC inactive state. The RAN node may then send an RRCRelease message 11 with the suspendConfig information element in message 13. The message may include an indication of the inactive transmission mode.

[0111] The NG-RAN may also release the UE directly to the RRC inactive state at this stage and may skip step 7. In this case, the RRC Release message may also include an indication of which sessions are provided using the inactive state transmission mode. The session(s) may be indicated by the TMGI(s).

[0112] The UE may also transition from the inactive state to the connected state. In this case, the RAN node may remove the TMGI(s) and the corresponding MTCH configuration from the MCCH, which may implicitly trigger the UE to request RRC connection resumption. The NG-RAN may also remove the TMGI(s) and the corresponding MTCH if there is no data for the multicast session or if the RAN node of the NG-RAN receives a deactivation of the multicast session from the core network. Therefore, when the UE receives paging (group paging or single CN / RAN paging), it may request resumption of the RRC connection.

[0113] The MCCH may also include an indication for each TMGI, indicating whether the session is provided by a transmission mode in an RRC connected state or a transmission mode in an RRC inactive state. If the UE receives an indication that the session is provided by a transmission mode in an RRC connected state, the UE may request resumption of the RRC connection.

[0114] Such operation may also be required if the RAN node wants to provide a session to a Rel-17 UE using the transmission (TX) mode for reception in the connected state, while there are Rel-18 UEs capable of receiving in the TX mode in the inactive state. In this case, if the MCCH indicates that the TX mode is for reception in the connected state, the Rel-18 UE may respond to the group paging and request the resumption of the RRC connection. Otherwise, the UE should avoid requesting the resumption of the RRC connection.

[0115] According to the example, Figure 1 and Figure 2 The device can be configured to implement a method, including: for a cell, deciding whether to apply a transmission mode received in an RRC inactive state or a transmission mode received in an RRC connected state for a multicast session; based on the decision, using the transmission mode received in an RRC inactive state or the transmission mode received in an RRC connected state for the multicast session and sending data for the multicast session in the cell; and providing information to a user equipment in the cell indicating that the transmission mode received in an RRC inactive state is used for the multicast session.

[0116] The method may also include receiving an indication of whether the served user equipment is capable of receiving multicast data in an RRC inactive state.

[0117] The method may also include receiving an indication of a served user equipment joining the multicast session.

[0118] The decision whether to apply a transmission mode received in an RRC inactive state or a transmission mode received in an RRC connected state for a multicast session in a cell may be based at least in part on at least one or more of the following criteria: the number of user devices that want to receive the multicast session in the cell; the RRC state of user equipment in the multicast session in the cell or in one or more RAN notification areas including the cell; the load in the cell; the ability of user equipment that has joined the multicast session in the cell to receive multicast data in an RRC inactive state; the preference of user equipment that has joined the multicast session in the cell to use a transmission mode received in an RRC inactive state or a transmission mode received in an RRC connected state; and the preference received from the core network to use a transmission mode received in an RRC inactive state or a transmission mode received in an RRC connected state.

[0119] In the method as described above, the user equipment in the RRC connected state or the RRC inactive state can receive the transmission mode received in the RRC inactive state.

[0120] The information received in the RRC inactive state that the transmission mode is used for the multicast session may also include an indication of whether the multicast session is active or inactive. The information received in the RRC inactive state that the transmission mode is used for the multicast session may also be provided only when the multicast session is active.

[0121] The information that the transmission mode is used for the multicast session received in the RRC inactive state may include an identifier of the multicast session.

[0122] The method may also include sending an indication of whether the transmission mode received in the RRC inactive state is used for the multicast session in one or more neighboring cells.

[0123] Providing the information that the transmission mode received in the RRC inactive state is used for the multicast session to the user equipment in the cell may include: configuring the user equipment to monitor one or more MCCH / MTCHs, and sending a multicast session identifier MTCH configuration for the multicast session in the MCCH. Alternatively, providing the information that the transmission mode received in the RRC inactive state is used for the multicast session to the user equipment in the cell may include: providing an indication that the transmission mode received in the RRC inactive state is used for the multicast session and a configuration for monitoring the MCCH / MTCH in the PDCCH-ConfigCommon, and sending the multicast session identifier in the MCCH.

[0124] The method may further include sending an indication to user equipment in the cell to use the transmission mode received in the RRC connected state. The indication sent to the user equipment in the cell to use the transmission mode received in the RRC connected state may include configuring the user equipment for reception of the multicast session using dedicated RRC signaling.

[0125] According to another example, Figure 1 and Figure 2 The apparatus may be configured to implement a method in a receiver device (e.g., a user equipment), comprising: receiving information that a transmission mode received in an RRC inactive state is used for a multicast session in a cell, and receiving data for the multicast session in the cell based on the transmission mode received in the RRC inactive state and the information based on the transmission mode received in the RRC inactive state.

[0126] The method in the receiver device may further include sending an indication of the capability of the user equipment to receive multicast data in the RRC inactive state.

[0127] The method in the receiver device may further include sending a request to join the multicast session, and receiving a response notifying the user device of the request to join successfully, and the multicast session identifier.

[0128] The method may further include, when in an RRC connected state or an RRC inactive state, receiving data of the multicast session in the cell using a transmission mode received in the RRC inactive state.

[0129] The information received in the RRC inactive state that the transmission mode is used for the multicast session may also include an indication of whether the multicast session is active or inactive.

[0130] Only when the multicast session is active, information that the transmission mode received in the RRC inactive state is used for the multicast session may be provided.

[0131] The information that the transmission mode is used for the multicast session received in the RRC inactive state may include an identifier of the multicast session.

[0132] The method may also include receiving an indication of whether a transmission mode received in an RRC inactive state is used for a multicast session in one or more neighboring cells, and preparing to use the transmission mode to receive data for the multicast session when selecting the cell or being handed over to the cell.

[0133] The receiving of information that the transmission mode is used for the multicast session in the RRC inactive state may include receiving a configuration for monitoring one or more MCCH / MTCHs, receiving a multicast session identifier, and receiving an MTCH configuration for the multicast session in the MCCH.

[0134] The reception of information that the transmission mode received in the RRC inactive state is used for the multicast session includes: receiving an indication that the transmission mode received in the RRC inactive state is used for the multicast session and a configuration for monitoring MCCH / MTCH in PDCCH-ConfigCommon, and receiving a multicast session identifier in MCCH.

[0135] The method may also include receiving an indication to use the transmission mode received in the RRC connected state.

[0136] The reception of the indication of the transmission mode received at the user equipment in the cell using the RRC connected state may comprise receiving the configuration in dedicated RRC signalling for reception of the multicast session.

[0137] The method may further include sending a service request when an indication to use a transmission mode received in an RRC connected state is received and in an RRC idle state.

[0138] The method may further include sending a service request when no indication of using a transmission mode received in an RRC inactive state is received within a period configured in the cell, is located within a service area of ​​the multicast session, and is in an RRC inactive or RRC idle state.

[0139] It is worth noting that, although exemplary embodiments are described above, several variations and modifications may be made to the disclosed solution without departing from the scope of the present invention. Different features from different embodiments may be combined.

[0140] Therefore, the embodiments may vary within the scope of the appended claims. In general, some embodiments may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device, but the embodiments are not limited thereto. Although various embodiments may be shown and described as block diagrams, flow charts, or using some other graphical representations, it is well understood that, as non-limiting examples, the boxes, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or controllers, or other computing devices, or some combination thereof.

[0141] Embodiment can be realized by computer software that is stored in memory and can be performed by at least one data processor of relevant entity, or by hardware, or by the combination of software and hardware.In addition, it should be noted in this respect that any above process can represent program steps, or interconnected logic circuits, frames and functions, or the combination of program steps and logic circuits, frames and functions.Software can be stored on physical media (such as memory chips or memory blocks realized in processors), on magnetic media (such as hard disks or floppy disks), and on optical media (such as, for example, DVDs and data variants thereof, CDs).

[0142] The memory can be any type suitable for the local technical environment, and can be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processor can be any type suitable for the local technical environment, and as a non-limiting example, can include one or more processors in a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a gate-level circuit and a processor based on a multi-core processor architecture. Alternatively or additionally, some embodiments can be implemented using a circuit system. The circuit system can be configured to perform one or more functions and / or method processes previously described. The circuit system can be provided in a network entity and / or in a communication device and / or a server and / or a device.

[0143] As used in this application, the term "circuitry" may refer to one or more or all of the following:

[0144] (a) hardware circuit implementation only (such as implementation using only analog and / or digital circuitry);

[0145] (b) a combination of hardware circuitry and software, such as: (i) a combination of analog and / or digital hardware circuitry and software / firmware, and (ii) any portion of hardware processor(s) with software (including digital signal processor(s), software and memory(s) that work together to enable a communications device and / or equipment and / or server and / or network entity to perform the various functions described above; and

[0146] (c) Hardware circuit(s) and / or processor(s), such as microprocessor(s) or portion(s) of microprocessor(s), that require software (e.g., firmware) to operate, but which may not be present when the software is not required for operation.

[0147] This definition of circuitry applies to all uses of the term in this application, including in any claims. As another example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its accompanying software and / or firmware. The term circuitry also covers, for example, an integrated device.

[0148] It is worth noting that although embodiments have been described for certain architectures, similar principles can be applied to other systems. Therefore, although certain embodiments are described above by way of example with reference to certain exemplary architectures, technical standards and protocols for wireless networks, the features described herein can be applied to any other suitable form of system, architecture and device other than the systems, architectures and devices shown and described in detail in the above examples. It is also worth noting that different combinations of different embodiments are possible. It is also worth noting herein that although exemplary embodiments are described above, various changes and modifications may be made to the disclosed solution without departing from the spirit and scope of the invention.

Claims

1. A method comprising: Determines the inactive receive transmission mode to use for multicast sessions in a zone, providing at least one device in the area with information indicating use of the transmission mode of inactive reception for the multicast session, and In the multicast session, data is sent using the transmission mode of inactive reception.

2. The method according to claim 1, comprising: Capability information indicating that the at least one device supports inactive state reception of a multicast session is received.

3. The method according to claim 1 or 2, wherein the inactive state receiving comprises: Reception in at least one of a radio resource control (RRC) inactive state or a radio resource control (RRC) idle state.

4. The method according to any of the preceding claims, wherein the decision to use the multicast transmission mode with inactive reception is based at least in part on at least one of: the number of devices in the area that wish to receive the multicast session, The load in the area, the capabilities of the devices in the area, a radio resource control status of devices in the multicast session in the area or in one or more notification areas including the area, the ability of devices that have joined the multicast session in the area to receive multicast data in a radio resource control inactive state, a preference of devices that have joined the multicast session in the area to use the transmission mode of reception in an inactive state or to use the transmission mode of reception in a connected state, a preference received from the core network to use said transmission mode for reception in a radio resource control inactive state or to use said transmission mode for reception in a radio resource control connected state, and / or At least one device in a connected state can also receive information about data based on the multicast transmission mode received in an inactive state.

5. A method according to any one of the preceding claims, comprising: Information on the use of the transmission mode for inactive state reception is broadcasted.

6. A method according to any one of the preceding claims, comprising: Send at least one of the following: information indicating that the transmission mode of inactive reception is used for the multicast session, information indicating the connection state receives the transmission mode to be used for the multicast session, The transmission mode received in the inactive state is used for an identifier of the multicast session, and / or The transmission mode indicating inactive reception is used for information of the multicast session in one or more neighboring cells.

7. A method according to any one of the preceding claims, wherein: The information about the use of the transmission mode received in an inactive state includes: an indication of whether the multicast session is inactive or active, or Said information of said usage of said transmission mode for inactive reception is provided only when said multicast session is active.

8. The method of any one of the preceding claims, wherein providing at least one device with the information indicating the use of the transmission mode of inactive state reception comprises: The at least one device is configured to monitor at least one point-to-multipoint control channel and to send an identifier associated with the multicast session.

9. The method of claim 8, wherein providing at least one device with the information indicating the use of the transmission mode of inactive state reception comprises: The at least one device is configured to monitor a multicast control channel / multicast traffic channel (MCCH / MTCH) and to send the identifier of the MTCH for the multicast session on the MCCH.

10. A method according to any one of the preceding claims, comprising: Information indicating the use of the transmission mode for connected state reception is transmitted, the transmitting comprising configuring at least one device for the reception of the multicast session using dedicated RRC signaling.

11. A method according to any one of the preceding claims, comprising: Indicates a transition between the connected state receive mode and the inactive state receive mode.

12. The method according to claim 11, comprising: A release message is sent for a device to transition from the connected state reception mode to the inactive state reception mode, and the multicast session for the inactive state reception is identified.

13. A method comprising receiving information indicating use of an inactive reception transmission mode for a multicast session in a region, and Data in the multicast session is received based on the information indicating the transmission mode of inactive reception.

14. The method according to claim 13, comprising: Capability information indicating support for the inactive state reception for the multicast session is sent.

15. The method according to claim 13 or 14, wherein the inactive state reception comprises at least one of: reception in a radio resource control (RRC) inactive state, and reception in a radio resource control (RRC) idle state.

16. The method according to any one of claims 13 to 15, comprising at least one of the following: receiving an identifier of the multicast session in which the transmission mode is used for receiving the inactive state, receiving information whether the multicast session is inactive or active, receiving information indicating that a transmission mode for connection state reception is to be used for a multicast session, and / or The information of the use of the transmission mode received in an inactive state is received only when the multicast session is active.

17. The method according to any one of claims 13 to 16, comprising: sending a request to join the multicast session; as well as A response is received including at least information regarding the request to join successfully, and a multicast session identifier.

18. The method according to any one of claims 13 to 17, comprising: When in a radio resource control connected state or a radio resource control inactive state, data of the multicast session is received based on the transmission mode of inactive state reception.

19. The method according to any one of claims 13 to 18, comprising: At least one point-to-multipoint control channel is monitored and an identifier associated with the multicast session is received on the at least one monitored point-to-multipoint control channel.

20. The method according to any one of claims 13 to 19, comprising: receiving information indicating that the transmission mode of inactive reception is used for the multicast session in at least one or more neighboring cells, and When selecting a cell among the one or more neighboring cells or when being handed over to a cell among the one or more neighboring cells, preparing to receive data of the multicast session is performed based on the transmission mode of inactive state reception.

21. The method according to any one of claims 13 to 20, comprising: Switching between a connected state receiving mode and said inactive state receiving mode.

22. The method according to claim 21, comprising: A release message is received that triggers a transition from the connected state reception mode to the inactive state reception mode, and the multicast session for the inactive state reception is identified.

23. The method according to claim 21 or 22, comprising: In response to participating in a multicast session in the inactive state, and in response to at least one of the following: receiving information indicating that the transmission mode received in the connected state is used for the multicast session, or not receiving information indicating that the transmission mode received in the inactive state is used for the multicast session, sending a request to transition from the inactive state to the connected state.

24. A method according to any preceding claim, wherein the area comprises a cell.

25. An apparatus for a radio access network node, comprising at least one processor and at least one memory, the at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to at least: Determines the inactive receive transmission mode to use for multicast sessions in a zone, providing at least one device in the area with information indicating use of the transmission mode of inactive reception for the multicast session, and In the multicast session, data is sent using the transmission mode of inactive reception.

26. The apparatus of claim 25, configured to receive capability information indicating that the at least one device supports inactive state reception of a multicast session.

27. The apparatus according to claim 25 or 26, wherein the inactive state receiving comprises: Reception in at least one of a radio resource control (RRC) inactive state or an RRC radio resource control (RRC) idle state.

28. The apparatus of any one of claims 25 to 27, configured to: determine to use the multicast transmission mode of inactive state reception based at least in part on at least one of the following: the number of devices in the area that wish to receive the multicast session, The load in the area, the capabilities of the devices in the area, a radio resource control status of devices in the multicast session in the area or in one or more notification areas including the area, the ability of devices that have joined the multicast session in the area to receive multicast data in a radio resource control inactive state, a preference of devices that have joined the multicast session in the area to use the transmission mode of reception in an inactive state or to use the transmission mode of reception in a connected state, a preference received from the core network to use said transmission mode for reception in a radio resource control inactive state or to use said transmission mode for reception in a radio resource control connected state, and / or At least one device in a connected state can also receive information about data based on the multicast transmission mode received in an inactive state.

29. An apparatus according to any one of claims 25 to 28, configured such that information of the use of the transmission mode of inactive state reception is broadcasted.

30. An apparatus according to any one of claims 25 to 29, configured to cause at least one of the following to be sent: information indicating that the transmission mode of inactive reception is used for the multicast session, information indicating the connection state receives the transmission mode to be used for the multicast session, the transmission mode of inactive reception being used for an identifier of the multicast session, information indicating that the transmission mode of inactive reception is used for the multicast session in one or more neighboring cells, information whether the multicast session is inactive or active, and / or Information for configuring the at least one device to monitor at least one point-to-multipoint control channel and to send an identifier associated with the multicast session.

31. The apparatus according to any one of claims 25 to 30, configured to: send information to at least one device indicating that a transmission mode of connection state reception is used to configure the at least one device for the reception of the multicast session using dedicated RRC signaling.

32. The apparatus according to any one of claims 25 to 31, configured to at least one of the following: providing said information of said use of said transmission mode for inactive reception only when said multicast session is active, indicating a transition between a connected state receiving mode and said inactive state receiving mode, and / or A release message for a device to transition from a connected state reception to an inactive state reception is sent, and the multicast session for the inactive state reception is identified.

33. An apparatus for a device, comprising at least one processor and at least one memory, the memory comprising computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to at least: receiving information indicating use of an inactive reception transmission mode for a multicast session in a region, and Data in the multicast session is received based on the information indicating the transmission mode of inactive reception.

34. The apparatus of claim 33, configured such that capability information indicating support for the inactive state reception for a multicast session is sent.

35. The apparatus of claim 33 or 34, configured to receive multicast data in at least one of a radio resource control (RRC) inactive state or a radio resource control (RRC) idle state.

36. The apparatus according to any one of claims 33 to 35, configured to at least one of the following: receiving an identifier of the multicast session in which the transmission mode is used for receiving the inactive state, receiving the information whether the multicast session is inactive or active, receiving information indicating use of a transmission mode for connection state reception for a multicast session, receiving the information of the use of the transmission mode received in an inactive state only when the multicast session is active, and / or A request to join the multicast session is sent, and a response including at least information about the request to join successfully, and a multicast session identifier is received.

37. The apparatus according to any one of claims 33 to 36, configured to: when in a radio resource control connected state or a radio resource control inactive state, receive data of the multicast session based on the transmission mode of inactive state reception.

38. The apparatus according to any one of claims 33 to 37, configured to: monitor at least one point-to-multipoint control channel and receive an identifier associated with the multicast session on the at least one monitored point-to-multipoint control channel.

39. The apparatus according to any one of claims 33 to 38, configured to: receiving information indicating that the transmission mode of inactive reception is used for the multicast session in at least one or more neighboring cells, and When selecting a cell among the one or more neighboring cells or when being handed over to a cell among the one or more neighboring cells, preparing to receive data of the multicast session is performed based on the transmission mode of inactive state reception.

40. An apparatus according to any one of claims 33 to 39, configured to switch between connected state reception and said inactive state reception.

41. The apparatus according to claim 40 is configured to: receive a release message triggering a transition from the connected state reception to the inactive state reception, and identify the multicast session used for the inactive state reception, and / or in response to participating in the multicast session in the inactive state, and in response to at least one of the following: receiving information indicating that the transmission mode of the connected state reception is used for the multicast session, or not receiving information indicating that the transmission mode of the inactive state reception is used for the multicast session, send a request to transition from the inactive state reception to the connected state reception.

42. An apparatus according to any one of claims 25 to 41, wherein the area comprises a cell.

43. A computer readable medium comprising program code for causing a processor to perform the method according to any one of claims 1 to 24.

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