Method for a user equipment to receive multicast / broadcast service data, user equipment, and method for a cell to provide multicast / broadcast service data

Abstract

To provide a method of user equipment (UE) receiving multicast / broadcast service (MBS) data, UE, and a method of a cell providing MBS data.SOLUTION: A method includes: receiving a multicast MBS configuration, wherein the multicast MBS configuration is associated with an MBS provided by a first cell; and in response to determining that the UE in an unconnected state camping on the first cell, receiving, from the first cell, the MBS data of the MBS provided by the first cell based on the multicast MBS configuration.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to communication technologies, and in particular, to a method for a user equipment (UE) to receive multicast / broadcast service (MBS) data, a UE, and a method for a cell to provide MBS data.

Background Art

[0002] In Release 17 (R-17) of the 5G communication system, the radio access network (RAN) designates multicast only for UEs in the RRC_CONNECTED state. Therefore, for a cell with a large number of UEs, it may not fully meet requirements such as mission critical services.

[0003] Also, keeping the UE always in the RRC_CONNECTED state is power inefficient. Therefore, it is important to support multicast for unconnected UEs (e.g., RRC_INACTIVE or RRC_IDLE).

[0004] In R-17, the multicast MBS configuration is delivered to the UE by dedicated signals, and only connected-mode UEs can obtain the multicast MBS configuration in R-17.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, when an unconnected (e.g., inactive or idle) UE reselects to another cell, the UE needs to enter the connected mode to obtain the multicast MBS configuration from the camping cell, resulting in a decrease in the UE's power efficiency.

Means for Solving the Problem

[0006] Accordingly, the present invention relates to a method for a user equipment (UE) capable of receiving MBS data for solving the above technical problem, a UE, and a method for a cell to provide MBS data.

[0007] Embodiments of the present invention provide a method for a user equipment (UE) to receive multicast / broadcast service (MBS) data, including receiving a multicast MBS configuration, where the multicast MBS configuration is related to MBS provided by a first cell, and when it is determined that an unconnected UE is camping on the first cell, in response thereto, receiving, from the first cell, MBS data of the MBS provided by the first cell based on the multicast MBS configuration.

[0008] Embodiments of the present invention provide a user equipment (UE) including a transceiver and a processor. The processor is coupled to the transceiver and controls the transceiver to receive a multicast / broadcast service (MBS) configuration, where the multicast MBS configuration is related to MBS provided by a first cell, and when it is determined that an unconnected UE is camping on the first cell, in response thereto, controls the transceiver to receive, from the first cell, MBS data of the MBS provided by the first cell based on the multicast MBS configuration.

[0009] Embodiments of the present invention provide a method for a cell to provide multicast / broadcast service (MBS) data, including transmitting a multicast MBS configuration, where the multicast MBS configuration is related to MBS provided by the cell, and transmitting, to an unconnected user equipment (UE) camping on the cell, MBS data of the MBS provided by the cell based on the multicast MBS configuration.

Advantages of the Invention

[0010] As described above, the embodiments of the present invention can improve the power efficiency of the UE.

Brief Description of the Drawings

[0011] The accompanying drawings are included to further understand the principles of the present invention, are incorporated herein, and constitute a part thereof. The drawings illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0012]

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Mode for Carrying Out the Invention

[0013] Hereinafter, preferred embodiments of the present invention will be described in detail using the attached drawings as examples. As much as possible, the same reference numerals are used in the drawings and the description to refer to the same or similar components.

[0014] Referring to FIG. 1, FIG. 1 shows a functional block diagram of a UE according to one embodiment of the present invention.

[0015] In FIG. 1, the UE 100 includes a transceiver 102 and a processor 104. The transceiver 102 may be configured to transmit and receive signals from other devices within its coverage area. The transceiver 102 can perform analog-to-digital signal conversion (ADC), digital-to-analog signal conversion (DAC), modulation, demodulation, signal amplification, low-pass filtering, and band-pass filtering. For example, the transceiver 102 is configured to provide the information of the received signal to the processor 104, modulate the data received from the processor 104 into a modulated signal, and transmit the modulated signal to other devices.

[0016] In some embodiments, UE 100 may further include other elements such as an antenna module for implementing the above-described functions of transceiver 102 and processor 104.

[0017] Processor 104 may be coupled to transceiver 102, and processor 104 may be, for example, a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, other types of integrated circuits (IC), a state machine, and the like.

[0018] In an embodiment of the present invention, processor 104 can access specific modules and / or program codes to implement a method for a UE to receive MBS data provided in the present invention. This will be further described below.

[0019] Referring to FIG. 2, FIG. 2 shows a flowchart of a method for a UE to receive MBS data according to an embodiment of the present invention. The method of this embodiment can be executed by UE 100 in FIG. 1, and each step in FIG. 2 will be described in detail below using the components shown in FIG. 1.

[0020] In step S210, processor 104 controls transceiver 102 to receive a multicast MBS configuration, and the multicast MBS configuration is related to the MBS provided by the first cell.

[0021] In an embodiment of the present invention, the first cell may be a first base station (e.g., gNB) that is currently providing services to UE100 (e.g., the base station where UE100 is currently camped), but the present invention is not limited thereto.

[0022] In step S220, when it is determined that the unconnected UE100 is camped on the first cell, in response thereto, the processor 104 controls the transceiver 102 to receive, from the first cell, MBS data of the MBS provided by the first cell based on the multicast MBS configuration.

[0023] In various embodiments, the procedures for executing steps S210 and S220 may be different, and will be described below. It should be noted that the description of the following processor 104 receiving / sending any data / information can be understood as an abbreviated form of the processor 104 controlling the transceiver 102 to receive / send the data / information to be considered. According to the same principle, the description of the following UE100 receiving / sending any data / information can also be understood as an abbreviated form of the processor 104 controlling the transceiver 102 to receive / send the data / information to be considered, but the present invention is not limited thereto.

[0024] In one embodiment, in the procedure for executing step S210, the processor 104 can receive multicast-MBS control channel (MCCH) scheduling information and receive the multicast MBS configuration based on the multicast-MCCH scheduling information.

[0025] In this embodiment, the multicast - MCCH scheduling information can carry the scheduling information of the multicast - MCCH, and the scheduling information of the multicast - MCCH can include at least information on the repeat period or the modification period.

[0026] Furthermore, the multicast - MCCH can carry the MBS multicast sessions provided within the cell, the corresponding scheduling - related information for these sessions, and the multicast MBS configuration messages indicating the multicast MBS configuration.

[0027] Referring to FIG. 3, FIG. 3 shows a schematic diagram of the multicast - MCCH according to one embodiment of the present invention. In FIG. 3, the multicast - MCCH messages may be the same within the same modification period. In one embodiment, the length of the modification period may be equal to or greater than the length of the repeat period.

[0028] In one embodiment, the UE100 can attempt to acquire the multicast - MCCH at least once within each modification period. In another embodiment, the UE100 can attempt to acquire the multicast - MCCH as soon as it receives a change notification (described in the third embodiment of the present invention).

[0029] In this embodiment, the processor 104 can receive the multicast - MCCH scheduling information from the second cell via a dedicated message in a connected state (e.g., an RRC connected state, where RRC means radio resource control), and the second cell provides services to the UEs in the connected state.

[0030] In the following embodiments of the present invention, when the UE 100 is in a connected state, it can be assumed that the UE 100 is provided with services by the second cell. Thereafter, the UE 100 can switch to a non-connected state (for example, RRC inactive state or RRC idle state) and move to the coverage area of the first cell, and thus camp on the first cell. In this case, the second cell can be understood as the last serving cell of the UE 100, and the first cell can be understood as the camping cell of the UE 100. In some embodiments, the first cell and the second cell may be the same cell, but the present invention is not limited thereto.

[0031] Referring to FIG. 4, FIG. 4 shows an application scenario according to one embodiment of the present invention. In FIG. 4, in step S411, the first cell can provide an MBS configuration via a multicast - MCCH. In step S412, the first cell and the second cell can negotiate multicast - MCCH scheduling information.

[0032] In FIG. 4, when the UE 100 is in a connected state, in step S413, the processor 104 can receive multicast - MCCH scheduling information from the second cell via a dedicated message. In one embodiment, the dedicated message may be an RRC release message.

[0033] In other embodiments, the dedicated message may be another type of signal such as an RRC reconfiguration message. In this case, the processor 104 can first receive a dedicated message including multicast - MCCH scheduling information from the second cell, and then can receive an RRC release message, but the present invention is not limited thereto.

[0034] In one embodiment, the second cell may further include, in the dedicated message, multicast-MCCH scheduling information for use by adjacent cells of the second cell, and the adjacent cells of the second cell may be a subset of a RAN notification area (RNA).

[0035] In FIG. 4, assuming that the first cell and the third / fourth / fifth cells are adjacent cells of the second cell (for example, these cells belong to the same RNA), the dedicated message from the second cell to UE100 may include not only the multicast-MCCH scheduling information of the second cell (for example, the multicast-MCCH scheduling information 2 in FIG. 4), but also the multicast-MCCH scheduling information of the first cell (for example, the multicast-MCCH scheduling information 1 in FIG. 4) and the multicast-MCCH scheduling information of the third / fourth / fifth cells (for example, the multicast-MCCH scheduling information 3 in FIG. 4), but the present invention is not limited thereto.

[0036] In step S414, UE100 can enter (for example, switch to) a non-connected state. Next, in step S415, UE100 performs cell selection, and for example, by moving to the coverage of the first cell, in step S416, UE100 can camp on the first cell.

[0037] In step S417, UE100 receives a multicast MBS configuration based on the multicast-MCCH scheduling information, and the multicast-MCCH scheduling information may be the one received previously in step S413.

[0038] In one embodiment, UE100 can monitor the MCCH based on the multicast-MCCH scheduling information, and the MCCH carries the multicast MBS configuration. Next, UE100 can receive the multicast MBS configuration via the MCCH. Since UE100 is in the disconnected state in step S414, it can be understood that while UE100 is in the disconnected state, it receives the multicast MBS configuration from the first cell based on the multicast-MCCH scheduling information.

[0039] In some embodiments, the multicast-MCCH scheduling information can include the content shown in Table 1 below.

[0040]

Table 1

[0041] In some embodiments, the multicast MBS configuration can include the content shown in Table 2 below.

[0042]

Table 2

[0043] In step S418, UE100 receives, from the first cell, the MBS data of the MBS provided by the first cell based on the multicast MBS configuration.

[0044] Therefore, UE100 can continue to receive the MBS data even after camping on the first cell, and it is not necessary to switch to the connected state to obtain information such as the multicast-MCCH scheduling information, which is more power-efficient for UE100.

[0045] Referring to FIG. 5A, FIG. 5A shows an application scenario according to one embodiment of the present invention. In this embodiment, the UE100 and the first / second cells can execute the corresponding steps S411 to S416. For related details, reference can be made to the related description in FIG. 4, so it will not be repeatedly described here.

[0046] In this embodiment, before receiving the multicast MBS configuration based on the multicast-MCCH scheduling information, the UE100 can additionally check the validity of the multicast-MCCH scheduling information related to the first cell.

[0047] In various embodiments, the UE100 can execute corresponding operations based on the determination result of the validity of the multicast-MCCH scheduling information.

[0048] Specifically, in FIG. 5A, in step S511, the first cell can send a status signal to the UE100. The status signal can include reference multicast-MCCH scheduling information related to the MBS and can be received by the UE100. In one embodiment, the first cell can send the status signal using broadcast and / or unicast, but the present invention is not limited thereto.

[0049] In one embodiment, the status of the multicast-MCCH scheduling information may be the version information of the multicast-MCCH scheduling information and / or the cell identification information of the first cell.

[0050] In some embodiments, each cell can transmit (e.g., broadcast) the state of the corresponding multicast - MCCH scheduling information. Taking FIG. 5A as an example, the state of the multicast - MCCH scheduling information from the first cell can include the multicast - MCCH scheduling information having version information 1. The state of the multicast - MCCH scheduling information from the second cell can include the multicast - MCCH scheduling information having version information 2. Also, the state of the multicast - MCCH scheduling information from the third / fourth / fifth cells can include the multicast - MCCH scheduling information having version information 3, but the present invention is not limited thereto.

[0051] In step S512, UE100 can determine whether the multicast - MCCH scheduling information is valid. If the multicast - MCCH scheduling information is valid, UE100 can then perform validity handling. On the other hand, if the multicast - MCCH scheduling information is invalid, UE100 can then perform invalidity handling.

[0052] In one embodiment, when it is determined that the state of the multicast - MCCH scheduling information (which may be the multicast - MCCH scheduling information received in step S413) matches the state of the reference multicast - MCCH scheduling information, in response, UE100 can determine that the multicast - MCCH scheduling information is valid. On the other hand, when it is determined that the state of the multicast - MCCH scheduling information does not match the state of the reference multicast - MCCH scheduling information, in response, UE100 can determine that the multicast - MCCH scheduling information is invalid, but the present invention is not limited thereto.

[0053] In one embodiment, if the stored version information does not match the state of the multicast - MCCH scheduling information broadcast from the first cell, the UE100 can consider the stored multicast - MCCH scheduling information (e.g., the multicast - MCCH scheduling information received in step S413) to be invalid. On the other hand, if the stored version information matches the state of the multicast - MCCH scheduling information broadcast from the first cell, the UE100 can consider the stored multicast - MCCH scheduling information to be valid.

[0054] In another embodiment, if the cell ID list of the multicast - MCCH scheduling information does not include the cell ID of the first cell, the UE100 can consider the stored multicast MCCH scheduling information to be invalid. On the other hand, if the cell ID list of the multicast - MCCH scheduling information includes the cell ID of the first cell, the UE100 can consider the stored multicast - MCCH scheduling information to be valid, but the present invention is not limited thereto.

[0055] Referring to FIG. 5B, FIG. 5B shows an application scenario related to the validity processing of the present invention. In FIG. 5B, after the UE100 receives the (broadcast) status signal of the multicast - MCCH scheduling information in step S511, the UE100 can determine whether the multicast - MCCH scheduling information is valid.

[0056] In step S521, when it is determined that the multicast - MCCH scheduling information is valid, in response, the UE100 can receive the multicast MBS configuration based on the multicast - MCCH scheduling information. Next, the UE100 can receive the MBS data of the MBS provided by the first cell based on the multicast MBS configuration from the first cell.

[0057] Referring to FIG. 6, FIG. 6 shows an application scenario based on the invalidation process of the present invention. In FIG. 6, after the UE 100 receives the (broadcast) status signal of the multicast - MCCH scheduling information in step S511, the UE 100 can determine whether the multicast - MCCH scheduling information is valid.

[0058] In step S531, when it is determined that the multicast - MCCH scheduling information is invalid, in response, the UE 100 returns to the connected state, requests a new / updated multicast MBS configuration, and accordingly, can receive MBS data. That is, the UE 100 can return to the RRC connected state using the first cell and request the first cell to provide an updated multicast MBS configuration. Using the updated multicast MBS configuration, the UE 100 can accordingly receive MBS data from the first cell, but the present invention is not limited thereto.

[0059] In one embodiment, when it is determined that the multicast - MCCH scheduling information is invalid, in response, the UE 100 applies / updates the multicast - MCCH scheduling information via an enhanced random access (RA) procedure and accordingly receives a multicast MBS configuration.

[0060] Referring to FIG. 7, FIG. 7 shows an enhanced RA procedure according to an embodiment of the present invention. In the enhanced RA procedure of FIG. 7, the UE 100 can start the enhanced RA procedure by transmitting Msg1 (e.g., an RA preamble) to the first cell, and the UE 100 can receive Msg2 (e.g., an RA response (RAR)) corresponding to Msg1 from the first cell.

[0061] Next, UE100 can send Msg3 (e.g., a resume request) to the first cell, and UE100 can receive Msg4 (e.g., a resume message or a release message) corresponding to Msg3 from the first cell.

[0062] In one embodiment, when it is determined that the stored multicast - MCCH scheduling information is invalid, in response, UE100 requests the first cell to provide reference multicast - MCCH scheduling information by using reserved RA resources. The reserved RA resources can be used exclusively for the request of reference multicast - MCCH scheduling information. In some embodiments, the reserved RA resources include at least one of a first reserved random access preamble and a reserved random access occasion, but the present invention is not limited thereto.

[0063] Next, UE100 can receive reference multicast - MCCH scheduling information from the first cell via at least one of an RA response (e.g., Msg2), a resume message, and a release message corresponding to the reserved RA resources. That is, when the first cell receives Msg1 via the reserved RA resources, the first cell can use at least one of an RA response (e.g., Msg2), a resume message, and a release message to provide the reference multicast - MCCH scheduling information to UE100. Thereafter, UE100 applies the reference multicast - MCCH scheduling information while remaining in the unconnected state (e.g., updates the multicast - MCCH scheduling information based on the reference multicast - MCCH scheduling information). That is, UE100 does not switch to the connected state in response to the extended RA procedure.

[0064] In the present invention, embodiments that use RA responses, resume messages, and release messages to carry reference multicast - MCCH scheduling information will be described with reference to FIGS. 8A to 8C respectively.

[0065] Referring to FIG. 8A, FIG. 8A shows an extended RA procedure according to an embodiment of the present invention. In FIG. 8A, when it is determined that the stored multicast - MCCH scheduling information is invalid, in response, UE100 can request the first cell to provide reference multicast - MCCH scheduling information by using the reserved RA resource in step S811. In this embodiment, the reserved RA resource is the first reserved RA preamble and can be used exclusively for requesting reference multicast - MCCH scheduling information. That is, UE100 can send the first reserved RA preamble to the first cell to request reference multicast - MCCH scheduling information.

[0066] In this embodiment, the reserved RA resource is a reserved RA occasion, and UE100 can send Msg1 in the reserved RA occasion that can be used exclusively for requesting reference multicast - MCCH scheduling information, but the present invention is not limited thereto.

[0067] In step S812, UE100 receives an RAR from the first cell. The RAR in this embodiment can carry reference multicast - MCCH scheduling information (which can be regarded as updated multicast - MCCH scheduling information), and the structure of the RAR can be referred to the right part of FIG. 8A.

[0068] In step S813, UE 100 applies the reference multicast - MCCH scheduling information (for example, updates the multicast - MCCH scheduling information based on the reference multicast - MCCH scheduling information), and accordingly, receives the multicast MBS configuration while remaining in the unconnected state. In one embodiment, UE 100 may not perform contention resolution.

[0069] Referring to FIG. 8B, FIG. 8B shows the extended RA procedure according to an embodiment of the present invention. In FIG. 8B, when it is determined that the stored multicast - MCCH scheduling information is invalid, in response, UE 100 can request the first cell to provide the reference multicast - MCCH scheduling information by using the reserved RA resource in step S811. For details, reference can be made to the related description in FIG. 8A, so it will not be repeated here.

[0070] In step S812, UE 100 receives the RAR from the first cell. In step S821, UE 100 transmits Msg3 to the first cell.

[0071] In step S822, UE 100 receives Msg4 corresponding to Msg3 from the first cell. Msg4 in this embodiment may be a resume message (for example, an RRC resume message), and the resume message can carry the reference multicast - MCCH scheduling information (which can be regarded as the updated multicast - MCCH scheduling information).

[0072] According to the reference multicast - MCCH scheduling information, UE 100 can accordingly execute step S813. For details, reference can be made to the related description in FIG. 8A, so it will not be repeated here. In one embodiment, UE 100 may not perform contention resolution.

[0073] Referring to FIG. 8C, FIG. 8C shows an extended RA procedure according to an embodiment of the present invention. In FIG. 8C, when it is determined that the stored multicast - MCCH scheduling information is invalid, in response thereto, UE 100 can request the first cell to provide reference multicast - MCCH scheduling information by using the reserved RA resources in step S811. For details, reference can be made to the related description in FIG. 8A, so it will not be repeatedly described here.

[0074] In step S812, UE 100 receives a RAR from the first cell. In step S821, UE 100 transmits Msg3 to the first cell.

[0075] In this embodiment, in response to Msg3, the first cell can send a request to the second cell (for example, the last serving cell of UE 100) to obtain the UE context related to UE 100. In FIG. 8C, the second cell can send a UE context acquisition failure message including an encapsulated release message (for example, an RRC release message), and the first cell can send that release message to UE 100 as Msg4.

[0076] In step S831, UE 100 receives Msg4 corresponding to Msg3 from the first cell. Msg4 in this embodiment may be a release message (for example, an RRC release message), and the release message can carry reference multicast - MCCH scheduling information (which can be regarded as updated multicast - MCCH scheduling information).

[0077] According to the reference multicast - MCCH scheduling information, UE 100 can execute step S813 accordingly. For details, reference can be made to the related description in FIG. 8A, so it will not be repeatedly described here. In one embodiment, UE 100 may not need to perform contention resolution.

[0078] In one embodiment, when it is determined that the stored multicast - MCCH scheduling information is invalid, in response, UE100 transmits a RA preamble (e.g., Msg1) to the first cell, receives a RAR (e.g., Msg2) corresponding to the RA preamble from the first cell, and the RA preamble and the corresponding RAR may be normal RA preamble and normal RAR in this embodiment.

[0079] Next, UE100 transmits a resume request (e.g., Msg3) to the first cell, and the resume request requests the first cell to provide reference multicast - MCCH scheduling information.

[0080] That is, in this embodiment, UE100 requests the first cell to provide reference multicast - MCCH scheduling information by using Msg3 instead of Msg1.

[0081] Thereafter, UE100 receives reference multicast - MCCH scheduling information from the first cell via at least one of a resume message and a release message corresponding to the resume request. That is, since UE100 uses Msg3 to request reference multicast - MCCH scheduling information, the first cell cannot provide reference multicast - MCCH scheduling information by using Msg2 and can only provide reference multicast - MCCH scheduling information by using Msg4.

[0082] With the reference multicast - MCCH scheduling information, UE100 can apply the reference multicast - MCCH scheduling information while remaining in the non - connected state (e.g., update the multicast - MCCH scheduling information based on the reference multicast - MCCH scheduling information).

[0083] In one embodiment, an embodiment in which restart messages and release messages are used to carry reference multicast - MCCH scheduling information will be described with reference to FIGS. 9A and 9B, respectively.

[0084] Referring to FIG. 9A, FIG. 9A shows an extended RA procedure according to an embodiment of the present invention. In FIG. 9A, when it is determined that the stored multicast - MCCH scheduling information is invalid, in response, UE100 transmits an RA preamble (e.g., Msg1) to the first cell in step S911, and receives an RAR (e.g., Msg2) corresponding to the RA preamble from the first cell in step S912.

[0085] In step S913, UE100 transmits a restart request (e.g., Msg3) to the first cell, and the restart request requests the first cell to provide reference multicast - MCCH scheduling information.

[0086] In step S914, UE100 receives reference multicast - MCCH scheduling information from the first cell via a restart message (e.g., an RRC restart message) corresponding to the restart request, and the restart message carries the reference multicast - MCCH scheduling information.

[0087] According to the reference multicast - MCCH scheduling information, UE100 can execute step S813 accordingly. For details, reference can be made to the related description in FIG. 8A, so it will not be repeated here. In one embodiment, UE100 may not perform contention resolution.

[0088] Referring to FIG. 9B, FIG. 9B shows the extended RA procedure according to an embodiment of the present invention. In FIG. 9B, when it is determined that the stored multicast - MCCH scheduling information is invalid, in response thereto, UE 100 transmits a RA preamble (e.g., Msg1) to the first cell in step S911, and receives a RAR (e.g., Msg2) corresponding to the RA preamble from the first cell in step S912.

[0089] In step S913, UE 100 transmits a resume request (e.g., Msg3) to the first cell, and the resume request requests the first cell to provide reference multicast - MCCH scheduling information.

[0090] In this embodiment, in response to Msg3, the first cell can transmit a request to the second cell (e.g., the last serving cell of UE 100) to obtain the UE context related to UE 100. In FIG. 9B, the second cell can transmit a UE context acquisition failure message including an encapsulated release message (e.g., an RRC release message), and the first cell can transmit the release message to UE 100 as Msg4.

[0091] In step S915, UE 100 receives the reference multicast - MCCH scheduling information from the first cell via a release message (e.g., an RRC release message) corresponding to the resume request, and the release message carries the reference multicast - MCCH scheduling information.

[0092] According to the reference multicast - MCCH scheduling information, UE 100 can execute step S813 accordingly. For details, reference can be made to the related description in FIG. 8A, so it will not be repeated here. In one embodiment, UE 100 may not perform contention resolution.

[0093] In one embodiment, when it is determined that the stored multicast - MCCH scheduling information is invalid, in response, UE100 transmits a second reserved RA preamble (e.g., Msg1) to the first cell, and the second reserved RA preamble notifies the first cell that UE100 intends to indicate interested multicast - MCCH scheduling information from among at least one of the candidate multicast - MCCH scheduling information. Next, UE100 receives a RAR (e.g., Msg2) corresponding to the second reserved random access preamble from the first cell.

[0094] Thereafter, in response to the RAR, UE100 transmits a resume request (e.g., Msg3) to the first cell, and the resume request indicates interested multicast - MCCH scheduling information.

[0095] Thereafter, UE100 receives the interested multicast - MCCH scheduling information from the first cell via at least one of a resume message and a release message corresponding to the resume request.

[0096] Specifically, in the current communication standard, only one piece of multicast - MCCH scheduling information is available. However, when multiple pieces of multicast - MCCH scheduling information (e.g., candidate multicast - MCCH scheduling information) are available, UE100 is permitted to use the second reserved RA preamble as Msg1 to notify the first cell that UE100 intends to indicate interested multicast - MCCH scheduling information from among the candidate multicast - MCCH scheduling information, and use Msg3 to indicate the interested multicast - MCCH scheduling information. In response to Msg3, the first cell can use Msg4 (e.g., a resume message or a release message) to provide the interested multicast - MCCH scheduling information to UE100.

[0097] Since the multicast - MCCH scheduling information of interest is indicated in Msg3, the first cell cannot provide the multicast - MCCH scheduling information of interest using Msg2 and can only provide the multicast - MCCH scheduling information of interest using Msg4.

[0098] With the multicast - MCCH scheduling information of interest, UE100 can apply the multicast - MCCH scheduling information of interest (e.g., update the multicast - MCCH scheduling information based on the multicast - MCCH scheduling information of interest), and accordingly, receive the multicast MBS configuration while remaining in the non - connected state.

[0099] In one embodiment, embodiments that carry the multicast - MCCH scheduling information of interest using resume messages and release messages will be described with reference to FIGS. 10A and 10B respectively.

[0100] Referring to FIG. 10A, FIG. 10A shows an extended RA procedure according to one embodiment of the present invention. In FIG. 10A, when it is determined that the stored multicast - MCCH scheduling information is invalid, in response, UE100 transmits a second reserved RA preamble (e.g., Msg1) to the first cell in step S1011, notifying the first cell that UE100 intends to indicate the multicast - MCCH scheduling information of interest. Next, UE100 receives a RAR (e.g., Msg2) corresponding to the RA preamble from the first cell in step S1012.

[0101] In step S1013, UE100 transmits a resume request (e.g., Msg3) to the first cell in response to the RAR, and the resume request indicates the multicast - MCCH scheduling information of interest.

[0102] In step S1014, UE100 receives the multicast - MCCH scheduling information of interest from the first cell via a resume message corresponding to the resume request (e.g., an RRC resume message), and the resume message carries the multicast - MCCH scheduling information of interest.

[0103] Based on the multicast - MCCH scheduling information of interest, UE100 accordingly executes step S1015, applies the multicast - MCCH scheduling information of interest (e.g., updates the multicast - MCCH scheduling information based on the multicast - MCCH scheduling information of interest), and accordingly can receive the multicast MBS configuration while remaining in the disconnected state. In one embodiment, UE100 may not perform contention resolution.

[0104] Referring to FIG. 10B, FIG. 10B shows an extended RA procedure according to one embodiment of the present invention. In FIG. 10B, when it is determined that the stored multicast - MCCH scheduling information is invalid, in response, UE100 transmits a second reserved RA preamble (e.g., Msg1) to the first cell in step S1011, notifying the first cell that UE100 intends to indicate the multicast - MCCH scheduling information of interest. Next, UE100 receives an RAR (e.g., Msg2) corresponding to the RA preamble from the first cell in step S1012.

[0105] In step S1013, UE100 transmits a resume request (e.g., Msg3) to the first cell in response to the RAR, and the resume request indicates the multicast - MCCH scheduling information of interest.

[0106] In this embodiment, in response to Msg3, the first cell can send a request to the second cell (e.g., the last serving cell of UE100) to obtain the UE context related to UE100. In FIG. 10B, the second cell can send a UE context acquisition failure message including an encapsulated release message (e.g., an RRC release message), and the first cell can send the release message to UE100 as Msg4.

[0107] In step S1016, UE100 receives the multicast - MCCH scheduling information of interest from the first cell via a release message (e.g., an RRC release message) corresponding to the resume request, and the release message carries the multicast - MCCH scheduling information of interest.

[0108] According to the multicast - MCCH scheduling information of interest, UE100 can, accordingly, execute step S1015, apply the multicast - MCCH scheduling information of interest (e.g., update the multicast - MCCH scheduling information based on the multicast - MCCH scheduling information of interest), and accordingly, receive the multicast MBS configuration while remaining in the disconnected state. In one embodiment, UE100 may not perform contention resolution.

[0109] In one embodiment, in the procedure of executing step S210, the processor 104 can receive the multicast MBS configuration from the second cell via a dedicated message in the connected state, and the second cell provides services to UE100 in the connected state.

[0110] That is, UE100 can directly obtain the multicast MBS configuration via the dedicated message from the second cell, and the dedicated message is used to carry the multicast - MCCH scheduling information in the above - described embodiment.

[0111] Referring to FIG. 11, FIG. 11 shows an application scenario according to an embodiment of the present invention. In FIG. 11, the first cell can provide MBS data based on the multicast MBS configuration in step S1111. In step S1112, the first cell and the second cell can negotiate the multicast MBS configuration.

[0112] In FIG. 11, when the UE 100 is in the connected state, the processor 104 can receive the multicast MBS configuration from the second cell via a dedicated message in step S1113. In one embodiment, the dedicated message may be an RRC release message.

[0113] In other embodiments, the dedicated message may be other types of signals such as an RRC reconfiguration message. In this case, the processor 104 first receives a dedicated message including the multicast MBS configuration from the second cell, and then receives an RRC release message, but the present invention is not limited thereto.

[0114] In one embodiment, the second cell can further include in the dedicated message the multicast MBS configuration used for the adjacent cells of the second cell, and the adjacent cells of the second cell may be a subset of the RNAs.

[0115] Assuming in FIG. 11 that the first cell and the third / fourth / fifth cells are adjacent cells of the second cell (for example, these cells belong to the same RNA), the dedicated message from the second cell to the UE 100 can include not only the multicast MBS configuration of the second cell (for example, the multicast MBS configuration 2 in FIG. 11), but also the multicast MBS configuration of the first cell (for example, the multicast MBS configuration 1 in FIG. 11) and the multicast MBS configuration of the third / fourth / fifth cells (for example, the multicast MBS configuration 3 in FIG. 11), but the present invention is not limited thereto.

[0116] After that, UE100 can execute steps S414 to S416 and S418. For details, refer to the description of FIG. 4, so it will not be repeatedly described here. In this embodiment, the multicast MBS configuration can include the content shown in Table 2, but the present invention is not limited thereto.

[0117] Therefore, even after camping on the first cell, UE100 can continue to receive MBS data and does not need to switch to the connected state to obtain information such as multicast - MCCH scheduling information, which is more power - efficient for UE100.

[0118] Referring to FIG. 12A, FIG. 12A shows an application scenario according to an embodiment of the present invention. In this embodiment, UE100, the first / second cells can execute corresponding steps S1111 to S1113 and steps S414 to S416. For details, refer to the related descriptions of FIGS. 4 and 11, so it will not be repeatedly described here.

[0119] In this embodiment, before receiving the MBS data of MBS provided by the first cell based on the multicast MBS configuration from the first cell, UE100 can additionally check the validity of the multicast MBS configuration related to the first cell.

[0120] In various embodiments, UE100 can execute corresponding operations based on the determination result of the validity of the multicast MBS configuration.

[0121] Specifically, in FIG. 12A, in step S1211, the first cell can send a status signal to UE100, and the status signal can include a reference multicast MBS configuration related to MBS, and the status signal can be received by UE100. In one embodiment, the first cell can send the status signal by using broadcast and / or unicast, but the present invention is not limited thereto.

[0122] In one embodiment, the status of the multicast MBS configuration may be the version information of the multicast MBS configuration and / or the cell identifier of the first cell.

[0123] In some embodiments, each cell can send (e.g., broadcast) the status of the corresponding multicast MBS configuration. Taking FIG. 12A as an example, the status of the multicast MBS configuration from the first cell can include a multicast MBS configuration having version information 1. The status of the multicast MBS configuration from the second cell can include a multicast MBS configuration having version information 2. Also, the status of the multicast MBS configuration from the third / fourth / fifth cell can include a multicast MBS configuration having version information 3, but the present invention is not limited thereto.

[0124] In step S1212, UE100 can determine whether the multicast MBS configuration is valid. If the multicast MBS configuration is valid, UE100 can then perform validity processing. On the other hand, if the multicast MBS configuration is invalid, UE100 can then perform invalidity processing.

[0125] In one embodiment, when it is determined that the state of the multicast MBS configuration (which may be the multicast MBS configuration received in step S1113) matches the state of the reference multicast MBS configuration, in response, UE100 determines that the multicast MBS configuration is valid. On the other hand, when it is determined that the state of the multicast MBS configuration does not match the state of the reference multicast MBS configuration, in response, UE100 determines that the multicast MBS configuration is invalid, but the present invention is not limited thereto.

[0126] In one embodiment, if the stored version information does not match the broadcast state of the multicast MBS configuration from the first cell, UE100 may consider that the stored multicast MBS configuration (e.g., the multicast MBS configuration received in step S1113) is invalid. On the other hand, if the stored version information matches the broadcast state of the multicast MBS configuration from the first cell, UE100 may consider that the stored multicast MBS configuration is valid.

[0127] In another embodiment, if the cell ID list of the multicast MBS configuration does not include the cell ID of the first cell, UE100 also considers that the stored multicast MBS configuration is invalid. On the other hand, if the cell ID list of the multicast MBS configuration includes the cell ID of the first cell, UE100 considers that the stored multicast MBS configuration is valid, but the present invention is not limited thereto.

[0128] Referring to FIG. 12B, FIG. 12B shows an application scenario according to one embodiment of the present invention. In FIG. 12B, after UE100 receives the (broadcast) state signal of the multicast MBS configuration in step S1211, UE100 can determine whether the multicast MBS configuration is valid.

[0129] In step S1221, when it is determined that the multicast MBS configuration is valid, in response thereto, UE100 receives multicast MBS data based on the multicast MBS configuration.

[0130] Referring to FIG. 13, FIG. 13 shows an application scenario according to one embodiment of the present invention. In FIG. 13, after UE100 receives a (broadcast) status signal of the multicast MBS configuration in step S1211, UE100 can determine whether the multicast MBS configuration is valid.

[0131] In step S1231, when it is determined that the multicast MBS configuration is invalid, in response thereto, UE100 returns to the connected state, requests a new / updated multicast MBS configuration, and accordingly can receive MBS data. That is, UE100 can return to the RRC connected state with the first cell and request the first cell to provide an updated multicast MBS configuration. With the updated multicast MBS configuration, UE100 can accordingly receive MBS data from the first cell, but the present invention is not limited thereto.

[0132] In one embodiment, when it is determined that the multicast MBS configuration is invalid, in response thereto, UE100 updates the multicast MBS configuration via an extended RA procedure and accordingly receives MBS data.

[0133] Referring to FIG. 14, FIG. 14 shows an extended RA procedure according to an embodiment of the present invention. In the extended RA procedure of FIG. 14, UE100 can start the extended RA procedure by transmitting Msg1 (e.g., an RA preamble) to the first cell, and UE100 can receive Msg2 (e.g., an RA response (RAR)) corresponding to Msg1 from the first cell.

[0134] Next, the UE 100 can send Msg3 (e.g., a resume request) to the first cell, and the UE 100 can receive Msg4 (e.g., a resume message or a release message) corresponding to Msg3 from the first cell.

[0135] In one embodiment, when it is determined that the stored multicast MBS configuration is invalid, in response, the UE 100 requests the first cell to provide a new / reference multicast MBS configuration by using the reserved RA resource. The reserved RA resource can be dedicatedly used to request a reference multicast MBS configuration. In some embodiments, the reserved RA resource includes at least one of a first reserved random access preamble and a reserved random access occasion, but the present invention is not limited thereto.

[0136] Next, the UE 100 can receive a reference multicast MBS configuration from the first cell via at least one of an RA response (e.g., Msg2), a resume message, and a release message corresponding to the reserved RA resource. That is, when the first cell receives Msg1 via the reserved RA resource, the first cell can use at least one of an RA response (e.g., Msg2), a resume message, and a release message to provide the UE 100 with a new / reference multicast MBS configuration. Thereafter, the UE 100 applies the reference multicast MBS configuration while remaining in the disconnected state (e.g., updates the multicast MBS configuration based on the reference multicast MBS configuration). That is, the UE 100 does not switch to the connected state in response to the extended RA procedure.

[0137] In one embodiment, embodiments in which a reference multicast MBS configuration is carried using an RA response, a resume message, and a release message will be described with reference to FIGS. 15A to 15C, respectively.

[0138] Referring to FIG. 15A, FIG. 15A shows the extended RA procedure according to an embodiment of the present invention. In FIG. 15A, when it is determined that the stored multicast MBS configuration is invalid, in response, UE 100 can request the first cell to provide a new / reference multicast MBS configuration by using the reserved RA resource in step S1511. In this embodiment, the reserved RA resource may be the first reserved RA preamble, and the first reserved RA preamble can be dedicatedly used to request the reference multicast MBS configuration. That is, UE 100 can send the first reserved RA preamble to the first cell to request the reference multicast MBS configuration.

[0139] In this embodiment, the reserved RA resource may be a reserved RA occasion. UE 100 can send Msg1 in the reserved RA occasion, and the reserved RA occasion can be dedicatedly used to request a new / reference multicast MBS configuration, but the present invention is not limited thereto.

[0140] In step S1512, UE 100 receives an RAR from the first cell. The RAR in this embodiment can carry a reference multicast MBS configuration (which can be regarded as an updated multicast MBS configuration), and the structure of the RAR can be referred to the right part of FIG. 15A.

[0141] In step S1513, UE 100 receives MBS data based on the reference multicast MBS configuration while remaining in the non-connected state.

[0142] In one embodiment, UE 100 may not perform contention resolution.

[0143] Referring to FIG. 15B, FIG. 15B shows an extended RA procedure according to an embodiment of the present invention. In FIG. 15B, when it is determined that the stored multicast MBS configuration is invalid, in response thereto, UE 100 can request the first cell to provide a new / reference multicast MBS configuration by using reserved RA resources in step S1511. For details, reference can be made to the related description in FIG. 15A, so it will not be repeatedly described here.

[0144] In step S1512, UE 100 receives an RAR from the first cell. In step S1521, UE 100 transmits Msg3 to the first cell.

[0145] In step S1522, UE 100 receives Msg4 corresponding to Msg3 from the first cell. Msg4 in this embodiment may be a resume message (e.g., an RRC resume message), and the resume message can carry a reference multicast MBS configuration (which can be regarded as an updated multicast MBS configuration).

[0146] According to the reference multicast MBS configuration, UE 100 can execute step S1513 accordingly. For details, reference can be made to the related description in FIG. 15A, so it will not be repeatedly described here. In one embodiment, UE 100 may not perform contention resolution.

[0147] Referring to FIG. 15C, FIG. 15C shows an extended RA procedure according to an embodiment of the present invention. In FIG. 15C, when it is determined that the stored multicast MBS configuration is invalid, in response thereto, UE 100 can request the first cell to provide a new / reference multicast MBS configuration by using reserved RA resources in step S1511. For details, reference can be made to the related description in FIG. 15A, so it will not be repeatedly described here.

[0148] In step S1512, UE100 receives an RAR from the first cell. In step S1521, UE100 transmits Msg3 to the first cell.

[0149] In this embodiment, in response to Msg3, the first cell can send a request to the second cell (e.g., the last serving cell of UE100) to obtain the UE context related to UE100. In FIG. 15C, the second cell can send a UE context acquisition failure message including an encapsulated release message (e.g., an RRC release message), and the first cell can send the release message to UE100 as Msg4.

[0150] In step S1531, UE100 receives Msg4 corresponding to Msg3 from the first cell. The Msg4 in this embodiment may be a release message (e.g., an RRC release message), and the release message can carry a reference multicast MBS configuration (which can be regarded as an updated multicast MBS configuration).

[0151] According to the reference multicast MBS configuration, UE100 can execute step S1513 accordingly. For details, reference can be made to the related description in FIG. 15A, so it will not be repeated here. In one embodiment, UE100 may not perform contention resolution.

[0152] In one embodiment, when it is determined that the saved multicast MBS configuration is invalid, in response, UE100 transmits an RA preamble (e.g., Msg1) to the first cell and receives an RAR (e.g., Msg2) corresponding to the RA preamble from the first cell. The RA preamble and the corresponding RAR may be normal RA preamble and normal RAR in this embodiment.

[0153] Next, UE100 sends a resume request (e.g., Msg3) to the first cell, and the resume request requests the first cell to provide a new / reference multicast MBS configuration.

[0154] That is, in this embodiment, UE100 requests the first cell to provide a reference multicast MBS configuration by using Msg3 instead of Msg1.

[0155] After that, UE100 receives the reference multicast MBS configuration from the first cell via at least one of a resume message and a release message corresponding to the resume request. That is, since UE100 requests a new / reference multicast MBS configuration by using Msg3, the first cell cannot provide the reference multicast MBS configuration by using Msg2 and can only provide the reference multicast MBS configuration by using Msg4.

[0156] With the reference multicast MBS configuration, UE100 can apply the reference multicast MBS configuration while remaining in the disconnected state (e.g., update the multicast MBS configuration based on the reference multicast MBS configuration).

[0157] In one embodiment, the embodiments in which the reference multicast MBS configuration is carried using a resume message and a release message will be described with reference to FIGS. 16A and 16B respectively.

[0158] Referring to FIG. 16A, FIG. 16A shows an extended RA procedure according to one embodiment of the present invention. In FIG. 16A, when it is determined that the stored multicast MBS configuration is invalid, in response thereto, UE100 transmits an RA preamble (e.g., Msg1) to the first cell in step S1611, and receives an RAR (e.g., Msg2) corresponding to the RA preamble from the first cell in step S1612.

[0159] In step S1613, UE100 transmits a resume request (e.g., Msg3) to the first cell, and the resume request requests the first cell to provide a new / reference multicast MBS configuration.

[0160] In step S1614, UE100 receives the reference multicast MBS configuration from the first cell via a resume message (e.g., an RRC resume message) corresponding to the resume request, and the resume message carries the reference multicast MBS configuration.

[0161] With the reference multicast MBS configuration, UE100 can accordingly execute step S1513. For details, reference can be made to the related description in FIG. 15A, so it will not be repeatedly described here. In one embodiment, UE100 may not perform contention resolution.

[0162] Referring to FIG. 16B, FIG. 16B shows an extended RA procedure according to one embodiment of the present invention. In FIG. 16B, when it is determined that the saved multicast MBS configuration is invalid, in response, UE100 transmits an RA preamble (e.g., Msg1) to the first cell in step S1611, and receives an RAR (e.g., Msg2) corresponding to the RA preamble from the first cell in step S1612.

[0163] In step S1613, UE100 transmits a resume request (e.g., Msg3) to the first cell, and the resume request requests the first cell to provide a new / reference multicast MBS configuration.

[0164] In this embodiment, in response to Msg3, the first cell can send a request to the second cell (e.g., the last serving cell of UE100) to obtain the UE context related to UE100. In FIG. 16B, the second cell can send a UE context acquisition failure message including an encapsulated release message (e.g., an RRC release message), and the first cell can send the release message to UE100 as Msg4.

[0165] In step S1615, UE100 receives a reference multicast MBS configuration from the first cell via a release message (e.g., an RRC release message) corresponding to the resume request, and the release message carries the reference multicast MBS configuration.

[0166] According to the reference multicast MBS configuration, UE100 can execute step S1513 accordingly. For the details, reference can be made to the related description in FIG. 15A, so it will not be repeatedly described here. In one embodiment, UE100 may not perform contention resolution.

[0167] In one embodiment, when it is determined that the saved multicast MBS configuration is invalid, in response thereto, UE100 sends a second reserved RA preamble (e.g., Msg1) to the first cell, and the second reserved RA preamble notifies the first cell that UE100 intends to indicate a multicast MBS configuration of interest in at least one of the candidate multicast MBS configurations. Next, UE100 receives an RAR (e.g., Msg2) corresponding to the second reserved random access preamble from the first cell.

[0168] Thereafter, in response to the RAR, UE100 sends a resume request (e.g., Msg3) to the first cell, and the resume request indicates the multicast MBS configuration of interest.

[0169] Thereafter, the UE 100 receives the interested multicast MBS configuration from the first cell via at least one of a resume message and a release message corresponding to the resume request.

[0170] Specifically, in the current communication standard, only one multicast MBS configuration is available. However, if multiple multicast MBS configurations (e.g., candidate multicast MBS configurations) are available, the UE 100 uses the second reserved RA preamble as Msg1 and notifies the first cell that the UE 100 intends to indicate the interested multicast MBS configuration from among the candidate multicast MBS configurations, and is permitted to indicate the interested multicast MBS configuration using Msg3. In response to Msg3, the first cell can use Msg4 (e.g., a resume message or a release message) to provide the interested multicast MBS configuration to the UE 100.

[0171] Since the interested multicast MBS configuration is indicated by Msg3, the first cell cannot provide the interested multicast MBS configuration using Msg2 and can only provide the interested multicast MBS configuration using Msg4.

[0172] With the interested multicast MBS configuration, the UE 100 can apply the interested multicast MBS configuration (e.g., update the multicast MBS configuration based on the interested multicast MBS configuration) and accordingly receive MBS data while remaining in the disconnected state.

[0173] In the present invention, embodiments in which the interested multicast MBS configuration is carried using a resume message and a release message are described with reference to FIGS. 17A and 17B, respectively.

[0174] Referring to FIG. 17A, FIG. 17A shows an extended RA procedure according to one embodiment of the present invention. In FIG. 17A, when it is determined that the stored multicast MBS configuration is invalid, in response thereto, UE 100 transmits a second reserved RA preamble (e.g., Msg1) to the first cell in step S1711, and notifies the first cell that UE 100 intends to indicate a multicast MBS configuration of interest. Next, UE 100 receives a RAR (e.g., Msg2) corresponding to the RA preamble from the first cell in step S1712.

[0175] In step S1713, UE 100 transmits a resume request (e.g., Msg3) to the first cell in response to the RAR, and the resume request indicates a multicast MBS configuration of interest.

[0176] In step S1714, UE 100 receives a multicast MBS configuration of interest from the first cell via a resume message (e.g., an RRC resume message) corresponding to the resume request, and the resume message carries the multicast MBS configuration of interest.

[0177] Due to the multicast MBS configuration of interest, UE 100 accordingly executes step S1715 to apply the multicast MBS configuration of interest (e.g., update the multicast MBS configuration based on the multicast MBS configuration of interest), and accordingly, can receive MBS data while remaining in the disconnected state. In one embodiment, UE 100 may not perform contention resolution.

[0178] Referring to FIG. 17B, FIG. 17B shows an extended RA procedure according to one embodiment of the present invention. In FIG. 17B, when it is determined that the stored multicast MBS configuration is invalid, in response, UE 100 transmits a second reserved RA preamble (e.g., Msg1) to the first cell in step S1711, and notifies the first cell that it intends to indicate a multicast MBS configuration of interest. Next, UE 100 receives a RAR (e.g., Msg2) corresponding to the RA preamble from the first cell in step S1712.

[0179] In step S1713, UE 100 transmits a resume request (e.g., Msg3) to the first cell in response to the RAR, and the resume request indicates a multicast MBS configuration of interest.

[0180] In this embodiment, in response to Msg3, the first cell can send a request to the second cell (e.g., the last serving cell of UE 100) to obtain the UE context related to UE 100. In FIG. 17B, the second cell can send a UE context acquisition failure message including an encapsulated release message (e.g., an RRC release message), and the first cell can send the release message to UE 100 as Msg4.

[0181] In step S1716, UE 100 receives the multicast MBS configuration of interest from the first cell via a release message (e.g., an RRC release message) corresponding to the resume request, and the release message carries the multicast MBS configuration of interest.

[0182] With the multicast MBS configuration of interest, the UE 100 can accordingly execute step S1715 to apply the multicast MBS configuration of interest (for example, update the multicast MBS configuration based on the multicast MBS configuration of interest), and accordingly can receive MBS data while remaining in the disconnected state. In one embodiment, the UE 100 may not need to perform conflict resolution.

[0183] In one embodiment of the present invention, the first cell can update the multicast MBS configuration of the camped UE (for example, UE 100).

[0184] Referring to FIG. 18A, FIG. 18A shows the update procedure of the multicast MBS configuration according to one embodiment of the present invention.

[0185] In FIG. 18A, in step S1811, the first cell can transmit the status signal of the reference multicast MBS configuration, and the status signal can include the version information and / or cell ID described above. In this embodiment, the first cell can broadcast a change notification related to the reference multicast MBS configuration as the status signal.

[0186] In this embodiment, any change in the multicast MBS configuration causes the first cell to update the status of the multicast MBS configuration.

[0187] In step S1812, the UE 100 can check the validity of the reference multicast MBS configuration based on the status signal. In step S1813, the UE 100 can request the updated reference multicast MBS configuration as described in the above embodiment.

[0188] In this embodiment, any change to the multicast MBS configuration causes the UE 100 to request the multicast MBS configuration. However, the updated multicast MBS configuration does not have to be the multicast MBS configuration that the UE 100 is interested in. That is, the UE 100 can execute S1813 unnecessarily.

[0189] Referring to FIG. 18B, FIG. 18B shows an update procedure for a multicast MBS configuration according to an embodiment of the present invention. In FIG. 18B, assume that the first cell provides services to UE1 and UE2, UE1 receives the MBS data of MBS1 provided by the first cell in step S1820, and UE2 receives the MBS data of MBS2 provided by the first cell.

[0190] Also, assume that in step S1821, the first cell modifies only the multicast MBS configuration of MBS1. In this case, the first cell can notify UE1 to update only the corresponding multicast MBS configuration by the following operation.

[0191] In an embodiment of the present invention, UE1 can receive the MBS data of the UE of MBS1 based on downlink control information (DCI). In this case, in step S1822, the first cell can carry a change notification using the DCI corresponding to UE1, and the change notification indicates that the new / reference multicast MBS configuration has been updated.

[0192] When it is determined in step S1823 that the DCI corresponding to UE1 carries a change notification, in response, UE1 can request the first cell to provide the new / reference multicast MBS configuration (updated) in step S1823. With the (updated) reference multicast MBS configuration, UE1 can receive the MBS data of MBS1 in step S1825 accordingly.

[0193] More specifically, when only the reference multicast MBS configuration of MBS1 (using group radio network temporary identifier (G-RNTI) 1) is changed, the first cell can use the bits of the DCI of G-RNTI1 as a change notification to trigger UE1 to request the (updated) reference multicast MBS configuration of MBS1.

[0194] On the other hand, in FIG. 18B, since the reference multicast MBS configuration of MBS2 (which can use G-RNTI2) has not been changed, UE2 does not determine that the DCI corresponding to UE2 carries a change notification. In this case, when it is determined that the DCI does not carry a change notification, in response, UE2 may not be required to request the first cell to provide the new / reference multicast MBS configuration of MBS2, but the present invention is not limited thereto.

[0195] Referring to FIG. 18C, FIG. 18C shows an update procedure for a multicast MBS configuration according to an embodiment of the present invention. In the present invention, the embodiment of FIG. 18C can be regarded as a combination of the embodiments of FIGS. 18A and 18B.

[0196] In FIG. 18C, in step S1811, the first cell transmits a status signal of the reference multicast MBS configuration. UE100 checks the validity of the reference multicast MBS configuration in step S1812. In step S1813, UE100 requests the updated reference multicast MBS configuration, and in response, UE100 receives the MBS data of MBS1 in step S1820.

[0197] In step S1822, the first cell carries a change notification using the DCI corresponding to UE1. In S1823, when it is determined that the DCI is carrying a change notification, in response, UE100 requests the first cell to provide a new / reference multicast MBS configuration, and in response, in step S1825, UE100 receives the MBS data of MBS1.

[0198] In step S1811’, the first cell can transmit a status signal of the (updated) reference multicast MBS configuration.

[0199] In this embodiment, after step S1825, UE100 can determine whether the DCI is lost. If it is not lost, UE100 can ignore the transmitted status signal in step S1811’, so UE100 does not execute step S1813 unnecessarily as shown in Fig. 18A. On the other hand, if the DCI is lost, UE100 can obtain the transmitted status signal in step S1811’.

[0200] In another alternative of the embodiment of Fig. 18C, a change in the broadcast state of the multicast MBS configuration does not trigger a change notification. Therefore, if the camped UE has not lost the G-RNTI, the camped UE does not re-acquire the broadcast state of the multicast MBS configuration, but the present invention is not limited thereto.

[0201] Referring to Fig. 18D, Fig. 18D shows the update procedure of the multicast MBS configuration according to one embodiment of the present invention.

[0202] In FIG. 18D, UE 100 receives MBS data of MBS1 in step S1820. In step S1821, the first cell modifies the multicast MBS configuration (only) of MBS1. In the present embodiment, the first cell can carry the updated multicast MBS configuration of MBS1 using the MBS data of MBS1 in step S1831. Accordingly, UE 100 can obtain the updated multicast MBS configuration of MBS1 from the MBS data of MBS1 in step S1832, and accordingly, can receive MBS data 1 of MBS1 in step S1833.

[0203] That is, the first cell can directly use the MBS data to carry the updated multicast MBS configuration of the corresponding MBS.

[0204] Referring to FIG. 18E, FIG. 18E shows an update procedure of a multicast MBS configuration according to an embodiment of the present invention. In the present invention, the embodiment of FIG. 18E can be regarded as a combination of the embodiments of FIGS. 18A and 18D.

[0205] In FIG. 18E, the first cell transmits a status signal of a reference multicast MBS configuration in step S1811. UE 100 checks the validity of the reference multicast MBS configuration in step S1812. In step S1813, UE 100 requests an updated reference multicast MBS configuration, and accordingly, receives MBS data of MBS1 in step S1820.

[0206] In step S1831, the first cell can carry the updated multicast MBS configuration of MBS1 using the MBS data of MBS1. Accordingly, in step S1832, UE100 can obtain the updated multicast MBS configuration of MBS1 from the MBS data of MBS1, and accordingly, in step S1833, it can receive the MBS data 1 of MBS1. In the first alternative of the embodiment of FIG. 18E, the change in the broadcast state of the multicast MBS configuration does not trigger a change notification. Therefore, if the UE has not lost the G-RNTI, the camped UE does not re-acquire the broadcast state of the multicast MBS configuration.

[0207] In the second alternative of the embodiment of FIG. 18E, the communication standard can define that if the UE has not lost the G-RNTI, the camped UE does not need to re-acquire the broadcast state of the multicast MBS configuration, but the present invention is not limited thereto.

[0208] In one embodiment of the present invention, UE100 can receive a status signal from the first cell, and the status signal can include the status of the reference multicast MBS configuration related to the MBS, and the status includes a version shared by a plurality of reference MBSs. That is, the version can be shared by all or a group of MBSs.

[0209] In one alternative of this embodiment, UE100 can receive a status signal from the first cell, and the status signal can include the status of the reference multicast MBS configuration related to the MBS, and the status includes a version dedicated to the MBS. That is, the version may be a one-to-one mapping for the MBS, but the present invention is not limited thereto.

[0210] In FIGS. 19A and 19B, preparations for entering the disconnected state will be described.

[0211] Referring to FIG. 19A, FIG. 19A shows the preparation for entering the disconnected state according to one embodiment of the present invention.

[0212] In FIG. 19A, the second cell can provide services to UE100. In this case, in step S1911, UE100 can receive MBS data via a point-to-point (PTP) or split MBS radio bearer (MRB). In step S1912, the second cell reconfigures UE100 so that it can receive MBS via point to multipoint (PTM). In step S1913, UE100 can receive MBS data via PTM. In step S1914, UE100 enters the disconnected state and can receive MBS via PTM.

[0213] Referring to FIG. 19B, FIG. 19B shows the preparation for entering the disconnected state according to one embodiment of the present invention.

[0214] In FIG. 19B, the second cell can provide services to UE100. In this case, in step S1921, UE100 can receive MBS data via PTP or a split MRB. In step S1922, the second cell can reconfigure UE100 and provide an RRC release message used to receive MBS via PTM.

[0215] In step S1914, UE100 enters the disconnected state and can receive MBS via PTM.

[0216] Referring to FIG. 20, FIG. 20 shows a flowchart of a method for a cell to provide MBS data according to an embodiment of the present invention. The method of FIG. 20 can be executed by a cell (for example, a base station operating the cell), and the cell may be the first cell and / or the second cell in the above-described embodiment, but the present invention is not limited thereto.

[0217] In step S2010, the cell transmits a multicast MBS configuration. In step S2020, the cell transmits MBS data of MBS provided by the cell to non-connected UEs camping on the cell based on the multicast MBS configuration.

[0218] In one embodiment, the step of transmitting the multicast MBS configuration includes transmitting multicast-MBS control channel (MCCH) scheduling information and transmitting the multicast MBS configuration based on the multicast-MCCH scheduling information.

[0219] In one embodiment, the step of transmitting the multicast MBS configuration based on the multicast-MCCH scheduling information includes configuring the MCCH based on the multicast-MCCH scheduling information, where the MCCH carries the multicast MBS configuration, and transmitting the multicast MBS configuration via the MCCH.

[0220] In one embodiment, the step of transmitting the multicast-MCCH scheduling information includes providing the multicast-MCCH scheduling information via a dedicated message in the connected state, where the cell provides services to UEs in the connected state.

[0221] In one embodiment, the step of transmitting the multicast MBS configuration based on the multicast-MCCH scheduling information includes providing the multicast MBS configuration based on the multicast-MCCH scheduling information while the UE is in the non-connected state.

[0222] In one embodiment, the step of transmitting the multicast MBS configuration includes transmitting the multicast MBS configuration via a dedicated message in a connected state and the cell providing services to the UE in the connected state.

[0223] In one embodiment, the method further includes providing a reference multicast MBS configuration in response to a request from the UE, the request being executed using a reserved random access resource and providing the reference multicast MBS configuration via at least one of a random access response, a resume message, and a release message corresponding to the reserved random access resource, and triggering the UE such that the reference multicast MBS configuration is applied (e.g., the multicast MBS configuration is updated based on the reference multicast MBS configuration).

[0224] In one embodiment, the reserved random access resource includes at least one of a first reserved random access preamble and a reserved random access occasion.

[0225] In one embodiment, the method further includes receiving a random access preamble from the UE, transmitting a random access response corresponding to the random access preamble to the UE, receiving a resume request from the UE, requesting the cell to provide a new multicast MBS configuration in response to the resume request, and transmitting the reference multicast MBS configuration to the UE via at least one of a resume message and a release message corresponding to the resume request, and triggering the UE such that the reference multicast MBS configuration is applied (e.g., the multicast MBS configuration is updated based on the reference multicast MBS configuration).

[0226] In one embodiment, the method further comprises receiving, from the UE, a second reserved random access preamble, notifying the cell that the second reserved random access preamble is intended to indicate an interested (e.g., specific) multicast MBS configuration among the candidate multicast MBS configurations of the UE, transmitting to the UE a random access response corresponding to the second reserved random access preamble, receiving, from the UE, a resume request for the random access response, the resume request indicating the interested multicast MBS configuration, transmitting to the UE the interested multicast MBS configuration via at least one of a resume message and a release message corresponding to the resume request, and triggering the UE to apply the interested multicast MBS configuration (e.g., update the multicast MBS configuration based on the interested multicast MBS configuration).

[0227] In one embodiment, the method further comprises transmitting, to the UE, a status signal, the status signal including the status of a reference multicast MBS configuration associated with the MBS.

[0228] In one embodiment, the MBS data of the MBS is transmitted to the UE based on downlink control information (DCI), the DCI carrying a change notification when the reference multicast MBS configuration is updated.

[0229] In one embodiment, the method further comprises transmitting, to the UE, a status signal, the status signal including the status of a reference multicast MBS configuration associated with the MBS, the status including a version shared by a plurality of reference MBSs.

[0230] In one embodiment, the method further comprises transmitting, to the UE, a status signal, the status signal including the status of a reference multicast MBS configuration associated with the MBS, the status including a version dedicated to the MBS.

[0231] For details of the embodiments related to FIG. 20, reference may be made to the above-described embodiments, and thus, they will not be repeatedly described here.

[0232] As described above, the embodiments of the present invention provide a solution for a UE to obtain multicast - MCCH scheduling information or a multicast MBS configuration from the last serving cell. In this case, even if the UE camps on another cell after entering the disconnected state, the UE can obtain MBS data based on the multicast - MCCH scheduling information or the multicast MBS configuration without switching to the connected state. Therefore, the power efficiency of the UE can be improved.

[0233] It will be understood by those of ordinary skill in the art that various modifications and changes can be made to the disclosed embodiments without departing from the scope or spirit of the present invention. In view of this, the present invention is intended to cover modifications and changes within the scope of the following claims and their equivalents.

Industrial Applicability

[0234] The method for a UE of the present invention to receive MBS data, the UE, and the method for a cell to provide MBS data can be applied to a communication system that provides MBS.

Explanation of Signs

[0235] 100 UE 102 Transceiver 104 Processor Steps S210, S220, S411~S418, S511, S512, S521, S531, S811~S813, S821, S822, S831, S911~S915, S1011~S1016, S1111~S1113, S1211, S1212, S1221, S1231, S1511~S1513, S1521, S1522, S1531, S1611~S1615, S1711~S1716, S1811~S1813, S1820~S1825, S1811’, S1831~S1833, S1911~S1914, S1921, S1922, S2010, S2020

Claims

1. A method for a user equipment (UE) to receive multicast / multicast broadcast service (MBS) data, comprising: receiving multicast-MBS control channel (MCCH) scheduling information; receiving a multicast MBS configuration based on the multicast-MCCH scheduling information, wherein the multicast MBS configuration is related to MBS provided by a first cell; performing cell selection in a non-connected state; after performing the cell selection, in response to determining that the UE in the non-connected state is camping on the first cell, receiving, from the first cell, the MBS data of the MBS provided by the first cell based on the multicast MBS configuration; A method comprising the above.

2. The step of receiving the multicast MBS configuration based on the multicast-MCCH scheduling information comprises: monitoring an MCCH based on the multicast-MCCH scheduling information, wherein the MCCH carries the multicast MBS configuration; receiving the multicast MBS configuration via the MCCH. The method according to claim 1, comprising the above.

3. The step of receiving the multicast-MCCH scheduling information comprises: receiving, from a second cell, the multicast-MCCH scheduling information via a dedicated message in a connected state, wherein the second cell provides services to the UE in the connected state. The method according to claim 1.

4. The step of receiving the multicast MBS configuration based on the multicast-MCCH scheduling information comprises: receiving, from the first cell, the multicast MBS configuration based on the multicast-MCCH scheduling information while the UE is in the non-connected state. The method according to claim 1.

5. Before the step of receiving the multicast MBS configuration based on the multicast-MCCH scheduling information, the method further comprises: determining whether the multicast-MCCH scheduling information is valid; In response to determining that the multicast - MCCH scheduling information is valid, receiving the multicast MBS configuration based on the multicast - MCCH scheduling information; In response to determining that the multicast - MCCH scheduling information is invalid, updating the multicast - MCCH scheduling information via an extended random access procedure and receiving the multicast MBS configuration; The method according to claim 1, comprising the above.

6. The method according to claim 1, further comprising receiving a status signal from the first cell, the status signal including the status of a reference multicast MBS configuration related to the MBS, and the status including a version shared by a plurality of reference MBSs.

7. The method according to claim 1, further comprising receiving a status signal from the first cell, the status signal including the status of a reference multicast MBS configuration related to the MBS, and the status including a version dedicated to the MBS.

8. A transceiver; Connected to the transceiver; Controlling the transceiver to receive multicast - MBS control channel (MCCH) scheduling information; Based on the multicast - MCCH scheduling information, controlling the transceiver to receive a multicast / multicast - broadcast service (MBS) configuration, the multicast MBS configuration being related to the MBS provided by a first cell; Performing cell selection in a non - connected state; After performing the cell selection, in response to determining that the non - connected user equipment (UE) is camping on the first cell, controlling the transceiver to receive MBS data of the MBS provided by the first cell from the first cell based on the multicast MBS configuration; A processor for executing the above; A user equipment (UE) comprising the above.

9. A method for a cell to provide multicast / multicast - broadcast service (MBS) data, comprising: Transmitting multicast - MBS control channel (MCCH) scheduling information; Transmit a multicast MBS configuration based on the multicast-MCCH scheduling information, wherein the multicast MBS configuration is related to the MBS provided by the cell, and after a user equipment (UE) makes a cell selection in a non-connected state and camps on the cell, transmit the MBS data of the MBS provided by the cell to the non-connected state UE camping on the cell based on the multicast MBS configuration, and A method comprising the above steps.

10. The step of transmitting the multicast MBS configuration based on the multicast-MCCH scheduling information includes configuring an MCCH based on the multicast-MCCH scheduling information, wherein the MCCH carries the multicast MBS configuration, and transmitting the multicast MBS configuration via the MCCH. The method according to claim 9, comprising the above steps.

11. The step of transmitting the multicast-MCCH scheduling information includes providing the multicast-MCCH scheduling information via a dedicated message in a connected state, wherein the cell provides services to the UE in the connected state. The method according to claim 9.

12. The step of transmitting the multicast MBS configuration based on the multicast-MCCH scheduling information includes providing the multicast MBS configuration based on the multicast-MCCH scheduling information while the UE is in the non-connected state. The method according to claim 9.

13. The method according to claim 9, further comprising transmitting a status signal to the UE, wherein the status signal includes the status of a reference multicast MBS configuration related to the MBS, and the status includes a version shared by a plurality of reference MBSs.

14. The method according to claim 9, further comprising transmitting a status signal to the UE, wherein the status signal includes the status of a reference multicast MBS configuration related to the MBS, and the status includes a version dedicated to the MBS.

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