Method and equipment for PDCP SDU (Packet Data Convergence Protocol Service Data Unit) receiving processing operation

Abstract

The embodiment of the invention relates to a method and equipment for packet data convergence protocol (PDCP) service data unit (SDU) receiving handling operation. In accordance with an embodiment of the present application, a user equipment (UE) includes a processor and a transceiver coupled to the processor; and the processor is configured to: receive, via the transceiver from a network, a configuration for enabling an update function of a delivery state variable associated with a first packet data convergence protocol (PDCP) service data unit (SDU), the first PDCP SDU being not delivered by a PDCP entity of a data radio bearer (DRB) to an upper layer of the UE; and enabling the update function of the delivery state variable for the PDCP entity of the DRB based on the configuration.

Description

Technical Field

[0001] Embodiments of the present application generally relate to wireless communication technology, and more particularly to methods and devices for packet data convergence protocol (PDCP) service data unit (SDU) reception and processing operations. Background Art

[0002] Extended Reality (XR), including Augmented Reality (AR) and Virtual Reality (VR), as well as Cloud Gaming (CG), presents new and promising categories of connected devices, applications and services. As a potential work area of ​​3GPP (3rd Generation Partnership Project) Rel-18, application and service awareness in the Radio Access Network (RAN) is one of the key features to improve the user experience of XR services. Currently, the details of PDCP SDU reception and handling operations have not been discussed. Summary of the invention

[0003] Some embodiments of the present application also provide a user equipment (UE). The UE includes a processor and a transceiver coupled to the processor; and the processor is configured to: receive a configuration for enabling an update function of a delivery state variable associated with a first packet data convergence protocol (PDCP) service data unit (SDU) from a network via the transceiver, the first PDCP SDU not being delivered to an upper layer of the UE by a PDCP entity of a data radio bearer (DRB); and enable the update function of the delivery state variable based on the configuration of the PDCP entity for the DRB.

[0004] In some embodiments, the processor of the UE is configured to: receive an update indication of the delivery state variable from the network via the transceiver; and update the delivery state variable to a target count value associated with a second PDCP SDU according to the update indication.

[0005] In some embodiments, the update indication is included in a header associated with the second PDCP SDU, and wherein the processor of the UE is configured to determine a count value of the second PDCP SDU as the target count value.

[0006] In some embodiments, the processor of the UE is configured to: after receiving the update indication, before updating the delivery state variable, deliver all one or more stored PDCP SDUs having a count value less than or equal to the target count value to the upper layer of the UE through the PDCP entity of the DRB.

[0007] In some embodiments, the first PDCP SDU belongs to a first frame, and wherein the update indication indicates at least one of: whether the second PDCP SDU belongs to a second frame; or whether the second PDCP SDU is a starting PDCP SDU of the second frame.

[0008] In some embodiments, in response to the second PDCP SDU not being the starting PDCP SDU of the second frame, the processor of the UE is configured to: determine whether a reordering timer of the PDCP entity of the DRB is running; and in response to determining that the reordering timer is running: restart the reordering timer; or stop the reordering timer.

[0009] In some embodiments, the update indication is included in a PDCP control protocol data unit (PDU) or a medium access control (MAC) sub-PDU.

[0010] In some embodiments, the processor of the UE is configured to, if the update indication is received, consider the reordering timer of the PDCP entity of the DRB to be expired if the reordering timer is running.

[0011] In some embodiments, the processor of the UE is configured to, in response to the PDCP control PDU including a PDCP sequence number (SN) or a PDCP count value, determine the target count value based on the PDCP SN or the PDCP count value.

[0012] In some embodiments, the processor of the UE is configured to: determine a count value of the PDCP control PDU based on the PDCP SN; and determine the count value of the PDCP control PDU as the target count value.

[0013] In some embodiments, the PDCP Control PDU comprises a PDCP header, the PDCP header comprises a PDU type field, and wherein the PDU type is associated with the update indication.

[0014] In some embodiments, the MAC sub-PDU includes a logical channel (LCH) identification (ID) field associated with the update indication.

[0015] In some embodiments, the first PDCP SDU belongs to a first frame, and wherein the processor of the UE is configured to: receive a third PDCP SDU from the network via the transceiver; and determine whether the third PDCP SDU is a first received PDCP SDU of a third frame.

[0016] In some embodiments, in response to determining that the third PDCP SDU is the first received PDCP SDU of the third frame, the processor of the UE is configured to deliver all one or more stored PDCP SDUs to the upper layer of the UE through the PDCP entity of the DRB.

[0017] In some embodiments, the processor of the UE is configured to: determine whether a reordering timer of the PDCP entity of the DRB is running in response to determining that the third PDCP SDU is the first received PDCP SDU of the third frame and is not the starting PDCP SDU of the third frame; and in response to determining that the reordering timer is running: restart the reordering timer; or stop the reordering timer.

[0018] In some embodiments, the processor of the UE is configured to update the delivery state variable to 1 plus a maximum count value of PDCP SDUs of the first frame stored by the UE.

[0019] In some embodiments, the processor of the UE is configured to deliver all one or more stored PDCP SDUs of the third frame having one or more consecutive count values ​​starting from the updated delivery state variable to the upper layer of the UE through the PDCP entity of the DRB.

[0020] In some embodiments, the processor of the UE is configured to: receive a fourth PDCP SDU from the network via the transceiver; determine whether the fourth PDCP SDU is the first received PDCP SDU of the fourth frame; and in response to determining that the fourth PDCP SDU is the first received PDCP SDU of the fourth frame, start a reordering frame timer associated with the fourth frame.

[0021] In some embodiments, in response to expiration of the reordering frame timer, the processor of the UE is configured to deliver all one or more stored PDCP SDUs of the fourth frame to the upper layer of the UE through the PDCP entity of the DRB.

[0022] In some embodiments, the processor of the UE is configured to update the delivery state variable to 1 plus a maximum count value of the PDCP SDUs of the fourth frame stored by the UE.

[0023] Some embodiments of the present application also provide a network node (e.g., a base station (BS)). The network node includes a processor and a transceiver coupled to the processor; and the processor is configured to receive from a user equipment (UE) via the transceiver a capability to support an update function of a delivery state variable associated with a packet data convergence protocol (PDCP) service data unit (SDU) received by the UE; and transmit to the UE via the transceiver a configuration of the update function of the delivery state variable of a PDCP entity for enabling a DRB of the UE.

[0024] In some embodiments, the processor of the network node is configured to transmit, via the transceiver, to a UE, an update indication of the delivery state variable of the PDCP entity of the DRB of the UE.

[0025] In some embodiments, the processor of the network node is configured to transmit a first PDCP SDU of a first frame, and wherein the update indication indicates at least one of: whether the second PDCP SDU belongs to a second frame; or whether the second PDCP SDU is a starting PDCP SDU of the second frame.

[0026] In some embodiments, the update indication indicates at least one of: the UE regards the count value of the second PDCP SDU as the target count value of the delivery state variable; or the UE regards the reordering timer as expired if the reordering timer of the PDCP entity of the DRB is running.

[0027] In some embodiments, the update indication is included in at least one of: a header associated with the second PDCP SDU; a PDCP control protocol data unit (PDU); or a medium access control (MAC) sub-PDU.

[0028] In some embodiments, the header associated with the second PDCP SDU implicitly instructs the UE to regard the count value of the second PDCP SDU as the target count value, or instructs the UE to regard the reordering timer as expired if the reordering timer of the PDCP entity of the DRB is running.

[0029] In some embodiments, the PDCP Control PDU comprises a PDCP header, the PDCP header comprises a PDU type field, and wherein the PDU type is associated with the update indication.

[0030] In some embodiments, the MAC sub-PDU includes a logical channel (LCH) identification (ID) field associated with the update indication.

[0031] In some embodiments, the processor of the network node is configured to transmit a configuration related to a reordering frame timer associated with a frame to the UE via the transceiver, wherein the reordering frame timer is used to control the update function of the delivery state variable of the PDCP entity of the DRB associated with the frame.

[0032] Some embodiments of the present application provide a method that can be performed by a UE. The method includes: receiving a configuration from a network for enabling an update function of a delivery state variable associated with a first packet data convergence protocol (PDCP) service data unit (SDU), the first PDCP SDU not being delivered to an upper layer of the UE by a PDCP entity of a data radio bearer (DRB); and enabling the update function of the delivery state variable for the PDCP entity of the DRB based on the configuration.

[0033] Some embodiments of the present application provide a method that can be performed by a network node (e.g., a BS). The method includes: receiving from the UE a capability to support an update function of a delivery state variable associated with a packet data convergence protocol (PDCP) service data unit (SDU) received by a user equipment (UE); and transmitting to the UE a configuration of the update function of the delivery state variable of a PDCP entity for enabling a DRB of the UE.

[0034] Some embodiments of the present application also provide a user equipment (UE). The UE includes a processor and a transceiver coupled to the processor; and the processor is configured to: receive a configuration for enabling a non-continuous packet data convergence protocol (PDCP) service data unit (SDU) delivery function of a PDCP entity of a data radio bearer (DRB) to an upper layer of the UE from a network via the transceiver; and enable the non-continuous PDCP SDU delivery function of the PDCP entity for the DRB based on the configuration.

[0035] Some embodiments of the present application also provide a network node (e.g., a base station (BS)). The network node includes a processor and a transceiver coupled to the processor; and the processor is configured to: receive from a user equipment (UE) via the transceiver a capability to support a non-continuous PDCP SDU delivery function associated with a packet data convergence protocol (PDCP) service data unit (SDU) received by the UE; and transmit to the UE via the transceiver a configuration of the non-continuous PDCP SDU delivery function for enabling a PDCP entity of a data radio bearer (DRB) of the UE.

[0036] Some embodiments of the present application provide a method that can be performed by a UE. The method includes: receiving a configuration for enabling a non-continuous packet data convergence protocol (PDCP) service data unit (SDU) delivery function of a PDCP entity of a data radio bearer (DRB) to an upper layer of the UE from a network; and enabling the non-continuous PDCP SDU delivery function for the PDCP entity of the DRB based on the configuration.

[0037] Some embodiments of the present application provide a method that can be performed by a network node (e.g., a BS). The method includes: receiving from a user equipment (UE) a capability to support a non-continuous PDCP SDU delivery function associated with a packet data convergence protocol (PDCP) service data unit (SDU) received by the UE; and transmitting to the UE a configuration of the non-continuous PDCP SDU delivery function for enabling a PDCP entity of a data radio bearer (DRB) of the UE.

[0038] Some embodiments of the present application also provide a device for wireless communication. The device includes: a non-transitory computer-readable medium having computer-executable instructions stored thereon; a receiving circuit system; a transmitting circuit system; and a processor coupled to the non-transitory computer-readable medium, the receiving circuit system, and the transmitting circuit system, wherein the computer-executable instructions cause the processor to implement any one of the above methods performed by a UE or a network node (e.g., a BS).

[0039] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to describe the manner in which the advantages and features of the present application can be obtained, the description of the present application is presented by reference to specific embodiments of the present application illustrated in the accompanying drawings. These drawings depict only example embodiments of the present application and therefore should not be considered as limiting the scope thereof.

[0041] Figure 1 A schematic diagram illustrating a wireless communication system according to some embodiments of the present application.

[0042] Figure 2 An exemplary schematic diagram illustrating a PDCP reordering management scheme according to some embodiments of the present application.

[0043] Figure 3 An exemplary diagram illustrating a PDCP SN gap between frames according to some embodiments of the present application.

[0044] Figure 4An exemplary diagram illustrating several PDCP SN gaps in a frame according to some embodiments of the present application.

[0045] Figure 5 and 6 An exemplary flow chart illustrating an update function regarding a delivery status variable according to some embodiments of the present application.

[0046] Figure 7 and 8 An exemplary schematic diagram illustrating updating a delivery status variable according to some embodiments of the present application is provided.

[0047] Figures 9 to 11B An exemplary PDCP control PDU and MAC CE including an update indication of a delivery state variable according to some embodiments of the present application are illustrated.

[0048] Fig.12 and 13 An exemplary schematic diagram illustrating updating a delivery status variable according to some embodiments of the present application is provided.

[0049] Fig.14 and 15 An exemplary schematic diagram illustrating a method for reordering frame timers according to some embodiments of the present application is shown.

[0050] Fig.16 and 17 An exemplary block diagram illustrating an apparatus for PDCP layer reception handling operations according to some embodiments of the present application. DETAILED DESCRIPTION

[0051] The detailed description of the accompanying drawings is intended as a description of the preferred embodiments of the present application and is not intended to represent the only form in which the present application can be practiced. It should be understood that the same or equivalent functions can be accomplished by different embodiments that are intended to be included in the spirit and scope of the present application.

[0052] Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under specific network architectures and new service scenarios (e.g., 3rd Generation Partnership Project (3GPP) LTE and Advanced LTE, 3GPP 5GNR, Advanced 5G, 6G, etc.). It is considered that with the development of network architectures and new service scenarios, all embodiments in the present application are also applicable to similar technical problems; and in addition, the terms stated in the present application may change, which should not affect the principles of the present application.

[0053] Figure 1 A schematic diagram illustrating a wireless communication system according to some embodiments of the present application.

[0054] like Figure 1, the wireless communication system 100 includes at least one base station (BS) 101 and at least one UE 102. Specifically, for the purpose of illustration, the wireless communication system 100 includes one BS 101 and two UEs 102 (eg, UE 102a and UE 102b). Figure 1 A specific number of BSs 101 and UEs 102 are depicted in FIG. 1 , but it is contemplated that any number of BSs 101 and UEs 102 may be included in wireless communication system 100 .

[0055] The wireless communication system 100 is compatible with any type of network capable of sending and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with wireless communication networks, cellular telephone networks, time division multiple access (TDMA)-based networks, code division multiple access (CDMA)-based networks, orthogonal frequency division multiple access (OFDMA)-based networks, LTE networks, 3GPP-based networks, 3GPP 5G networks, satellite communication networks, high altitude platform networks, and / or other communication networks.

[0056] BS 101 may also be referred to as an NG-RAN node, a RAN node, an access point, an access terminal, a base station, a macro cell, a Node-B, an enhanced Node B (eNB), a gNB, a home Node B, a relay node, or a device, or described using other terms used in the art. BS 101 is typically part of a radio access network that may include a controller communicatively coupled to BS 101.

[0057] According to some embodiments of the present application, UE 102 may include a computing device, such as a desktop computer, a laptop computer, a personal digital assistant (PDA), a tablet computer, a smart TV (e.g., a TV connected to the Internet), a set-top box, a game console, a security system (including a security camera), a vehicle-mounted computer, a network device (e.g., a router, a switch, and a modem), or the like. According to some other embodiments of the present application, UE 102 may include a portable wireless communication device, a smart phone, a cellular phone, a flip phone, a device with a subscriber identity module, a personal computer, a selective call receiver, or any other device capable of sending and receiving communication signals on a wireless network.

[0058] According to some other embodiments of the present application, UE 102 may include a wearable device, such as a smart watch, a fitness bracelet, an optical head-mounted display, or the like. In addition, UE 102 may be referred to as a subscriber unit, a mobile device, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, or a device, or described using other terms used in the art.

[0059] Figure 1In embodiments, both UE 102a and UE 102b may transmit information to and receive control information from BS 101 via, for example, an LTE or NR Uu interface.

[0060] Generally, for XR services, a group of IP packets will be used to carry the payload of a PDU set (e.g., video frames or video slices), and the size of the PDU set is variable, and the PDU set arrives periodically. At the application layer, the packets in this PDU set should be processed as a whole, i.e., the group of packets within the PDU set has an inherent dependency on each other.

[0061] Figure 2 Exemplary schematic diagram illustrating a PDCP reordering management scheme according to some embodiments of the present application. In Figure 2 an example, the PDCP reordering management scheme may involve four parameters, which include:

[0062] (1) RX_NEXT: This state variable indicates the count value of the next PDCP SDU expected to be received;

[0063] (2) RX_DELIV: This state variable indicates the count value of the first PDCP SDU that has not been delivered to the upper layer but is still waiting;

[0064] (3) RX_REORD: This state variable indicates the count value after the count value associated with the PDCP data PDU that triggered t-Reordering; and

[0065] (4) t-Reordering: This parameter is the PDCP reordering timer, and the duration of the timer is configured by RRC signaling.

[0066] Referring to Figure 2 , assume that PDCP SDUs with count values (or sequence numbers (SN)) #1 and #4 are received at the PDCP layer, and a PDCP SDU with a count value (or SN) #2 is not received at the PDCP layer. Then, RX_NEXT is #5, and RX_DELIV is #2. Since RX_DELIV < RX_NEXT, the UE may start the timer t-Reordering when it receives PDCP SDU #4 earlier than PDCP SDU #3, as shown in Figure 2 . During the running of t-Reordering, PDCP SDUs with count values (or sequence numbers (SN)) #4 and #8 are received, and PDCP SDUs with count values (or SN) #2, #5, #6, #7, #9, and #10 are not received at the PDCP layer. RX_NEXT is finally updated to #9, and RX_DELIV remains #2.

[0067] While the timer t-Reordering is running, the UE waits for packets with an associated count value of RX_DELIV and does not forward non-consecutive stored PDCP SDUs due to in-order delivery ( Figure 2 When the timer t-Reordering expires, the receiving PDCP entity may deliver to the upper layer all stored PDCP SDUs with associated count values ​​less than RX_REORD and all stored PDCP SDUs with consecutive associated count values ​​starting from RX_REORD. When the timer t-Reordering expires, the UE may:

[0068] (1) The RX_DELIV value from PDCP SDU #2 is updated to the count value of the first packet that has not been delivered to the upper layer but is still waiting (i.e., PDCP SDU #5 in this example).

[0069] (2) The RX_NEXT value from PDCP SDU #4 is updated to the count value of the next packet expected to be received (ie, PDCP SDU #9 in this example).

[0070] (3) Restart timer t-Reordering because the updated RX_DELIV value is less than the updated RX_NEXT value. Figure 2 As shown in FIG. 1 , the timer t-Reordering is started when the PDCP SDU #4 is received, and the timer t-Reordering is started after the timer t-Reordering expires.

[0071] For downlink (DL) data transmission of XR services, there may be PDCP SN gaps between frames or within frames of XR services, for example, Figure 3 , 4 , 7, 8 and 12 to 15. Each frame of the XR service may include different numbers of PDCP SDUs according to different embodiments. For example, Figure 3 Frame 1 in PDCP includes 9 PDCP SDUs in total, namely, PDCP SDU #1 to #9. Figure 3 Frame 2 in FIG. 1 includes a total of 10 PDCP SDUs, namely, PDCP SDUs #10 to #19. Figure 4 Frame 1 in includes 14 PDCP SDUs in total, namely, PDCP SDUs #1 to #14. Figure 4 Frame 2 in contains a total of 9 PDCP SDUs, namely, PDCP SDUs #15 to #23. Figure 3 , 4, 7, 8, and 12 to 15 depict a specific number of PDCP SDUs, but it is contemplated that any number of PDCP SDUs may be included in a frame of an XR service without departing from the spirit and scope of the present disclosure.

[0072] In addition, without departing from the spirit and scope of the present disclosure, Figure 3 , 4 , 7, 8, and 12 to 15 may be labeled as frame i and frame i+1 or the like, with frame i+1 following frame i. Figure 3 , 4 , 7, 8 and 12 to 15, the parameters (e.g., RX_NEXT, RX_DELIV, RX_REORD and / or t-Reordering) have the same Figure 2 The parameters in the embodiments have the same functions and roles.

[0073] Figure 3 An exemplary schematic diagram illustrating a PDCP SN gap between frames according to some embodiments of the present application. Figure 3 In the embodiment of FIG. 1 , for example, if some consecutive PDCP PDUs of frame 1 (e.g., PDCP SDUs with count values ​​(or SNs) #5 to #9) are not received by the UE, then it must bring a PDCP SN gap to the UE after receiving the PDCP SDU of frame 2. This will trigger the timer t-Reordering to run. For example, Figure 3 , timer t-Reordering is started when PDCP SDU #11 of frame 2 is received. Typically, the timer length is likely to be approximately less than or equal to the packet delay budget (PDB) length. Therefore, even though the UE has successfully received frame 2 within the PDB, delivery to the upper layers of the UE for frame 2 is delayed due to the running t-Reordering triggered by the data loss of frame 1.

[0074] Figure 4 An exemplary schematic diagram illustrating several PDCP SN gaps in a frame according to some embodiments of the present application. Figure 4 In the embodiment of FIG. 1 , if some PDCP PDUs of frame 1 (e.g., PDCP SDUs with count values ​​(or SNs) #5 to #7, #11, and #12) are not received by the UE, it brings two PDCP SN gaps in frame 1 to the UE. The timer t-Reordering may be triggered twice for the UE. For example, Figure 4, timer t-Reordering is first started when PDCP SDU #8 of frame 1 is received without receiving PDCP SDUs with count values ​​(or SN) #5 to #7 of frame 1, and timer t-Reordering is started after expiration of timer t-Reordering due to receiving PDCP SDU with count value (or SN) #13 of frame 1 without receiving PDCP SDUs with count values ​​(or SN) #11 and #12. However, this may bring additional delivery delay to upper layers of the UE not only for frame 1 but also for frame 2. Once timer t-Reordering expires, non-consecutive PDCP SDUs will be delivered to the upper layers regardless of whether the data is valid for the upper layers.

[0075] In view of the above, there is no friendly delivery solution for delay-sensitive XR services, and a mechanism for delivering data to the upper layer needs to be designed for XR services to avoid delays as much as possible. An embodiment of the present application proposes a mechanism for PDCP SDU reception and processing for DL ​​XR services, which can at least solve the above-mentioned problems (for example, how to avoid delays during the delivery of data to the upper layer for XR services as much as possible). In addition, in the case of receiving non-continuous PDCP SDUs, the data may be invalid for the application layer, and unnecessary decoding processing will consume additional power. The present application also proposes a mechanism for controlling the delivery operation of non-continuous PDCP SDUs.

[0076] More specifically, in some embodiments of the present application, the UE may update RX_DELIV to a target count value according to the received delivery update indication, and deliver all stored PDCP SDUs having count values ​​less than or equal to the target count value, and if the first received PDCP SDU of the new frame is not the starting PDCP SDU of the new frame, then the timer t-Reordering may be further restarted. In some embodiments of the present application, an indicator (e.g., 1-bit size) is included in a PDCP header associated with the PDCP SDU, and the target count value is updated to the RDVD_COUNT of the PDCP SDU.

[0077] Some embodiments of the present application design a new PDCP control PDU or MAC CE as a delivery update indication, with or without an explicit target PDCP SN or count value. Some embodiments of the present application design a delivery update indication as a new frame indicator first received by the UE, and the target count value is updated to "1 + the maximum count value of the current frame".

[0078] In some embodiments of the present application, the UE starts the timer t-Reordering-Frame when the PDCP SDU of the new frame is first received. For example, when the timer t-Reordering-Frame expires, the UE may deliver all stored PDCP SDUs having a maximum count value greater than RX_DELIV, and may further update RX_DELIV to "1+the maximum count value of the PDCP SDU of the new frame that has been received".

[0079] In an embodiment of the present application, the frame of the XR service may be replaced by a PDU set, a data burst, or an application data unit (ADU). A PDU set may include one or more PDUs carrying the payload of an information unit generated at the application layer, which have the same importance requirements at the application layer. In an embodiment of the present application, an IP packet may be replaced by a PDCP SDU or a PDCP PDU.

[0080] More details will be described below in conjunction with the accompanying drawings. It should be clear to those skilled in the art that the terms "first", "second", and "third" are only used for clear description and should not be regarded as any substantial limitation, such as sequence limitation.

[0081] Figure 5 An exemplary flow chart illustrating an update function regarding a delivery status variable according to some embodiments of the present application. Figure 5 The exemplary method 500 in may be performed by a UE (e.g., Figure 1 Although described with respect to a UE, it should be understood that other devices may be configured to perform similar Figure 5 method of method of method.

[0082] exist Figure 5 In the exemplary method 500 of , in operation 501, the UE receives a configuration for enabling an update function of a delivery state variable associated with a PDCP SDU that is not delivered to an upper layer of the UE by a PDCP entity of a DRB. In operation 502, the UE enables an update function of a delivery state variable (e.g., RX_DELIV) based on the configuration of the PDCP entity of the DRB.

[0083] In some embodiments, the UE receives an update indication of the delivery state variable from the network, and updates the delivery state variable (eg, RX_DELIV) to a target count value associated with another PDCP SDU according to the update indication.

[0084] In some embodiments, the update indication is included in a header associated with another PDCP SDU, and the UE determines the count value of the other PDCP SDU as the target count value. In some further embodiments, the update indication is included in a header associated with another PDCP SDU, and the UE considers the reordering timer (e.g., timer t-Reordering) of the PDCP entity of the DRB to be expired if the reordering timer is running.

[0085] In some embodiments, after receiving the update indication, before updating the delivery state variable (e.g., RX_DELIV), the UE delivers all one or more stored PDCP SDUs having a count value less than or equal to the target count value to the upper layer of the UE through the PDCP entity of the DRB. Figure 7 and 8 An embodiment of the present invention is described below, where the update indication of the delivery state variable (e.g., RX_DELIV) may be a delivery update indication (DUI) transmitted in a header associated with the PDCP SDU.

[0086] In some embodiments, the PDCP SDU not delivered by the PDCP entity of the DRB to the upper layer of the UE belongs to a frame (e.g., frame 1), and the update indication indicates at least one of the following: whether another PDCP SDU belongs to another frame (e.g., frame 2). Figure 8 2); or whether the other PDCP SDU is the starting PDCP SDU of another frame (e.g., Figure 8 In an embodiment, in the case where the other PDCP SDU is not the start PDCP SDU of another frame, the UE determines whether the reordering timer of the PDCP entity of the DRB is running. In response to determining that the reordering timer is running, the UE may restart the reordering timer or stop the reordering timer. Figure 8 The embodiments are described as follows.

[0087] In some embodiments, the update indication is included in a PDCP control protocol data unit (PDU) or a medium access control (MAC) sub-PDU. In an embodiment, the PDCP control PDU includes a PDCP header, the PDCP header includes a PDU type field, and the PDU type is associated with the update indication. Fig. 9 , 11A In an embodiment of 11B and 11B, the MAC sub-PDU includes a logical channel (LCH) identification (ID) field associated with the update indication. Fig.10 The embodiments are described as follows.

[0088] In some embodiments, if the update indication is included in the PDCP control PDU or the MAC sub-PDU, the UE considers the reordering timer (e.g., timer t-Reordering) of the PDCP entity of the DRB to be expired if the reordering timer is running. In some embodiments, in the case where the PDCP control PDU including the update indication includes a PDCP SN or a PDCP count value, the UE determines a target count value based on a PDCP sequence number (SN) or a PDCP count value. The UE may then determine a count value of the PDCP control PDU based on the PDCP SN, and determine the count value of the PDCP control PDU as the target count value. A specific example is in Fig.12 The embodiments are described below.

[0089] In some embodiments, a PDCP SDU that is not delivered to the upper layer of the UE by the PDCP entity of the DRB belongs to a frame (denoted as "first frame" for simplicity) (e.g., frame 1), and the UE receives another PDCP SDU from the network and determines whether this PDCP SDU is the first received PDCP SDU of the other frame. In an embodiment, in response to determining that this PDCP SDU is the first received PDCP SDU of the other frame (e.g., frame 2), the UE delivers all one or more stored PDCP SDUs of the first frame to the upper layer of the UE through the PDCP entity of the DRB. A specific example is in Fig.13 An embodiment of the invention is described as follows, in which PDCP SDU#19 of frame 2 is first received by the UE before other PDCP SDUs of frame 2.

[0090] In another embodiment, in response to determining that the PDCP SDU is a first received PDCP SDU (e.g., such as Frame 2) of another frame (e.g., Frame 2), Figure 8 2) but not the starting PDCP SDU of another frame (e.g., Figure 8 In the example of PDCP SDU #15 of frame 2 shown in FIG. 1 , the UE determines whether a reordering timer (e.g., timer t-Reordering) of the PDCP entity of the DRB is running. In response to determining that the reordering timer is running, the UE may restart the reordering timer or stop the reordering timer. Figure 8 The embodiments are described below.

[0091] In some embodiments, the UE updates the delivery state variable (e.g., RX_DELIV) to "1 plus the maximum count value of the PDCP SDU of the first frame (e.g., frame 1) stored by the UE". In an embodiment, the UE delivers all one or more stored PDCP SDUs of the above-mentioned another frame (e.g., frame 2) having one or more consecutive count values ​​starting from the updated delivery state variable to the upper layer of the UE through the PDCP entity of the DRB.

[0092] In some embodiments, after the UE receives an additional PDCP SDU from the network, the UE determines whether this PDCP SDU is the first received PDCP SDU of the frame (e.g., frame 1). In response to determining that the PDCP SDU is the first received PDCP SDU of the frame, the UE starts a reordering frame timer associated with the frame (e.g., timer t-Reordering-Frame). In an embodiment, in response to expiration of the reordering frame timer, the UE delivers all one or more stored PDCP SDUs of the frame to the UE's upper layers via the PDCP entity of the DRB. In an embodiment, the UE updates the delivery state variable (e.g., RX_DELIV) to "1 plus the maximum count value of the PDCP SDUs of the frame stored by the UE". The specific example is in Fig.14 and 15 The embodiments are described below.

[0093] Figure 6 An exemplary flow chart illustrating an update function regarding a delivery status variable according to some embodiments of the present application. Figure 6 The exemplary method 600 in FIG. 600 may be performed by a network node (eg, a BS). Although described with respect to a BS, it should be understood that other devices may be configured to perform similar Figure 6 method of method of method.

[0094] exist Figure 6 In the exemplary method 600 of , in operation 601, a network node (e.g., Figure 1 BS101 shown in FIG. 1) from UE (such as Figure 1 102) receives a capability to support an update function of a delivery state variable (e.g., RX_DELIV) associated with a PDCP SDU received by the UE. In operation 602, the network node transmits to the UE a "configuration of an update function of a delivery state variable of a PDCP entity for enabling DRBs of the UE".

[0095] In some embodiments, the network node transmits to the UE an "update indication of the delivery state variable of the PDCP entity of the DRB of the UE".

[0096] In some embodiments, the network node transmits a PDCP SDU of a frame (e.g., frame 1), and the update indication indicates at least one of the following: whether the other PDCP SDU belongs to another frame (e.g., frame 2). Figure 8 2); or whether the other PDCP SDU is the starting PDCP SDU of another frame (e.g., Figure 8 PDCP SDU#15 of frame 2 shown in FIG.

[0097] In some embodiments, the update indication indicates at least one of the following: the UE regards the count value of another PDCP SDU as the target count value of the delivery state variable; or the UE regards the reordering timer (e.g., timer t-Reordering) of the PDCP entity of the DRB as expired when the reordering timer is running.

[0098] In some embodiments, the update indication is included in at least one of: a header associated with the another PDCP SDU; a PDCP control PDU; or a MAC sub-PDU.

[0099] In an embodiment, a header associated with another PDCP SDU implicitly indicates that the UE regards the count value of the other PDCP SDU as the target count value. In an embodiment, a header associated with another PDCP SDU indicates that the UE regards the reordering timer (e.g., timer t-Reordering) of the PDCP entity of the DRB as expired if the reordering timer is running. In an embodiment, the PDCP control PDU includes a PDCP header, and the PDCP header includes a PDU type field associated with the update indication. Specific examples are in Fig. 9 , 11A and 11B are described below.

[0100] In an embodiment, the MAC sub-PDU includes a logical channel (LCH) identification (ID) field associated with the update indication. Fig.10 The embodiments are described as follows.

[0101] In some embodiments, the network node transmits to the UE a configuration related to a reordering frame timer (e.g., timer t-Reordering-Frame) associated with a frame (e.g., frame 1). The reordering frame timer may be used to control an update function of a delivery state variable of a PDCP entity for a DRB associated with the frame. A specific example is Fig.14 and 15 The embodiments are described as follows.

[0102] Those skilled in the art will appreciate that the sequence of operations in exemplary process 500 or 600 may be changed, and some operations in exemplary process 500 or 600 may be eliminated or modified without departing from the spirit and scope of the present disclosure. Figure 5 and 6 In addition, in Figure 5 and 6 The details described in the embodiments may be applied to Figures 1 to 4 And all embodiments from 7 to 17.

[0103] Specifically, in some embodiments of the present application, when the BS detects that the IP packet of a frame (e.g., frame 1) has not been successfully transmitted to the UE within the delay budget and determines that the PDCP SN gap has occurred or will occur when the next frame (e.g., frame 2) is received, the BS sends a delivery update indication (DUI) to the UE. The delivery update indication (DUI) may also be referred to as a "delivery update indicator (DUI)" or "delivery function update indication" or "delivery function update indicator" or the like. For example, the UE may update RX_DELIV to the count value (or the sum of the count value and the offset value) (e.g., RCVD_COUNT) of the PDCP SDU associated with the DUI upon receiving the DUI. In an embodiment of the present application, the frame of the XR service may be replaced by a PDU set, a data burst, or an ADU; and the IP packet may be replaced by a PDCP SDU or a PDCP PDU. The offset value may be a positive number or a negative number. The offset value may be configured by a network node or may be a default value (e.g., 1).

[0104] Figure 7 and 8 An exemplary schematic diagram illustrating an example of updating a delivery status variable according to some embodiments of the present application is provided. Figure 7 and 8 In an embodiment, upon receiving a DUI from a network node, the UE updates RX_DELIV to a count value of PDCP SDUs associated with the DUI (e.g., RCVD_COUNT), or the UE updates RX_DELIV to a sum of a count value of PDCP SDUs and an offset value (e.g., RCVD_COUNT). The offset value may be a positive number or a negative number. The offset value may be configured by the network node or may be a default value (e.g., 1).

[0105] Specifically, Figure 7 The embodiment corresponds to Figure 3 The scenario shown in Figure 1, where there are PDCP SN gaps between frames. Figure 7 The embodiment comprises the following steps 1 to 4.

[0106] In step 1, the BS may transmit, for example, via an RRC message, an update function for enabling a delivery state variable (e.g., RX_DELIV) and / or a configuration of a discontinuous data delivery function. For example, the BS configures a DELIV information element (IE) for a specific DRB. For example, the DELIV IE may include at least one of the following two IEs:

[0107] (1) DELIV Update IE. For example, a value of TRUE in this IE in an RRC message indicates that the update function of RX_DELIV is enabled for the DRB. For example, a value of FALSE in this IE or the absence of this IE in an RRC message indicates that the update function of RX_DELIV is disabled for the DRB.

[0108] (2) DELIV integrity IE. For example, a value of TRUE for this IE in an RRC message indicates that: if a delivery update indication (DUI) is received, then all stored consecutive data belonging to the frame or all stored consecutive data associated with a count value less than or equal to a target count value that has been successfully received are delivered to the upper layer; or all stored data containing consecutive data associated with a count value less than or equal to RX_REORD is delivered to the upper layer. That is, if there is data loss of a frame, then in the case where a delivery update indication (DUI) is received, any of the stored non-continuous data belonging to the frame or any of the stored non-continuous data associated with a count value less than or equal to the target count value is not delivered to the upper layer; or any of the stored non-continuous data associated with a count value less than or equal to RX_REORD is not delivered to the upper layer. All non-continuous PDCP SDUs less than or equal to the target count (e.g., RX_REORD) are discarded. For example, the value of this IE is FALSE or this IE indication does not exist in the RRC message. When non-continuous data is received, if the timer t-reordering expires, then all stored non-continuous data associated with a count value less than or equal to RX_REORD or non-continuous data belonging to the frame are delivered to the upper layer; or if DUI is received, then all stored non-continuous data associated with a count value less than or equal to the target count value or non-continuous data belonging to the frame are delivered to the upper layer.

[0109] In step 2, the BS detects the number of packets belonging to a frame (e.g., Figure 7 DL data transmission of the PDCP SDU of frame 1) shown in FIG. 1 fails. If the BS determines to update RX_DELIV to the PDCP count value of the UE, the BS determines to send a delivery update indication (DUI) associated with the target count value to the UE.

[0110] In an embodiment, the DUI may be presented in a frame that is similar to the next frame (e.g., Figure 7 The DUI may be represented by one bit or two bits in the PDCP header associated with the start PDCP SDU of the frame 2 shown in FIG. 1 . For example, the DUI is represented by one bit or two bits. The value of DUI “0” is reserved. The value of DUI “1” indicates the count value (or the sum of the count value and the offset value) associated with the PDCP SDU as the target count value to be used to update the UE's RX_DELIV. Typically, the count value (or the sum of the count value and the offset value) associated with the PDCP SDU is implicitly indicated as the target count to be used to update the RX_DELIV.

[0111] In another embodiment, the DUI may be an indicator indicating whether the PDCP SDU carrying the DUI is the starting PDCP SDU of a new frame. For example, one bit value of the DUI is used to indicate whether the PDCP SDU belongs to a new frame, and another bit value of the DUI is used to indicate whether the PDCP SDU is the starting PDCP SDU of a new frame.

[0112] In step 3, the BS sets the value in DUI to "1" in the PDCP header associated with the PDCP SDU, which is associated with the target count value, and sends the PDCP SDU to the UE (e.g., Figure 7 PDCP SDU #10 of frame 2) and the associated PDCP header are shown in FIG.

[0113] In step 4, when the UE receives a PDCP SDU and an associated PDCP header, the UE determines the RCVD_COUNT of the PDCP SDU; if the value of DUI in the associated PDCP header is equal to "1", and if the offset is 0 and the DELIV integrity IE is disabled (i.e., the value of the DELIV integrity IE in the RRC message is FALSE), then the UE delivers all stored non-contiguous PDCP SDUs with associated count values ​​less than or equal to RCVD_COUNT, and updates RX_DELIV to the count value of the PDCP SDU (i.e., if Figure 7 2 ). If the offset is 0 and DELIV integrity is enabled (i.e., the value of the DELIV integrity IE in the RRC message is TRUE), the UE does not deliver any of the stored non-contiguous PDCP SDUs with an associated count value less than or equal to RCVD_COUNT. That is, all non-contiguous PDCP SDUs with an associated count value less than or equal to RCVD_COUNT are discarded.

[0114] In an embodiment, if the DELIV Update IE is enabled and the DELIV Integrity IE is disabled for a UE's DRB (i.e., the value of the DELIV Update IE is TRUE and the value of the DELIV Integrity IE is FALSE in the RRC message), the UE may perform the following operations:

[0115]

[0116] In view of the above, Figure 7 In an embodiment, timer t-Reordering is not triggered by data loss of the previous frame 1 to be running (for example, timer t-Reordering is not started when PDCP SDU #10 of frame 2 is received), and delivery delay of frame 2 caused by frame 1 is avoided.

[0117] Figure 8 The embodiment corresponds to Figure 4 The scenario shown in FIG. 1 is that there are several PDCP SN gaps in the frame. Figure 8 An embodiment comprises steps 1 to 4. Figure 8 Steps 1 to 3 of the embodiment are Figure 7 Steps 1 to 3 of the embodiment are the same as those of Figure 8 In step 4 of the embodiment of the present invention, when the timer t-Reordering is running (for example, the timer t-Reordering is started when the PDCP SDU #8 of the frame 1 is received), the UE may receive the PDCP SDU belonging to the new frame (that is, PDCP SDU #19 of the frame 2) from the BS at the first time (that is, PDCP SDU #19 is the PDCP SDU received first before the starting PDCP SDU #15 of the frame 2). For example, the timer t-Reordering is started when the PDCP SDU #8 of the frame 1 is received, or is started due to the reception of PDCP SDU #13 of the frame 1 but the non-reception of PDCP SDU #11 and #12 of the frame 1 after the previous timer t-Reordering expires. If the timer t-Reordering is running and the DUI value associated with the first received PDCP SDU is "0", the UE may restart the timer t-Reordering to ensure that the timer t-Reordering is started at an appropriate timing for the new frame.

[0118] In an embodiment, the UE may perform the following operations:

[0119]

[0120] In a similar Figure 8In some other embodiments of the embodiments of the present invention, the DUI is not limited to the starting PDCP SDU of a frame (e.g., frame 2), and the DUI may be included in any PDCP SDU of the frame. Steps 1 to 3 in such embodiments are similar to Figure 8 Steps 1 to 3 are the same as in the embodiment of Figure 8 Specifically, in step 4, when the UE first receives the PDCP SDU of the new frame (i.e., frame 2) from the BS, if the PDCP SDU is not the start PDCP SDU of the new frame, and if the timer t-Reordering is running, in an embodiment, the UE restarts the timer t-Reordering to ensure that the timer t-Reordering starts at an appropriate timing for the new frame; and in another embodiment, the UE may stop the timer t-Reordering.

[0121] In an embodiment, the UE may perform the following operations:

[0122]

[0123] Figures 9 to 11B An exemplary PDCP control PDU and MAC CE including an update indication of a delivery state variable according to some embodiments of the present application are described. In these embodiments, the DUI may be sent by the BS to the UE separately from the PDCP SDU. In other words, Figures 9 to 11B In steps 1 and 2, Figure 7 and 8 The same as the embodiment of Figure 7 and 8 In steps 3 and 4, the DUI Figure 7 and 8 In the embodiment of the present invention, the PDCP SDU is sent, but Figures 9 to 11B In the embodiment, it is sent separately from the PDCP SDU.

[0124] In an embodiment, in step 4, the DUI may be presented in the PDCP header associated with the PDCP SDU. For example, the DUI is represented by one bit or two bits. The value of DUI "0" is reserved. The value of DUI "1" indicates that the PDPC entity of the UE considers the timer t-Reordering as expired when the timer t-Reordering is running.

[0125] Fig. 9An exemplary PDCP control PDU carrying DUI is shown. The field of "PDU Type" indicates the type of PDCP control PDU. The length of the field of "PDU Type" may be 3 bits. That is, a new PDU type in the PDCP control PDU is assigned to identify a delivery update command, such as a DELIV update command.

[0126] Specifically, in Fig. 9 In the embodiment of the present invention, in step 3, the BS sends a PDCP control PDU with only a PDCP header to the UE. The new PDU type is regarded as DUI. In step 4, when the PDCP control PDU is received from the BS, if the timer t-Reordering is running, the PDPC entity of the UE regards the timer t-Reordering as expired. Fig. 9 In an embodiment of the present invention, the UE may perform the following operations:

[0127]

[0128] For example, in some embodiments, in step 4, if the DELIV integrity IE is configured (e.g., in the RRC message), then when RX_REORD is combined with the PDCP PDU (e.g., Figure 3 When the frame 1) in is associated, when the timer t-Reordering expires:

[0129] (1) If the DELIV Integrity IE is disabled (ie, the value of the DELIV Integrity IE in the RRC message is FALSE), the UE delivers all stored non-contiguous PDCP SDUs associated with a count value less than or equal to RX_REORD.

[0130] (2) If the DELIV integrity IE is enabled (i.e., the value of the DELIV integrity IE in the RRC message is TRUE), the UE may not deliver any of the stored non-contiguous PDCP SDUs associated with a count value less than or equal to RX_REORD. All non-contiguous PDCP SDUs less than or equal to RX_REORD are discarded.

[0131] Fig.10 An exemplary MAC CE and a MAC subheader carrying a DUI are shown. The field of "LCID" is a logical channel ID field that identifies the DUI type in the MAC CE. The field of "DRB ID" indicates the identity of the DRB for which the timer t-Reordering of the PDCP entity is considered expired if it is running. The length of the field of "DRB ID" may be 8 bits.

[0132] Specifically, in Fig.10 In an embodiment of the present invention, in step 3, the DUI may be included in the MAC CE. In step 4, upon receiving the MAC CE including the DUI from the BS, the MAC entity of the UE indicates the DUI to the PDCP layer of the specific DRB included in the MAC CE. In the case where the timer t-Reordering corresponding to the specific DRB is running, the UE may regard the timer t-Reordering as expired.

[0133] exist Fig.10 In the case of split BS-CU and BS-DU of the embodiment of the present invention, the BS-CU may send DUI-related information to the BS-DU via the NR user plane protocol or the NR control plane protocol. The DUI-related information is used to indicate the DUI of a specific DRB. Then, the BS-DU sends a MAC CE containing the DUI, which is used to indicate a DELIV update command for a specific DRB.

[0134] Fig.11A and 11B An exemplary PDCP control PDU carrying DUI is shown. Fig.11A As shown in FIG. 1 , DUI includes a target count value or a target PDCP SN in a PDCP control PDU, which may be named a DELIV update command. The PDU type is DUI. The UE updates RX_DELIV based on the target count value or the target PDCP SN.

[0135] Specifically, in Fig.11A In the embodiment of the present invention, in step 3, the BS sends a PDCP control PDU including a target count value to the UE. In step 4, if the target count value is received from the BS in the PDCP control PDU, the UE updates RX_DELIV to the target count value. Fig.11A As shown in FIG. 1 , the target count value may include 32 bits, for example, 4 bits in Oct 1, 8 bits in Oct 2, and the other 20 bits in the other octets ( Fig.11A It is contemplated that, without departing from the spirit and scope of the present disclosure, the target count value in the PDCP control PDU may contain different total number of bits according to different embodiments. Fig.11A In an embodiment of the present invention, the UE may perform the following operations:

[0136]

[0137] exist Fig. 11B In the embodiment of the present invention, in step 3, the BS sends a PDCP control PDU including a target PDCP SN to the UE. Fig. 11BAs shown in , the target PDCP SN may include 12 bits, for example, 4 bits in Oct 1 and 8 bits in Oct 2. It is contemplated that, according to different embodiments, the target PDCP SN in the PDCP control PDU may contain a different total number of bits without departing from the spirit and scope of the present disclosure. In step 4, if the target PDCP SN is received from the BS in the PDCP control PDU, the UE updates RX_DELIV based on the target PDCP SN. For example, the UE may determine a count value of the PDCP control PDU based on the target PDCP SN, and determine the count value of the PDCP control PDU as the target count value. Then, the UE may update RX_DELIV to the target count value. The specific example is in Fig.12 The embodiments are described below.

[0138] exist Fig. 11B In an embodiment of the present invention, the UE may perform the following operations:

[0139]

[0140] Fig.12 and 13 An exemplary schematic diagram illustrating updating a delivery status variable according to some embodiments of the present application is provided.

[0141] Fig.12 The embodiment corresponds to Figure 3 The scenario shown in , where there are PDCP SN gaps between frames. Fig.12 In an embodiment of the present invention, in step 1, the BS may transmit a configuration for enabling an update function of a delivery state variable (e.g., RX_DELIV). For example, the BS configures a DELIV IE of a specific DRB. In step 2, after the BS determines to update the RX_DELIV of the UE, the BS determines to send a DUI to include a target PDCP SN in the PDCP control PDU. In step 3, the BS sends a DUI to the UE including a target PDCP SN (e.g., Fig.12 In step 4, the UE determines a count value of the PDCP control PDU based on the target PDCP SN (e.g., SN0), and determines the count value of the PDCP control PDU as the target count value. For example, the UE may determine that the count value of the PDCP control PDU corresponding to SN0 is the count value of PDCP SDU#10 of frame 2, such as Fig.12 Then, the UE updates RX_DELIV to the target count value, that is, the count value of PDCP SDU#10.

[0142] Fig.13 The embodiment corresponds to Figure 4The scenario shown in Figure 1 shows that there are several PDCP SN gaps in the frame. Fig.13 In an embodiment of the present invention, if a PDU SDU of a new frame (e.g., PDCP SDU#19 in frame 2) arrives at the UE for the first time, the UE may further deliver the old frame (e.g., frame 1) to the upper layer first according to the DELIV integrity IE when configured, and may then further deliver all stored PDCP SDUs having consecutively associated count values ​​starting from "1+maximum count value of PDCP SDU of the old frame". Fig.13 As shown in FIG. 1 , the maximum count value of the stored PDCP SDUs of the old frame is the count value of PDCP SDU #14 in Frame 1. “1+maximum count value of PDCP SDUs of the old frame” refers to the count value of PDCP SDU #15 in Frame 2.

[0143] For example, in Fig.13 In some embodiments, in step 4, if the DELIV integrity IE is configured (e.g., in an RRC message), then when the UE receives a PDCP SDU of an old frame (e.g., frame 1), if the value of DUI in the associated PDCP header is equal to "1":

[0144] (1) If the offset is 0 and the DELIV integrity IE is disabled (i.e., the value of the DELIV integrity IE in the RRC message is FALSE), the UE delivers all stored non-contiguous PDCP SDUs with an associated count value less than the RCVD_COUNT of the PDCP SDUs of the old frame (e.g., frame 1), and updates RX_DELIV to “1 + the maximum count value of the PDCP SDUs of the old frame” (i.e., as Fig.13 RCVD_COUNT of PDCP SDU#15 of frame 2 shown in FIG.

[0145] (2) If the offset is 0 and DELIV integrity is enabled (i.e., the value of the DELIV integrity IE in the RRC message is TRUE), the UE does not deliver any of the stored non-contiguous PDCP SDUs having an associated count value less than RCVD_COUNT of the PDCP SDU of the old frame (e.g., Frame 1). That is, all non-contiguous PDCP SDUs having an associated count value less than RCVD_COUNT are discarded.

[0146] exist Fig.13 In the embodiment of the present invention, the UE first updates RX_DELIV to "1+maximum count value of PDCP SDU of the old frame", and then updates RX_DELIV to "1+maximum count value of PDCP SDU" with consecutively associated count values ​​starting from RX_DELV. Fig.13, the UE first updates RX_DELIV to “1+count value of PDCP SDU #14 in frame 1”. The UE may further deliver all consecutive data with associated count values ​​starting from RX_DELIV, and may update the count value to the first PDCP SDU with count value >= RX_DELIV that has not been delivered to the upper layer.

[0147] exist Fig.13 In an embodiment, if the PDU SDU of a new frame that arrives at the UE for the first time (e.g., PDCP SDU#19 in frame 2) is not the starting PDCP SDU of the new frame, and the timer t-Reordering is running, the UE may restart the timer t-Reordering or may stop the timer t-Reordering.

[0148] exist Fig.13 In an embodiment of the present invention, the UE may perform the following operations:

[0149]

[0150] In an embodiment of the present application, if the PDU SDU of the new frame (e.g., PDCP SDU#19 in frame 2) arrives at the UE for the first time and the timer t-Reordering is running, the UE stops the timer t-Reordering and updates RX_DELIV to "1+the maximum count value of the old frame", for example, "1+the count value of PDCP SDU#14 in frame 1", such as Fig.13 Displayed in.

[0151] Fig.14 and 15 An exemplary schematic diagram illustrating a method for reordering frame timers according to some embodiments of the present application is provided. Fig.14 and 15In an embodiment, the BS configures a t-Reordering-Frame timer for a specific DRB for the UE. The timer t-Reordering-Frame may also be named "t-ReorderingFrame" or "Frame t-Reordering" or the like. The timer t-Reordering-Frame may have a fixed length. This timer is used to replace the timer t-Reordering to manage data delivery to the upper layer of the UE. Then, the UE starts the timer t-Reordering-Frame when it receives the PDCP SDU of the new frame for the first time. The timer t-Reordering-Frame may have a fixed length. When the timer t-Reordering-Frame expires, the UE further delivers the stored PDCP SDU of the new frame to the upper layer according to the DELIV integrity IE (if configured), and updates RX_DELIV to at least "1 + the count value of the PDCP SDU of the new frame whose maximum count value is greater than RX_DELIV".

[0152] For example, in Fig.14 or Fig.15 In some embodiments, in step 4, if the DELIV integrity IE is configured (e.g., in an RRC message), then when the UE receives a PDCP SDU of a new frame (e.g., Frame 2), upon expiration of a timer t-Reordering-Frame associated with the new frame:

[0153] (1) If the DELIV integrity IE is disabled (i.e., the value of the DELIV integrity IE in the RRC message is FALSE), the UE delivers all stored PDCP SDUs belonging to the new frame associated with the timer and updates RX_DELIV to at least “1 + the maximum count value of the PDCP SDUs of the new frame” (i.e., Fig.14 RCVD_COUNT of PDCP SDU#16 of frame 2 as shown in Fig.15 2). The UE may further deliver all consecutive data having an associated count value starting from RX_DELIV, and may update the count value to the first PDCP SDU with a count value >= RX_DELIV that has not been delivered to the upper layer.

[0154] (2) If DELIV integrity is enabled (i.e., the value of the DELIV integrity IE in the RRC message is TRUE), the UE may not deliver all stored non-contiguous PDCP SDUs belonging to the new frame associated with the timer, but may update RX_DELIV to at least “1 + the maximum count value of PDCP SDUs of the new frame” (i.e., Fig.14 RCVD_COUNT of PDCP SDU#16 of frame 2 as shown in Fig.15 2). The UE may further deliver all consecutive data having an associated count value starting from RX_DELIV, and may update the count value to the first PDCP SDU with a count value >= RX_DELIV that has not been delivered to the upper layer.

[0155] exist Fig.14 and 15 In some embodiments, the UE may perform the following operations:

[0156]

[0157] like Fig.14 As shown in FIG. 1 , upon first receiving a PDCP SDU of frame 1 (e.g., PDCP SDU #1 of frame 1), the UE may start a timer t-Reordering-Frame for frame 1. When the timer t-Reordering-Frame associated with frame 1 expires, the UE further delivers all stored PDCP SDUs of frame 1 to an upper layer (e.g., with the DELIV integrity IE if configured) according to the DELIV integrity IE. Fig.13 ), and RX_DELIV is updated to at least "1+the maximum count value of PDCP SDU#4 that has been received in frame 1 is greater than RX_DELIV". Fig.14 , it is shown that the UE does not receive or store any of PDCP SDU #5 to #9, so the UE does not deliver any PDCP SDU. In addition, the updated RX_DELIV is still equal to the count value of PDCP SDU #5. Similarly, when the PDCP SDU of frame 2 is received for the first time (e.g., PDCP SDU #14 of frame 2), the UE may start the timer t-Reordering-Frame ( Fig.14). When the timer t-Reordering-Frame associated with frame 2 expires, the UE further delivers all stored PDCP SDUs of frame 2 to the upper layer according to the DELIV integrity IE (if configured), and updates RX_DELIV to at least "1 + the count value of the PDCP SDUs of frame 2 whose maximum count value has been received is greater than RX_DELIV".

[0158] like Fig.15 , upon first receiving PDCP SDU #1 of frame 1, the UE starts the timer t-Reordering-Frame. When the timer t-Reordering-Frame associated with frame 1 expires, the UE further delivers the stored PDCP SDUs of frame 1 (i.e., PDCP SDUs #8 to #10, #13, and #14 of frame 1) to the upper layer (e.g., with the DELIV integrity IE if configured) according to the DELIV integrity IE. Fig.13 The same as the embodiment of the present invention), and RX_DELIV is updated to "1 + the maximum count value of frame 1 that has been received is greater than the count value of PDCP SDU #14 of RX_DELIV". That is, the updated RX_DELIV is equal to the count value of PDCP SDU #15 of frame 2, such as Fig.15 Similarly, upon first receiving the PDCP SDU of frame 2 (e.g., PDCP SDU#15 of frame 2), the UE may start the timer t-Reordering-Frame ( Fig.15 ). When the timer t-Reordering-Frame associated with frame 2 expires, the UE further delivers the stored PDCP SDU of frame 2 to the upper layer according to the DELIV integrity IE (if configured), and updates RX_DELIV to "1 + the count value of the PDCP SDU of frame 2 whose maximum count value has been received is greater than RX_DELIV".

[0159] exist Fig.14 and 15 In some embodiments, the UE may perform the following operations:

[0160]

[0161] Fig.16 An exemplary block diagram of an apparatus 1600 for data discarding operation according to some embodiments of the present application is illustrated. Fig.16, the apparatus 1600 may include at least one non-transitory computer-readable medium 1602, at least one receiving circuit system 1604, at least one transmitting circuit system 1606, and at least one processor 1608 coupled to the non-transitory computer-readable medium 1602, the receiving circuit system 1604, and the transmitting circuit system 1606. The at least one processor 1608 may be a CPU, a DSP, a microprocessor, etc. The apparatus 1600 may be a network node (e.g., a BS) or a UE or the like configured to perform the method described above.

[0162] Although elements such as at least one processor 1608, receive circuitry 1604, and transmit circuitry 1606 are described in singular form in this figure, plural form is contemplated unless limitation to the singular form is explicitly stated. In some embodiments of the present application, receive circuitry 1604 and transmit circuitry 1606 may be combined into a single device, such as a transceiver. In a specific embodiment of the present application, apparatus 1600 may further include an input device, a memory, and / or other components.

[0163] In some embodiments of the present application, a non-transitory computer-readable medium 1602 may store thereon computer-executable instructions for causing a processor to implement the method described or illustrated above with respect to a UE or a network node (e.g., a BS). For example, when the computer-executable instructions are executed, the processor 1608 interacts with the receiving circuit system 1604 and the transmitting circuit system 1606 to perform the steps described or illustrated above with respect to a UE or a network node (e.g., a BS).

[0164] Fig.17 Another exemplary block diagram of an apparatus 1700 for data discarding operation according to some embodiments of the present application is illustrated. Fig.17 , the device 1700 (e.g., a BS or a UE) may include at least one processor 1702 and at least one transceiver 1704 coupled to the at least one processor 1702. The transceiver 1704 may include at least one separate receiving circuit system 1706 and transmitting circuit system 1708, or at least one integrated receiving circuit system 1706 and transmitting circuit system 1708. The at least one processor 1702 may be a CPU, a DSP, a microprocessor, etc.

[0165] According to some embodiments of the present application, when the device 1700 is a UE, the processor 1702 is configured to: receive a configuration for enabling an update function of a delivery state variable associated with a first packet data convergence protocol (PDCP) service data unit (SDU) from the network via the transceiver 1704, wherein the first PDCP SDU is not delivered to an upper layer of the UE by a PDCP entity of a data radio bearer (DRB); and enable the update function of the delivery state variable based on the configuration of the PDCP entity for the DRB.

[0166] According to some other embodiments of the present application, when the device 1700 is a network node (e.g., a BS), the processor 1702 is configured to receive from a user equipment (UE) via the transceiver 1704 a capability to support an update function for delivery state variables associated with a packet data convergence protocol (PDCP) service data unit (SDU) received by the UE; and to transmit to the UE via the transceiver 1704 a configuration for enabling the update function for the delivery state variables of the PDCP entity for enabling the DRB of the UE.

[0167] According to some embodiments of the present application, when the device 1700 is a UE, the processor 1702 is configured to: the transceiver 1704 receives a configuration of a non-continuous packet data convergence protocol (PDCP) service data unit (SDU) delivery function from the network to the upper layer of the UE via a PDCP entity for enabling a data radio bearer (DRB); and enable the non-continuous PDCP SDU delivery function based on the PDCP entity configured as the DRB.

[0168] According to some other embodiments of the present application, when the device 1700 is a network node (e.g., a BS), the processor 1702 is configured to: receive from a user equipment (UE) via the transceiver 1704 a capability to support a non-continuous PDCP SDU delivery function associated with a packet data convergence protocol (PDCP) service data unit (SDU) received by the UE; and transmit to the UE via the transceiver 1704 a configuration of the non-continuous PDCP SDU delivery function of a PDCP entity for enabling a data radio bearer (DRB) of the UE.

[0169] The methods of the present disclosure may be implemented on a programmed processor. However, the controller, flow charts, and modules may also be implemented on a general or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit components, an integrated circuit, a hardware electronic or logic circuit (e.g., a discrete component circuit), a programmable logic device, or the like. In general, any device having a finite state machine capable of implementing the flow charts shown in the figures may be used to implement the processing functions of the present disclosure.

[0170] Although the present disclosure has been described with reference to specific embodiments of the present disclosure, it is apparent that many substitutions, modifications, and variations may be apparent to those skilled in the art. For example, the various components of the embodiments may be interchanged, added, or substituted in other embodiments. Moreover, all elements of each figure are not necessary for the operation of the disclosed embodiments. For example, those skilled in the art will be able to make and use the teachings of the present disclosure by simply adopting the elements of the independent claims. Therefore, the embodiments of the present disclosure set forth herein are intended to be illustrative rather than restrictive. Various changes may be made without departing from the spirit and scope of the present disclosure.

[0171] In this archive, the term "includes / including" or any other variation thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including the element list not only includes those elements but also may include other elements that are not explicitly listed or inherent to this process, method, article or equipment. The element starting with "a / an" or the like does not exclude the existence of additional identical elements in the process, method, article or equipment including the element without more constraints. Moreover, the term "another" is defined as at least one second or more. As used herein, the term "having" and the like are defined as "including". For example, the expression of "A and / or B" or "at least one of A and B" may include any and all combinations of words listed together with the expression. For example, the expression "A and / or B" or "at least one of A and B" may include A, B or both A and B. The words of "first", "second" or the like are only used to clearly illustrate the embodiments of the present application, and are not used to limit the essence of the present application.

Claims

1. A user equipment UE, comprising: Transceiver; and a processor coupled to the transceiver, wherein the processor is configured to: receiving, via the transceiver, from a network a configuration for enabling an update function of a delivery state variable associated with a first packet data convergence protocol PDCP service data unit SDU, the first PDCP SDU not being delivered to an upper layer of the UE by a PDCP entity of a data radio bearer DRB; as well as The updating function of the delivery state variable is enabled based on the configuration of the PDCP entity for the DRB.

2. The UE of claim 1, wherein the processor of the UE is configured to: receiving, via the transceiver, from the network an indication of an update of the delivery state variable; and According to the update indication, the delivery state variable is updated to a target count value associated with the second PDCP SDU.

3. The UE according to claim 2, wherein the update indication is included in a header of the second PDCP SDU, and wherein the processor of the UE is configured to determine the count value of the second PDCP SDU as the target count value.

4. The UE of claim 2, wherein the processor of the UE is configured to: After receiving the update indication, the PDCP entity through the DRB delivers all one or more stored PDCP SDUs having count values ​​less than or equal to the target count value to the upper layer of the UE before updating the delivery state variable.

5. The UE of claim 2, wherein the first PDCP SDU belongs to a first frame, and wherein the update indication indicates at least one of: whether the second PDCP SDU belongs to a second frame; or Whether the second PDCP SDU is a start PDCP SDU of the second frame.

6. The UE according to claim 5, wherein: In response to the second PDCP SDU not being the start PDCP SDU of the second frame, the processor of the UE is configured to: determining whether a reordering timer of the PDCP entity of the DRB is running; and In response to determining that the reordering timer is running: restarting the reordering timer; or The reordering timer is stopped.

7. The UE according to claim 2, wherein the update indication is contained in a PDCP control protocol data unit (PDU) or a medium access control (MAC) sub-PDU.

8. The UE according to claim 2 or claim 7, wherein the processor of the UE is configured to regard the reordering timer as expired if the reordering timer is running.

9. The UE according to claim 7, wherein the processor of the UE is configured to determine the target count value based on a PDCP sequence number SN or a PDCP count value in response to the PDCP control PDU including the PDCP SN or the PDCP count value.

10. The UE of claim 1, wherein the first PDCP SDU belongs to a first frame, and wherein the processor of the UE is configured to: receiving, via the transceiver, a third PDCP SDU from the network; and It is determined whether the third PDCP SDU is a first received PDCP SDU of a third frame.

11. The UE according to claim 10, wherein: In response to determining that the third PDCP SDU is the first received PDCP SDU of the third frame, the processor of the UE is configured to deliver all one or more stored PDCP SDUs to the upper layer of the UE through the PDCP entity of the DRB.

12. The UE of claim 10, wherein the processor of the UE is configured to: In response to determining that the third PDCP SDU is the first received PDCP SDU of the third frame and is not a starting PDCP SDU of the third frame, determining whether a reordering timer of the PDCP entity of the DRB is running; and In response to determining that the reordering timer is running: restarting the reordering timer; or The reordering timer is stopped.

13. The UE according to claim 11 or claim 12, wherein the processor of the UE is configured to update the delivery state variable to 1 plus a maximum count value of the PDCP SDUs of the first frame stored by the UE.

14. The UE of claim 13, wherein the processor is configured to deliver all one or more stored PDCP SDUs of the third frame having one or more consecutive count values ​​starting from the updated delivery state variable to the upper layer of the UE through the PDCP entity of the DRB.

15. A network node, comprising: Transceiver; and a processor coupled to the transceiver, wherein the processor is configured to: receiving, via the transceiver, from a user equipment UE, a capability to support an update function of a delivery state variable associated with a Packet Data Convergence Protocol PDCP Service Data Unit SDU received by the UE; and Transmitting, via the transceiver, to the UE a configuration of the update function of the delivery state variable of the PDCP entity for enabling the DRB of the UE.

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