WO2025112799A1 - Method for multicast service and small data transmission in wireless communication, and device - Google Patents

Abstract

The present application discloses a method for a multicast service and small data transmission in wireless communication, and a device. The method comprises: receiving first signaling, the first signaling being configured for small data transmission in an RRC inactive state, and the first signaling being configured to receive a multicast service in the RRC inactive state; and in the RRC inactive state, in response to any condition in a first condition set being satisfied, sending first information, the sending first information depending on whether the small data transmission is being performed. The present application allows for better reception of a multicast service and ensures the continuity of multicast service reception.

Description

A method and device for multicast service and small data transmission in wireless communication Technical Field

The present application relates to a method and apparatus for multicast services and small data transmission in a wireless communication system, and relates to receiving multicast services and small data transmission in an RRC inactive state, and in particular to simultaneously receiving multicast services and performing small data transmission.

Background Art

The application scenarios of wireless communication systems in the future will become more and more diversified, and different application scenarios will put forward different performance requirements for the system. In order to meet the different performance requirements of various application scenarios, the 3GPP (3rd Generation Partner Project) RAN (Radio Access Network) #72 plenary meeting decided to study the new air interface technology (NR, New Radio) (or Fifth Generation, 5G), and the NR WI (Work Item) was passed at the 3GPP RAN #75 plenary meeting, starting the standardization work on NR.

In communication, both LTE (Long Term Evolution) and 5G NR involve accurate reception of reliable information, optimized energy efficiency, determination of information validity, flexible resource allocation, scalable system structure, efficient non-access layer information processing, low service interruption and drop rate, and support for low power consumption. This is of great significance to the normal communication between base stations and user equipment, the reasonable scheduling of resources, and the balancing of system load. It can be said to be the cornerstone of high throughput, meeting the communication needs of various services, improving spectrum utilization, and improving service quality. It is indispensable for eMBB (ehanced Mobile BroadBand), URLLC (Ultra Reliable Low Latency Communication) and eMTC (enhanced Machine Type Communication). At the same time, in IIoT (Industrial Internet of Things), V2X (Vehicular to X), device to device, unlicensed spectrum communication, user communication quality monitoring, network planning and optimization, TN (Territial Network), dual connectivity system, wireless resource management and multi-antenna codebook selection, signaling design, neighbor cell management, business management, and beamforming, there are extensive demands. The information transmission methods are divided into broadcast and unicast. Both transmission methods are indispensable for 5G systems because they are very helpful in meeting the above requirements.

As the scenarios and complexity of the system continue to increase, higher requirements are placed on reducing interruption rates, reducing latency, enhancing reliability, enhancing system stability, business flexibility, and power saving. At the same time, compatibility between different versions of different systems also needs to be considered during system design.

The meanings of the concepts, terms and abbreviations in this application may refer to the 3GPP standards, including but not limited to:

https://www.3gpp.org/ftp/Specs/archive/21_series/21.905/21905-h10.zip

https://www.3gpp.org/ftp/Specs/archive/38_series/38.300/38300-h10.zip

https://www.3gpp.org/ftp/Specs/archive/38_series/38.331/38331-h10.zip

https://www.3gpp.org/ftp/Specs/archive/38_series/38.133/38133-h10.zip

https://www.3gpp.org/ftp/Specs/archive/38_series/38.304/38304-h10.zip

https://www.3gpp.org/ftp/Specs/archive/32_series/32.422/32422-h10.zip

https://www.3gpp.org/ftp/Specs/archive/37_series/37.320/37320-h10.zip

Summary of the invention

The researchers found that in a non-RRC connected state, when receiving or needing to receive multicast services, how to select an appropriate control channel to send uplink information based on whether small data transmission is in progress is a problem that needs to be solved.

In view of the above-mentioned problems, this application provides a solution.

It should be noted that, in the absence of conflict, the embodiments and features in any node of the present application can be applied to any other node. In the absence of conflict, the embodiments and features in the embodiments of the present application can be arbitrarily combined with each other. At the same time, the method proposed in the present application can also be used to solve other problems in communication, such as NR evolution and problems in 6G systems.

As an embodiment, the interpretation of the terminology in the present application refers to the definition of the 3GPP specification protocol TS38 series.

As an example, the interpretation of the terms in the present application refers to the definitions of the TS37 series of specification protocols of 3GPP.

The present application discloses a method in a first node used for wireless communication, comprising:

receiving a first signaling, wherein the first signaling is configured to transmit small data in an RRC inactive state; and the first signaling is configured to receive a multicast service in an RRC inactive state;

In the RRC inactive state, as a response to any condition in the first condition set being met, sending the first information; the sending of the first information depends on whether the small data transmission is in progress;

The first condition set includes receiving a first system information block that triggers multicast service reception, the configuration of at least one active multicast service session joined by the first node is unavailable, the serving cell does not provide at least one active multicast service session joined by the first node to the RRC inactive state, and the measurement of the serving cell is lower than at least one of the given thresholds for at least one active multicast service session joined by the first node; the sending of the first information depends on whether small data transmission is in progress, including: when small data transmission is in progress, sending the first information through a dedicated control channel; when small data transmission is not in progress, sending the first information through a common control channel, wherein the first information includes an RRC connection recovery request.

As an embodiment, the problem to be solved by the present application includes: in a non-RRC connected state, when receiving or needing to receive a multicast service, how to select a suitable control channel to send the first information according to whether a small data transmission is in progress.

As an embodiment, the benefits of the above method include: saving signaling overhead, having good flexibility, ensuring reception of multicast services, and avoiding conflicts between sending the first information and transmitting small data.

Specifically, according to one aspect of the present application, the first information is used to request reception of a multicast service in an RRC connected state.

Specifically, according to one aspect of the present application, when small data transmission is in progress, the first information includes UE auxiliary information.

Specifically, according to one aspect of the present application, when small data transmission is not in progress, any condition in the first condition set is met to trigger the initiation of the RRC connection recovery process.

Specifically, according to one aspect of the present application, the configuration of at least one active multicast service session joined by the first node is unavailable, which means that the configuration of at least one active multicast service session joined by the first node is unavailable in the cell after cell selection or reselection; the serving cell does not provide at least one active multicast service session joined by the first node to the RRC inactive state, which means that the cell after cell selection or reselection does not provide at least one active multicast service session joined by the first node to the RRC inactive state.

Specifically, according to one aspect of the present application, when small data transmission is in progress, the first information is sent via SRB1; when there is no small data transmission in progress, the first information is sent via SRB0.

Specifically, according to one aspect of the present application, when small data transmission is in progress, the first information occupies only one bit in the UE auxiliary information.

Specifically, according to one aspect of the present application, the first node, along with the execution of the first signaling, enters an RRC inactive state.

Specifically, according to one aspect of the present application, second information is sent, where the second information indicates the arrival of at least one of data and signaling mapped to a radio bearer other than a radio bearer configured for small data transmission; the second information is sent via a dedicated control channel;

Among them, small data transmission is ongoing.

Specifically, according to one aspect of the present application, the first condition set includes: being unable to simultaneously receive multiple active multicast service sessions joined by the first node.

Specifically, according to one aspect of the present application, the first condition set includes: failure to obtain MCCH.

Specifically, according to one aspect of the present application, the first node is an Internet of Things terminal.

Specifically, according to one aspect of the present application, the first node is a user equipment.

Specifically, according to one aspect of the present application, the first node is an access network device.

Specifically, according to one aspect of the present application, the first node is a vehicle-mounted terminal.

Specifically, according to one aspect of the present application, the first node is a mobile phone.

The present application discloses a first node used for wireless communication, comprising:

A first receiver receives a first signaling, wherein the first signaling is configured to transmit small data in an RRC inactive state; the first signaling is configured to receive a multicast service in an RRC inactive state;

The first transmitter, in an RRC inactive state, sends first information as a response to any condition in a first condition set being met; the sending of the first information depends on whether a small data transmission is in progress;

The first condition set includes receiving a first system information block that triggers multicast service reception, a configuration of at least one active multicast service session joined by the first node is unavailable, the serving cell does not provide the at least one active multicast service session joined by the first node to the RRC inactive state, and the measurement of the serving cell is lower than a given value for at least one active multicast service session joined by the first node. At least one of the thresholds; the sending of the first information depends on whether small data transmission is in progress, including: when small data transmission is in progress, sending the first information through a dedicated control channel; when small data transmission is not in progress, sending the first information through a public control channel, wherein the first information includes an RRC connection recovery request.

As an embodiment, compared with the traditional solution, this application has the following advantages:

It can better support receiving multicast services and performing small data transmission in RRC inactive state.

The sending of the first information triggered by or for receiving a multicast service uses a more appropriate control channel; generally speaking, a dedicated control channel has better security and lower latency; a public control channel is simpler, has fewer prerequisites, and is available at any time.

Using a dedicated control channel has a lower signaling overhead, for example, only one bit may be used for indication.

This is beneficial to ensure continuous reception of multicast services. For example, when the channel quality deteriorates, the RRC connection state can be entered as quickly as possible to continue receiving multicast services.

It saves more power and can better support receiving multicast services and small data transmission in RRC inactive state.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

FIG1 shows a flowchart of executing first signaling and sending first information according to an embodiment of the present application;

FIG2 shows a schematic diagram of a network architecture according to an embodiment of the present application;

FIG3 is a schematic diagram showing an embodiment of a wireless protocol architecture of a user plane and a control plane according to an embodiment of the present application;

FIG4 shows a schematic diagram of a first communication device and a second communication device according to an embodiment of the present application;

FIG5 shows a flow chart of wireless signal transmission according to an embodiment of the present application;

FIG6 is a schematic diagram showing a first information being used to request receiving a multicast service in an RRC connected state according to an embodiment of the present application;

7 is a schematic diagram showing the arrival of at least one of data and signaling mapped to a radio bearer other than a radio bearer configured for small data transmission according to a second information indication according to an embodiment of the present application;

FIG8 illustrates a schematic diagram of a processing device used in a first node according to an embodiment of the present application.

Implementation

The technical solution of the present application will be further described in detail below in conjunction with the accompanying drawings. It should be noted that, unless there is a conflict, the embodiments in the present application and the features in the embodiments can be combined with each other arbitrarily.

Example 1

Embodiment 1 illustrates a flowchart of executing a first signaling and sending a first message according to an embodiment of the present application, as shown in FIG1. In FIG1, each box represents a step, and it should be emphasized that the order of the boxes in the figure does not represent the temporal sequence between the steps represented.

In Embodiment 1, the first node in the present application receives the first signaling in step 101; sends the first information in step 102;

Among them, the first signaling configuration is small data transmission in the RRC inactive state; the first signaling configuration is to receive multicast services in the RRC inactive state; in the RRC inactive state, any condition in the first condition set is met to trigger the sending of the first information; the sending of the first information depends on whether small data transmission is in progress; the first condition set includes receiving a first system information block that triggers multicast service reception, the configuration of at least one active multicast service session joined by the first node is unavailable, the serving cell does not provide at least one active multicast service session joined by the first node to the RRC inactive state, and the measurement of the serving cell is lower than at least one of the given thresholds for at least one active multicast service session joined by the first node; the sending of the first information depends on whether small data transmission is in progress, including: when small data transmission is in progress, sending the first information through a dedicated control channel; when small data transmission is not in progress, sending the first information through a common control channel, wherein the first information includes an RRC connection recovery request.

As an embodiment, the first node is UE (User Equipment).

As an embodiment, any parameter in the present application may be either configured by the network or generated by the first node according to an internal algorithm, such as randomly.

As an example, the value of any parameter in the present application, including but not limited to the value of a timer and the value of a counter, is limited unless otherwise stated.

As a sub-embodiment of this embodiment, the upper limit of the value of any parameter in this application is 1024 times of 65536.

As a sub-embodiment of this embodiment, the upper limit of the value of any parameter in this application is 65536 or 65535.

As a sub-embodiment of this embodiment, the upper limit of the value of any parameter in this application is 1024.

As a sub-embodiment of this embodiment, the upper limit of the value of any parameter in this application is 640 or 320.

As an embodiment, the present application is directed to NR.

As an embodiment, the present application is directed to wireless communication networks after NR.

As an embodiment, the serving cell refers to the cell where the UE resides. Performing a cell search includes the UE searching for a suitable cell of the selected PLMN (Public Land Mobile Network) or SNPN (Stand-alone Non-Public Network), selecting the suitable cell to provide available services, and monitoring the control channel of the suitable cell. This process is defined as residing on a cell; that is, a cell that is resided on is the serving cell of the UE relative to the UE. Staying in a cell in RRC idle or RRC inactive state has the following benefits: it allows the UE to receive system messages from the PLMN or SNPN; after registration, if the UE wishes to establish an RRC connection or continue a suspended RRC connection, the UE can do so by performing initial access on the control channel of the cell where it is staying; the network can page the UE; and it allows the UE to receive ETWS (Earthquake and Tsunami Warning System) and CMAS (Commercial Mobile Alert System) notifications.

As an embodiment, for a UE in an RRC connected state without configuring CA/DC (carrier aggregation/dual connectivity), there is only one serving cell including a primary cell. For a UE in an RRC connected state with configured CA/DC (carrier aggregation/dual connectivity), the serving cell is used to indicate a collection of cells including a special cell (SpCell) and all cells from the cells. The primary cell (Primary Cell) is a MCG (Master Cell Group) cell, which operates on the primary frequency. The UE performs an initial connection establishment process or initiates connection reconstruction on the primary cell. For dual connection operation, the special cell refers to the PCell (Primary Cell) of the MCG or the PSCell (Primary SCG Cell) of the SCG (Secondary Cell Group); if it is not a dual connection operation, the special cell refers to the PCell.

As an embodiment, the operating frequency of SCell (Secondary Cell) is the secondary frequency.

As an example, individual contents of an information element are referred to as fields.

As an embodiment, MR-DC (Multi-Radio Dual Connectivity) refers to the dual connection of E-UTRA and NR nodes, or the dual connection between two NR nodes.

As an embodiment, in MR-DC, the wireless access node that provides the control plane connection to the core network is the master node, which may be a master eNB, a master ng-eNB, or a master gNB.

As an embodiment, MCG refers to a group of service cells associated with a master node in MR-DC, including SpCells, and may also, optionally, include one or more SCells.

As an embodiment, PCell is the SpCell of MCG.

As an embodiment, the PSCell is the SpCell of the SCG.

As an embodiment, in MR-DC, the control plane connection to the core network is not provided, and the radio access node that provides additional resources to the UE is a slave node. The slave node can be an en-gNB, a slave ng-eNB or a slave gNB.

As an embodiment, in MR-DC, a group of service cells associated with a slave node is a SCG (secondary cell group), including a SpCell and, optionally, one or more SCells.

As an embodiment, the SpCell is a PCell or the SpCell is a PSCell.

As an embodiment, in the RRC inactive state, DC is not used.

As an example, in the RRC inactive state, CA is typically not used.

As an embodiment, the RRC information block refers to an information block (information element) in an RRC message.

As an embodiment, SSB may be referred to as SS\PBCH, or SS block.

As an embodiment, L1 is Layer-1 or physical layer.

As an embodiment, the present application is directed to NR and NR evolved networks, such as 6G networks.

As an embodiment, one RRC information block may include one or more RRC information blocks.

As an embodiment, an RRC information block may not include any RRC information block, but only include at least one parameter.

As an embodiment, the radio bearer includes at least a signaling radio bearer and a data radio bearer.

As an embodiment, the radio bearer is a service or an interface of a service provided by the PDCP layer to a higher layer.

As a sub-embodiment of this embodiment, the higher layer includes one of the RRC layer, NAS, and SDAP layer.

As an embodiment, the signaling radio bearer is a service or an interface of services provided by PDCP to a higher layer.

As a sub-embodiment of this embodiment, the higher layer includes the RRC layer, at least the former in the NAS.

As an embodiment, the data radio bearer is a service or an interface of services provided by PDCP to a higher layer.

As a sub-embodiment of this embodiment, the higher layer includes the SDAP layer, at least the former in NAS.

As an embodiment, after the first node establishes an RRC connection with the network, the first node enters an RRC connection state.

As a sub-embodiment of this embodiment, the network is a Radio Access Network (RAN).

As an embodiment, when the first node does not establish an RRC connection with the network, the first node is in an RRC idle state.

As a sub-embodiment of this embodiment, the network is a Radio Access Network (RAN).

As an embodiment, when the RRC connection established between the first node and the network is suspended, the first node enters an RRC inactive state.

As a sub-embodiment of this embodiment, the network is a Radio Access Network (RAN).

As an embodiment, the first node supports different functions in different RRC states.

As an embodiment, the first node only supports very limited functions in a non-RRC connected state.

As an embodiment, the non-RRC connected state is or includes an RRC idle state.

As an embodiment, the non-RRC connected state is or includes an RRC inactive state.

As an embodiment, in the RRC idle state, the supported features include: DRX (Discontinuous reception) specific to the first node configured by a higher layer.

As an embodiment, in the RRC idle state, the supported features include: at a lower layer, the first node can be configured with DRX for PTM (point to multi point) transmission broadcast for MBS (multicast broadcast service).

As an embodiment, in the RRC idle state, the supported features include: mobility based on network configuration.

As an embodiment, in the RRC idle state, the supported features include: monitoring paging, listening to P-RNTI (paging radio network temporary identity) encrypted short messages, performing neighbor cell measurements and cell reselection, obtaining system information, sending system information requests, recording available measurements, performing idle or inactive state measurements, and obtaining MCCH (MBS Control channel) change notifications.

As an embodiment, in the RRC inactive state, the supported features include: DRX (Discontinuous reception) specific to the first node configured by a higher layer.

As an embodiment, in the RRC inactive state, the supported features include: at a lower layer, the first node can be configured with DRX for PTM (point to multi point) transmission broadcast for MBS (multicast broadcast service).

As an embodiment, in the RRC inactive state, the supported features include: mobility based on network configuration.

As an embodiment, in the RRC inactive state, the supported features include: storing UE inactive AS (access stratum) context.

As an embodiment, in the RRC inactive state, the supported features include: configuring a RAN-based notification area.

As an embodiment, in the RRC inactive state, the supported features include: transmitting data and/or signaling using a wireless bearer configured with SDT (small data transmission).

As an embodiment, in the RRC inactive state, the supported features include: monitoring paging, listening to P-RNTI encrypted short messages, performing neighbor cell measurements and cell reselection, obtaining system information, sending system information requests, recording available measurements, performing idle or inactive state measurements, and obtaining MCCH (MBS Control channel) change notifications.

As an embodiment, in the RRC inactive state, the supported features include: monitoring the control channel during the SDT process.

As an embodiment, in the RRC inactive state, the supported features include: sending SRS (sounding reference signal) for positioning during the SDT process.

As an embodiment, in the RRC connected state, the supported features include: storing AS context.

As an embodiment, in the RRC connected state, the supported features include: sending and receiving unicast data.

As an embodiment, in the RRC connected state, the supported features include: receiving MBS data.

As an embodiment, in the RRC connected state, the supported features include: configuring the first node-specific DRX by a higher layer.

As an embodiment, in the RRC connected state, the supported features include: at a lower layer, the first node may be configured with DRX for PTM transmission of MBS broadcast.

As an embodiment, in the RRC connected state, the supported features include: if CA is supported, using one or more SCells.

As an embodiment, in the RRC connected state, the supported features include: if DC is supported, use SCG.

As an embodiment, in the RRC connected state, the supported features include: network controlled mobility.

As an embodiment, in the RRC connected state, the supported features include: monitoring the short message encrypted by P-RNTI, and monitoring the control channel associated with the shared control channel.

As an embodiment, in the RRC connected state, the supported features include: providing channel quality information.

As an embodiment, in the RRC connected state, the supported features include: performing adjacent cell measurement and reporting.

As an embodiment, in the RRC connected state, the supported features include: obtaining system information.

As an embodiment, in the RRC connected state, the supported features include: performing intermediate MDT measurements and reporting available location information.

As an embodiment, in the RRC connected state, the supported features include: obtaining MCCH change notification to receive MBS broadcast.

As an embodiment, the first signaling indicates the given threshold for at least one active multicast service session joined by the first node.

As an embodiment, the multicast service is or includes MBS (multicast broadcast service) service.

As an embodiment, the multicast service is a multicast MBS service.

As an embodiment, the multicast service includes data from an application layer.

As an embodiment, typical applications of the multicast service include streaming media.

As an embodiment, the multicast service is transmitted in PTM (point to multipoint) mode.

As an embodiment, the multicast service and the broadcast service are different. In this field, the terminal can receive the broadcast service in any RRC state including the RRC idle state, but can only receive the multicast service in the RRC inactive state or the RRC connected state. This shows that the transmission method and control means of the broadcast service and the multicast service are completely different.

As an embodiment, the network may not know which users receive the broadcast service, but whether the terminal can receive the multicast service is controlled by the network.

As an embodiment, the multicast service is sent via MRB (MBS Radio Bearer).

As an embodiment, the small data transmission is sent via DRB (data radio bearer) and/or SRB (Signaling radio bearer).

As an embodiment, the first signaling is actively sent by the network.

As an embodiment, the first signaling is actively sent by the network according to, for example, load conditions, whether the first node has other services to receive, and an active MBS service session to which the first node joins.

As an embodiment, the first signaling is RRC signaling.

As an embodiment, the first signaling indicates the release of the RRC connection.

As an embodiment, the first signaling is RRCRelease signaling.

As an embodiment, the first signaling uses encryption and integrity protection.

As an embodiment, the first signaling is sent using SRB1 (signaling radio bearer 1).

As an embodiment, along with the reception of the first signaling, the first node suspends only the former of the RB configured for small data transmission and the MRB used for transmitting the active multicast service session joined by the first node.

As an embodiment, the first condition set includes receiving a first system information block that triggers multicast service reception, the configuration of at least one active multicast service session joined by the first node is unavailable, the serving cell does not provide at least one active multicast service session joined by the first node to the RRC inactive state, and the measurement of the serving cell is lower than a given threshold for at least one active multicast service session joined by the first node.

As an embodiment, the measurement of the serving cell includes RSRP.

As an embodiment, the measurement of the serving cell includes RSRQ.

As an embodiment, how the first node joins a multicast service or a multicast service session is prior art in the art.

As an embodiment, the network indicates whether the multicast service session is active.

As an embodiment, the serving cell is a cell that receives multicast services.

As an embodiment, the serving cell is a resident cell.

As an embodiment, the serving cell is the current cell.

As an embodiment, in the RRC inactive state, the first node has only one serving cell.

As an embodiment, in the RRC inactive state, the first node only receives the multicast service of one serving cell.

As an embodiment, the first signaling is downlink signaling.

As an embodiment, the meaning of receiving the first signaling in the RRC connection state includes: using DCCH (dedicated Control channel) to receive the first signaling.

As an embodiment, in the RRC idle state, the reception of control signaling can only use CCCH (common control channel) or BCCH (broadcast control channel).

As an embodiment, in this field, small data transmission (SDT) is a specific technology, which means a specific transmission method and control method.

As an embodiment, the first signaling configuration of small data transmission in the RRC inactive state includes: configuring a DRB that allows the use of SDT.

As an embodiment, the first signaling configuration of small data transmission in the RRC inactive state includes: configuring whether to allow the use of SRB2 (signaling radio bearer 2) in small data transmission.

As an embodiment, the first signaling configuration of small data transmission in the RRC inactive state includes: configuring an uplink grant (configured grant) for small data transmission.

As a sub-embodiment of this embodiment, it includes the configuration of downlink and/or uplink BWP (bandwidth part).

As a sub-embodiment of this embodiment, a CS-RNTI is included for uplink grant transmission.

As a sub-embodiment of this embodiment, a threshold for determining whether small data transmission granted by uplink can be used is included.

As a sub-embodiment of this embodiment, a timing advance check configuration is included.

As a sub-embodiment of this embodiment, timing advance information is included.

As a sub-embodiment of this embodiment, it includes identifying a logical channel for small data transmission.

As an embodiment, the first signaling configuration of small data transmission in the RRC inactive state includes: indicating whether to continue header compression.

As a sub-embodiment of this embodiment, the indication of whether to continue header compression refers to whether the PDCP entity configured for the radio bearer for small data transmission continues or resets the header compression protocol when the PDCP in small data transmission is reestablished.

As an embodiment, the sdt-config field of the first signaling configures small data transmission in the RRC inactive state.

As an embodiment, the first signaling configuration for receiving multicast services in an RRC inactive state includes: configuring an inactive PTM.

As an embodiment, the first signaling configuration for receiving multicast services in an RRC inactive state includes: configuring an inactive MCCH (mbs control channel, MBS control channel).

As an embodiment, the first signaling configuration for receiving multicast services in an RRC inactive state includes: indicating an MBS session information list.

As an embodiment, the first signaling configuration for receiving multicast services in the RRC inactive state includes: indicating an MBS neighbor cell list.

As an embodiment, the first signaling configuration for receiving multicast services in an RRC inactive state includes: configuring DRX for PTM.

As an embodiment, the first signaling configuration for receiving multicast services in the RRC inactive state includes: configuring MTCH (MBS traffic channel).

As an embodiment, the first signaling configuration for receiving multicast services in the RRC inactive state includes: configuring a PDSCH (physical downlink shared channel) carrying the MTCH.

As an embodiment, the first signaling configuration for receiving multicast services in the RRC inactive state includes: configuring the SSB mapping window of MTCH.

As an embodiment, the first signaling configuration for receiving multicast services in an RRC inactive state includes: configuring a given threshold for at least one active multicast service session joined by the first node.

As an embodiment, the given threshold for each active multicast service session joined by the first node is the same.

As a sub-embodiment of this embodiment, the given threshold is applicable to each active multicast service session joined by the first node.

As an embodiment, the given threshold for the active multicast service session joined by the first node includes at least one of RSRP (Reference Signal Receiving Power) and RSRQ (Reference Signal Receiving Quality).

As an embodiment, the presence of multicastConfigInactive in the first signaling indicates that the first node is configured to receive multicast services in an RRC inactive state.

As an embodiment, any condition in the first condition set being met will trigger the sending of the first information.

As an embodiment, whether the small data transmission is in progress refers to whether the process of small data transmission is in progress.

As an embodiment, the small data transmission starts from the initiation of SDT to the end of SDT.

As an embodiment, when small data transmission is in progress, the network does not need to page the first node.

As an embodiment, the first condition set does not include receiving a paging call.

As an embodiment, the first condition set includes receiving a first system information block that triggers reception of a multicast service.

As an embodiment, the first system information block is SIB1 (System Information Block 1).

As an embodiment, the received first system information block for triggering multicast service reception includes: the received SIB1 unscheduled second system information block.

As an embodiment, the received first system information block for triggering multicast service reception includes: a SIB1 unscheduled second system information block received after cell selection or cell reselection.

As an embodiment, the received first system information block for triggering multicast service reception includes: SIB1 of the cell after cell selection or cell reselection does not schedule the second system information block.

As an embodiment, the second system information block includes the configuration of the multicast MCCH and/or MTCH required to be acquired in order to receive the MBS in the RRC inactive state.

As an embodiment, the second system information block is SIB22.

As an embodiment, the second system information block is SIB23.

As an embodiment, the second system information block is SIB24.

As an embodiment, the second system information block is SIB25.

As an embodiment, the second system information block is SIB26.

As an embodiment, the first condition set includes: the first system information block schedules the second system information block, the first system information block indicates that the broadcast status of the second system information block is not broadcast, and the first node fails to successfully request the second system information block.

As a sub-embodiment of this embodiment, the meaning of this embodiment is or includes: the first system information block obtained after cell selection or cell reselection schedules the second system information block, the first system information block indicates that the broadcast status of the second system information block is not broadcast, and the first node fails to successfully request the second system information block.

As a sub-embodiment of this embodiment, the meaning of this embodiment is or includes: failing to successfully acquire the second system information block within a given time.

As a sub-embodiment of this embodiment, the meaning of this embodiment is or includes: the first system information block indicates the given time.

As an embodiment, the first condition set includes that configuration of at least one active multicast service session joined by the first node is unavailable.

As an embodiment, the configuration of at least one active multicast service session joined by the first node is unavailable, including: the configuration of at least one active multicast service session joined by the first node cannot be obtained.

As a sub-embodiment of this embodiment, for example, the received system information block does not include the configuration of at least one active multicast service session joined by the first node.

As an embodiment, the configuration of at least one active multicast service session joined by the first node is unavailable, including: the acquired configuration for the multicast service does not include the configuration of at least one active multicast service session joined by the first node.

As an embodiment, the configuration of at least one active multicast service session joined by the first node is unavailable includes: the acquired configuration for the multicast service does not support the at least one active multicast service session joined by the first node.

As an embodiment, the configuration for the multicast service includes MBSMulticastConfiguration.

As an embodiment, the first node obtains the configuration for the multicast service by receiving a system information block.

As an embodiment, the first node obtains the configuration for the multicast service by receiving MCCH.

As an embodiment, the multicast service is MBS.

As an embodiment, the multicast service is multicast transmission of MBS.

As an embodiment, the multicast service session is an MBS session.

As an embodiment, MBS is a downlink service.

As an embodiment, the first condition set includes that the serving cell does not provide at least one active multicast service session joined by the first node to the RRC inactive state.

As an embodiment, the serving cell does not provide at least one active multicast service session that the first node joins to the RRC inactive state, including: the cell indicated by the first signaling that provides at least one active multicast service session that the first node joins does not include the cell selected after performing cell selection or cell reselection.

As an embodiment, the serving cell not providing at least one active multicast service session joined by the first node to the RRC inactive state includes: the serving cell after cell selection or cell reselection does not provide at least one active multicast service session joined by the first node to the RRC inactive state.

As an embodiment, the serving cell not providing at least one active multicast service session joined by the first node in the RRC inactive state includes: the serving cell does not support providing at least one active multicast service session joined by the first node in the RRC inactive state.

As an embodiment, the serving cell not providing at least one active multicast service session joined by the first node in the RRC inactive state includes: the serving cell does not support receiving at least one active multicast service session joined by the first node in the RRC inactive state.

As an embodiment, the first condition set includes that a measurement of a serving cell is lower than a given threshold for at least one active multicast service session joined by the first node.

As an embodiment, the measurement of the serving cell being lower than a given threshold for at least one active multicast service session joined by the first node includes: the measurement of the serving cell after cell selection or cell reselection is lower than a given threshold for at least one active multicast service session joined by the first node.

As an embodiment, the measurement of the serving cell being lower than a given threshold for at least one active multicast service session joined by the first node includes: the measurement of the serving cell is at least one of RSRP and RSRQ of the serving cell.

As an embodiment, the measurement of the service cell is lower than a given threshold for at least one active multicast service session joined by the first node means that the measurement of the service cell is lower than a given threshold for at least one active multicast service session joined by the first node when the at least one multicast service session joined by the first node is in an active state.

As an embodiment, the measurement of the service cell is lower than a given threshold for at least one active multicast service session joined by the first node, including: when all multicast service sessions joined by the first node are not in an active state, the first node does not detect whether the measurement of the service cell is lower than a given threshold for at least one active multicast service session joined by the first node.

As an embodiment, the benefits of the above method include: avoiding unnecessary RRC connection recovery, reducing signaling overhead, and saving more power.

As an embodiment, the detection of whether the first node's measurement of the service cell is lower than a given threshold for at least one active multicast service session joined by the first node may occur after cell selection or cell reselection, or may occur during the process of receiving multicast services.

As an embodiment, the measurement of the serving cell being lower than a given threshold for at least one active multicast service session joined by the first node includes: the measurement of the serving cell is a channel quality of the serving cell.

As an embodiment, the first condition set includes: multiple active multicast service sessions joined by the first node cannot be received simultaneously.

As a sub-embodiment of this embodiment, the benefits of this method include: being able to receive all active multicast service sessions that have been joined as much as possible.

As an embodiment, the first condition set includes: failure to obtain MCCH.

As a sub-embodiment of this embodiment, the benefits of this method include: it is facilitating the continued reception of active multicast service sessions that have been joined when the acquisition of MCCH fails.

As an embodiment, the first condition set includes: selecting L2 U2N (UE to Network) relay.

As an embodiment, the first condition set includes: L2 U2N relay UE is selected.

As a sub-embodiment of this embodiment, the benefits of this method include: avoiding the situation where an L2 U2N relay UE is unable to receive an active multicast service session that it has joined when the UE is selected.

As an embodiment, the sending of the first information depends on whether the small data transmission is in progress, which means that when the small data transmission is in progress, the first information is sent through the dedicated control channel; when the small data transmission is not in progress, the first information is sent through the public control channel. The first information includes an RRC connection recovery request.

As an embodiment, sending the first information through a dedicated control channel includes: sending the first information using a dedicated control channel.

As an embodiment, sending the first information through a dedicated control channel includes: the first information occupies a dedicated control channel to send the first information.

As an embodiment, the first information is or belongs to an RRC message.

As an embodiment, the first information is or belongs to a domain or field in an RRC message.

As an embodiment, the first information is carried by a domain or field in an RRC message.

As an embodiment, when small data transmission is in progress, the first information is carried by a field in an RRC message.

As an embodiment, when small data transmission is not in progress, the first information is an RRC message.

As an embodiment, the dedicated control channel is DCCH (dedicated control channel).

As an embodiment, the dedicated control channel is a logical channel.

As an embodiment, the benefits of sending the first information through a dedicated control channel include: better security, lower signaling overhead, lower transmission delay, and greater reliability.

As an embodiment, sending the first information through a common control channel includes: sending the first information using a common control channel.

As an embodiment, sending the first information through a public control channel includes: the first information occupies the public control channel to send the first information.

As an embodiment, the common control channel is CCCH (common control channel) or CCCH1 (common control channel 1).

As an embodiment, the common control channel is a logical channel.

As an embodiment, the benefits of sending the first information through a public control channel include: fewer restrictions on sending, greater flexibility, and sending at any time.

As an embodiment, the RRC connection recovery request is an RRC message.

As an embodiment, the RRC connection resumption request is RRCResumeRequest.

As an embodiment, the RRC connection resumption request is RRCConnectionResumeRequest.

As an embodiment, the RRC connection recovery request is RRCResumeReq.

As an embodiment, the RRC connection recovery request is used to recover the RRC connection.

As an embodiment, the first node joins at least one multicast service.

As an embodiment, the first node joins at least one multicast service session.

As an embodiment, the first node joins at least one active multicast service session.

As an embodiment, the first information is used to request reception of a multicast service in an RRC connected state.

As an embodiment, the first information is used to explicitly request to receive a multicast service in an RRC connected state.

As an embodiment, the first information is used to implicitly request to receive a multicast service in an RRC connected state.

As an embodiment, when small data transmission is in progress, the first information includes UE auxiliary information.

As an embodiment, when small data transmission is in progress, the first information includes a partial field in the UE auxiliary information.

As an embodiment, the UE assistance information is an RRC message.

As an embodiment, the UE auxiliary information is an uplink message.

As an embodiment, the UE assistance information is UEAssistanceInformation.

As an embodiment, the UE auxiliary information includes auxiliary information provided by the UE.

As an embodiment, the UE assistance information is always sent using a dedicated control channel.

As an embodiment, the UE auxiliary information is sent using SRB1.

As an embodiment, in the RRC inactive state, the UE assistance information is always sent using SRB1.

As an embodiment, the UE auxiliary information is not sent using SRB0.

As an embodiment, when small data transmission is in progress, the first information occupies only one bit in the UE auxiliary information.

As an embodiment, when small data transmission is in progress, the first information is one bit of UE auxiliary information.

As an embodiment, the benefits of the above method include: signaling overhead can be saved.

As an embodiment, when small data transmission is in progress, the first information is mbsIndication in UE auxiliary information.

As an embodiment, when small data transmission is in progress, the first information is mbsRequestIndication in UE assistance information.

As an embodiment, when small data transmission is in progress, the first information is nonSDT-mbsIndication in UE assistance information.

As an embodiment, when small data transmission is in progress, the first information is mbsRequest in UE assistance information.

As an embodiment, when small data transmission is in progress, the first information is an indication in UE auxiliary information.

As an embodiment, when small data transmission is in progress, the first information is nonSDT-DataIndication in the UE auxiliary information.

As an embodiment, when small data transmission is not in progress, any condition in the first condition set is met to trigger the initiation of the RRC connection recovery process.

As a sub-embodiment of this embodiment, the first information is or includes an RRC message in the RRC connection recovery process.

As a sub-embodiment of this embodiment, the first information includes an RRC recovery request message in the RRC connection recovery process.

As a sub-embodiment of this embodiment, the RRC connection recovery process initiated is for MBS reception.

As an embodiment, when small data transmission is in progress, the first information is sent via SRB1; when small data transmission is not in progress, the first information is sent via SRB0.

As an embodiment, although the SRB1 and the SRB0 are both signaling radio bearers, their functions are completely different.

As an embodiment, the SRB0 is for an RRC message using CCCH and/or CCCH1.

As an embodiment, the configuration of SRB0 is fixed.

As an embodiment, the SRB0 does not use encryption and integrity protection.

As an embodiment, SRB1 is used for RRC messages and NAS messages using the DCCH logical channel.

As a sub-embodiment of this embodiment, the NAS message transmitted on SRB1 is generally a NAS message before SRB2 is established.

As an example, SRB1 generally uses encryption and integrity protection.

As an embodiment, SRB1 is network configured.

Example 2

Embodiment 2 illustrates a schematic diagram of a network architecture according to the present application, as shown in FIG2 .

FIG2 illustrates a diagram of a network architecture 200 for 5G NR, LTE (Long-Term Evolution) and LTE-A (Long-Term Evolution Advanced) systems. The 5G NR or LTE network architecture 200 may be referred to as 5GS (5G System)/EPS (Evolved Packet System) 200 or some other suitable terminology. The 5GS/EPS 200 may include one or more UEs (User Equipment) 201, NG-RAN (Next Generation Radio Access Network) 202, 5GC (5G Core Network)/EPC (Evolved Packet Core) 210, HSS (Home Subscriber Server)/UDM (Unified Data Management) 220 and Internet Services 230. The 5GS/EPS may be interconnected with other access networks, but these entities/interfaces are not shown for simplicity. As shown, 5GS/EPS provides packet-switched services, however, those skilled in the art will readily appreciate that the various concepts presented throughout this application can be extended to networks providing circuit-switched services or other cellular networks. NG-RAN includes NR Node B (gNB) 203 and other gNBs 204. gNB 203 provides user and control plane protocol terminations toward UE 201. gNB 203 can be connected to other gNBs 204 via an Xn interface (e.g., backhaul). gNB 203 may also be referred to as a base station, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a TRP (transmitting receiving node), or some other suitable term. gNB 203 provides an access point to 5GC/EPC 210 for UE 201. Examples of UE 201 include cellular phones, smart phones, session initiation protocol (SIP) phones, laptop computers, personal digital assistants (PDAs), satellite radios, non-terrestrial base station communications, satellite mobile communications, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, drones, aircraft, narrowband Internet of Things devices, machine type communication devices, land vehicles, cars, wearable devices, or any other similar functional devices. Those skilled in the art may also refer to UE 201 as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable term. gNB203 is connected to 5GC/EPC210 via S1/NG interface. 5GC/EPC210 includes MME (Mobility Management Entity)/AMF (Authentication Management Field)/SMF (Session Management Function) 211, other MME/AMF/SMF214, S-GW (Service Gateway)/UPF (User Plane Function) 212 and P-GW (Packet Data Network Gateway)/UPF213. MME/AMF/SMF211 is the control node that handles the signaling between UE201 and 5GC/EPC210. In general, MME/AMF/SMF211 provides bearer and connection management. All user IP (Internet Protocal) packets are transmitted through S-GW/UPF212, which itself is connected to P-GW/UPF213. P-GW provides UE IP address allocation and other functions. P-GW/UPF213 is connected to Internet services 230. Internet services 230 include operator-corresponding Internet protocol services, which may specifically include Internet, intranet, IMS (IP Multimedia Subsystem) and packet switching streaming services.

As an embodiment, the first node in the present application is UE201.

As an embodiment, the base station of the second node in the present application is gNB203.

As an embodiment, the wireless link from the UE201 to the NR Node B is an uplink.

As an embodiment, the wireless link from the NR Node B to UE201 is a downlink.

As an embodiment, the UE 201 includes a mobile phone.

As an embodiment, the UE 201 is a vehicle including a car.

As an embodiment, the gNB203 is a macrocellular base station.

As an embodiment, the gNB203 is a micro cell base station.

As an embodiment, the gNB203 is a pico cell base station.

As an embodiment, the gNB203 is a flying platform device.

As an embodiment, the gNB203 is a satellite device.

Example 3

Embodiment 3 shows a schematic diagram of an embodiment of a wireless protocol architecture for a user plane and a control plane according to the present application, as shown in FIG3. FIG3 is a schematic diagram illustrating an embodiment of a radio protocol architecture for a user plane 350 and a control plane 300. FIG3 shows the radio protocol architecture of the control plane 300 for a first node (UE, gNB) and a second node (gNB, UE), or between two UEs using three layers: layer 1, layer 2, and layer 3. Layer 1 (L1 layer) is the lowest layer and implements various PHY (physical layer) signal processing functions. The L1 layer will be referred to as PHY301 herein. Layer 2 (L2 layer) 305 is above PHY301 and is responsible for the link between the first node and the second node and the two UEs through PHY301. The L2 layer 305 includes a MAC (Medium Access Control) sublayer 302, an RLC (Radio Link Control) sublayer 303, and a PDCP (Packet Data Convergence Protocol) sublayer 304, which terminate at the second node. The PDCP sublayer 304 provides multiplexing between different radio bearers and logical channels. The PDCP sublayer 304 also provides security by encrypting data packets, and provides support for inter-zone mobility of the first node between the second node. The RLC sublayer 303 provides segmentation and reassembly of upper layer data packets, retransmission of lost data packets, and reordering of data packets to compensate for out-of-order reception due to HARQ. The MAC sublayer 302 provides multiplexing between logical and transport channels. The MAC sublayer 302 is also responsible for allocating various radio resources (e.g., resource blocks) in a cell between the first nodes. The MAC sublayer 302 is also responsible for HARQ operations. The RRC (Radio Resource Control) sublayer 306 in layer 3 (L3 layer) in the control plane 300 is responsible for obtaining radio resources (i.e., radio bearers) and configuring the lower layers using RRC signaling between the second node and the first node. The PC5-S (PC5 Signaling Protocol) sublayer 307 is responsible for processing the signaling protocol of the PC5 interface. The radio protocol architecture of the user plane 350 includes layer 1 (L1 layer) and layer 2 (L2 layer). The radio protocol architecture for the first node and the second node in the user plane 350 is substantially the same as the corresponding layers and sublayers in the control plane 300 for the physical layer 351, the PDCP sublayer 354 in the L2 layer 355, the RLC sublayer 353 in the L2 layer 355, and the MAC sublayer 352 in the L2 layer 355, but the PDCP sublayer 354 also provides header compression for upper layer data packets to reduce radio transmission overhead. The L2 layer 355 in the user plane 350 also includes a SDAP (Service Data Adaptation Protocol) sublayer 356, which is responsible for mapping between QoS flows and data radio bearers (DRBs) to support the diversity of services. SRB can be regarded as a service or interface provided by the PDCP layer to a higher layer, such as the RRC layer. In the NR system, SRBs include SRB1, SRB2, and SRB3, which are used to transmit different types of control signaling. SRB is a bearer between the UE and the access network, and is used to transmit control signaling including RRC signaling between the UE and the access network. SRB1 has a special meaning for the UE. After each UE establishes an RRC connection, there will be SRB1 for transmitting RRC signaling. Most of the signaling is transmitted through SRB1. If SRB1 is interrupted or cannot be used, the UE must perform RRC reconstruction. SRB2 is generally only used to transmit NAS signaling or signaling related to security. The UE may not configure SRB3. Except for emergency services, the UE must establish an RRC connection with the network for subsequent communication. Although not shown, the first node may have several upper layers above the L2 layer 355. Also included is a network layer (e.g., The IP layer) and the application layer that terminates at the other end of the connection (e.g., a remote UE, a server, etc.).

As an embodiment, the wireless protocol architecture in FIG. 3 is applicable to the first node in the present application.

As an embodiment, the wireless protocol architecture in FIG. 3 is applicable to the second node in the present application.

As an embodiment, the first signaling in the present application is generated in RRC306.

As an embodiment, the first information in the present application is generated in RRC306.

As an embodiment, the second information in the present application is generated in RRC306.

As an embodiment, the first system information block in the present application is generated in RRC306.

As an embodiment, the second system information block in the present application is generated in RRC306.

As an embodiment, the signaling on the MCCH in the present application is generated in RRC306.

Example 4

Embodiment 4 shows a schematic diagram of a first communication device and a second communication device according to an embodiment of the present application, as shown in Figure 4. Figure 4 is a block diagram of a first communication device 450 and a second communication device 410 communicating with each other in an access network.

The first communication device 450 includes a controller/processor 459, a memory 460, a data source 467, a transmit processor 468, a receive processor 456, and may optionally also include a multi-antenna transmit processor 457, a multi-antenna receive processor 458, a transmitter/receiver 454 and an antenna 452.

The second communication device 410 includes a controller/processor 475 , a memory 476 , a receiving processor 470 , a transmitting processor 416 , and may optionally also include a multi-antenna receiving processor 472 , a multi-antenna transmitting processor 471 , a transmitter/receiver 418 and an antenna 420 .

In the transmission from the second communication device 410 to the first communication device 450, at the second communication device 410, the upper layer data packets from the core network are provided to the controller/processor 475. The controller/processor 475 implements the functionality of the L2 (Layer-2) layer. In the transmission from the second communication device 410 to the first communication device 450, the controller/processor 475 provides header compression, encryption, packet segmentation and reordering, multiplexing between logical and transport channels, and radio resource allocation to the first communication device 450 based on various priority metrics. The controller/processor 475 is also responsible for the retransmission of lost packets and signaling to the first communication device 450. The transmit processor 416 and the multi-antenna transmit processor 471 implement various signal processing functions for the L1 layer (i.e., the physical layer). The transmit processor 416 implements coding and interleaving to facilitate forward error correction (FEC) at the second communication device 410, as well as mapping of signal constellations based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The multi-antenna transmit processor 471 performs digital spatial precoding, including codebook-based precoding and non-codebook-based precoding, and beamforming processing on the coded and modulated symbols to generate one or more spatial streams. The transmit processor 416 then maps each spatial stream to a subcarrier, multiplexes it with a reference signal (e.g., a pilot) in the time domain and/or frequency domain, and then uses an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain multi-carrier symbol stream. The multi-antenna transmit processor 471 then performs a transmit analog precoding/beamforming operation on the time-domain multi-carrier symbol stream. Each transmitter 418 converts the baseband multi-carrier symbol stream provided by the multi-antenna transmit processor 471 into a radio frequency stream, and then provides it to a different antenna 420.

In the transmission from the second communication device 410 to the first communication device 450, at the first communication device 450, each receiver 454 receives a signal through its corresponding antenna 452. Each receiver 454 recovers the information modulated onto the RF carrier and converts the RF stream into a baseband multi-carrier symbol stream and provides it to the receiving processor 456. The receiving processor 456 and the multi-antenna receiving processor 458 implement various signal processing functions of the L1 layer. The multi-antenna receiving processor 458 performs a receiving analog precoding/beamforming operation on the baseband multi-carrier symbol stream from the receiver 454. The receiving processor 456 uses a fast Fourier transform (FFT) to convert the baseband multi-carrier symbol stream after the receiving analog precoding/beamforming operation from the time domain to the frequency domain. In the frequency domain, the physical layer data signal and the reference signal are demultiplexed by the receiving processor 456, wherein the reference signal will be used for channel estimation, and the data signal is recovered after multi-antenna detection in the multi-antenna receiving processor 458 to any spatial stream destined for the first communication device 450. The symbols on each spatial stream are demodulated and recovered in the receiving processor 456, and soft decisions are generated. The receiving processor 456 then decodes and deinterleaves the soft decisions to recover the upper layer data and control signals transmitted by the second communication device 410 on the physical channel. The upper layer data and control signals are then provided to the controller/processor 459. The controller/processor 459 implements the functions of the L2 layer. The controller/processor 459 may be associated with a memory 460 that stores program codes and data. The memory 460 may be referred to as a computer-readable medium. In the transmission from the second communication device 410 to the second communication device 450, the controller/processor 459 provides multiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover the upper layer data packets from the core network. The upper layer data packets are then provided to all protocol layers above the L2 layer. Various control signals may also be provided to L3 for L3 processing.

In the transmission from the first communication device 450 to the second communication device 410, at the first communication device 450, the number The controller/processor 459 is provided with an upper layer data packet according to a source 467. The data source 467 represents all protocol layers above the L2 layer. Similar to the transmission function at the second communication device 410 described in the transmission from the second communication device 410 to the first communication device 450, the controller/processor 459 implements header compression, encryption, packet segmentation and reordering, and multiplexing between logical and transport channels based on wireless resource allocation, and implements L2 layer functions for the user plane and the control plane. The controller/processor 459 is also responsible for retransmission of lost packets and signaling to the second communication device 410. The transmit processor 468 performs modulation mapping and channel coding processing, and the multi-antenna transmit processor 457 performs digital multi-antenna spatial precoding, including codebook-based precoding and non-codebook-based precoding, and beamforming processing. Subsequently, the transmit processor 468 modulates the generated spatial stream into a multi-carrier/single-carrier symbol stream, which is provided to different antennas 452 via the transmitter 454 after analog precoding/beamforming operations in the multi-antenna transmit processor 457. Each transmitter 454 first converts the baseband symbol stream provided by the multi-antenna transmit processor 457 into a radio frequency symbol stream, and then provides it to the antenna 452.

In the transmission from the first communication device 450 to the second communication device 410, the function at the second communication device 410 is similar to the reception function at the first communication device 450 described in the transmission from the second communication device 410 to the first communication device 450. Each receiver 418 receives a radio frequency signal through its corresponding antenna 420, converts the received radio frequency signal into a baseband signal, and provides the baseband signal to the multi-antenna reception processor 472 and the reception processor 470. The reception processor 470 and the multi-antenna reception processor 472 jointly implement the functions of the L1 layer. The controller/processor 475 implements the L2 layer functions. The controller/processor 475 can be associated with a memory 476 storing program codes and data. The memory 476 can be referred to as a computer-readable medium. In the transmission from the first communication device 450 to the second communication device 410, the controller/processor 475 provides multiplexing between transport and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover the upper layer data packets from the UE 450. Upper layer packets from controller/processor 475 may be provided to the core network.

As an embodiment, the first communication device 450 apparatus includes: at least one processor and at least one memory, the at least one memory including computer program code; the at least one memory and the computer program code are configured to be used together with the at least one processor, and the first communication device 450 apparatus at least: receives a first signaling, the first signaling configures a small data transmission in an RRC inactive state; the first signaling configures a multicast service to be received in an RRC inactive state; in the RRC inactive state, as a response to any condition in a first condition set being met, sends a first message; the sending of the first message depends on whether a small data transmission is in progress; wherein the first condition set includes The method comprises receiving a first system information block that triggers reception of a multicast service, configuration of at least one active multicast service session joined by the first node is unavailable, the serving cell does not provide at least one active multicast service session joined by the first node to an RRC inactive state, and measurement of the serving cell is lower than at least one of the given thresholds for at least one active multicast service session joined by the first node; the sending of the first information depends on whether a small data transmission is in progress, comprising: when a small data transmission is in progress, sending the first information through a dedicated control channel; when a small data transmission is not in progress, sending the first information through a common control channel, wherein the first information includes an RRC connection recovery request.

As an embodiment, the first communication device 450 includes: a memory storing a computer-readable instruction program, the computer-readable instruction program generates an action when executed by at least one processor, the action including: receiving a first signaling, the first signaling configuring a small data transmission in an RRC inactive state; the first signaling configuring receiving a multicast service in an RRC inactive state; in the RRC inactive state, sending a first information as a response to any condition in a first condition set being met; the sending of the first information depends on whether the small data transmission is in progress; wherein the first condition set includes receiving a first system information block that triggers the reception of multicast services, the configuration of at least one active multicast service session joined by the first node is unavailable, the serving cell does not provide the at least one active multicast service session joined by the first node to the RRC inactive state, and the measurement of the serving cell is lower than at least one of the given thresholds for at least one active multicast service session joined by the first node; the sending of the first information depends on whether the small data transmission is in progress, including: when the small data transmission is in progress, sending the first information through a dedicated control channel; when the small data transmission is not in progress, sending the first information through a common control channel, wherein the first information includes an RRC connection recovery request.

As an embodiment, the first communication device 450 corresponds to the first node in this application.

As an embodiment, the second communication device 410 corresponds to the second node in this application.

As an embodiment, the first communication device 450 is a UE.

As an embodiment, the first communication device 450 is a vehicle-mounted terminal.

As an embodiment, the first communication device 450 is a mobile phone.

As an embodiment, the second communication device 450 is a relay.

As an embodiment, the second communication device 410 is a satellite.

As an embodiment, the second communication device 410 is an aircraft.

As an embodiment, the second communication device 410 is a base station.

As an embodiment, the receiver 454 (including the antenna 452), the receiving processor 456 and the controller/processor 459 are used to receive the first signaling in the present application.

As an embodiment, the receiver 454 (including the antenna 452), the receiving processor 456 and the controller/processor 459 are used to receive the first system information block in the present application.

As an embodiment, the receiver 454 (including the antenna 452), the receiving processor 456 and the controller/processor 459 are used to receive the second system information block in the present application.

As an embodiment, the receiver 454 (including the antenna 452), the receiving processor 456 and the controller/processor 459 are used to receive the MCCH in the present application.

As an embodiment, the transmitter 454 (including the antenna 452), the transmit processor 468 and the controller/processor 459 are used to send the first information in the present application.

As an embodiment, the transmitter 454 (including the antenna 452), the transmit processor 468 and the controller/processor 459 are used to send the second information in the present application.

Example 5

Embodiment 5 illustrates a wireless signal transmission flow chart according to an embodiment of the present application, as shown in FIG5. In FIG5, U01 corresponds to the first node of the present application, and it is particularly noted that the order in this example does not limit the signal transmission order and implementation order in the present application, wherein the steps in F51 are optional.

For the first node U01 , the first signaling is received in step S5101; the first information is sent in step S5102; and the second information is sent in step S5103.

For the second node U02 , the first signaling is sent in step S5201; the first information is received in step S5202; and the second information is received in step S5203.

In Example 5, the first signaling configuration is a small data transmission in an RRC inactive state; the first signaling configuration is a multicast service reception in an RRC inactive state; the sending of the first information depends on whether the small data transmission is in progress; any condition in the first condition set is satisfied to trigger the sending of the first information; the first condition set includes receiving a first system information block that triggers the reception of multicast services, the configuration of at least one active multicast service session joined by the first node is unavailable, the serving cell does not provide at least one active multicast service session joined by the first node to the RRC inactive state, and the measurement of the serving cell is lower than at least one of the given thresholds for at least one active multicast service session joined by the first node; the sending of the first information depends on whether the small data transmission is in progress, including: when the small data transmission is in progress, sending the first information through a dedicated control channel; when the small data transmission is not in progress, sending the first information through a common control channel, wherein the first information includes an RRC connection recovery request.

As an embodiment, the first node U01 sends the first information in an RRC inactive state.

As an embodiment, the first node U01 receives the first signaling in the RRC connected state.

As an embodiment, the second node U02 is the base station corresponding to the SpCell of the first node U01.

As an embodiment, the second node U02 is the PCell of the first node U01 or the base station to which the PCell of the first node U01 belongs.

As an embodiment, the second node U02 is the PCell when the first node U01 is in the RRC connected state or the base station to which the PCell when the first node U01 is in the RRC connected state belongs.

As an embodiment, FIG5 shows that the sender of the first signaling and the receiver of the first information are both the second node U02, but the method proposed in the present application is also applicable to the scenario where the sender of the first signaling is different from the receiver of the first information.

As a sub-embodiment of this embodiment, when the first node U01 has moved to another cell after receiving the first signaling, that is, cell selection or cell reselection has occurred, the recipient of the first information is the other cell.

As a sub-embodiment of this embodiment, similarly, the method proposed in the present application is also applicable to the scenario where the sender of the first signaling is different from the receiver of the second signaling.

As an embodiment, step S5101 precedes step S5102.

As an embodiment, there is no obvious order relationship between step S5102 and step S5103.

As an embodiment, step S5101 precedes step S5103.

As an embodiment, the first node U01 is in different RRC states when receiving the first signaling and sending the first information.

As an embodiment, the first node U01 receives at least one same active multicast service session before entering the RRC inactive state and after entering the RRC inactive state.

As an embodiment, the first node U01 does not receive any active multicast service session before entering the RRC inactive state.

As an embodiment, the execution of the first signaling includes executing cell selection.

As an embodiment, after performing cell selection or cell reselection, the first node U01 needs to read first system information, the first system information schedules second system information, and the second system information indicates the configuration of receiving multicast services in RRC inactive state.

As an embodiment, the first node U01 needs to read the information on the MCCH after performing cell selection or cell reselection.

As an embodiment, the first node U01, in an RRC inactive state, wants to receive a multicast service.

As a sub-embodiment of this embodiment, when the first information is sent.

As a sub-embodiment of this embodiment, before the first information is sent.

As an embodiment, the first node U01, in an RRC inactive state, wants to receive a multicast service session.

As a sub-embodiment of this embodiment, when the first information is sent.

As a sub-embodiment of this embodiment, before the first information is sent.

As an embodiment, in the RRC inactive state, the first node U01 has at least one active multicast service session.

As a sub-embodiment of this embodiment, when the first information is sent.

As a sub-embodiment of this embodiment, before the first information is sent.

As an embodiment, in the RRC inactive state, at least one multicast service session of the first node U01 is active or becomes active.

As a sub-embodiment of this embodiment, when the first information is sent.

As a sub-embodiment of this embodiment, before the first information is sent.

As an embodiment, in the RRC inactive state, at least one multicast service session of the first node U01 is about to become active.

As a sub-embodiment of this embodiment, when the first information is sent.

As a sub-embodiment of this embodiment, before the first information is sent.

As an embodiment, in the RRC inactive state, at least one multicast service session of the first node U01 starts or is about to start.

As a sub-embodiment of this embodiment, when the first information is sent.

As a sub-embodiment of this embodiment, before the first information is sent.

As an embodiment, the first node U01, in an RRC inactive state, is receiving at least one multicast service session.

As a sub-embodiment of this embodiment, when the first information is sent.

As a sub-embodiment of this embodiment, before the first information is sent.

As an embodiment, before receiving the first signaling, the first node U01 sends a first indication to indicate whether there is a preference for receiving multicast services in an RRC inactive state.

As an embodiment, before receiving the first signaling, the first node U01 sends a first indication indicating a preference for receiving multicast services in an RRC inactive state.

As an embodiment, the first information triggers RRC recovery signaling.

As an embodiment, the first information triggers the second node U02 to send RRC recovery signaling.

As an embodiment, the network or the second node U02 determines whether to send RRC recovery signaling based on the first information.

As an embodiment, the RRC recovery signaling instructs the first node U01 to enter the RRC connected state.

As an embodiment, the RRC recovery signaling is configured to receive multicast services in the RRC connected state.

As an embodiment, the second information indicates the arrival of at least one of data and signaling mapped to a radio bearer other than a radio bearer configured for small data transmission.

As a sub-embodiment of this embodiment, small data transmission is in progress.

As an embodiment, the second information is sent via a dedicated control channel.

As a sub-embodiment of this embodiment, small data transmission is in progress.

As a sub-embodiment of this embodiment, the dedicated control channel is DCCH.

As an embodiment, the period during which the small data transmission is in progress corresponds to the running period of the timer T319a.

As an embodiment, the second information is sent via UE auxiliary information.

As an embodiment, when small data transmission is in progress, the first information and the second information are transmitted by the UE using different fields in UE assistance information.

As an embodiment, when small data transmission is in progress, the first node U01 may send the first information and the second information via UE auxiliary information.

As an embodiment, the first information and the second information are used to determine whether to send RRC recovery signaling.

As an embodiment, at least one of the data and signaling mapped to the radio bearer other than the radio bearer configured for small data transmission is uplink.

As an embodiment, the first information and the second information occupy different fields in the UE auxiliary information.

As an embodiment, the first node U01 enters an RRC inactive state along with the execution of the first signaling.

As a sub-embodiment of this embodiment, the meaning of this embodiment is: the first signaling triggers the first node U01 to enter the RRC inactive state.

As a sub-embodiment of this embodiment, the meaning of this embodiment is that the execution of the first signaling includes entering the RRC inactive state.

Example 6

Embodiment 6 illustrates a schematic diagram of a first information according to an embodiment of the present application being used to request reception of a multicast service in an RRC connected state, as shown in FIG6 .

As an embodiment, the meaning that the first information is used to request to receive a multicast service in an RRC connected state includes: the first information is used to trigger the network to instruct the first node to restore the RRC connection, and after the RRC connection is restored, the first node enters the RRC connected state.

As an embodiment, the meaning that the first information is used to request receiving multicast services in the RRC connected state includes: the first information is used to trigger the network to instruct the first node to restore the RRC connection, the signaling for restoring the RRC connection includes the configuration of receiving multicast services in the RRC connected state, and the first node enters the RRC connected state.

As an embodiment, the meaning that the first information is used to trigger the network to instruct the first node to restore the RRC connection includes: the network can instruct the first node to restore the RRC connection after receiving the first information.

As an embodiment, the network instructs the first node to resume the RRC connection by sending RRC resumption signaling.

As an embodiment, the network saves the context in which the first node is configured to receive multicast services, so the network can determine which multicast services the first node needs to continue to receive in the RRC connected state.

As a sub-embodiment of this embodiment, the network refers to an access network.

As an embodiment, the network may obtain from the core network which multicast service sessions the first node has joined, so that the network may determine which multicast services the first node needs to continue to receive in the RRC connected state.

As a sub-embodiment of this embodiment, the network refers to an access network.

As an embodiment, the meaning that the first information is used to request receiving multicast services in the RRC connected state includes: the first information is sent in order to receive multicast services in the RRC connected state.

As an embodiment, when small data transmission is not performed, the first information includes an RRC recovery request, and the RRC recovery request triggers RRC recovery signaling.

As an embodiment, when small data transmission is not performed, the first information includes an RRC recovery request, the RRC recovery request triggers RRC recovery signaling, and after receiving the RRC recovery signaling, the first node enters the RRC connected state.

As an embodiment, the RRC recovery signaling includes configuration for receiving multicast services in the RRC connected state.

As an embodiment, when small data transmission is in progress, the first information is sent via UE auxiliary information, and the first information is used to trigger the network to instruct the first node to resume the RRC connection.

As an embodiment, the first information is sent in order to continue receiving the multicast service.

As an embodiment, the meaning that the first information is used to request reception of multicast services in the RRC connected state includes: the first information includes an RRC recovery request, and the RRC recovery process initiated by the RRC recovery request is for reception of multicast services.

As a sub-embodiment of this embodiment, small data transmission is not in progress.

As an embodiment, when small data transmission is in progress, the sending of the first information helps the network to instruct the first node to resume the RRC connection, thereby receiving the multicast service in the RRC connected state.

Example 7

Embodiment 7 illustrates a schematic diagram of the arrival of at least one of data and signaling mapped to a radio bearer other than a radio bearer configured for small data transmission according to a second information indication of an embodiment of the present application, as shown in FIG7 .

As an embodiment, the arrival of data at the first node refers to that higher-layer data and signaling of the first node arrive at the access layer.

As an embodiment, the arrival of data at the first node means that there is uplink data and signaling to be sent.

As an embodiment, the first radio bearer is any radio bearer other than a radio bearer configured for small data transmission.

As an embodiment, the first radio bearer is not any radio bearer configured for small data transmission.

As an embodiment, at least one of the data and signaling mapped to the radio bearer other than the radio bearer configured for small data transmission is at least one of the data and signaling mapped to the first radio bearer.

As an embodiment, the mapping of data and signaling to which radio bearer is performed by network configuration or a predetermined method.

As an embodiment, the data or signaling mapped to the first radio bearer cannot be sent through the small data transmission process.

As a sub-embodiment of this embodiment, unless there is a new configuration.

As an embodiment, when the first wireless bearer is a data wireless bearer, the arrival of at least one of the data and signaling mapped to a wireless bearer other than the wireless bearer configured for small data transmission refers to the arrival of data mapped to a wireless bearer other than the wireless bearer configured for small data transmission.

As an embodiment, when the first wireless bearer is a signaling wireless bearer, the arrival of at least one of the data and signaling mapped to a wireless bearer other than the wireless bearer configured for small data transmission refers to the arrival of signaling mapped to a wireless bearer other than the wireless bearer configured for small data transmission.

As an embodiment, the second information explicitly indicates the arrival of at least one of data and signaling mapped to a radio bearer other than a radio bearer configured for small data transmission.

As an embodiment, after receiving the second information, the network may configure resources for transmitting at least one of data and signaling mapped to a radio bearer other than a radio bearer configured for small data transmission.

As an embodiment, receiving multicast services in the RRC connected state is more conducive to ensuring the reception quality. For example, the PTP (point to point) transmission method can be used, a richer retransmission mechanism can be used, and more resources can be allocated.

As an embodiment, receiving multicast services in the RRC inactive state saves more power.

Example 8

Embodiment 8 illustrates a structural block diagram of a processing device in a first node according to an embodiment of the present application, as shown in FIG8. In FIG8, the processing device 800 in the first node includes a first receiver 801 and a first transmitter 802.

In Embodiment 8, a first receiver 801 receives a first signaling, wherein the first signaling configures a small data transmission in an RRC inactive state; the first signaling configures receiving a multicast service in an RRC inactive state;

The first transmitter 802, in an RRC inactive state, sends first information as a response to any condition in a first condition set being met; the sending of the first information depends on whether a small data transmission is in progress;

The first condition set includes receiving a first system information block that triggers multicast service reception, the configuration of at least one active multicast service session joined by the first node is unavailable, the serving cell does not provide at least one active multicast service session joined by the first node to the RRC inactive state, and the measurement of the serving cell is lower than at least one of the given thresholds for at least one active multicast service session joined by the first node; the sending of the first information depends on whether small data transmission is in progress, including: when small data transmission is in progress, sending the first information through a dedicated control channel; when small data transmission is not in progress, sending the first information through a common control channel, wherein the first information includes an RRC connection recovery request.

As an embodiment, the first information is used to request reception of a multicast service in an RRC connected state.

As an embodiment, when small data transmission is in progress, the first information includes UE auxiliary information.

As an embodiment, when small data transmission is not in progress, any condition in the first condition set is met to trigger the initiation of the RRC connection recovery process.

As an embodiment, the configuration of at least one active multicast service session joined by the first node is unavailable, which means that the configuration of at least one active multicast service session joined by the first node is unavailable in the cell after cell selection or reselection; the serving cell does not provide the at least one active multicast service session joined by the first node to the RRC inactive state, which means that the configuration of at least one active multicast service session joined by the first node is unavailable in the cell after cell selection or reselection. At least one active multicast service session joined by the first node is not provided to the RRC inactive state.

As an embodiment, when small data transmission is in progress, the first information is sent via SRB1; when small data transmission is not in progress, the first information is sent via SRB0.

As an embodiment, when small data transmission is in progress, the first information occupies only one bit in the UE auxiliary information.

As an embodiment, the first node, along with the execution of the first signaling, enters an RRC inactive state.

As an embodiment, second information is sent, wherein the second information indicates the arrival of at least one of data and signaling mapped to a radio bearer other than a radio bearer configured for small data transmission; the second information is sent via a dedicated control channel;

Among them, small data transmission is ongoing.

As an embodiment, the first condition set includes: multiple active multicast service sessions joined by the first node cannot be received simultaneously.

As an embodiment, the first condition set includes: failure to obtain MCCH.

As an embodiment, the first condition set includes: L2 U2N relay UE selection occurs.

As an embodiment, the first condition set includes: expiration of a first timer.

As an embodiment, the first node is a user equipment (UE).

As an embodiment, the first node is a terminal supporting a large delay difference.

As an embodiment, the first node is a terminal supporting NTN.

As an embodiment, the first node is an aircraft or a ship.

As an embodiment, the first node is a mobile phone or a vehicle-mounted terminal.

As an embodiment, the first node is a terminal supporting MUSIM.

As an embodiment, the first node is an Internet of Things terminal or an industrial Internet of Things terminal.

As an embodiment, the first node is a device supporting low-latency and high-reliability transmission.

As an embodiment, the first receiver 801 includes at least one of the antenna 452, receiver 454, receiving processor 456, multi-antenna receiving processor 458, controller/processor 459, memory 460, or data source 467 in Example 4.

As an embodiment, the first transmitter 802 includes at least one of the antenna 452, transmitter 454, transmit processor 468, multi-antenna transmit processor 457, controller/processor 459, memory 460, or data source 467 in Embodiment 4.

A person skilled in the art can understand that all or part of the steps in the above method can be completed by instructing the relevant hardware through a program, and the program can be stored in a computer-readable storage medium, such as a read-only memory, a hard disk or an optical disk. Optionally, all or part of the steps in the above embodiment can also be implemented using one or more integrated circuits. Accordingly, each module unit in the above embodiment can be implemented in the form of hardware or in the form of a software function module, and the present application is not limited to any specific form of software and hardware combination. The user equipment, terminal and UE in the present application include but are not limited to drones, communication modules on drones, remote-controlled aircraft, aircraft, small aircraft, mobile phones, tablet computers, notebooks, vehicle-mounted communication equipment, wireless sensors, Internet cards, Internet of Things terminals, RFID terminals, NB-IoT terminals, MTC (Machine Type Communication) terminals, eMTC (enhanced MTC) terminals, data cards, Internet cards, vehicle-mounted communication equipment, low-cost mobile phones, low-cost tablet computers, satellite communication equipment, ship communication equipment, NTN user equipment and other wireless communication equipment. The base stations or system equipment in this application include but are not limited to macrocell base stations, microcell base stations, home base stations, relay base stations, gNB (NR Node B) NR Node B, TRP (Transmitter Receiver Point), NTN base stations, satellite equipment, flight platform equipment and other wireless communication equipment.

The present invention may be implemented in other specified forms without departing from its core or essential features. Therefore, the embodiments disclosed herein should be considered as illustrative rather than restrictive in any way. The scope of the invention is determined by the appended claims rather than the preceding description, and all modifications within their equivalent meanings and regions are considered to be included therein.

Claims (10)

A first node used for multicast services and small data transmission, comprising: A first receiver receives a first signaling, wherein the first signaling is configured to transmit small data in an RRC inactive state; the first signaling is configured to receive a multicast service in an RRC inactive state; The first transmitter, in an RRC inactive state, sends first information as a response to any condition in a first condition set being met; the sending of the first information depends on whether a small data transmission is in progress; The first condition set includes receiving a first system information block that triggers multicast service reception, the configuration of at least one active multicast service session joined by the first node is unavailable, the serving cell does not provide at least one active multicast service session joined by the first node to the RRC inactive state, and the measurement of the serving cell is lower than at least one of the given thresholds for at least one active multicast service session joined by the first node; the sending of the first information depends on whether small data transmission is in progress, including: when small data transmission is in progress, sending the first information through a dedicated control channel; when small data transmission is not in progress, sending the first information through a common control channel, wherein the first information includes an RRC connection recovery request. The first node according to claim 1, characterized in that The first information is used to request to receive a multicast service in an RRC connected state. The first node according to claim 1 or 2, characterized in that When small data transmission is in progress, the first information includes UE assistance information. The first node according to any one of claims 1 to 3, characterized in that: When small data transmission is not in progress, any condition in the first condition set is met to trigger the initiation of the RRC connection recovery process. The first node according to any one of claims 1 to 4, characterized in that: The configuration of at least one active multicast service session joined by the first node is unavailable, which means that the configuration of at least one active multicast service session joined by the first node is unavailable in the cell after cell selection or reselection; the serving cell does not provide at least one active multicast service session joined by the first node to the RRC inactive state, which means that the cell after cell selection or reselection does not provide at least one active multicast service session joined by the first node to the RRC inactive state. The first node according to any one of claims 1 to 5, characterized in that: When small data transmission is in progress, the first information is sent via SRB1; when small data transmission is not in progress, the first information is sent via SRB0. The first node according to any one of claims 1 to 6, characterized in that: When small data transmission is in progress, the first information occupies only one bit in the UE assistance information. The first node according to any one of claims 1 to 7, characterized in that: The first node, along with the execution of the first signaling, enters an RRC inactive state. The first node according to any one of claims 1 to 8, characterized in that it comprises: The first transmitter sends second information, wherein the second information indicates the arrival of at least one of data and signaling mapped to a radio bearer other than a radio bearer configured for small data transmission; the second information is sent via a dedicated control channel; Among them, small data transmission is ongoing. A method in a first node for multicast services and small data transmission, comprising: receiving a first signaling, wherein the first signaling is configured to transmit small data in an RRC inactive state; and the first signaling is configured to receive a multicast service in an RRC inactive state; In the RRC inactive state, as a response to any condition in the first condition set being met, sending the first information; the sending of the first information depends on whether the small data transmission is in progress; The first condition set includes receiving a first system information block that triggers multicast service reception, the configuration of at least one active multicast service session joined by the first node is unavailable, the serving cell does not provide at least one active multicast service session joined by the first node to the RRC inactive state, and the measurement of the serving cell is lower than at least one of the given thresholds for at least one active multicast service session joined by the first node; the sending of the first information depends on whether small data transmission is in progress, including: when small data transmission is in progress, sending the first information through a dedicated control channel; when small data transmission is not in progress, sending the first information through a common control channel, wherein the first information includes an RRC connection recovery request.