Method executed by user equipment, and user equipment

Abstract

Provided in the present invention are a method executed by a user equipment (UE), and a UE. The method executed by a UE comprises: a packet data convergence protocol (PDCP) entity receiving from an upper layer a request for reestablishing a PDCP; and when the PDCP entity receiving the request is a transmitting PDCP entity, a UE determining whether a radio bearer (RB) to which the PDCP entity belongs is a multi-modal data radio bearer (DRB), or a multi-model radio bearer associated with at least one unacknowledged mode radio link control (UM RLC) entity, or a multi-model radio bearer associated with at least one acknowledged mode radio link control (AM RLC) entity, wherein the multi-modal DRB is a DRB associated with the at least one UM RLC entity and the at least one AM RLC entity.

Description

Method performed by user equipment and user equipment TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of wireless communication, and more particularly, to a method performed by user equipment and user equipment. BACKGROUND

[0002] Currently, one of the research goals of eXtended Reality (XR) in 3GPP is to improve the effective support for XR applications with multi-QoS flows that have multi-modal inter-dependencies, so as to achieve synchronization or coordination between data streams while meeting multi-modal QoS requirements. A feasible solution is to associate multiple radio link control entities (RLC entities) in the same radio bearer (RB). To meet different QoS requirements, these RLC entities can be configured in different modes. In implementation, such RLC entities are associated with the same PDCP entity, thereby realizing coordinated management between data streams. For the PDCP entity associated with RLC entities of different modes, how to perform reestablishment and data recovery is a problem to be solved. SUMMARY

[0003] To solve the above problems, the present application provides a method performed by user equipment and user equipment.

[0004] According to one aspect of the present application, a method performed by user equipment UE is provided, comprising: a PDCP entity receiving a request for reestablishment of packet data convergence protocol PDCP from an upper layer; and in the case that the PDCP entity receiving the request is a transmitting PDCP entity, the user equipment UE determines whether a radio bearer RB to which the PDCP entity belongs is a multi-modal data radio bearer DRB, or is a multi-modal radio bearer associated with at least one unacknowledged mode radio link control UM RLC entity, or is a multi-modal radio bearer associated with at least one acknowledged mode radio link control AM RLC entity, the multi-modal DRB being a DRB associated with at least one UM RLC entity and at least one AM RLC entity.

[0005] In the method performed by the user equipment UE, preferably, in case the user equipment UE determines that the RB to which the PDCP entity belongs is a multi-mode DRB or a multi-mode radio bearer associated with at least one UM RLC entity, for each PDCP service data unit PDCP SDU to which a PDCP sequence number has been associated, if the user equipment UE determines that the PDCP protocol data unit PDCP PDU corresponding to the PDCP SDU has not been delivered to the lower layer UM RLC entity, the user equipment UE considers that the PDCP SDU is received from the upper layer of PDCP and transmits the PDCP SDU.

[0006] In the method performed by the user equipment UE, preferably, in case the user equipment UE determines that the RB to which the PDCP entity belongs is a multi-mode DRB or a multi-mode radio bearer associated with at least one AM RLC entity, if the PDCP entity corresponding to the multi-mode DRB or the multi-mode radio bearer has been suspended or transmission has been paused at the time of PDCP re-establishment or before PDCP re-establishment, for each PDCP service data unit PDCP SDU to which a PDCP sequence number has been associated, if the user equipment UE determines that the PDCP protocol data unit PDCP PDU corresponding to the PDCP SDU has not been successfully delivered by the lower layer AM RLC entity, the user equipment UE considers that the PDCP SDU is received from the upper layer of PDCP and transmits the PDCP SDU.

[0007] In the method performed by the user equipment UE, preferably, the user equipment UE performs one or more of the following operations for each PDCP SDU during transmission of the PDCP SDU:

[0008] starting a timer for the PDCP SDU;

[0009] associating a COUNT value for the PDCP SDU;

[0010] performing header compression for the PDCP SDU;

[0011] performing uplink data compression for the PDCP SDU;

[0012] performing integrity protection and ciphering for the PDCP SDU using the value of the state variable TX_NEXT;

[0013] setting the value of the PDCP sequence number of the PDCP PDU corresponding to the PDCP SDU, which can be obtained based on the state variable TX_NEXT.

[0014] - updating the value of the state variable TX_NEXT by increasing it by 1 ;

[0015] - submitting the processed PDCP PDU to the corresponding RLC entity.

[0016] In the method performed by the user equipment UE, it is preferred that, in the case where the user equipment UE determines that the RB to which the PDCP entity belongs is a multi-mode DRB or a multi-mode radio bearer associated with at least one AM RLC entity, if the PDCP entity corresponding to the multi-mode DRB or the multi-mode radio bearer has not been suspended or has not been suspended from transmission at the time of PDCP re-establishment or before the PDCP re-establishment, for each PDCP service data unit PDCP SDU that has been associated with a PDCP sequence number, if the user equipment UE determines that the PDCP protocol data unit PDCP PDU corresponding to the PDCP SDU has not been successfully delivered by the underlying AM RLC entity, the user equipment UE performs transmission or retransmission of the PDCP SDU.

[0017] In the method performed by the user equipment UE, it is preferred that the user equipment UE performs one or more of the following operations during transmission:

[0018] - performing header compression on the PDCP SDU;

[0019] - performing uplink data compression on the PDCP SDU;

[0020] - submitting the PDCP SDU to an integrity protection and ciphering function module for processing;

[0021] - submitting the processed PDCP PDU to the corresponding RLC entity.

[0022] In the method performed by the user equipment UE, it is preferred that the method performed by the user equipment UE further comprises: receiving a request from an upper layer to resume PDCP data; and in the case where the user equipment UE determines that the RB to which the PDCP entity belongs is a multi-mode DRB or a multi-mode radio bearer associated with at least one AM RLC entity, the transmitting PDCP entity retransmits a PDCP service data unit PDCP PDU that has been submitted to an AM RLC entity that has been re-established or released before the request is received and has not been successfully delivered by the underlying layer.

[0023] According to another aspect of the present application, there is provided a user equipment (UE) comprising: a processor; and a memory storing instructions; wherein the instructions, when executed by the processor, perform the method performed by the user equipment (UE) according to any one of claims 1 to 7.

[0024] Inventive Effects

[0025] According to the present application, for the PDCP entity associated with the RLC entity of different modes, reestablishment and data recovery can be performed. BRIEF DESCRIPTION OF DRAWINGS

[0026] The above and other features of the present disclosure will become more apparent by describing in detail our embodiments thereof with reference to the attached drawings, in which:

[0027] FIG. 1 is a schematic diagram showing the association between a PDCP entity and an RLC entity.

[0028] FIG. 2 is a flowchart showing a method performed by a user equipment (UE) according to an embodiment of the present application.

[0029] FIG. 3 is a schematic block diagram of a user equipment (UE) according to an embodiment of the present application. DETAILED DESCRIPTION

[0030] The present disclosure will be described in detail below with reference to the attached 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 simplicity, detailed descriptions of well-known technology related to the present disclosure will be omitted so as not to cause confusion in understanding the present disclosure.

[0031] Some terms related to the present disclosure will be described below. The specific meanings of the terms can be found in the latest related documents of 3GPP, such as TS 38.300, TS 38.321, TS 38.323, TS 38.331, etc. In addition, the embodiments of the present disclosure are not limited to broadcast / groupcast services, but can also be applied to other application scenarios.

[0032] UE: User Equipment, user equipment.

[0033] RRC: Radio Resource Control, radio resource control (layer).

[0034] RRC_CONNECTED: RRC connected state.

[0035] RRC_INACTIVE: RRC inactive state.

[0036] RRC_IDLE: RRC idle state.

[0037] RAN: Radio Access Network, wireless access network.

[0038] NR: New RAT, new radio access technology.

[0039] PDCP: Packet Data Convergence Protocol, packet data convergence protocol (layer).

[0040] RLC: Radio Link Control, radio link control (layer).

[0041] SDAP: Service Data Adaptation Protocol, service data adaptation protocol (layer)

[0042] ROHC: Robust Header Compression, robust header compression

[0043] EHC: Ethernet Header Compression, Ethernet header compression

[0044] UDC: Uplink Data Compression, uplink data compression

[0045] SN: Sequence Number, sequence number

[0046] As an example, the RLC can be an RLC in acknowledged mode (AM), i.e. an AM RLC, or an RLC in unacknowledged mode (UM), i.e. an UM RLC, or an RLC in transparent mode (TM), i.e. a TM RLC. Among them:

[0047] The UM RLC entity is configured to transmit or receive UM RLC entities and submit or receive RLC data PDUs;

[0048] The AM RLC entity includes a transmitting end and a receiving end, and submits or receives RLC data PDUs and RLC control PDUs. In AM mode, the RLC entity submits or receives RLC data PDUs and RLC control PDUs (i.e. status PDUs), and the receiving end of the AM RLC entity uses the status PDUs to inform the peer RLC entity (i.e. the transmitting end of another AM RLC entity) about the RLC data PDUs it has successfully received and the RLC data PDUs it has detected as lost.

[0049] SDU: Service Data Unit, service data unit. The data packet received or delivered by this layer from or to the upper layer is called SDU.

[0050] PDU: Protocol Data Unit, protocol data unit. The data packet received or delivered by this layer from or to the lower layer is called PDU. For example, the PDCP data PDU is the data packet obtained by adding the PDCP header to the PDCP SDU.

[0051] RB: Radio Bearer, radio bearer.

[0052] DRB: Data Radio Bearer, data radio bearer.

[0053] 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.

[0054] PDCP entity

[0055] The PDCP entity is located in the PDCP layer, and one PDCP entity can be associated with one radio bearer (Radio Bearer, RB) for transmitting data of the bearer. Such a PDCP can be referred to as a PDCP corresponding to a radio bearer, or as a PDCP belonging to a radio bearer.

[0056] The RLC entity is located in the RLC layer, and the functions of the RLC layer are implemented by the RLC entity. The RLC entity can be configured in one of the following three modes:

[0057] Transparent Mode (TM),

[0058] Unacknowledged Mode (UM)

[0059] Acknowledged Mode (AM).

[0060] The RLC entity configured in UM mode can be referred to as UM RLC, and the RLC entity configured in AM mode can be referred to as AM RLC.

[0061] One PDCP entity is associated with at least one RLC entity. One PDCP can be associated with one UM RLC (as in (a) of FIG. 1), and can also be associated with multiple UM RLCs (as in (b) of FIG. 1). The DRB corresponding to the structures of (a) and (b) of FIG. 1 can be referred to as UM DRB.

[0062] One PDCP can also be associated with one AM RLC (as in (c) of FIG. 1), and can also be associated with multiple AM RLCs (as in (d) of FIG. 1). A DRB corresponding to the structures of (c) and (d) of FIG. 1 can be referred to as an AM DRB.

[0063] One radio bearer can correspond to one PDCP or a PDCP associated therewith, and the PDCP associated therewith can also be associated with at least one AM RLC and at least one UM RLC (as in (e) of FIG. 1). A radio bearer corresponding to the structure of (e) of FIG. 1 can be referred to as a multi-mode radio bearer. Alternatively, a radio bearer associated with at least one AM RLC and at least one UM RLC can be defined as a multi-mode radio bearer. In addition, it can be said that the RLCs associated with this radio bearer or the RLCs associated with the PDCP of this radio bearer have the same meaning. Such a multi-mode bearer can be used to transmit data, and thus can also be referred to as a multi-mode data radio bearer (multi-mode DRB). Here, "multi-mode" means that the RLC entity can be in multiple modes.

[0064] In addition, according to the content or service type carried by a radio bearer, a radio bearer can be defined for carrying multiple model services, which can be referred to as a multi-modality radio bearer. Here, "multi-modality" means that the service type has multiple modes. One multi-modality radio bearer corresponds to one PDCP entity, and can be associated with one or more RLC entities, and the modes of these RLC entities can be the same or different. Therefore, such a multi-modality bearer can be a UM DRB, an AM DRB, or a multi-mode DRB as described above. Therefore, a multi-modality radio bearer associated with at least one AM RLC entity can be a multi-mode DRB or an AM DRB, and a multi-modality radio bearer associated with at least one UM RLC entity can be a multi-mode DRB or a UM DRB.

[0065] A PDCP entity can be divided into a transmitting PDCP entity and a receiving PDCP entity, which can be located at the UE and the base station side, or at the base station and the UE side, or at the UE and the UE side, respectively. When a PDCP receives a PDCP SDU from an upper layer, such as an RRC layer or a NAS layer, the following operations can be performed:

[0066] - start a discardTimerForLowImportance or a discardTimer associated with this PDCP SDU. When the discardTimerForLowImportance or the discardTimer expires, the UE can discard this PDCP SDU and also other one or more PDCP SDUs associated with it.

[0067] - associate with this PDCP SDU the current value of the state variable TX_NEXT as the value of COUNT;

[0068] - update the value of TX_NEXT by incrementing its current value by 1 to obtain a new value of TX_NEXT

[0069] A PDCP PDU can be a PDCP DATA PDU containing data, and can also be a PDCP Control PDU containing control information.

[0070] Among the control PDUs can be included:

[0071] - a PDCP status report;

[0072] - an interspersed ROHC feedback;

[0073] - an EHC feedback;

[0074] - a UDC feedback.

[0075] In a multi-mode DRB or a multi-mode radio bearer, when a PDCP SDU from an upper layer arrives, a PDCP entity can determine a RLC entity associated with the PDCP SDU from a plurality of RLC entities associated with the PDCP entity, and then deliver a PDCP PDU corresponding to the PDCP SDU to the RLC entity for transmission. This determination can be achieved by configuration information or by an indication provided by an SDAP from the upper layer. In general, one PDCP SDU is associated with one RLC entity, which can be a UM RLC or an AM RLC. The association means that a PDCP PDU generated after integrity protection, ciphering, and possibly other processing of the PDCP SDU is delivered to the determined RLC entity for transmission. This operation can be referred to as a routing operation, which is responsible for the PDCP entity.

[0076] Embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0077] Embodiments

[0078] FIG. 2 is a flowchart illustrating a method performed by a user equipment (UE) according to an embodiment of the present application. As shown in FIG. 2, the method includes steps S101 and S102.

[0079] In step S101, a PDCP entity receives a request for re-establishment of a packet data convergence protocol (PDCP) from an upper layer. In step S102, in a case where the PDCP entity that receives the request is a transmitting PDCP entity, the UE determines whether a radio bearer (RB) to which the PDCP entity belongs is a multi-mode data radio bearer (DRB), or a multi-mode radio bearer associated with at least one unacknowledged mode radio link control (UM RLC) entity, or a multi-mode radio bearer associated with at least one acknowledged mode radio link control (AM RLC) entity.

[0080] Hereinafter, operations performed by the PDCP entity will be described according to whether the PDCP entity is a transmitting PDCP entity or a receiving PDCP entity.

[0081] When the PDCP entity that receives the request for re-establishment of the PDCP entity from an upper layer (a layer above the PDCP layer, e.g., an RRC layer) is a transmitting PDCP entity, the transmitting PDCP entity can perform the following operations:

[0082] Preferably, the UE can first determine whether the RB to which the PDCP entity belongs is a multi-mode DRB, and perform the following operations in the case that it is determined that the RB to which the PDCP entity belongs is a multi-mode DRB:

[0083] Alternatively, the UE can first determine whether the RB to which the PDCP entity belongs is a multi-mode radio bearer associated with at least one UM RLC entity, and perform the following operations in the case that it is determined that the RB to which the PDCP entity belongs is a multi-mode radio bearer associated with at least one UM RLC entity:

[0084] Alternatively, the UE can first determine whether the RB to which the PDCP entity belongs is a multi-mode radio bearer associated with at least one AM RLC entity, and perform the following operations in the case that it is determined that the RB to which the PDCP entity belongs is a multi-mode radio bearer associated with at least one AM RLC entity:

[0085] For a multi-mode DRB (or a multi-mode radio bearer associated with at least one UM RLC entity), for each PDCP SDU to which a PDCP SN has been associated, if the UE determines that the PDCP PDU corresponding to the PDCP SDU has not been delivered to the lower layer, wherein the lower layer refers to the RLC layer, preferably to the RLC entity configured in UM mode in the lower layer, i.e. the PDCP SDU or the PDCP PDU corresponding thereto is associated with a UM RLC entity, the UE can consider that the PDCP SDU or the PDCP PDU corresponding thereto is received from the upper layer of the PDCP, and transmit the PDCP SDU or the PDCP PDU corresponding thereto;

[0086] For a multi-mode DRB (or a multi-mode radio bearer associated with at least one AM RLC entity), if the PDCP entity corresponding to the multi-mode DRB (or the multi-mode radio bearer) has been suspended or transmission has been suspended before or at the time of PDCP re-establishment, for each PDCP SDU that has been associated with a PDCP SN, if the UE determines that the PDCP PDU corresponding to the PDCP SDU has not been successfully delivered by the lower layer (i.e., the RLC layer, preferably, the RLC entity configured in AM mode), since successful delivery is always performed by the AM RLC entity, it is implied that the PDCP SDU or the PDCP PDU corresponding to the PDCP SDU is associated with an AM RLC entity, only the PDCP SDU or PDCP PDU associated with an AM RLC entity needs to be considered, and the PDCP SDU associated with a UM RLC entity does not need to be considered. In this case, the UE can consider that the PDCP SDU or the PDCP SDUs are received from the upper layer of the PDCP, and transmit the PDCP SDU or the PDCP SDUs.

[0087] For a multi-mode radio bearer associated with at least one UM RLC entity, it can also be associated with at least one AM RLC entity, and the UE can perform the operation for the multi-mode radio bearer associated with at least one AM RLC entity after or at the same time as performing the operation for the multi-mode radio bearer associated with at least one UM RLC entity.

[0088] For a multi-mode radio bearer associated with at least one AM RLC entity, it can also be associated with at least one UM RLC entity, and the UE can perform the operation for the multi-mode radio bearer associated with at least one UM RLC entity after or at the same time as performing the operation for the multi-mode radio bearer associated with at least one AM RLC entity.

[0089] The operation "the UE can consider that the PDCP SDU or the PDCP SDUs are received from the upper layer of the PDCP, and transmit the PDCP SDU or the PDCP SDUs" in the above operation can be one or more of the following operations performed by the UE for each PDCP SDU during transmission:

[0090] - start a timer discardTimerForLowImportance or a timer discardTimer for this PDCP SDU

[0091] - associate a COUNT value for this PDCP SDU

[0092] - perform header compression on this PDCP SDU

[0093] - perform uplink data compression on this PDCP SDU

[0094] - perform integrity protection and ciphering on this PDCP SDU using the value of TX_NEXT

[0095] - set the value of PDCP SN of the PDCP PDU corresponding to this PDCP SDU, which can be obtained based on TX_NEXT

[0096] - update the value of TX_NEXT by incrementing TX_NEXT by one

[0097] - submit the processed PDCP PDU to lower layers, i.e. to the corresponding RLC entity.

[0098] For a multi-mode DRB (or a multi-mode radio bearer associated with at least one AM RLC entity), if the PDCP entity corresponding to the multi-mode DRB (or the multi-mode radio bearer) has not been suspended or has not been suspended transmission at the time of PDCP re-establishment or before the PDCP re-establishment, for each PDCP SDU that has been associated with a PDCP SN, if the UE determines that the PDCP PDU corresponding to the PDCP SDU has not been successfully delivered by the lower layer, preferably, the lower layer is the RLC layer, and more preferably, the lower layer is the RLC entity configured in AM mode, then the UE performs one or more of the following operations for the PDCP SDU:

[0099] - performs header compression for the PDCP SDU

[0100] - performs uplink data compression for the PDCP SDU, preferably, if the PDCP SDU has been compressed before the PDCP re-establishment, the compressed PDCP SDU is submitted to the integrity protection and ciphering function module for processing;

[0101] - submits the PDCP SDU to the integrity protection and ciphering function module for processing

[0102] - submits the processed PDCP PDU to the lower layer, i.e., to the corresponding RLC entity.

[0103] When the PDCP entity receiving the request for PDCP data recovery from upper layers (above PDCP layer, e.g. RRC layer) for a multi-mode DRB (or for a multi-mode radio bearer associated with at least one AM RLC entity) is the transmitting PDCP entity, the transmitting PDCP entity can also perform the following operations:

[0104] Preferably, the UE can first determine whether the RB to which the PDCP entity belongs is a multi-mode DRB, and perform the following operations if it is determined that the RB to which the PDCP entity belongs is a multi-mode DRB:

[0105] Alternatively, the UE can first determine whether the RB to which the PDCP entity belongs is a multi-mode radio bearer associated with at least one AM RLC entity, and perform the following operations if it is determined that the RB to which the PDCP entity belongs is a multi-mode radio bearer associated with at least one AM RLC entity:

[0106] perform retransmission of PDCP PDUs that were previously submitted to the AM RLC entity, where "previously" preferably means before the request for PDCP data recovery is received, and where the RLC entity to which the PDCP PDUs were submitted is an AM RLC entity that has been re-established or released, and where the PDCP PDUs are PDCP PDUs for which the successful delivery has not been confirmed by lower layers. The retransmission of the PDCP PDUs can be performed in a certain order. The order can be determined based on the COUNT value associated with the PDCP PDUs, e.g. in ascending order of COUNT value.

[0107] Additionally, upon receiving the request for PDCP data recovery for a multi-mode DRB, the retransmission of PDCP PDUs as described above is not required for PDCP PDUs that were submitted to a UM RLC entity in the multi-mode DRB or in the multi-mode radio bearer.

[0108] When the PDCP entity receiving the request for PDCP entity re-establishment from upper layers (above PDCP layer, e.g. RRC layer) is the receiving PDCP entity, the receiving PDCP entity can also perform the following operations:

[0109] - Set RX_NEXT and RX_DELIV to initial values for multi-mode DRB (or for multi-mode radio bearer associated with at least one AM RLC entity)

[0110] - Reset the ROHC protocol for downlink for multi-mode DRB (or for multi-mode radio bearer associated with at least one AM RLC entity)

[0111] - Perform header decompression using ROHC for all stored PDCP SDUs for multi-mode DRB (or for multi-mode radio bearer associated with at least one AM RLC entity).

[0112] A PDCP entity can be configured to perform uplink data compression. For one DRB, a UE can perform uplink data compression on all PDCP SDUs received from upper layers. However, for multi-mode DRB (or for multi-mode radio bearer associated with at least one AM RLC entity), a UE can not need to perform uplink data compression on all PDCP SDUs received from upper layers, but only on PDCP SDUs destined to a specified RLC entity. For example, in the PDCP configuration information received by the UE, there can be an indication of the identity of the RLC entity, e.g. logical channel number, for which uplink data compression is needed. If there are more than one associated RLC entities for which uplink data compression is needed and different compression dictionaries are used, the transmitting PDCP entity of the UE can differentiate the UDC feedback control PDUs by the receiving PDCP entity in the following ways.

[0113] Way 1: For a transmitting PDCP entity associated with multi-mode DRB (or multi-mode radio bearer associated with at least one AM RLC entity),

[0114] In case the UE determines that a PDCP PDU is a PDCP DATA PDU, the PDCP DATA PDU is submitted to the corresponding or associated RLC entity;

[0115] In case the UE determines that a PDCP PDU is not a PDCP DATA PDU, i.e. in case the UE determines that a PDCP PDU is a PDCP Control PDU, ​​​​​​​​​​​​​​

[0116] If the PDCP Control PDU is a PDCP Control PDU for UDC feedback,

[0117] It can be submitted to a corresponding or associated RLC entity, which can be the aforementioned RLC entity indicated to require uplink data compression processing;

[0118] If the PDCP Control PDU is not a PDCP Control PDU for UDC feedback, for example, the PDCP Control PDU is a PDCP Control PDU for interspersed ROHC feedback, or the PDCP Control PDU is a PDCP status report, it can be submitted to a default RLC entity. Such a default RLC entity can be indicated in the configuration information, which can be set to a logical channel number whose value is a certain logical channel number, and the RLC entity identified by the logical channel number is the default RLC entity. Such a default RLC entity can also be implicitly indicated, for example, always taking the RLC entity managed by the logical channel number with the smallest or largest value as the default RLC entity, or for example, comparing the values of the channel priorities corresponding to all RLC entities associated with a PDCP, and always taking the RLC entity corresponding to the channel priority with the smallest or largest value as the default RLC entity.

[0119] Another embodiment of the above scheme can be

[0120] For a transmitting PDCP entity associated with a multi-mode DRB (or a multi-mode radio bearer associated with at least one AM RLC entity),

[0121] In the case where the UE determines that a PDCP PDU is a PDCP DATA PDU, the PDCP DATA PDU is submitted to a corresponding or associated RLC entity;

[0122] In the case where the UE determines that a PDCP PDU is not a PDCP DATA PDU, i.e., in the case where the UE determines that a PDCP PDU is a PDCP Control PDU,

[0123] If the PDCP Control PDU is a PDCP status report, it can be delivered to a default RLC entity. Such a default RLC entity can be indicated in the configuration information, which can be setting the value of the default RLC entity to a certain logical channel number, and the RLC entity identified by the logical channel number is the default RLC entity.

[0124] If the PDCP Control PDU is not a PDCP status report, for example, the PDCP Control PDU can be a PDCP Control PDU for UDC feedback, it can be delivered to the corresponding or associated RLC entity, which can be the aforementioned RLC entity indicated to be required to perform uplink data compression processing;

[0125] Method two:

[0126] The PDCP Control PDU generated by the UE can contain the identification information of the RLC entity, such as the logical channel number, or can indicate the identification information of the RLC entity, such as for a PDCP associated with two RLC entities, using sequence number 1 for the first RLC entity associated with the PDCP entity, and using sequence number 2 for the second RLC entity associated with the PDCP entity. The order of the RLC entities can be arranged in ascending order from small to large according to the size of the logical signal, and the RLC entity with a smaller logical channel number is the first RLC entity, and the RLC entity with a larger logical channel number is the second RLC entity. By including the identification information in the PDCP Control PDU, the receiving PDCP entity can distinguish which control management is used for which RLC entity. Taking the UDC feedback PDCP control PDU as an example, a PDCP control PDU can be designed to contain feedback information and identification information of the RLC entity.

[0127] In the case where the UE determines that a PDCP PDU is a PDCP Control PDU,

[0128] If the PDCP Control PDU contains the identification information of the RLC entity,

[0129] Then it can be delivered to the corresponding or associated RLC entity, i.e. the RLC entity indicated by the identification information or the corresponding RLC entity;

[0130] If the PDCP Control PDU does not contain the identification information of the RLC entity,

[0131] Then it can be submitted to a default RLC entity.

[0132] It can also be

[0133] In the case that the UE determines that a PDCP PDU is a PDCP Control PDU,

[0134] If the PDCP Control PDU contains the identification information of the RLC entity, it can be submitted to a default RLC entity.

[0135] In addition, the meanings of the parameters involved in the embodiments of the present disclosure are briefly described below, and the specific meanings can be seen from the latest technical specifications of 3GPP. t-Reordering is used to detect the loss of PDCP data PDU, the COUNT value is composed of a HFN and the PDCP SN (The COUNT value is composed of a HFN and the PDCP SN). TX_NEXT is a state variable used to indicate the COUNT value of the next transmitted PDCP SDU, and the initial value of TX_NEXT is zero. RX_NEXT is a state variable used to indicate the COUNT value of the next expected received PDCP SDU, RX_DELIV is a state variable used to indicate the COUNT value of the first un-delivered upper layer but still waiting to receive PDCP SDU, and HFN is the Hyper Frame Number. The HFN of the initial value (COUNT) of RX_NEXT and RX_DELIV is determined by HFN_Initial, and the PDCP SN is determined by the sequence number x of the first received PDCP PDU or SDU, for example, the PDCP SN is (x-0.5×2[pdcp-SN-SizeDL-1]) modulo (2[pdcp-SN-SizeDL]). pdcp-SN-SizeDL is the PDCP sequence number size for downlink.

[0136] FIG. 3 is a brief block diagram of a user equipment (UE) to which the present disclosure relates. As shown in FIG. 3, the UE 300 includes a processor 301 and a memory 302. The processor 301 can include, for example, a microprocessor, a microcontroller, an embedded processor, or the like. The memory 302 can 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 storage media. The memory 302 stores program instructions thereon. The program instructions, when executed by the processor 301, can perform the above-described method executed by the UE in detail.

[0137] In addition, the computer-executable instructions or programs that are executed on the device according to the present disclosure can be programs that control a central processing unit (CPU) to enable a computer to implement the functions of the embodiments of the present disclosure. The programs or information processed by the programs can be temporarily stored in 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 storage media.

[0138] The computer-executable instructions or programs for implementing the functions of the embodiments of the present disclosure can be recorded on a computer-readable storage medium. The corresponding functions can be implemented by causing a computer system to read the programs recorded on the recording medium and execute the programs. The so-called "computer system" here can be a computer system embedded in the device and can include an operating system or hardware (such as a peripheral device). The "computer-readable storage medium" can be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a short-time dynamic storage program recording medium, or any other computer-readable recording medium.

[0139] The various features or functional modules of the device used in the above-described embodiments can be implemented or executed by a circuit (for example, a single-chip or multi-chip integrated circuit). The circuit designed to perform the functions described in the present specification can include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, or any combination thereof. The general-purpose processor can be a microprocessor, or any existing processor, controller, microcontroller, or state machine. The above-mentioned circuit can be a digital circuit or an analog circuit. In the case of a new integrated circuit technology that replaces the existing integrated circuit technology due to the advancement of semiconductor technology, one or more embodiments of the present disclosure can also be implemented using these new integrated circuit technologies.

[0140] Furthermore, 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 devices installed indoors or outdoors can be used as terminal devices or communication devices, such as AV devices, kitchen devices, cleaning devices, air conditioners, office devices, vending machines, and other home appliances.

[0141] As described above, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. However, the specific configuration is not limited to the above-described embodiments, and the present disclosure includes any design modification without departing from the gist of the present disclosure. In addition, various modifications can be made to the present disclosure within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments are also included in the technical scope of the present disclosure. Furthermore, components described in the above-described embodiments having the same effects can be substituted for each other.

Claims

1. A method performed by a user equipment (UE), comprising: receiving, by a PDCP entity, a request from an upper layer to re-establish a packet data convergence protocol (PDCP) ; and in case the PDCP entity receiving the request is a transmitting PDCP entity, determining, by the UE, whether a radio bearer (RB) to which the PDCP entity belongs is a multi-mode data radio bearer (DRB), or is a multi-mode radio bearer associated with at least one unacknowledged mode radio link control (UM RLC) entity, or is a multi-mode radio bearer associated with at least one acknowledged mode radio link control (AM RLC) entity, the multi-mode DRB being a DRB associated with at least one UM RLC entity and at least one AM RLC entity. 2.The method performed by the UE according to claim 1, wherein in case the UE determines that the RB to which the PDCP entity belongs is a multi-mode DRB, or is a multi-mode radio bearer associated with at least one UM RLC entity, for each PDCP service data unit (PDCP SDU) that has been associated with a PDCP sequence number, the UE considers the PDCP SDU to be received from the upper layer of the PDCP and transmits the PDCP SDU if the UE determines that a PDCP protocol data unit (PDCP PDU) corresponding to the PDCP SDU has not been delivered to a UM RLC entity of a lower layer. 3.The method performed by the UE according to claim 1, wherein in case the UE determines that the RB to which the PDCP entity belongs is a multi-mode DRB, or is a multi-mode radio bearer associated with at least one AM RLC entity, for each PDCP service data unit (PDCP SDU) that has been associated with a PDCP sequence number, the UE considers the PDCP SDU to be received from the upper layer of the PDCP and transmits the PDCP SDU if the UE determines that a PDCP protocol data unit (PDCP PDU) corresponding to the PDCP SDU has not been successfully delivered by an AM RLC entity of a lower layer, in case a PDCP entity corresponding to the multi-mode DRB or the multi-mode radio bearer has been suspended or transmission has been paused at or before the time of PDCP re-establishment. 4.The method performed by the UE according to claim 2 or 3, wherein the UE performs one or more of the following operations for each PDCP SDU during transmission of the PDCP SDU: starting a timer for the PDCP SDU; associating a COUNT value for the PDCP SDU; performing header compression for the PDCP SDU; performing uplink data compression for the PDCP SDU; performing integrity protection and ciphering for the PDCP SDU using a value of a state variable TX_NEXT. - setting a value of a PDCP sequence number of a PDCP PDU corresponding to the PDCP SDU, which value can be obtained based on a state variable TX_NEXT; - updating the value of the state variable TX_NEXT by increasing it by 1; - submitting the processed PDCP PDU to a corresponding RLC entity.

5. The method performed by the user equipment (UE) of claim 1, wherein, in case the user equipment (UE) determines that the RB to which the PDCP entity belongs is a multi-mode DRB or is a multi-mode radio bearer associated with at least one AM RLC entity, if the PDCP entity corresponding to the multi-mode DRB or the multi-mode radio bearer has not been suspended or has not been suspended from transmission at the time of PDCP re-establishment or before the PDCP re-establishment, then for each PDCP service data unit (PDCP SDU) that has been associated with a PDCP sequence number, the user equipment (UE) performs transmission or retransmission of the PDCP SDU if the user equipment (UE) determines that a PDCP protocol data unit (PDCP PDU) corresponding to the PDCP SDU has not been successfully delivered by the underlying AM RLC entity.

6. The method performed by the user equipment (UE) of claim 5, wherein, in the transmission, the user equipment (UE) performs one or more of the following: - header compression of the PDCP SDU; - uplink data compression of the PDCP SDU; - submission of the PDCP SDU to an integrity protection and ciphering function module for processing; - submission of the processed PDCP PDU to a corresponding RLC entity.

7. The method performed by the user equipment (UE) of claim 1, wherein, the method performed by the user equipment (UE) further comprises: receiving a request from an upper layer to resume PDCP data; and in case the user equipment (UE) determines that the RB to which the PDCP entity belongs is a multi-mode DRB or is a multi-mode radio bearer associated with at least one AM RLC entity, the transmitting PDCP entity retransmits a PDCP service data unit (PDCP PDU) that has been submitted to an AM RLC entity that has been re-established or released before the request is received and that has not been successfully delivered by the underlying layer.

8. A user equipment (UE) comprising: a processor; and a memory storing instructions that, when executed by the processor, perform the method performed by the user equipment (UE) of any one of claims 1 to 7. ​ ​ ​ ​

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