WO2023036173A1

WO2023036173A1 - State report sending method, radio bearer retransmission execution method and user equipment

Info

Publication number: WO2023036173A1
Application number: PCT/CN2022/117521
Authority: WO
Inventors: 肖芳英; 刘仁茂
Original assignee: 夏普株式会社; 肖芳英
Priority date: 2021-09-09
Filing date: 2022-09-07
Publication date: 2023-03-16
Also published as: CN115802406A

Abstract

Provided in the present invention are a state report sending method that is executed by a user equipment, a radio bearer retransmission execution method that is executed by a base station, and a user equipment. The state report sending method that is executed by a user equipment comprises: when a PDCP PDU is received by means of a specific RLC entity among a plurality of RLC entities, determining whether the currently received PDCP PDU is the first of PDCP PDUs that are continuously received by means of the specific RLC entity, wherein the plurality of RLC entities are configured to be used for transmitting a corresponding split radio bearer; and when the currently received PDCP PDU is the first PDCP PDU, sending a PDCP state report to a base station, wherein the PDCP state report comprises information for indicating whether a historical PDCP PDU that has been sent by the base station has been correctly received by a user equipment.

Description

Status report sending method, radio bearer retransmission execution method and user equipment

technical field

The present disclosure relates to the technical field of wireless communication, and more specifically, the present disclosure relates to a method for sending a status report performed by a user equipment, a method for performing radio bearer retransmission performed by a base station, and the user equipment.

Background technique

A research project SI (see SP-190625 for details) on 5G Multicast Broadcast Service Architecture Improvement has been approved and is in progress. One of the goals of this SI (referred to as Goal A) is to support generic MBS services in 5GS, identified use cases that could benefit from this feature include (but are not limited to) public safety, V2X applications, transparent IPv4/IPv6 multicast transport , IPTV, wireless software transmission, group communication and IoT applications. Correspondingly, at the 3rd Generation Partnership Project (3rd Generation Partnership Project: 3GPP) RAN#86 plenary meeting, Huawei proposed the work item of NR Multicast and Broadcast Service (NR MBS) (see non-patent literature: RP-193248 : New WID: NR Multicast and Broadcast Service) was approved. This work item is intended to provide support for Objective A in the RAN.

This disclosure discusses related issues involved in the RAN achieving the above work objectives.

Contents of the invention

The purpose of the present invention is to provide a solution capable of retransmitting radio bearers in time to reduce data loss.

In order to solve the above problems, an aspect of the present invention provides a method of transmitting a status report performed by a user equipment, including: when a PDCP PDU is received via a specific RLC entity among a plurality of RLC entities, it is determined whether the currently received PDCP PDU is the first PDCP PDU received consecutively via the specific RLC entity configured to transmit the corresponding split radio bearer; and the currently received PDCP PDU is the first In the case of a PDCP PDU, a PDCP status report is sent to the base station, and the PDCP status report includes information indicating whether the historical PDCP PDUs sent by the base station are correctly received by the user equipment.

Optionally, the separate radio bearer is a separate MBS radio bearer, and the specific RLC is a PTP RLC entity among multiple RLC entities configured to transmit the separate MBS radio bearer.

Optionally, the method further includes: before sending the PDCP status report to the base station, determining whether the detached radio bearer corresponding to the currently received PDCP PDU is configured with report sending indication information, and the report sending indication information is used to indicate sending the PDCP status report to the base station. When the currently received PDCP PDU is the first PDCP PDU, sending the PDCP status report to the base station may include: when the currently received PDCP PDU is the first PDCP PDU, and the currently received PDCP PDU When the detached radio bearer corresponding to the PDU is configured with report sending indication information, the PDCP status report is sent to the base station.

Optionally, the report sending instruction information is configured for any of the following separate radio bearers: each separate radio bearer; the corresponding multiple RLC entities are configured with separate radio bearers with different response modes. Configuration, the response mode indicates whether to respond to the base station mode (such as the AM mode and UM mode described in this specification); at least one of the corresponding RLC entities in the plurality of RLC entities is configured to send The base station responds to the separated radio bearer in the acknowledged mode; the corresponding PTP RLC entity among the plurality of RLC entities is configured as the separated radio bearer in the acknowledged mode.

Optionally, determining whether the currently received PDCP PDU is the first PDCP PDU received consecutively via the specific RLC entity comprises: determining that the currently received PDCP PDU is The first PDCP PDU successively received via the specific RLC entity, the timer is started or restarted upon receipt of the PDCP PDU via the specific RLC entity.

Optionally, the timer is stopped when any of the following conditions is met: a PDCP PDU is received via another RLC entity of the plurality of RLC entities that is different from the specific RLC entity type; via the A PDCP PDU is received by another RLC entity and a PDCP PDU is not received by the specific RLC entity within a predetermined period from when the PDCP PDU is received by the other RLC entity; receiving by the other RLC entity to PDCP PDU and no PDCP PDU is received via the specific RLC entity during the period until the PDCP PDU received via the other RLC entity reaches a predetermined number; handover information is received from the base station, the handover The information indicates switching from the first transmission mode corresponding to the certain RLC entity to the second transmission mode corresponding to the other RLC entity.

Optionally, the report sending indication information includes timer configuration information for the timer.

According to another aspect of the present invention, there is also provided a method for performing radio bearer retransmission performed by a base station, including: determining whether there is a PDCP PDU that has not been successfully received by the user equipment according to a PDCP status report received from the user equipment, The PDCP status report is sent to the base station by the user equipment through the method of sending a status report as described above; and if there is a PDCP PDU that is not successfully received by the user equipment, send a message to the corresponding PTP PLC entity via the corresponding PTP PLC entity The user equipment retransmits the PDCP PDU.

Optionally, the method further includes: sending timer configuration information to the user equipment, where the timer configuration information is used to configure a timer for determining the first PDCP PDU.

According to another aspect of the present invention, there is also provided user equipment, including: a processor; and a memory storing instructions, wherein the instructions execute the method for sending a status report as described above when executed by the processor.

Invention effect

According to the present invention, the radio bearer can be retransmitted in time to reduce data loss.

Description of drawings

The above and other features of the present disclosure will become more apparent from the following detailed description in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram showing an example of a PDCP status report format according to an embodiment of the present invention.

Fig. 2 is a flowchart of a transmission method performed by a user equipment.

FIG. 3 is a block diagram for explaining a user equipment according to an embodiment of the present invention.

Fig. 4 is a flowchart of an example of a method for sending a status report according to an embodiment of the present invention.

Fig. 5 is a flowchart of another example of a method for sending a status report according to an embodiment of the present invention.

FIG. 6 is a diagram for explaining an example of a switching procedure from the PTM transfer mode to the PTP transfer mode.

FIG. 7 is a block diagram of a user equipment according to an embodiment of the present invention.

Fig. 8 is a schematic diagram of the parameters involved in the illustration.

Detailed ways

The present disclosure will be described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the present disclosure should not be limited to the specific embodiments described below. In addition, for the sake of brevity, detailed descriptions of well-known technologies that are not directly related to the present disclosure are omitted to prevent confusion to the understanding of the present disclosure.

Some terms involved in the present disclosure are described below, and the specific meanings of the terms can be found in the latest relevant documents of 3GPP, such as TS38.300, TS38.321, TS38.323, TS38.331 and so on. In addition, the embodiments of the present disclosure are not limited to broadcast/multicast services, and may also be applied to other application scenarios.

UE: User Equipment, user equipment.

RRC: Radio Resource Control, radio resource control.

RRC_CONNECTED: RRC connected state.

RRC_INACTIVE: RRC is inactive.

RRC_IDLE: RRC idle state.

RAN: Radio Access Network, wireless access network.

NR: New RAT, new radio access technology.

MBMS: Multimedia Broadcast/Multicast Service, multimedia broadcast multicast service.

MBS: Multicast Broadcast Services, multicast broadcast service.

PDCP: Packet Data Convergence Protocol, packet data convergence protocol.

FIG. 1 shows an example of the format of a PDCP status report (PDCP Status Report). As shown in Figure 1, D/C occupies 1 bit and is used to indicate whether the corresponding PDCP PDU is a PDCP data PDU or a PDCP control PDU; the PDU type (PDU Type) occupies 3 bits and is used to indicate the corresponding PDCP control PDU. The type of control information; FMC (First Missing COUNT) occupies 32 bits and is used to indicate the first missing COUNT (COUNT represents the number of PDU, COUNT is composed of HFN and PDCP serial number PDCP SN, as shown in Figure 8), this The field indicates the COUNT value of the first lost PDCP SDU in the reordering window (that is, RX_DELIV); the bitmap (Bitmap) has a variable length and is used to indicate which SDUs are lost and which SDUs have been correctly received in the receiving PDCP entity (indicates which SDUs are missing and which SDUs are correctly received in the receiving PDCP entity), Table 1 gives an example of the meaning of each bit value, where the bit position of the Nth bit in the bitmap is (bit position of N ^th bit in the Bitmap is N); R occupies 1 bit, which is a reserved bit, and the reserved bit will be ignored by the receiving end.

Table 1

比特bits	含义meaning
00	COUNT＝(FMC+比特位)模2 ³²的PDCP SDU丢失 COUNT=(FMC+bits) Modulo 2 ³² PDCP SDU loss
11	COUNT＝(FMC+比特位)模2 ³²的PDCP SDU正确接收 COUNT=(FMC+bit) Modulo 2 ³² PDCP SDU received correctly

RLC: Radio Link Control, wireless link control.

As an example, the RLC can be an RLC in an acknowledged mode (Acknowledged Mode, AM), that is, AM RLC, or an RLC in an unacknowledged mode (Unacknowledged Mode, UM), that is, UM RLC, or a transparent mode (Transparent Mode). , TM) RLC, namely TM RLC. A UM RLC entity is configured as a transmitting UM RLC entity or as a receiving UM RLC entity, and submits or receives RLC data PDUs. The AM RLC entity includes a transmitting end and a receiving end, and submits or receives RLC data PDUs and RLC control PDUs. In the AM mode, the RLC entity submits or receives RLC data PDU and RLC control PDU (i.e. status PDU), and the receiving end of the AM RLC entity uses the status PDU to inform the peer RLC entity (i.e. the sending end of another AM RLC entity) about Its successfully received RLC data PDUs and RLC data PDUs detected as lost.

SDU: Service Data Unit, service data unit. The data packet received or delivered by this layer from the upper layer is called SDU.

PDU: Protocol Data Unit, protocol data unit. The data packets received or delivered by this layer from the lower layer are called PDUs. For example, a PDCP data PDU is a data packet obtained by adding a PDCP header to a PDCP SDU.

RB: Radio Bearer, radio bearer.

MRB: MBS radio bearer, that is, a radio bearer that is configured for MBS multicast/broadcast transmission (A radio bearer that is configured for MBS multicast/broadcast delivery).

MCCH: Multicast Control Channel, multicast control channel. The MBS-MCCH is used to transmit control information related to receiving MBS services.

SC-MCCH: Single Cell Multicast Control Channel, single cell multicast control channel.

TMGI: Temporary Mobile Group Identity, temporary mobile group identity.

PLMN: Public Land Mobile Network, public land mobile network.

RNTI: Radio Network Temporary Identifier, wireless network temporary identifier.

PTM: Point to Multipoint, point to multipoint, a delivery method of MBS business. In the PTM delivery mode, the RAN node delivers a single copy of MBS data packets over radio to a set of UEs via radio (a RAN node delivers a single copy of MBS data packets over radio to a set of UEs).

PTP: Point to Point, point to point, a delivery method of MBS business. In the PTP delivery method, the RAN node delivers copies of multiple MBS data packets to each UE via radio (a RAN node delivers separate copies of MBS data packet over radio to individual UE).

LTE SC-PTM: LTE Single Cell Point to Multipoint, long term evolution single cell point to multipoint.

MTCH: Multicast Traffic Channel, multicast traffic channel. MBS multicast (or multicast communication service) means that the same service and the same specific content are simultaneously provided to a group of specific UEs. A multicast traffic is delivered to the UE using the multicast session.

A UE in RRC_CONNECTED can use PTP and/or PTM to receive a multicast communication service.

G-RNTI: Group RNTI, group RNTI, used to scramble the scheduling and transmission of MTCH (used to scramble the scheduling and transmission of MTCH). NR MBS supports 1-1 mapping between G-RNTI and MBS session (One-to-one mapping between G-RNTI and MBS session is supported in NR MBS).

In this disclosure, network, base station and RAN can be used interchangeably, and the network can be a long-term evolution LTE network, an NR network, an enhanced long-term evolution eLTE network, or other networks defined in subsequent evolution versions of 3GPP.

In LTE SC-PTM, the base station broadcasts the MBMS service and its scheduling information supported by the system information and the message transmitted on the SC-MCCH channel. The radio bearer configuration information used to transmit the MBMS service is predefined . The UE can know the MBMS service that the current cell or base station supports or is in progress by receiving the corresponding system information and the message transmitted on the SC-MCCH. When the UE needs to receive a certain MBMS service, it establishes a radio bearer according to predefined parameters and receives data. In this case, UE can receive MBMS service without establishing RRC connection.

In NR MBS, some MBS services (services) can also be scheduled in a manner similar to SC-PTM, so that UEs in the RRC idle state and RRC inactive state can also receive the MBS services. However, there are another part of MBS services that require the UE to establish an RRC connection with the base station, and then the base station configures for the UE through dedicated RRC signaling (also called a dedicated RRC message), and the radio bearer for receiving these MBS services can also be configured by the base station through dedicated RRC signaling. The order is UE configuration. FIG. 2 is a block diagram representing such a transmission method performed by a user equipment. In S101, the UE establishes an RRC connection with the base station, and in S102, the base station configures a radio bearer for the UE to receive the MBS service through an RRC message. The radio bearer may be an MRB configured with only PTM transmission (as shown in (a) of Figure 3), or a separate MRB (split MRB) configured with PTM and PTP at the same time (as shown in (b) of Figure 3) Or only MRBs for PTP transmission are configured (as shown in (c) of FIG. 3 ). It should be noted that (a)-(c) of FIG. 3 only show the PDCP entity and RLC entity corresponding to the bearer and the relationship between them. In the downlink direction, the PDCP PDU encapsulated by the PDCP entity (that is, the PDCP header is added) is delivered to the RLC entity. For separate MRBs, the base station can dynamically decide whether to use PTM or PTP to transmit the MBS session (or PDCP PDU). For example, when the quality of the link corresponding to PTM deteriorates or cannot meet the quality of service (QoS) of the MBS session, the base station can use PTP transmission (that is, the base station submits the PDCP PDU to the PTP RLC entity). For an MRB configured with only PTM transmission, the base station reconfigures the MRB as an MRB with PTP transmission through RRC signaling. For separate MRBs configured with PTM transmission and PTP transmission at the same time, the base station dynamically decides to use PTM transmission or PTP transmission and does not explicitly indicate to the UE, that is, when the base station enables PTP or PTM transmission, it directly transmits data without sending an indication to the UE . In this case, when the quality of the link corresponding to PTM deteriorates, the base station uses PTP for transmission. However, in order to meet the QoS requirements for MBS services, the base station will retransmit some PDCP PDUs through PTP (or PTP RLC entity) to reduce data loss, and these PDCP PDUs have been submitted to PTM (or PTM RLC entity). How the UE triggers the PDCP status report so that the base station determines which PDCP PDUs should be retransmitted over the PTP is a problem that needs to be solved.

The present disclosure provides the following embodiments to solve the above-mentioned problems.

The present invention will be described in detail below in conjunction with the accompanying drawings.

FIG. 4 is a flow chart of + examples of a method of sending a status report according to an embodiment of the present invention.

As shown in FIG. 4, at S202, the user equipment receives PDCP PDUs via multiple RLC entities. The multiple RLC entities may be, for example, the RLC entities for the split MRB in (b) of FIG. 3 , namely, the PTM RLC entity and the PTP RLC entity. A split radio bearer may be a split MBS radio bearer. At this time, among the multiple RLC entities, for example, one PTM RLC entity and one PTP RLC entity may be included. In other examples, the number of PTM RLC entities and PTP RLC entities can be arbitrary.

Upon receiving the PDCP PDU, the user equipment determines at S204 whether the received PDCP PDU is a PDCP PDU received via a specific RLC entity.

In one example, in case the split radio bearer is a split MBS radio bearer, the specific RLC entity may be a PTP RLC entity among a plurality of RLC entities configured to transport the split MBS radio bearer.

If the PDCP PDU is received via a specific RLC entity, that is, if a PDCP PDU is received via a specific RLC entity, then at S206, determine whether the currently received PDCP PDU is the first one received continuously via a specific RLC entity PDCP PDUs.

If the currently received PDCP PDU is the first PDCP PDU continuously received via the specific RLC entity, then at S208, the user equipment sends a PDCP status report to the base station. The PDCP status report includes information indicating whether the historical PDCP PDUs sent by the base station are correctly received by the user equipment. When the base station receives the PDCP status report, it can determine whether there is a PDCP PDU that has not been correctly received by the user equipment according to the PDCP status report. If there is a PDCP PDU that is not correctly received by the user equipment, retransmission may be initiated for the PDCP PDU. That is, retransmit the PDCP PDU to the user equipment.

For example, it may be determined whether the currently received PDCP PDU is the first PDCP PDU received continuously via a specific RLC entity through the running state of the timer. This timer may be started or restarted upon receipt of a PDCP PDU via a specific RLC entity. If the timer is not running when a PDCP PDU is received via a specific RLC entity, it can be determined that the currently received PDCP PDU is the first PDCP PDU successively received via the specific RLC entity. At this point, start the timer. Then when the PDCP PDU is received via the specific RLC entity next time, since the timer is in the running state, it can be determined that the PDCP PDU received this time is not the first PDCP PDU received continuously via the RLC entity. At this point, the timer can be restarted. Therefore, if the base station maintains the state of transmitting radio bearers through a specific RLC entity, the user equipment will continuously receive PDCP PDUs via the specific RLC entity, and then receive the first PDCP PDU via the specific RLC entity Afterwards, when the PDCP PDU is received via the specific RLC entity again, the timer is in the running state, so that it can be determined that the currently received PDCP PDU is not the first PDCP PDU continuously received via the specific RLC entity.

The value of the timer can be appropriately set according to actual needs, which is not particularly limited in the present invention. The base station may send a configuration message for the timer to the user equipment through an RRC message, and the base station may set the timer according to the configuration message.

In one example, the timer may be stopped if the user equipment considers that the base station has switched from a first transmission mode corresponding to a specific RLC entity to another transmission mode different from the first transmission mode, wherein the other transmission mode corresponds to Another RLC entity whose corresponding transmission mode is different from the specific RLC entity. Thus, when the base station switches to the first transmission mode again, when the user equipment receives a PDCP PDU via a specific RLC entity corresponding to the first transmission mode, if the timer is not in the running state, it can be determined that this The PDCP PDU received at this time is the first PDCP PDU received consecutively via this particular RLC entity.

The so-called base station switching transmission mode means that the base station switches the RLC entity used for data transmission. RLC entities exist on the base station side and the user equipment side correspondingly. For example, when the base station side includes a PTP RLC entity and a PTM RLC entity, the user equipment side also correspondingly has a PTP RLC entity and a PTM RLC entity corresponding to the PTP RLC entity and the PTM RLC entity on the base station side. The PTP RLC entity (or PTM RLC entity) on the base station side and the PTP RLC entity (or PTM RLC entity) on the UE side are called peer RLC entities. When the base station decides to transmit data through the PTP mode, the data is sent to the user equipment side via the PTP RLC entity on the base station side, and the user equipment receives data through its PTP RLC entity accordingly. When the base station switches the transmission mode, for example, the base station switches from the PTP mode to the PTM mode, the base station side switches from the PTP RLC entity to the PTM RLC entity, and the user equipment side also switches to receive data through the corresponding PTM RLC entity.

However, which transmission mode to use to transmit the PDCP PDU is decided by the base station, not by the user equipment. In this regard, the user equipment may determine whether the base station has switched the transmission mode according to a certain strategy. The user equipment may consider that the base station has switched the transmission mode when any of the following conditions is met, and the timer may be stopped at this time: to PDCP PDU; a PDCP PDU is received via another RLC entity and a PDCP PDU is not received via a specific RLC entity within a predetermined period from when a PDCP PDU is received via another RLC entity (the base station may configure the UE via an RRC message the predetermined period); a PDCP PDU is received via another RLC entity and no PDCP PDU is received via a specific RLC entity during the period until the PDCP PDU received via another RLC entity reaches a predetermined number; received from the base station Referring to switching information, the switching information indicates switching from a first transmission mode corresponding to a certain RLC entity to a second transmission mode corresponding to another RLC entity.

In FIG. 5, the operation of S302 is the same as that of S202, and the operation of S304 may be the same as that of S304. In addition, the operation of S308 is the same as that of S206, and the operation of S310 is the same as that of S208. Therefore, descriptions of these operations are not repeated.

As shown in FIG. 5, the user equipment may determine in S306 whether the detached radio bearer corresponding to the currently received PDCP PDU is configured with report sending indication information. The report sending indication information is used to instruct to send the PDCP status report to the base station, and can be configured by the base station.

The base station may configure report sending indication information for each separate radio bearer. The report sending indication information may also be configured only for the separated radio bearers meeting the requirements. In the case that the above-mentioned first PDCP PDU is determined by a timer, the report sending indication information may include timer configuration information for the timer. In the following, the case where the report sending instruction information is the timer configuration information for the timer is taken as an example to describe which separate radio bearer the report sending instruction information is configured for.

If the detached radio bearer corresponding to the currently received PDCP PDU is configured with report sending indication information, further perform operations of S308 and S310. In another example, the operation of S306 may also be performed after the operation of S308.

It should be noted that the received PDCP PDU described in the embodiment of the present disclosure may also be replaced by the received PDCP SDU. It may be further defined that the received PDCP PDU is a PDCP data PDU.

The following specific examples are given to further illustrate the present invention.

Example

A split radio bearer is configured with a first RLC entity and a second RLC entity. The PDCP entity corresponding to the separated radio bearer receives the PDCP PDU from the lower layer (that is, the RLC entity), and if the PDCP PDU (or the PDCP SDU corresponding to the PDCP PDU) is received from the first RLC entity, perform the following operations:

(1) If the timer is not running, trigger a PDCP status report and/or start the timer.

(2) If the timer is running, restart the timer. It should be noted that, in the present disclosure, restarting the timer may also be described as starting the timer.

Optionally, the value of the timer is configured for the UE by the base station through RRC signaling. If the value of the timer is configured by the base station, it may also be stipulated that only the separated radio bearer configured with the timer can execute this embodiment. Furthermore, it may also be stipulated whether the corresponding radio bearer or PDCP entity is configured with the information element statusReportRequired, and only when statusReportRequired is configured or its value is true, this embodiment is executed. Wherein, statusReportRequired is included in the RRC message sent by the base station to the UE (may be included in the RRC message configuring the first timer), and is used to indicate whether the corresponding radio bearer is configured to send a PDCP status report on the uplink.

Optionally, when the PDCP entity is reestablished, the timer is stopped. When the PDCP entity is re-established, the parameters of the RLC entity corresponding to the PDCP entity will be reset, and the timer can be stopped at this time.

Optionally, when the second RLC entity is enabled, the timer is stopped.

The base station may configure the timer for each separate radio bearer. The base station may also configure the timer only for separate radio bearers configured with different modes for the associated first RLC entity and the second RLC entity, for example, the mode of the first RLC entity is UM, and the mode of the second RLC entity is UM. The mode is AM, that is, the first RLC entity is a UM RLC entity, and the second RLC entity is an AM RLC entity. The base station may also only configure the timer for the detached radio bearer associated with at least one AM RLC entity. AM RLC is usually configured for services with high QoS requirements. For such services, when the transmission of the first RLC entity cannot meet the QoS requirements, the base station will enable the second RLC entity. In order to avoid data loss, it is necessary to trigger the UE to send PDCP Status reporting, so that the base station can retransmit those PDCP PDUs or SDUs that have been sent but have not been correctly received by the UE.

The above process will be described below by taking the separation of MRB as an example.

The base station configures a separate MRB for the UE through RRC signaling, and the separate MRB is associated with two RLC entities, one of which is a PTM RLC entity and the other is a PTP RLC entity. Optionally, a timer (or a value of the timer) is configured for the corresponding detached MRB in the RRC signaling.

The PDCP entity separating the MRB receives the PDCP PDU from the lower layer entity (ie, the RLC entity), and when the PDCP PDU (or the PDCP SDU corresponding to the PDCP PDU) is received from the PTP RLC entity, the following operations are performed:

(1) If the timer is not running, trigger the PDCP status report, and/or start the timer (the value of the timer is set to the configured value).

(2) If the timer is running, restart the timer (the value of the timer is set to the configured value).

An example of the scene of this embodiment will be described with reference to FIG. 6 . As shown in Figure 6, it is assumed that the PDCP PDUs used to transmit separate MRBs include PDCP PDU No. 1 to PDCP PDU No. N, where N is a positive integer. The base station transmits PDCP PDU No. 1 through PTM transmission, but when transmitting PDCP PDU No. 2, it detects QoS degradation, which may affect data loss, so the base station can decide to switch to PTP mode to transmit PDCP PDU No. 2. Correspondingly, the user equipment receives PDCP PDU No. 2 via PTP RLC. When the user equipment receives the No. 2 PDCP PDU, since the No. 2 PDCP PDU is the first PDCP PDU received via the PTP RLC, the user equipment can perform the operations of this embodiment to send the PDCP status report to the base station. The status report may include information indicating whether each PDCP PDU sent by the base station has been successfully received so far. For example, if the user equipment has not received the No. 1 PDCP PDU, the PDCP status report may include information indicating that the No. 1 PDCP PDU has not been received. After receiving the PDCP status report, the base station can retransmit the No. 1 PDCP PDU through PTP transmission.

It can be stipulated that only when the mode of the PTP RLC entity is AM, the timer is configured. It may also be stipulated that the timer is configured only when the two RLC entities associated with the separated MRB are used for PTM transmission and PTP transmission respectively.

The detached MRB is configured by upper layers to send a PDCP status report in the uplink (configured by upper layers to send a PDCP status report in the uplink), and the receiving PDCP entity triggers a PDCP status report when the following conditions are met: a PDCP PDU from a PTP RLC entity is received ( or the PDCP SDU corresponding to the PDCP PDU) and the timer is not running. The PDCP entity can judge whether it is configured by the upper layer to send a PDCP status report through the information element statusReportRequired. statusReportRequired is included in the RRC message sent by the base station to the UE (may be included in the RRC message configuring the first timer), used to indicate the corresponding radio Whether the bearer is configured to send PDCP status reports on the uplink.

If the PDCP data PDU (its COUNT value is RCVD_COUNT) received from the PTP RLC entity is not discarded, then the receiving PDCP entity (receiving PDCP entity) performs the following operations: start or restart the timer. Wherein, RCVD_COUNT is the COUNT of the received PDCP data PDU, that is, [RCVD_HFN, RCVD_SN]; where, RCVD_HFN and RCVD_SN are the parameters of the two fields of RCVD_COUNT. RCVD_SN is the PDCP SN of the received PDCP data PDU, the PDCP SN is included in the PDU header of the PDU (PDCP SN of the received PDCP Data PDU, included in the PDU header), RCVD_HFN is the received PDCP data PDU The HFN is calculated by the receiving PDCP entity (the HFN of the received PDCP Data PDU, calculated by the receiving PDCP entity).

In the embodiments of the present disclosure, the PTM RLC entity is also referred to as the RLC entity associated with PTM or the RLC entity configured with G-RNTI or the RLC entity associated with G-RNTI or the RLC entity used for PTM transmission; the PTP RLC entity is also referred to as PTP The associated RLC entity or the RLC entity used for PTP transport.

It should be noted that an MBS service (or MBS session) can be identified by an MBS identifier, and the MBS identifier can be a TMGI and/or a session identifier sessionId, where the TMGI can include a PLMN identifier and/or a service identifier, so The above service identifier uniquely identifies an MBS service within a PLMN.

Fig. 7 is a brief structural block diagram of a user equipment UE involved in the present disclosure. As shown in FIG. 7 , the user equipment user equipment 700 includes a processor 701 and a memory 702 . The processor 701 may include, for example, a microprocessor, a microcontroller, an embedded processor, and the like. The memory 702 may include, for example, a volatile memory (such as a random access memory RAM), a hard disk drive (HDD), a non-volatile memory (such as a flash memory), or other memories. Memory 702 has program instructions stored thereon. When the instructions are executed by the processor 701, the above method described in detail in this disclosure and executed by the user equipment may be executed.

In addition, computer-executable instructions or programs running on the device according to the present disclosure may be programs that cause a computer to realize the functions of the embodiments of the present disclosure by controlling a central processing unit (CPU). The program or information processed by the program may be temporarily stored in volatile memory (such as random access memory RAM), hard disk drive (HDD), non-volatile memory (such as flash memory), or other memory systems.

Computer-executable instructions or programs for implementing the functions of the various embodiments of the present disclosure can be recorded on computer-readable storage media. The corresponding functions can be realized by causing a computer system to read programs recorded on the recording medium and execute the programs. The so-called "computer system" here may be a computer system embedded in the device, which may include an operating system or hardware (such as peripheral devices). The "computer-readable storage medium" may be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a recording medium that dynamically stores a program for a short period of time, or any other recording medium readable by a computer.

Various features or functional modules of the devices used in the above-mentioned embodiments may be implemented or executed by circuits (for example, single-chip or multi-chip integrated circuits). Circuits designed to perform the functions described in this specification may include general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination of the above. A general-purpose processor can be a microprocessor, or it can be any existing processor, controller, microcontroller, or state machine. The above-mentioned circuits may be digital circuits or analog circuits. Where new integrated circuit technologies have emerged to replace existing integrated circuits due to advances in semiconductor technology, one or more embodiments of the present disclosure may also be implemented using these new integrated circuit technologies.

In addition, the present disclosure is not limited to the above-described embodiments. Although various examples of the embodiments have been described, the present disclosure is not limited thereto. Fixed or non-mobile electronic equipment installed indoors or outdoors can be used as terminal equipment or communication equipment, such as AV equipment, kitchen equipment, cleaning equipment, air conditioners, office equipment, vending machines, and other household appliances.

As above, the embodiments of the present disclosure have been described in detail with reference to the drawings. However, the specific structure is not limited to the above embodiments, and the present disclosure also includes any design changes that do not deviate from the gist of the present disclosure. In addition, various changes can be made to the present disclosure within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. In addition, components having the same effect described in the above embodiments can be substituted for each other.

Claims

A method of sending a status report performed by a user equipment, comprising:

When a PDCP PDU is received via a specific RLC entity among a plurality of RLC entities, determining whether the currently received PDCP PDU is the first PDCP PDU continuously received via the specific RLC entity, the plurality of RLC entities being configured for transporting a corresponding disjoint radio bearer; and

In the case that the currently received PDCP PDU is the first PDCP PDU, a PDCP status report is sent to the base station, and the PDCP status report includes indicating whether the historical PDCP PDU sent by the base station is correctly received by the user equipment Information.
The method according to claim 1, wherein the split radio bearer is a split MBS radio bearer, and the specific RLC is a PTP RLC entity among a plurality of RLC entities configured to transmit the split MBS radio bearer.
The method according to claim 1, further comprising:

Before sending the PDCP status report to the base station, determine whether the separated radio bearer corresponding to the currently received PDCP PDU is configured with report sending indication information, and the report sending indication information is used to indicate sending the PDCP status report to the base station ;

In the case that the currently received PDCP PDU is the first PDCP PDU, sending the PDCP status report to the base station includes:

When the currently received PDCP PDU is the first PDCP PDU, and the detached radio bearer corresponding to the currently received PDCP PDU is configured with report sending indication information, send a PDCP status report to the base station.
The method according to claim 3, wherein the report sending indication information is configured for any of the following separated radio bearers:

each separate radio bearer;

The corresponding RLC entities are configured with separate radio bearers configured with different response modes, and the response mode indicates whether to respond to the base station;

At least one of the corresponding RLC entities in the plurality of RLC entities is configured as a separate radio bearer in an acknowledgment mode that responds to the base station;

The corresponding PTP RLC entity among the plurality of RLC entities is configured as a separate radio bearer in acknowledged mode.
The method according to any one of claims 1 to 4, wherein determining whether the currently received PDCP PDU is the first PDCP PDU received continuously via the specific RLC entity comprises:

In the case that the timer is not in the running state, it is determined that the currently received PDCP PDU is the first PDCP PDU continuously received via the specific RLC entity, the timer is received via the specific RLC entity The PDCP PDU is activated or restarted.
The method of claim 5, wherein the timer is stopped when any of the following conditions are met:

receiving a PDCP PDU via another RLC entity of the plurality of RLC entities that is of a different type than the specific RLC entity;

receiving a PDCP PDU via said another RLC entity and not receiving a PDCP PDU via said particular RLC entity within a predetermined period from when a PDCP PDU was received via said another RLC entity;

receiving a PDCP PDU via said another RLC entity and not receiving a PDCP PDU via said specific RLC entity from a period until PDCP PDUs received via said another RLC entity reach a predetermined number;

Switching information is received from the base station, the switching information indicating switching from a first transmission mode corresponding to the certain RLC entity to a second transmission mode corresponding to the other RLC entity.
The method according to claim 5 when dependent on claim 3, wherein the report sending indication information includes timer configuration information for the timer.
A method performed by a base station for performing radio bearer retransmission, comprising:

According to the PDCP status report received from the user equipment, it is determined whether there is a PDCP PDU that has not been successfully received by the user equipment, and the PDCP status report is performed by the user equipment through the method described in any one of claims 1-7 and sent to the base station; and

If there is a PDCP PDU that is not successfully received by the user equipment, retransmit the PDCP PDU to the user equipment via the corresponding PTP PLC entity.
The method of claim 8, further comprising:

Send timer configuration information to the user equipment, where the timer configuration information is used to configure a timer for determining the first PDCP PDU.
A user equipment, comprising:

processor; and

memory, storing instructions,

Wherein, the instructions, when executed by the processor, perform the method according to any one of claims 1-7.