EP4623601A1

EP4623601A1 - Methods and apparatuses for a discard timer

Info

Publication number: EP4623601A1
Application number: EP23878572.9A
Authority: EP
Inventors: Xiaoying Xu; Mingzeng Dai; Jing HAN; Congchi ZHANG; Lianhai WU
Original assignee: Lenovo Beijing Ltd
Current assignee: Lenovo Beijing Ltd
Priority date: 2023-04-06
Filing date: 2023-04-06
Publication date: 2025-10-01
Also published as: CN120500878A; GB202510158D0; WO2024082572A1; GB2641183A; MX2025008105A

Abstract

Embodiments of the present application relate to methods and apparatuses of adjusting a protocol data unit (PDU) discard timer for extended reality (XR) traffic. According to an embodiment of the present application, a user equipment (UE) includes a transceiver and a processor coupled to the transceiver, and the processor is configured to cause the UE to: determine a discard timer for data of a PDU set type of a data radio bearer (DRB); and handle the discard timer for the data of the PDU set type of the DRB.

Description

METHODS AND APPARATUSES FOR A DISCARD TIMER

TECHNICAL FIELD

Embodiments of the present application generally relate to wireless communication technology, especially to methods and apparatuses for a discard timer for extended reality (XR) traffic.

BACKGROUND

Extended reality (XR) , including augmented reality (AR) and virtual reality (VR) , as well as cloud gaming (CG) , presents a new promising category of connected devices, applications, and services. As a potential working area of 3GPP (3rd generation partnership project) Rel-18, power saving of a XR device is one of key topics. Currently, details regarding handling a discard timer for XR traffic have not been discussed yet.
SUMMARY
Some embodiments of the present application provide a user equipment (UE) . The UE includes a transceiver and a processor coupled to the transceiver; and the processor is configured to cause the UE to: determine a discard timer for data of a protocol data unit (PDU) set type of a data radio bearer (DRB) ; and handle the discard timer for the data of the PDU set type of the DRB.
In some embodiments, the processor is configured to cause the UE to handle the discard timer for the data of the PDU set type of the DRB based on an uplink (UL) congestion status or a first indication or pre-configuration information.
In some embodiments, the processor is configured to cause the UE to: receive first configuration information, wherein the first configuration information includes the first indication, and the discard timer is determined based on the first configuration information.
In some embodiments, the first configuration information is included in radio resource control (RRC) signaling.
In some embodiments, the first indication indicates at least one of the following: information to indicate the DRB; information to indicate a timer length of the discard timer of the DRB; activated or deactivated status of the discard timer; information to indicate a PDU set type to activate or deactivate the discard timer; information to indicate an importance level to activate or deactivate the discard timer; or information to indicate a packet data convergence protocol (PDCP) sequence number (SN) or a PDU set ID according to which the discard timer is activated or deactivated.
In some embodiments, the first configuration information or the first indication includes one or more bits, each bit within the one or more bits is associated with one DRB configured with the discard timer, and a value of the each bit represents an activated or deactivated status of the discard timer for the PDU set type of one DRB.
In some embodiments, the first indication indicates the UL congestion status detected at the network node.
In some embodiments, the processor is configured to cause the UE to: activate the discard timer in response to that the UL congestion status is high or not low; or deactivate the discard timer in response to that the UL congestion status is low or not high.
In some embodiments, the processor is configured to cause the UE to: receive UL congestion detection configuration information from the network node; and detect the UL congestion status based at least on the UL congestion detection configuration information.
In some embodiments, the UL congestion detection configuration information includes criteria of the UL congestion status.
In some embodiments, the pre-configuration information indicates at least one of the following: information to indicate a timer length of the discard timer; information to indicate a PDU set type to activate or deactivate the discard timer; or information to indicate an importance level to activate or deactivate the discard timer.
In some embodiments, to handle the discard timer, the processor is further configured to cause the UE to apply the discard timer to the data of the PDU set type if the discard timer is activated for the PDU set type of the DRB.
In some embodiments, if the discard timer for the PDU set type is activated, the processor is configured to cause the UE to apply the discard timer to the data of the PDU set type based at least on: upon receiving the data of the PDU set type from an upper layer; running status of a first discard timer associated with the data of the PDU set type or associated with a PDU set of the PDU set type including the data; submission status of the data of the PDU set type to a radio link control (RLC) layer; or submission status of the PDU set including the data to the RLC layer.
In some embodiments, upon receiving the data of the PDU set type from the upper layer, the processor is configured to cause the UE to apply the discard timer to the data of the PDU set type: if at least one service data unit (SDU) or PDU in the PDU set of the PDU set type including the data has been received and is available for transmission; or if no SDU or PDU in the PDU set including the data has been received and is available for transmission.
In some embodiments, the processor is configured to cause the UE to apply the discard timer to the data of the PDU set type based on the running status of the first discard timer associated with the data of the PDU set type: if the first discard timer is running for at least one SDU within the PDU set of the PDU set type including the data; if the first discard timer is not running for any SDU within the PDU set including the data; if the first discard timer is running or not running for the data; if the data has or has not been submitted to the RLC layer data; if at least one SDU within the PDU set including the data has been submitted to the RLC layer data; or if no SDU within the PDU set including the data has been submitted to the RLC layer data.
In some embodiments, if the discard timer for the PDU set type is activated, the processor is configured to cause the UE to: determine whether buffer delay of the data is equal to or greater than a timer length of the discard timer or whether a timer length of the discard timer is equal to zero; and in response to the buffer delay of the data being equal to or greater than the timer length of the discard timer or in response to the timer length of the discard timer is equal to zero, consider the discard timer or the first discard timer as expired.
In some embodiments, if the discard timer for the PDU set type is activated, the processor is configured to cause the UE to: determine whether a first discard timer associated with the data of the PDU set type is running; in response to not starting the first discard timer associated with the data, start the discard timer associated with the data; in response to the first discard timer associated with the data being running, stop the first discard timer associated with the data and start the discard timer associated with the data; or in response to not starting the first discard timer associated with one or more SDUs within the data, start the discard timer associated with the one or more SDUs within the data.
In some embodiments, to stop the first discard timer associated with the data and start the discard timer associated with the data, the processor is configured to cause the UE to: determine whether a timer length of the discard timer is equal to zero; and in response to the timer length of the discard timer being equal to zero, stop the first discard timer associated with the data and start the discard timer associated with the data.
In some embodiments, to stop the first discard timer associated with the data and start the discard timer associated with the data, the processor is configured to cause the UE to: set a difference value between the timer length of the discard timer and the buffer delay as the timer length of the discard timer; and start the discard timer associated with the data.
In some embodiments, to stop the first discard timer associated with the data and start the discard timer associated with the data, the processor is configured to cause the UE to: determine whether remaining running time of the first discard timer associated with the data is greater than a timer length of the discard timer; and in response to the remaining running time of the first discard timer associated with the data being greater than the timer length of the discard timer, stop the first discard timer associated with the data and start the discard timer associated with the data.
In some embodiments, to handle the discard timer, the processor is further configured to cause the UE to: apply a first discard timer associated with the data of the PDU set type if the discard timer is deactivated for the PDU set type of the DRB.
In some embodiments, if the discard timer for the PDU set type is deactivated, the processor is configured to cause the UE to apply the first discard timer to the data of the PDU set type based at least on: upon receiving the data of the PDU set type from an upper layer; running status of the discard timer associated with the data of the PDU set type or associated with a PDU set of the PDU set type including the data; submission status of the data of the PDU set type to a radio link control (RLC) layer; or submission status of the PDU set including the data to the RLC layer.
In some embodiments, upon receiving the data of the PDU set type from the upper layer, the processor is configured to cause the UE to apply the first discard timer to the data of the PDU set type: if at least one service data unit (SDU) or PDU in the PDU set including the data has been received and is available for transmission; or if no SDU or PDU in the PDU set including the data has been received and is available for transmission.
In some embodiments, the processor is configured to cause the UE to apply the first discard timer to the data of the PDU set type based on the running status of the discard timer associated with the data of the PDU set type: if the discard timer is running for at least one SDU within the PDU set of the PDU set type including the data; if the discard timer is not running for any SDU within the PDU set including the data; or if the discard timer is running or not running for the data.
In some embodiments, if the discard timer for the PDU set type is deactivated, the processor is configured to cause the UE to: determine whether the discard timer associated with the data of the PDU set type is running; in response to not starting the discard timer associated with the data, start a first discard timer associated with the data; in response to the discard timer associated with the data being running, stop the discard timer associated with the data and start the first discard timer associated with the data; or in response to not starting the discard timer associated with any SDU within the data, start the first discard timer associated with the SDU within the data.
In some embodiments, if the discard timer for the PDU set type is deactivated, the processor is configured to cause the UE to: determine whether buffer delay of the data is equal to or less than a timer length of the first discard timer; and in response to the buffer delay of the data being equal to or less than the timer length of the first discard timer: stop the discard timer associated with the data, and start the first discard timer associated with the data; or stop the discard timer associated with the data, set a difference value between the timer length of the first discard timer and the buffer delay as the timer length of the first discard timer, and start the first discard timer associated with the data; or in response to the buffer delay of the data being greater than the timer length of the first discard timer, consider the first discard timer or the discard timer if running as expired.
In some embodiments, the first indication is for updating the discard timer.
In some embodiments, the first indication includes at least one of the following: information to indicate the DRB; information to indicate a timer length of the discard timer; information to indicate a PDU set type to update the discard timer; information to indicate an importance level to update the discard timer; or information to indicate a packet data convergence protocol (PDCP) sequence number (SN) or a PDU set ID according to which the discard timer is updated.
In some embodiments, the first indication is included in one of the following: a medium access control (MAC) control element (CE) ; a packet data convergence protocol (PDCP) control PDU; a radio link control (RLC) control PDU; and downlink control information (DCI) .
In some embodiments, if the first indication is received, the processor is configured to cause the UE to update the discard timer associated with the data of the PDU set type based at least in part on: upon receiving the data of the PDU set type from an upper layer; running status of the discard timer associated with the data or associated with a PDU set of the PDU set type including the data; submission status of the data of the PDU set type to a radio link control (RLC) layer; or submission status of the PDU set including the data to the RLC layer.
In some embodiments, upon receiving the data of the PDU set type from the upper layer, the processor is configured to cause the UE to update the discard timer: if at least one service data unit (SDU) or PDU in the PDU set including the data has been received and is available for transmission; or if no SDU or PDU in the PDU set including the data has been received and is available for transmission.
In some embodiments, the processor is configured to cause the UE to update the discard timer based on the running status of the discard timer associated with the data or associated with the PDU set of the PDU set type including the data: if the discard timer is running for at least one SDU within the PDU set of the PDU set type including the data; if the discard timer is not running for any SDU within the PDU set including the data; if the discard timer is running or not running for the data; if the data has or has not been submitted to the RLC layer data; if at least one SDU within the PDU set including the data has been submitted to the RLC layer data; or if no SDU within the PDU set including the data has been submitted to the RLC layer data.
In some embodiments, to update the discard timer associated with the data of the PDU set type, the processor is further configured to cause the UE to: determine whether buffer delay of the data is equal to or greater than the updated timer length of the discard timer; or determine whether the updated timer length of the discard timer is equal to zero.
In some embodiments, the processor is further configured to cause the UE to consider the discard timer having the updated timer length or the running discard timer associated with the data as expired, in response to: the buffer delay of the data being equal to or greater than the updated timer length of the discard timer; or the updated timer length of the discard timer is equal to zero.
In some embodiments, to update the discard timer associated with the data of the PDU set type, the processor is further configured to cause the UE to: determine whether the discard timer associated with the data is running; in response to not starting the discard timer associated with the data, start the discard timer having an updated timer length associated with the data; in response to the discard timer associated with the data being running, stop the discard timer associated with the data, and start the discard timer having the updated timer length associated with the data; or in response to not starting the discard timer associated with one or more SDUs within the data, start the discard timer having the updated timer length associated with the one or more SDUs within the data.
In some embodiments, to start the discard timer, the processor is configured to cause the UE to: determine whether the updated timer length of the discard timer is equal to zero or whether the updated timer length is less than the timer length of the discard timer; and in response to the updated timer length being equal to zero or in response to the updated timer length being less than the timer length of the discard timer, (re) start the discard timer having the updated timer length associated with the data.
In some embodiments, to start the discard timer, the processor is configured to cause the UE to: determine whether buffer delay of the data is equal to or greater than the updated timer length of the discard timer; and in response to the buffer delay of the data being equal to or greater than the updated timer length, consider the discard timer having the updated timer length as expired; or in response to the buffer delay of the data being less than the updated timer length: stop the discard timer having the timer length associated with the data if running and start the discard timer having the updated timer length associated with the data; or stop the discard timer having the timer length associated with the data if running, set a difference value between the updated timer length and the buffer delay as the timer length of the discard timer, and start the discard timer associated with the data.
In some embodiments, to start the discard timer, the processor is configured to cause the UE to: determine whether remaining running time of the discard timer associated with the data is equal to or greater than the updated timer length of the discard timer; and in response to the remaining running time of the discard timer associated with the data being equal to or greater than the updated timer length, stop the discard timer having the timer length associated with the data, and start the discard timer having the updated timer length associated with the data.
In some embodiments, to start the discard timer, the processor is configured to cause the UE to: determine whether buffer delay of the data is equal to or less than the updated timer length of the discard timer or whether the updated timer length is greater than the timer length of the discard timer; and in response to the buffer delay of the data being equal to or less than the updated timer length or in response to the updated timer length being greater than the timer length of the discard timer: stop the discard timer having the timer length associated with the data if running, and start the discard timer having the updated timer length associated with the data; or stop the discard timer having the timer length associated with the data if running, set a difference value between the updated timer length and the buffer delay as the timer length of the discard timer, and start the discard timer for the data.
In some embodiments, to start the discard timer, the processor is configured to cause the UE to: determine whether remaining running time of the discard timer for the data is equal to or less than the updated timer length of the discard timer; and in response to the remaining running time of the discard timer for the data being equal to or less than the updated timer length, stop the discard timer having the timer length if running, and start the discard timer having the updated timer length associated with the data.
Some embodiments of the present application provide a network node. The network node includes a transceiver and a processor coupled to the transceiver; and the processor is configured to cause the network node to: receive capability information of a user equipment (UE) , wherein the capability information includes handling a discard timer for data of a protocol data unit (PDU) set type of a data radio bearer (DRB) ; and transmit a first indication or uplink (UL) congestion detection configuration information to the UE to handle the discard timer for the data of the PDU set type of the DRB.
In some embodiments, the processor is configured to cause the network node to transmit first configuration information to the UE, and the first configuration information indicates at least one of the following: information to indicate a timer length of the discard timer of the DRB; activated or deactivated status of the discard timer; information to indicate a PDU set type to activate or deactivate the discard timer; or information to indicate an importance level to activate or deactivate the discard timer.
In some embodiments, the first configuration information is included in radio resource control (RRC) signaling.
In some embodiments, the first indication indicates at least one of the following: information to indicate the DRB; activated or deactivated status of the discard timer; information to indicate a PDU set type to activate or deactivate the discard timer; information to indicate an importance level to activate or deactivate the discard timer; or information to indicate a packet data convergence protocol (PDCP) sequence number (SN) or a PDU set ID according to which the discard timer is activated or deactivated.
In some embodiments, the first configuration information or the first indication includes one or more bits, each bit within the one or more bits is associated with one DRB configured with the discard timer, and a value of the each bit represents an activated or deactivated status of the discard timer for the PDU set type of each DRB.
In some embodiments, the first indication includes an uplink (UL) congestion status detected at the network node.
In some embodiments, the UL congestion detection configuration information includes criteria of a UL congestion status.
In some embodiments, the first indication is for updating the discard timer.
In some embodiments, the first indication includes at least one of the following: information to indicate the DRB; information to indicate a timer length of the discard timer; information to indicate a PDU set type to update the discard timer; information to indicate an importance level to update the discard timer; or information to indicate a packet data convergence protocol (PDCP) sequence number (SN) or a PDU set ID according to which the discard timer is updated.
In some embodiments, the first indication is included in one of the following: a medium access control (MAC) control element (CE) ; a packet data convergence protocol (PDCP) control PDU; a radio link control (RLC) control PDU; and downlink control information (DCI) .
Some embodiments of the present application provide a method performed by a UE. The method includes: determining a discard timer for data of a protocol data unit (PDU) set type for a data radio bearer (DRB) ; and handling the discard timer for the data of the PDU set type of the DRB.
Some embodiments of the present application provide a method performed by a network node. The method includes: receiving capability information of a user equipment (UE) , wherein the capability information includes handling a discard timer for data of a protocol data unit (PDU) set type of a data radio bearer (DRB) ; and transmitting a first indication or uplink (UL) congestion detection configuration information to the UE to handle the discard timer for the data of the PDU set type of the DRB.
Some embodiments of the present application provide an apparatus for wireless communications. The apparatus comprises: a non-transitory computer-readable medium having stored thereon computer-executable instructions; a receiving circuitry; a transmitting circuitry; and a processor coupled to the non-transitory computer-readable medium, the receiving circuitry and the transmitting circuitry, wherein the computer-executable instructions cause the processor to implement the abovementioned method performed by a UE or a network node (e.g. a base station (BS) ) .
The details of one or more examples are set forth in the accompanying drawings and the descriptions below. Other features, objects, and advantages will be apparent from the descriptions and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which advantages and features of the application can be obtained, a description of the application is rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. These drawings depict only example embodiments of the application and are not therefore to be considered limiting of its scope.
FIG. 1 illustrates a schematic diagram of a wireless communication system in accordance with some embodiments of the present application.
FIG. 2 illustrates an exemplary diagram of important and unimportant PDU sets in an XR traffic stream in accordance with some embodiments of the present application.
FIG. 3 illustrates an exemplary flowchart of handling a discard timer in accordance with some embodiments of the present application.
FIG. 4 illustrates an exemplary flowchart performed by a network node in accordance with some embodiments of the present application.
FIG. 5 illustrates an exemplary flowchart of transmitting configuration information regarding a discard timer in accordance with some embodiments of the present application.
FIG. 6 illustrates an exemplary diagram of a discard timer command MAC CE in accordance with some embodiments of the present application.
FIG. 7 illustrates an exemplary flowchart of receiving discard timer command timing in accordance with some embodiments of the present application.
FIG. 8 illustrates a block diagram of an exemplary apparatus in accordance with some embodiments of the present application.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of preferred embodiments of the present application and is not intended to represent the only form in which the present application may be practiced. It should be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present application.
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 architecture and new service scenarios, such as 3GPP 5G, 3GPP LTE Release 8 and so on. It is contemplated that along with developments of network architectures and new service scenarios, all embodiments in the present application are also applicable to similar technical problems; and moreover, the terminologies recited in the present application may change, which should not affect the principle of the present application.
FIG. 1 illustrates a schematic diagram of a wireless communication system in accordance with some embodiments of the present application. As shown in FIG. 1, the wireless communication system 100 includes at least one base station (BS) 101 and at least one user equipment (UE) 102. In particular, the wireless communication system 100 includes one BS 101 and two UE 102 (e.g. UE 102a and UE 102b) for illustrative purpose. Although a specific number of BSs and UEs are illustrated in FIG. 1 for simplicity, it is contemplated that the wireless communication system 100 may include more or less BSs and UEs in some other embodiments of the present application.
The wireless communication system 100 is compatible with any type of network that is capable of sending and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with a wireless communication network, a cellular telephone network, a time division multiple access (TDMA) -based network, a code division multiple access (CDMA) -based network, an orthogonal frequency division multiple access (OFDMA) -based network, an LTE network, a 3GPP-based network, a 3GPP 5G network, a satellite communications network, a high altitude platform network, and/or other communications networks.
BS 101 may communicate with a core network (CN) node (not shown) , e.g. a mobility management entity (MME) or a serving gateway (S-GW) , a mobility management function (AMF) or a user plane function (UPF) etc. via an interface. A BS also be referred to as an access point, an access terminal, a base, 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 terminology used in the art. In 5G NR, a BS may also refer to as a RAN node or network apparatus. Each BS may serve a number of UE (s) within a serving area, for example, a cell or a cell sector via a wireless communication link. Neighbour BSs may communicate with each other as necessary, e.g. during a handover procedure for a UE.
UE 102, e.g. UE 102a and UE 102b, should be understood as any type terminal device, which may include computing devices, such as desktop computers, laptop computers, personal digital assistants (PDAs) , tablet computers, smart televisions (e.g. televisions connected to the Internet) , set-top boxes, game consoles, security systems (including security cameras) , vehicle on-board computers, network devices (e.g. routers, switches, and modems) , or the like. According to an embodiment of the present application, UE 102 may include a portable wireless communication device, a smart phone, a cellular telephone, a flip phone, a device having a subscriber identity module, a personal computer, a selective call receiver, or any other device that is capable of sending and receiving communication signals on a wireless network. In some embodiments, UE 102 may include wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, UE 102 may be referred to as a subscriber unit, a mobile, 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 terminology used in the art. UE 102 may communicate directly with BSs 101 via uplink (UL) communication signals.
Typically, XR, including AR and VR, as well as Cloud Gaming (CG) , presents a new promising category of connected devices, applications, and services. A PDU set and quality of service (QoS) characteristics of a PDU set have been introduced for XR service. In general, a PDU set is composed of one or more PDUs carrying the payload of one unit of information generated at the application level (e.g. a frame or video slice for XR and media (XRM) services) . In some implementations, all PDUs in a PDU set are needed by the application layer to use the corresponding unit of information. In other implementations, the application layer can still recover a part of or the entire information unit, when some PDUs are missing. PDU sets can carry different content with different importance levels called “PSI” (PDU-Set importance) , e.g. I-Frames, B-Frames, or P-Frames, P-slices or I-slices (e.g. slices/tiles within an I-Frame, a B-Frame, or a P-Frame) , and etc. PSI identifies the relative importance of a PDU Set compared to other PDU Sets within a QoS Flow. A PDU Set with high importance may still be needed in the decoding of subsequent PDU Sets, even after it misses its own decoding deadline (PSDB) . However, one PDCP discard timer is used for a legacy PDCP entity. Therefore, 3gpp is discussing the PSI may be used for PDU set discarding in uplink, a PDU set discard mechanism taking the PSI into account will be introduced in case of congestion.
In some embodiments of the present application, PDU set types can be characterised by, for example, the PDU set importance (PSI) . In an embodiment, there are two PDU set types, one is important PDU set type, and the other is unimportant or less important PDU set type. In another embodiment, there may be PDU set types characterized by multiple PSI, e.g. importance level#1, importance level#2 importance level#3, importance level#4, and etc.; or high importance level and less importance level. For example, 10 is highest importance level, and 1 is the lowest importance level.
A PDU set type may be characterized by a notion of “importance” indicating how important the PDU set (e.g. a video frame) is for the application. For example, an important PDU set could be an I-Frame within a burst or I-slice within a frame, while an unimportant PDU set could be a P-Frame within a burst or a P-slice within a frame. A specific example is described in the embodiments of FIG. 2 as follows. In some other embodiments of the present application, PDU set types can be characterised by the PDU set’s other parameters or characters.
FIG. 2 illustrates an exemplary diagram of important and unimportant PDU sets in an XR traffic stream in accordance with some embodiments of the present application. PDU set #1 is important and may include packet #1, packet #2, packet #3, packet #4, and packet #5. PDU set #2 is unimportant and may include packet #6, packet #7, and packet #8.
Currently, to implement a PDU set discard mechanism taking PSI (PDU-Set importance) into consideration, some solutions propose that PDU sets with different importance levels can be configured with different PDCP discard timers. For example, for the data within the important PDU set, the PDCP discard timer length can be greater than the PSDB, and for the data within the less important PDU set, the PDCP discard timer length can be equal to the PSDB. However, the congestion is dynamically changed, issues of when and how to adjust the discard timer according to PSI to quickly adapt the UL congestion need to be solved.
Embodiments of the present application aims to solve the issue on how to apply the discard timer based on PSI to quickly adapt the UL congestion. More specifically, some embodiments of the present application provide a method of PDU (set) discard timer adjusting based on PDU set importance level. In some embodiments of present application, a UE dynamically applies a discard timer with a discard timer length for the data with a PSI (e.g. unimportant) on a DRB based on the dynamic activation command, the UL congestion status detected at the UE, or indicated by a network node, while applying the discard timer with another discard timer length for the data with another PSI (e.g. important) . In some other embodiments of present application, a UE dynamically applies a discard timer with a discard timer length for the data with a PSI (e.g. important) on a DRB based on the dynamic activation command, the UL congestion status detected at the UE, or indicated by a network node, while applying the discard timer with another discard timer length for the data with another PSI (e.g. unimportant) .
In some embodiments of present application, a UE dynamically applies a discard timer for the data with a PSI (e.g. unimportant) on a DRB based on the dynamic activation command, the UL congestion status detected at the UE, or indicated by a network node, while applying another discard timer for the data with another PSI (e.g. important) . In some other embodiments of present application, a UE dynamically applies a discard timer for the data with a PSI (e.g. important) on a DRB based on the dynamic activation command, the UL congestion status detected at the UE, or indicated by a network node, while applying another discard timer for the data with another PSI (e.g. unimportant) .
Some embodiments of the present application define which data to apply a discard timer with a discard timer length according to the running status of another discard timer, according to the running status of the discard timer with another discard time length, according to the submission status of the whole PDU set to an RLC layer, and/or according to the submission status of a part of the PDU set to an RLC layer. In some embodiments of present application, a UE dynamically updates a discard timer length value for the data with a certain PSI (e.g. unimportant or important) on a DRB based on the dynamic update command. Some embodiments of the present application define which data to apply the updated timer length value. In this invention, data may be a PDCP SDU or a PDCP PDU or a PDU set.
In some embodiments of the present application, a UL congestion status may also be named as “a UL congestion level” or the like. A discard timer may also be named as “a PDCP discard timer” which is associated with a PDCP SDU or a PDU set, “a PDU set discard timer” which is associated with a PDU set, or the like.
In the embodiments of the present application, “stopping a discard timer (e.g. discard timer #1 as described in the embodiments of FIG. 3) associated with the data and starting another discard timer (e.g. discard timer #2 as described in the embodiments of FIG. 3) associated with the data” may be replaced by other similar descriptions, for example, “restarting the running discard timer with another discard timer length associated with the data” , “resetting a discard timer associated with the data and starting the discard timer with another discard timer length associated with the data, ” without departing from the spirit and scope of the disclosure. In the embodiments of the present application, “associated with the data” can be considered as “associated with a PDU set including the data” or “associated with the data itself. ” In some embodiments of the present application, “importance level” can be replaced by “PDU set importance level” or “PSI level” or the like. In some embodiments of the present application, “PDU set type” can be replaced by “PDU set importance level” or “PSI level” . More details will be illustrated in following text in combination with the appended drawings.
FIG. 3 illustrates an exemplary flowchart of handling a discard timer in accordance with some embodiments of the present application. The exemplary flowchart 300 in the embodiments of FIG. 3 may be performed by a UE (e.g. UE 102 or UE 501 as shown and illustrated in FIG. 1 or FIG. 5) . Although described with respect to a UE, it should be understood that other devices may be configured to perform a method similar to that of FIG. 3.
In the exemplary flowchart 300 as shown in FIG. 3, in operation 301, a UE may determine a discard timer for data of a PDU set type of a DRB. The discard timer may be a PDCP discard timer or a PDU set discard timer. For example, if PDU set based discarding is enabled, when the PDCP discard timer associated with a PDCP SDU of a PDU in a PDU set is expired or when the PDCP discard timer associated with a PDU set is expired, all remaining SDUs/PDUs in that PDU set could be discarded.
In operation 302, the UE may handle the discard timer for the data of the PDU set type of the DRB. For example, the UE handles the discard timer for the data of the PDU set type of the DRB based on a UL congestion status or an indication (denoted as indication #1 for simplicity) or pre-configuration information.
In some embodiments, indication #1 may be a discard timer activation command or a discard timer deactivation command, e.g. as described in Embodiment 1-1 of FIG. 5 as follows. For instance, indication #1 indicates at least one of the following:
(1) information to indicate the DRB;
(2) information to indicate a timer length of the discard timer of the DRB, e.g. the timer length of the discard timer, an offset value related to another discard timer length, or a ratio value related to another discard timer length;
(3) activated or deactivated status of the discard timer;
(4) information to indicate one or more PDU set types to activate or deactivate the discard timer (i.e., the information to indicate the PDU set type for which the discard timer is activated or deactivated) ;
(5) information to indicate one or more PDU set importance (e.g. PSI) levels to activate or deactivate the discard timer (i.e., the information to indicate the data importance level for which the discard timer is activated or deactivated) ; or
(6) information to indicate a PDCP SN or a PDU set ID according to which the discard timer is activated or deactivated.
In some embodiments of the exemplary flowchart 300, the UE may receive configuration information (denoted as configuration information #1 for simplicity) . For instance, configuration information #1 includes indication #1. In an embodiment, configuration information #1 of a DRB indicates at least one of the following:
(1) information to indicate a timer length of the discard timer , e.g. the timer length of the discard timer, an offset value related to another discard timer length, or a ratio value related to another discard timer length;
(2) activated or deactivated status of the discard timer;
(3) information to indicate one or more PDU set types to activate or deactivate the discard timer (i.e., the information to indicate the one or more PDU set types for which the discard timer is activated or deactivated) ; or
(4) information to indicate the one or more PSI levels to activate or deactivate the discard timer (i.e., the information to indicate the one or more PSI levels for which the discard timer is activated or deactivated) .
In operation 301, the discard timer may be determined based on configuration information #1. In an embodiment, configuration information #1 is included in RRC signaling. Configuration information #1 may also be named as “PDCP discard timer configuration information” or the like, e.g. as described in Embodiment 1-1 of FIG. 5 as follows.
In some embodiments, the UE may determine at least two timer lengths of the discard timer based on configuration information #1. In an embodiment, configuration information #1 of a DRB indicates at least one of the following:
(1) information to indicate one or more timer lengths of the discard timer, e.g. for one or more PSI levels or for one or more PDU set types; for example, the information indicates one or more timer lengths of the discard timer, one more offset values related to another discard timer length, or one or more ratio values related to another discard timer length (e.g. the discard timer with one timer length for certain PSI of unimportant, or the discard timer with another timer length for certain PSI of important) ;
(2) activated or deactivated status of the discard timers with a timer length within one or more timer lengths;
(3) information to indicate one or more PDU set types to activate or deactivate the discard timer with a timer length within one or more timer lengths;
(4) information to indicate the one or more PSI levels to activate or deactivate the discard timer with a timer length within one or more timer lengths; or
(5) information to indicate another discard timer length of the discard timer with a timer length within one or more timer lengths, e.g. for all PSI levels or all PDU set types.
In some further embodiments, the UE may further determine another discard timer based on configuration information #1. In these embodiments, configuration information #1 of a DRB further indicates timer length information of the another discard timer, e.g. a timer length of the another discard timer.
In some additional embodiments, the UE may determine one or more another discard timers based on configuration information #1. In an embodiment, configuration information #1 of a DRB indicates timer length information of one or more another discard timers (e.g. each discard timer is for one or more PSI levels, or each discard timer is for one or more PDU set types) , e.g. one or more timer lengths of the one or more another discard timers.
In some embodiments of the exemplary flowchart 300, configuration information #1 or indication #1 includes one or more bits (e.g. field D_i in a bitmap manner as described in the embodiments of FIG. 6 as follows) . Each bit may be associated with one DRB configured with the discard timer. A value of each bit may represent an activated or deactivated status of the discard timer for the PDU set type of one DRB.
In some embodiments, indication #1 indicates the UL congestion status detected at the network node. In an embodiment, the UE may activate the discard timer in response to that the UL congestion status is high or not low. In another embodiment, the UE may deactivate the discard timer in response to that the UL congestion status is low or not high. A specific example of the UE activating or deactivating the discard timer based on an indication indicating a UL congestion status is described in Embodiment 1-2 of FIG. 5 as follows.
In some embodiments of the exemplary flowchart 300, the UE may receive UL congestion detection configuration information (e.g. ULCongestionDectection information element (IE) ) from the network node, and detect the UL congestion status based at least on this configuration information. In an embodiment, this configuration information includes criteria of the UL congestion status. A specific example of the UE activating or deactivating the discard timer based on a UL congestion status detected by the UE is described in Embodiment 1-3 of FIG. 5 as follows.
In some embodiments of the exemplary flowchart 300, the pre-configuration information indicates at least one of the following:
(1) information to indicate one or more timer length (s) of the discard timer (s) for one or more PDU set types;
(2) information to indicate one or more PDU set type (s) , with which the discard timer with a timer length is associated, to activate or deactivate the discard timer (i.e., the information to indicate the PDU set type for which the discard timer is activated or deactivated) ; or
(3) information to indicate one or more importance level (s) , with which the discard timer with a timer length is associated, to activate or deactivate the discard timer (i.e., the information to indicate the importance level for which the discard timer is activated or deactivated) . A specific example of the UE activating or deactivating the discard timer based on pre-configuration information is described in Embodiment 1-4 of FIG. 5 as follows.
In some embodiments of the exemplary flowchart 300, to handle the discard timer, the UE may apply the discard timer to the data of the PDU set type if the discard timer is activated for the PDU set type of the DRB. Specific examples of the UE activating the discard timer for the data of the PDU set type of the DRB are described in Embodiments 1-1 to 1-4 of FIG. 5 as follows.
In some embodiments of the exemplary flowchart 300, if the discard timer for the PDU set type is activated, the UE may apply the discard timer to the data of the PDU set type based at least on:
(1) upon receiving the data of the PDU set type from an upper layer;
(2) running status of another discard timer associated with the data of the PDU set type or associated with a PDU set of the PDU set type including the data;
(3) running status of the discard timer with another timer length associated with the data of the PDU set type or associated with a PDU set of the PDU set type including the data;
(4) submission status of the data of the PDU set type to an RLC layer; or
(5) submission status of the PDU set including the data to the RLC layer.
In an embodiment, upon receiving the data of the PDU set type from the upper layer, the UE may apply the discard timer to the data of the PDU set type:
(1) if at least one SDU or PDU in the PDU set of the PDU set type including the data has been received and is available for transmission; or
(2) if no SDU or PDU in the PDU set including the data has been received (and is available for transmission) .
In an embodiment, the UE may apply the discard timer (i.e. the discard timer determined in operation 301, which is denoted as discard timer #2 for simplicity) to the data of the PDU set type based on the running status of another discard timer (denoted as discard timer #1 for simplicity) associated with the data of the PDU set type:
(1) if discard timer #1 is running for at least one SDU of a PDU within the PDU set of the PDU set type including the data;
(2) if discard timer #1 is not running for any SDU of a PDU within the PDU set including the data;
(3) if discard timer #1 is not running for any SDU of any PDU within the PDU set including the data;
(4) if discard timer #1 is running or not running for the data;
(5) if the data has or has not been submitted to the RLC layer data;
(6) if at least one SDU/PDU within the PDU set including the data has been submitted to the RLC layer data; or
(7) if no SDU/PDU within the PDU set including the data has been submitted to the RLC layer data.
In some embodiments, if the discard timer for the PDU set type is activated, the UE may determine whether buffer delay of the data is equal to or greater than a timer length of the discard timer or whether a timer length of the discard timer is equal to zero. If the buffer delay of the data is equal to or greater than the timer length of the discard timer or if the timer length of the discard timer is equal to zero, the UE may consider the discard timer or the running (another) discard timer associated with the data as expired.
In some embodiments, if the discard timer (e.g. discard timer #2) for the PDU set type is activated, the UE may determine whether another discard timer (e.g. discard timer #1) associated with the data of the PDU set type is running. For example, the discard timer and another discard timer may be the same timer with different length values. In response to not starting discard timer #1 associated with the data, the UE may start discard timer #2 associated with the data. If discard timer #1 associated with the data is running, the UE may stop discard timer #1 associated with the data and start discard timer #2 associated with the data; or the UE restarts current running discard timer, which is set to a length of the discard timer, associated with the data. In response to not starting discard timer #1 associated with one or more SDUs within the data, the UE may start discard timer #2 associated with the one or more SDUs within the data.
In some embodiments, to stop discard timer #1 associated with the data and start discard timer #2 associated with the data, the UE may determine whether a timer length of discard timer #2 is equal to zero. If the timer length of discard timer #2 is equal to zero, the UE may stop discard timer #1 associated with the data and start discard timer #2 associated with the data.
In some embodiments, to stop discard timer #1 associated with the data and start discard timer #2 associated with the data, the UE may set “a difference value between the timer length of discard timer #2 and the buffer delay” as the timer length of discard timer #2, and start discard timer #2 associated with the data.
In some embodiments, to stop discard timer #1 associated with the data and start discard timer #2 associated with the data, the UE may determine whether remaining running time of discard timer #1 associated with the data is greater than a timer length of discard timer #2. If the remaining running time of discard timer #1 associated with the data is greater than the timer length of discard timer #2, the UE may stop discard timer #1 associated with the data and start discard timer #2 associated with the data or restart the current running discard timer, which is set to the timer length of discard timer #2.
In some embodiments of the exemplary flowchart 300, to handle the discard timer, the UE may apply another discard timer (denoted as discard timer #a for simplicity) associated with the data of the PDU set type if the discard timer (i.e. the discard timer determined in operation 301, which is denoted as discard timer #b for simplicity) is deactivated for the PDU set type of the DRB. Specific examples of the UE deactivating the discard timer for the data of the PDU set type of the DRB are described in Embodiments 1-1 to 1-4 of FIG. 5 as follows.
In some embodiments, if discard timer #b for the PDU set type is deactivated, the UE may apply discard timer #a to the data of the PDU set type based at least on:
(1) upon receiving the data of the PDU set type from an upper layer;
(2) running status of discard timer #b associated with the data of the PDU set type or associated with a PDU set of the PDU set type including the data;
(3) submission status of the data of the PDU set type to a radio link control (RLC) layer; or
(4) submission status of the PDU set including the data to the RLC layer.
In some embodiments, upon receiving the data of the PDU set type from the upper layer, the UE may apply discard timer #a to the data of the PDU set type:
(1) if at least one SDU or PDU in the PDU set including the data has been received and is available for transmission; or
(2) if no SDU or PDU in the PDU set including the data has been received and is available for transmission.
In some embodiments, the UE may apply discard timer #a to the data of the PDU set type based on the running status of discard timer #b associated with the data of the PDU set type:
(1) if discard timer #b is running for at least one SDU of a PDU within the PDU set of the PDU set type including the data;
(2) if discard timer #b is not running for any SDU within the PDU set including the data; or
(3) if discard timer #b is running or not running for the data.
In some embodiments, if discard timer #b for the PDU set type is deactivated, the UE may determine whether discard timer #b associated with the data of the PDU set type is running. In response to not starting discard timer #b associated with the data, the UE may start discard timer #a associated with the data. If discard timer #b associated with the data is running, the UE may stop discard timer #b associated with the data and start discard timer #a associated with the data. If discard timer #b associated with the data is running, the UE may restart the running discard timer associated with the data, which is set to the length of discard timer #a. In response to not starting discard timer #b associated with a SDU within the data, the UE may start discard timer #a associated with the SDU within the data.
In some embodiments, if discard timer #b for the PDU set type is deactivated, the UE may determine whether buffer delay of the data is equal to or less than a timer length of discard timer #a. If the buffer delay of the data is equal to or less than the timer length of discard timer #a, the UE may: (1) stop discard timer #b associated with the data, and start discard timer #a associated with the data; (2) restart the running discard timer associated with the data, which is set to the length of discard timer #a; or (3) stop discard timer #b associated with the data, set a difference value between the timer length of discard timer #a and the buffer delay as the timer length of discard timer #a, and start discard timer #a associated with the data. If the buffer delay of the data is greater than the timer length of discard timer #a, the UE may consider discard timer #a or the running discard timer as expired.
In some embodiments of the exemplary flowchart 300, indication #1 is for updating the discard timer. For instance, indication #1 may be a dynamic discard timer update command, e.g. as described in Embodiment 2 of FIG. 5 as follows. In an embodiment, indication #1 includes at least one of the following:
(1) information to indicate the DRB;
(2) information to indicate a timer length of the discard timer determined in operation 301;
(3) information to indicate a PDU set type to update the discard timer;
(4) information to indicate an importance level to update the discard timer; or
(5) information to indicate a PDCP SN or a PDU set ID according to which the discard timer is updated.
In some embodiments, indication #1 is included in one of the following: a MAC CE; a PDCP control PDU; an RLC control PDU; and DCI.
In some embodiments of the exemplary flowchart 300, if indication #1 is received, the UE may update the discard timer associated with the data of the PDU set type based at least in part on:
(1) upon receiving the data of the PDU set type from an upper layer;
(2) running status of the discard timer associated with the data or associated with a PDU set of the PDU set type including the data;
(3) submission status of the data of the PDU set type to an RLC layer; or
(4) submission status of the PDU set including the data to the RLC layer.
In some embodiments, upon receiving the data of the PDU set type from the upper layer, the UE may update the discard timer: (1) if at least one SDU or PDU in the PDU set including the data has been received and is available for transmission; or (2) if no SDU or PDU in the PDU set including the data has been received and is available for transmission. A specific example of the UE updating the discard timer for the data of the PDU set type of the DRB is described in Embodiment 2 of FIG. 5 as follows.
In some embodiments, the UE may update the discard timer based on the running status of the discard timer associated with the data or associated with the PDU set of the PDU set type including the data:
(1) if the discard timer is running for at least one SDU within the PDU set of the PDU set type including the data;
(2) if the discard timer is not running for any SDU within the PDU set including the data;
(3) if the discard timer is running or not running for the data;
(4) if the data has or has not been submitted to the RLC layer data;
(5) if at least one SDU within the PDU set including the data has been submitted to the RLC layer data; or
(6) if no SDU within the PDU set including the data has been submitted to the RLC layer data.
In some embodiments, to update the discard timer associated with the data of the PDU set type, the UE may: (1) determine whether buffer delay of the data is equal to or greater than the updated timer length of the discard timer; or (2) determine whether the updated timer length of the discard timer is equal to zero.
In some embodiments, the UE may consider the discard timer having the updated timer length or the running discard timer as expired, if: (1) the buffer delay of the data is equal to or greater than the updated timer length of the discard timer; or (2) the updated timer length of the discard timer is equal to zero.
In some embodiments, to update the discard timer associated with the data of the PDU set type, the UE may determine whether the discard timer associated with the data is running. In response to not starting the discard timer associated with the data, the UE may start the discard timer having an updated timer length associated with the data. If the discard timer associated with the data is running, the UE may stop the discard timer associated with the data, and start the discard timer having the updated timer length associated with the data. In response to not starting the discard timer associated with one or more SDUs within the data, the UE may start the discard timer having the updated timer length associated with the one or more SDUs within the data.
In some embodiments, to start the discard timer, the UE may determine whether the updated timer length of the discard timer is equal to zero or whether the updated timer length is less than the timer length of the discard timer. If the updated timer length is equal to zero or if the updated timer length is less than the timer length of the discard timer, the UE may (re) start the discard timer having the updated timer length associated with the data.
In some embodiments, to start the discard timer, the UE may determine whether buffer delay of the data is equal to or greater than the updated timer length of the discard timer. If the buffer delay of the data is equal to or greater than the updated timer length, the UE may consider the discard timer having the updated timer length or the running discard timer as expired. If the buffer delay of the data is less than the updated timer length, the UE may:
(1) stop the discard timer having the timer length associated with the data if running, and start the discard timer having the updated timer length associated with the data; or
(2) stop the discard timer having the timer length associated with the data if running, set a difference value between the updated timer length and the buffer delay as the timer length of the discard timer, and start the discard timer associated with the data.
In some embodiments, to start the discard timer, the UE may determine whether remaining running time of the discard timer associated with the data is equal to or greater than the updated timer length of the discard timer. If the remaining running time of the discard timer associated with the data is equal to or greater than the updated timer length, the UE may stop the discard timer having the timer length associated with the data, and start the discard timer having the updated timer length associated with the data.
In some embodiments, to start the discard timer, the UE may determine whether buffer delay of the data or the PDU set including the data is equal to or less than the updated timer length of the discard timer or whether the updated timer length is greater than the timer length of the discard timer. If the buffer delay of the data is equal to or less than the updated timer length or if the updated timer length is greater than the timer length of the discard timer, the UE may:
(1) stop the discard timer having the timer length associated with the data if running, and start the discard timer having the updated timer length associated with the data; or
(2) stop the discard timer having the timer length associated with the data if running, set a difference value between the updated timer length and the buffer delay as the timer length of the discard timer, and start the discard timer for the data.
In some embodiments, to start the discard timer, the UE may determine whether remaining running time of the discard timer for the data is equal to or less than the updated timer length of the discard timer. If the remaining running time of the discard timer for the data is equal to or less than the updated timer length, the UE may stop the discard timer having the timer length if running, and start the discard timer having the updated timer length associated with the data.
FIG. 4 illustrates an exemplary flowchart performed by a network node in accordance with some embodiments of the present application. The exemplary flowchart 400 in the embodiments of FIG. 4 may be performed by a network node (e.g. BS 101 or BS 504 as shown and illustrated in FIG. 1or FIG. 5) . Although described with respect to a network node, it should be understood that other devices may be configured to perform a method similar to that of FIG. 4.
In the exemplary flowchart 400 as shown in FIG. 4, in operation 401, a network node may receive capability information of a UE. The capability information may include handling a discard timer for data of a PDU set type of a DRB. In operation 402, the network node may transmit, to the UE, configuration information for the UE handling the discard timer for the data of the PDU set type of the DRB. For instance, the configuration information may be an indication (e.g. indication #1 as described in the embodiments of FIG. 3) or UL congestion detection configuration information. In an embodiment, the UL congestion detection configuration information includes criteria of a UL congestion status.
In some embodiments, the indication is for activating or deactivating the discard timer. For instance, the indication indicates at least one of the following:
(1) information to indicate the DRB;
(2) activated or deactivated status of the discard timer;
(3) information to indicate a PDU set type to activate or deactivate the discard timer;
(4) information to indicate an importance level to activate or deactivate the discard timer; or
(5) information to indicate a PDCP SN or a PDU set ID according to which the discard timer is activated or deactivated.
In some embodiments, the indication includes an UL congestion status detected at the network node.
In some embodiments, the indication is for updating the discard timer. For instance, the indication includes at least one of the following:
(1) information to indicate the DRB;
(2) information to indicate a timer length of the discard timer;
(3) information to indicate a PDU set type to update the discard timer;
(4) information to indicate an importance level to update the discard timer; or
(5) information to indicate a PDCP SN or a PDU set ID according to which the discard timer is updated.
In some embodiments, the indication is included in one of the following: a MAC CE; a PDCP control PDU; an RLC control PDU; and DCI.
In some embodiments of the exemplary flowchart 400, the network node may transmit configuration information (e.g. configuration information #1 as described in the embodiments of FIG. 3) to the UE, which indicates at least one of the following:
(1) timer length information of the discard timer of the DRB;
(2) activated or deactivated status of the discard timer;
(3) PDU set type to activate or deactivate the discard timer; or
(4) importance level to activate or deactivate the discard timer.
In some embodiments, the configuration information is included in RRC signaling.
In some embodiments, the configuration information or the indication includes one or more bits. Each bit within the one or more bits is associated with one DRB configured with the discard timer. A value of each bit represents an activated or deactivated status of the discard timer for the PDU set type of each DRB.
Details described in all other embodiments of the present application are applicable for the embodiments of FIGS. 3 and 4. Moreover, details described in the embodiments of FIGS. 3 and 4 are applicable for all the embodiments of FIGS. 1, 2, and 5-8. It should be appreciated by persons skilled in the art that the sequence of the operations in these exemplary procedures may be changed and some of the operations in these exemplary procedures may be eliminated or modified, without departing from the spirit and scope of the disclosure. Specific examples of exemplary flowchart 300 or 400 are described in the embodiments of FIGS. 5-7 as follows.
FIG. 5 illustrates an exemplary flowchart of transmitting configuration information regarding a discard timer in accordance with some embodiments of the present application. In particular, the exemplary flowchart 500 in the embodiments of FIG. 5 includes specific Embodiment 1 (regarding how to activate or deactivate a discard timer) and Embodiment 2 (regarding how to update a discard timer) as follows in different cases.
Embodiment 1
In Embodiment 1, a transmitting PDCP entity may activate the additional discard timer for a specific PDU set type according to a network node’s indication or a UL Congestion status.
In the embodiments of the present application, a discard timer may be a PDCP discard timer or a PDU set discard timer. A UE could discard all remaining SDUs/PDUs of a PDU set in the following cases if PDU set based discarding is enabled:
(1) if using a PDCP discard timer of a PDCP SDU in a PDU set, if the PDCP discard timer of one of PDCP SDU (e.g. the first PDCP SDU) in a PDU set expires; or
(2) if using a PDU set discard timer for a PDU set, if the PDU set discard timer of a PDU set expires.
A PDU set type may be characterized by a notion of “PDU set importance” identifies the relative importance of a PDU set compared to other PDU Sets within a QoS Flow. It indicates how important the PDU set (e.g. a video frame) is for the application. For example, an important PDU set could be an I-Frame, while a less important PDU set could be a P-Frame. In an example, the PDU set type with high importance is defined as primary PDU set or PDU set type1. While the PDU set type with less importance is called as “secondary PDU set” or “PDU set type #2” .
In particular, Embodiment 1 may include specific Embodiments 1-1, 1-2, 1-3, and 1-4 as follows in different cases.
Embodiment 1-1
In Embodiment 1-1, UE 501 applies the additional discard timer for the specific PDU set type based on dynamic signaling from a network node.
In operation 511, a network node, e.g. BS 504 or CU 503 (in case of CU and DU split) , may transmit PDCP discard timer configuration information for a DRB to UE 501 in RRC signaling. For example, the RRC signaling may be RRCreconfiguraiton message, RRCResume message, or RRCSetup message.
In some embodiments, the PDCP discard timer configuration information may be related to a PDCP discard timer (i.e. 1^st discard timer, e.g. discard timer #1 as described in the embodiments of FIG. 3) and/or an additional PDCP discard timer (i.e. 2^nd discard timer, e.g. discard timer #2 as described in the embodiments of FIG. 3) . In some embodiments, the PDCP discard timer configuration information may be related to one or more PDCP discard timers (i.e. 1^st discard timer, e.g. discard timer #1 as described in the embodiments of FIG. 3) and/or the PDCP discard timer configuration information may be related to one or more additional PDCP discard timers (i.e. 2^nd discard timer, e.g. discard timer #2 as described in the embodiments of FIG. 3) , for example, each PDCP discard timer is for one or more PDU set types. The 2^nd discard timer may be configured by the network node or predefined by a standard specification (e.g. timer length value = 0) . In the embodiments of the present application, the 1^st or 2^nd discard timer may also be named as the 1^st or 2^nd PDCP discard timer, the 1^st or 2^nd PDU set discard timer, or the like.
In Embodiment 1-1, if the 2^nd discard timer for one or more specific PDU set types has not been activated, UE 501 may only apply the 1^st discard timer to all PDU set type (s) of the DRB. Otherwise, UE 501 may apply the 2^nd discard timer to the specific PDU set type of the DRB, which may be PDU set type #1 (i.e. an important PDU set) or PDU set type #2 (i.e. a less important PDU set) . If more than one 2^nd discard timers, which are for different PDU set types, are activated, UE 501 may apply the 2^nd discard timers to the specific PDU set types of the DRB.
In an embodiment, both the 1^st or 2^nd discard timers may be used to PDU set discard handling. If the 1^st discard timer of one PDCP SDU in a PDU set expires and PDU set based discarding is enabled by BS 504, UE 501 may discard all the remaining data of the PDU set. Otherwise, UE 501 only discards the one PDCP SDU. If the 2^nd discard timer of one PDCP SDU in a PDU set expires and PDU set based discarding is enabled by BS 504, UE 501 may discard the remaining data of the PDU set. Otherwise, UE 501 only discards the one PDCP SDU.
For example, the 2^nd discard timers for one or more PDU set types may be presented in a form of at least one of the following:
(1) An absolute value, e.g. 5ms, the actual length of the 2^nd discard timer = 5ms.
(2) A rate relative value to 1^st discard timer, e.g. 0.5, the actual length of the 2^nd discard timer = a length of the 1^st discard timer *0.5.
(3) An offset value relative to 1^st discard timer, e.g. 5ms, the actual length of the 2^nd discard timer = a length of the 1^st discard timer +/–offset value.
In some embodiments, the PDCP discard timer configuration information includes an indication, e.g. additional PDCP discard timer status IE, which may be used to indicate the status of the 2^nd discard timers for the specific PDU set types of the DRB. If only one 2^nd discard timer is configured, for example:
The additional PDCP discard timer status IE may indicate the status to apply the 2^nd discard timer to the specific PDU set type at the time when this IE is configured and activated.
(1) TRUE means that the status is activated. UE 501 may activate the 2^nd discard timer for specific PDU set type of the PDCP entity.
(2) FALSE means that the status is not activated. UE 501 does not activate the 2^nd discard timer for the specific PDU set type of the PDCP entity, i.e. using the 1^st discard timer for the specific PDU set type.
In some embodiments, the PDCP discard timer configuration information may include an indication, e.g. PDUSetInfo IE or importancelevel IE, which may be used to indicate the PDU set type to apply the 2^nd discard timer.
(1) PDUSetInfo: this indication may indicate which PDU set type to activate the 2^nd discard timer if the 2^nd discard timer is activated. For example, PDU set type #1 indicates a PDU set type with higher or highest importance, and PDU set type #2 indicates a PDU set type with less importance.
a) In an example, if the PDUSetInfo value is set to PDU set type #2, UE 501 may apply the 2^nd discard timer to the data of PDU set type #2.
b) In another example, if the PDUSetInfo value is set to PDU set type #1, UE 501 may apply the 2^nd discard timer to the data of PDU set type #1.
c) In an example, the PDUSetInfo IE may be configured as follows.
(2) importanceLevel: this indication may indicate which PSI of a PDCP SDU to apply the 2^nd discard timer.
a) In an example, if the importanceLevel value is set to a specific PSI level, UE 501 may apply the 2^nd discard timer to the data of the PDU set with a PSI level which is equal to or lower than the specific PSI level.
b) In another example, if the importanceLevel value is set to a specific PSI level, UE 501 may apply the 2^nd discard timer to the data of the PDU set with a PSI level which is equal to or higher than the specific PSI level.
c) In an example, the importanceLevel IE may be configured as follows.
d) For example, 10 is highest importance level, while 1 is the lowest importance level.
After UE 501 receives the PDCP discard timer configuration information in operation 511, if the status of the 2^nd discard timer (s) is set to TRUE, UE 501 may activate the 2^nd discard timer to the specific PDU set (s) , i.e. using the 2^nd discard timer for PDU set discard handling.
In operation 513 or 515, the network node, e.g. DU 502, may transmit a dynamic discard timer activation or deactivation command to UE 501, to assist UE 501 to determine whether to apply the 2^nd discard timer to the specific PDU set type. In an embodiment, in operation 513, DU 502 may transmit a dynamic discard timer activation command to UE 501. In operation 515, DU 502 may transmit a dynamic discard timer deactivation command to UE 501.
In some embodiments of the present application, a dynamic discard timer activation command may be named as “a dynamic activation discard timer command” , “an activation discard timer command” , “an activation command” , “an activation indication” , or the like. A dynamic deactivation discard timer command may be named as “a dynamic deactivation discard timer command” , “a deactivation discard timer command” , “a deactivation command” , “a deactivation indication” , or the like.
In case of CU and DU split, CU 503 optionally preconfigures the 2^nd discard timer command allowed indication to DU 502 via, for example, F1AP message or CU 503 indicates the 2^nd discard timer command allowed indication to DU 502 via user plane, e.g. in operation 512. If receiving this indication from CU 503, DU 502 may transmit an activation or deactivation command to UE 501.
In some embodiments, when BS 504 detects that the UL congestion status is high or not low, BS 504 may determine to send an activation command to UE 501. The activation command indicates UE 501 to activate the 2^nd discard timer for the specific PDU set type for a DRB. In some other embodiments, when BS 504 detects that the UL congestion status is low or not high, BS 504 may determine to send a deactivation command to UE 501. The deactivation command indicates UE 501 to deactivate the 2^nd discard timer for the specific PDU set type for a DRB.
For instance, an activation command may be transmitted via a MAC CE and an associated MAC-subheader. A MAC sub-header associated with the MAC CE may include an assigned logical channel ID (LCID) field to identify this MAC CE. The MAC CE may also include at least one field of the following.
(1) which DRB (s) , e.g. DRB field. For example, it is a 5 bit length field which includes the DRB ID.
a) In an example, this information may be not included in this MAC CE, and UE 501 may consider that the command is applicable for all the DRB (s) configured with the 2^nd discard timer or only applicable for the DRBs with additional PDCP discard timer status of the DRB which is set to TURE in the receiving RRC signaling in operation 511.
(2) Activation or deactivation status of the 2^nd discard timer (s) , e.g. Status field. For example, it is a 1 bit length field, wherein value 1 indicates an activation status for one or more PDU set types, and value 0 indicates a deactivation status for one or more PDU set types. For example, a bitmap, each bit indicates an activation status for the 2^nd discard timer. Each bit position in the bitmap presents the 2^nd discard timer i, wherein i is in (ascending or descending) order of the PDU set type value among the PDU set types configured/associated with the 2^nd discard timer (s) .
(3) Which PDU set type (s) to activate the 2^nd discard timer.
(4) Which PSI level (s) to activate the 2^nd discard timer.
(5) Which PDCP SDU SN or which PDU set SN, from which UE 501 may start applying the command.
(6) A timer length value or an offset value or a ratio value of the 2^nd discard timer. For example:
a) If using an absolute length value of the 2^nd discard timer, e.g. 5ms, the actual length of the 2^nd discard timer = 5ms.
b) If using an offset value relative to the 1^st or 2^nd discard timer, e.g. 5ms, the actual length of the 2^nd discard timer = a length of the 1^st discard timer +/–the offset value.
c) If using a rate relative value to the 1^st or 2^nd discard timer, e.g. 0.5, the actual length of the 2^nd discard timer = a length of the 1^st discard timer *0.5.
In the embodiments of the present application, a deactivation command may be of a similar format to an activation command, for example, including the fields as described above.
For example, an activation or deactivation command can be transmitted in a MAC CE in the embodiments of FIG. 6 and an associated MAC-subheader. For instance, “the DRB field” and “the status filed” described above may be replaced by a bitmap. For example, each bit position in the bitmap presents a DRB configured with the 2^nd discard timer, and each bit value presents the activation or deactivation status of the 2^nd discard timer of the DRB.
FIG. 6 illustrates an exemplary diagram of a discard timer command MAC CE in accordance with some embodiments of the present application. As shown in the embodiments of FIG. 6, the MAC-subheader may include:
(1) field D_i: This field indicates an activation or deactivation status of the 2^nd discard timer of DRB i, wherein i is the ascending order of the DRB ID among the DRBs configured with the 2^nd discard timer (and with RLC entity (ies) ) associated with this MAC entity. The D_i field is set to 1 to indicate that the 2^nd discard timer of DRB i shall be activated. The D_i field is set to 0 to indicate that the 2^nd discard timer of DRB i shall be deactivated.
Referring back to Embodiment 1-1, in some embodiments, the activation or deactivation command can be transmitted in a PDCP control PDU and an associated PDCP header. The associated PDCP header may include a PDU type to identify this PDCP control PDU. The PDCP payload may include at least one of the abovementioned fields in the MAC CE. This activation or deactivation command can also be transmitted in an RLC control PDU or DCI. The payload may include at least one of the above fields.
In some embodiments, after UE 501 receives the activation command from BS 504 in operation 513 to activate the 2^nd discard timer for a DRB, UE 501 may activate the 2^nd discard timer for the data of a specific PDU set type on the DRB in operation 514.
FIG. 7 illustrates an exemplary flowchart of receiving discard timer command timing in accordance with some embodiments of the present application. In some embodiments of FIG. 7, if UE 501 receives an activation command for a DRB via a MAC CE, the MAC entity may notify an activation indication to the PDCP entity of the DRB. Some embodiments of FIG. 7 assume that the 1^st and 2^nd discard timers are for the same PDU set type. For example, the PDCP entity may activate or apply the 2^nd discard timer to PDCP SDU (s) of the specific PDU set type (s) which is available for transmission according to at least one of:
(1) the running status of the 1^st discard timer of the PDU set including the PDU of the PDCP SDU (started for the whole PDU set) ;
(2) the submission status of the whole PDU set including the PDU of the PDCP SDU to an RLC layer;
(3) the submission status of a part of the PDU set including the PDU of the PDCP SDU to the RLC layer;
(4) the running status of the 1^st discard timer of the PDCP SDU in the PDU set (started for each SDU in the whole PDU set) ; or
(5) the submission status of the PDCP SDU in the PDU set to the RLC layer.
For example, the PDU set (s) may include at least one of the following bullets (1) - (6) :
(1) Future arriving PDU set (s) .
a) Referring to FIG. 7, if receiving the activation command at t1, a UE may activate or apply the 2^nd discard timer to the data of the PDU set to be received after or at t1, e.g. PDU Set SN = 1, i.e. the next PDU set available for transmission to be expected to receive from the upper layer.
b) In an example, if the UE receives a new PDU set with the specific PDU set type during or after the 2^nd discard timer is activated for the specific PDU set type, the UE may start the 2^nd discardtimer associated with a PDU SDU in the PDU set. For example:
(2) The 1^st discard timer has not been started for any data in PDU set, i.e. the timer is not running. Referring to FIG. 7, if receiving the activation command at t2 and the PDCP entity has not started the 1^st discard timer for any one of data in the PDU set, the UE may apply the 2^nd discard timer to the data of the PDU set, e.g. PDCP Set SN = 1. For example:
(3) The 1^st discard timer has been started for partial data of the PDU set, i.e. the 1^st discard timer is running.
a) Referring to FIG. 7, if receiving the activation command at t3 and the PDCP entity has started the 1^st discard timer for some data (PDCP SN = 1) in the PDU set SN = 1, the UE applies the 2^nd discard timer to the data (e.g. PDCP SN = 2, 3, 4) of the PDU set SN = 1, for which has not started the 1^st discard timer, i.e. the next PDCP SDU available for transmission to start a discard timer. When any one timer expires, the UE may discard the remaining data of the PDU set. For example:
b) Referring to FIG. 7, if receiving the activation command at t3 and the PDCP entity has started the 1^st discard timer for some data (e.g. PDCP SN = 1) in the PDU set (e.g. PDU Set SN = 1) , the UE may apply the 2^nd discard timer to the all data (e.g. PDCP SN = 1, 2, 3, 4) of the PDU set (e.g. PDU Set SN =1) , regardless of the running status of the 1^st discard timer of the data. For the PDCP SN = 1 or for PDU Set SN = 1, the UE may reset or stop the running 1^st discard timer and start the 2^nd discard timer according to the 2^nd discard timer value and/or the buffer delay of the data. Or, for the PDCP SN = 1 or for PDU Set SN = 1, the UE may restart the running 1^st discard timer, using the length of the 2^nd discard timer according to the 2^nd discard timer value and/or the buffer delay of the data. The short discard timer value (e.g. 0ms) may benefit from the earlier packet dropping especially for the UE. For example:
c) In an example, when either the 1^st or the 2^nd discard timer expires for a PDCP SDU in the PDU set, the transmitting PDCP entity may discard the PDCP SDU(s) in the PDU set along with the corresponding PDCP data PDU.
Optionally, if the 2^nd discard timer value is equal to 0, the UE may reset or stop the 1^st discard timer and start the 2^nd discard timer for the PDU SDU or the PDU set. Or, if the 2^nd discard timer value is equal to 0, the UE may restart the running 1^st discard timer, using the length of the 2^nd discard timer for the PDU SDU or the PDU set. For example:
Optionally, if the buffer delay of a PDCP SDU or a PDU set is equal to or larger than the 2^nd discard timer value, the UE may consider the 2^nd discard timer or the running 1^st discard timer as expired for the PDU SDU or the PDU set, i.e. the UE does not start the 2^nd discard timer. For example:
Optionally, if the buffer delay of a PDCP SDU or a PDU set is smaller than the 2^nd discard timer value, the UE may reset or stop the 1^st discard timer, sets (2^nd discard timer value –buffer delay) as a new timer length of the 2^nd discard timer, and start the 2^nd discard timer for the PDU SDU or the PDU set. If the buffer delay of a PDCP SDU or a PDU set is smaller than the 2^nd discard timer value, the UE may restart the running 1^st discard timer, and set (2^nd discard timer value –buffer delay) as a new timer length of the 2^nd discard timer for the PDU SDU or the PDU set. For example:
Optionally, if the remaining time of the running 1^st discard timer is equal to or smaller than the 2^nd discard timer value, the UE does not start the 2^nd discard timer for the PDU SDU or the PDU set. This can at least avoid the buffer time is longer than 1^st timer length. If the remaining time of the running discard timer is equal to or larger than the 2^nd discard timer value, the UE may reset or stop the running 1^st discard timer and start the 2nd discard timer for the PDU SDU or the PDU set. For example:
(4) The whole PDU set has not been submitted to the RLC entity.
a) For example, if the data of the whole PDU set has not been submitted to the RLC entity, the UE may apply the 2^nd discard timer to the PDCP SDU in the PDU set. Otherwise, the UE does not apply the 2^nd discard timer to the PDCP SDU in the PDU set.
b) The bullet (4) can be combined with above bullet (1) , (2) , or (3) .
c) For example, if the data of the whole PDU set has not been submitted to the RLC entity and no data in PDU set (s) has started the 1^st discard timer, UE applies the 2^nd discard timer to the PDCP SDU in the PDU set.
d) For example, if the data of the whole PDU set has not been submitted to the RLC entity and part of the PDU set has started the 1^st discard timer, UE applies the 2^nd discard timer to the PDCP SDU in the PDU set, associated which PDCP SDU UE has not started the 1^st discard timer.
e) For example, if the data of the whole PDU set has not been submitted to the RLC entity and part of the PDU set has started the 1^st discard timer, UE applies the 2^nd discard timer to the PDCP SDU in the PDU set even if the 1^st discard timer has started associated with the PDCP SDU.
(5) The part of the PDU set has not been submitted to the RLC entity.
a) For examples, some PDCP SDU (s) of the PDU set have not been submitted to the RLC entity, and some PDCP SDU (s) of the PDU set have been submitted to the RLC entity.
b) For example, the UE only applies the 2^nd discard timer to the PDCP SDU (s) in the PDU set, which has not been submitted to the RLC entity. This can be combined with above bullet (1) , (2) , or (3) .
c) For example, if a part of the PDU set has not been submitted to the RLC entity and the part of the PDU set has started the 1^st discard timer, if the UE has not started the 1^st discard timer associated with the PDCP SDU, and the PDCP SDU has not been submitted to the RLC entity, the UE applies the 2^nd discard timer to the PDCP SDU in the PDU set.
d) For example, if a part of the PDU set has not been submitted to the RLC entity and the part of the PDU set has started the 1^st discard timer, the UE applies the 2^nd discard timer to the PDCP SDU in the PDU set, and the PDCP SDU has not been submitted to the RLC entity, and the 1^st discard timer has been started associated with the PDCP SDU.
e) For example, the UE also applies the 2^nd discard timer to the PDCP SDU (s) in the PDU set, which has been submitted to the RLC entity. This can be combined with above bullet (1) , (2) , or (3) .
f) For example, if a part of the PDU set has not been submitted to the RLC entity and the part of the PDU set has started the 1^st discard timer, the UE applies the 2^nd discard timer to the PDCP SDU in the PDU set, and the PDCP SDU has been submitted to the RLC entity, and the 1^st discard timer has been started associated with the PDCP SDU.
(6) From the specified PDU set SN or PDCP SN, from the next SN of the specified PDU set SN or PDCP SN.
In operation 515, DU 502 may transmit a deactivation command to UE 501, to assist UE 501 to determine to deactivate the 2^nd discard timer to the specific PDU set type. In an example, when DU 502 detects that the UL congestion is not high or low, DU 502 determines to sends the deactivation command for a DRB to UE 501.
In operation 516, if UE 501 receives the deactivation command from DU 502 to deactivate the 2^nd discard timer for the DRB, UE 501 deactivates the 2^nd discard timer to the specific PDU set type on the DRB, i.e. UE 501 may resume or apply the 1^st discard timer to the specific PDU set type.
With reference to the embodiments of FIG. 7, if UE 501 receives a deactivation command for a DRB via a MAC CE, the MAC entity may notify a deactivation indication to the PDCP entity of the DRB.
For instance, UE 501 may start the 1^st discard timer for PDU set (s) upon reception of the deactivation command according to at least one of: (1) the running status of the 2^nd discard timer, (2) the submission status of the whole PDU set to an RLC layer, (3) the submission status of part of the PDU set to the RLC layer.
For example, the PDU set (s) may include at least one of the following bullets (1) - (6) :
(1) Future arriving PDU set (s) .
a) Referring to FIG. 7, if receiving the deactivation command at t1, the UE applies the 1^st discard timer to the data of the PDU set to be received after or at t1, e.g. PDU Set SN = 1, i.e. the next PDU set available for transmission to be expected to receive from the upper layer.
(2) No data in PDU set (s) has started the 2^nd discard timer, i.e. the timer is not running.
a) Referring to FIG. 7, if receiving the deactivation command at t2 and the PDCP entity has not started the 2^nd discard timer for any one of data in the PDU set, UE applies the 1^st discard timer to the data of the PDU set, e.g. PDCP Set SN = 1.
(3) Partial data of the PDU set has already started the 2^nd discard timer, i.e. it is running.
a) Referring to FIG. 7, if receiving the deactivation command at t3 and the PDCP entity has started the 2^nd discard timer for some data (PDCP SN = 1) in the PDU set SN = 1, UE applies the 1^st discard timer to the data (e.g. PDCP SN = 2, 3, 4) of the PDU set SN = 1, which has not started the 2^nd discard timer, i.e. the next PDCP SDU available for transmission to start a discard timer.
b) Referring to FIG. 7, if receiving the deactivation command at t3 and the PDCP entity has started the 2^nd discard timer for some data (e.g. PDCP SN =1) in the PDU set (e.g. PDCP Set SN = 1) or for the whole PDU set, the UE applies the 1^st discard timer to the all data (e.g. PDCP SN = 1, 2, 3, 4) of the PDU set (e.g. PDCP Set SN = 1) , regardless of the running status of the 2^nd discard timer of the data. For PDCP SN = 1 or for PDU set SN = 1, the UE may reset or stop the 2^nd discard timer and starts the 1^st discard timer.
c) Optionally, if the buffer delay of a PDCP SDU or a PDU set is equal to or smaller than the 1^st discard timer value, the UE may reset or stop the 2^nd discard timer and starts the 1^st discard timer for the PDU SDU or the PDU set. It may cause the longer the buffer time. Considering there is no UL congestion, the extending buffer time is not critical.
d) Optionally, if the buffer delay of a PDCP SDU or a PDU set is equal to or smaller than the 1^st discard timer value, the UE may reset or stop the 2^nd discard timer and set (1^st discard timer value –buffer delay) to the 1^st discard timer and starts the 1^st discard timer for the PDU SDU or the PDU set.
e) Optionally, if the buffer delay of a PDCP SDU or a PDU set is larger than the 1^st discard timer value, the UE considers the 1^st discard timer expires for the PDU SDU or the PDU set, i.e. does not start the 1^st discard timer.
(4) The whole PDU set has not been submitted to the RLC entity.
(5) The part of the PDU set has not been submitted to the RLC entity.
(6) From the specified PDU set SN or PDCP SN, from the next SN of the specified PDU set SN or PDCP SN.
Embodiment 1-2
In Embodiment 1-2, a UE may activate or deactivate an additional PDCP discard timer based on dynamic UL congestion status from a network node. In Embodiment 1-2, operations 511, 513, 514, 515, and 516 may be performed.
In operation 511, CU 503 may transmit the PDCP discard timer configuration for a DRB to the UE in an RRC message. The PDCP discard timer configuration may include a (i.e. 1^st) PDCP discard timer and an additional (i.e. 2^nd) PDCP discard timer.
In operation 513, DU 502 may transmit UL congestion status signaling to UE 501.
In operation 514, upon receiving the UL congestion status signaling from BS 504, UE 501 may activate the 2^nd discard timer for the specific PDU set type on the DRB if the UL congestion status is high or not low.
In an example, when BS 504 detects the UL congestion is high or not low, BS 504 may determine to send the UL congestion status to UE 501. The status can be enumerated with high or low or a numeric congestion level which varies from 0～1. For example, 1 represents highest congestion level, 0.5 represents middle congestion level, and 0 represents no congestion.
In operation 515, DU 502 may transmit the UL congestion status signaling to UE 501.
In operation 516, upon receiving the UL congestion status signaling from BS 504, UE 501 may deactivate the 2^nd discard timer for a DRB if the UL congestion status is not high or low.
The UL congestion status signaling in operation 513 and 515 may be replaced in-band marking, i.e. the UL congestion status is included in Layer2 header (e.g. SDAP, PDCP, RLC, or MAC header) or IP header.
Embodiment 1-3
In Embodiment 1-3, a UE may activate or deactivate an additional PDCP discard timer based on detected UL congestion status at the UE. In Embodiment 1-3, operations 511, 513, and 514 may be performed.
In operation 511, CU 503 may transmit the PDCP discard timer configuration for a DRB to UE in an RRC message. The PDCP discard timer configuration may include a PDCP discard timer (i.e. 1^st discard timer) and an additional discard timer (i.e. 2^nd discard timer) .
In operation 513, DU 502 may optionally transmit UL congestion detection configuration to UE 501 in an RRC message. For example, the RRC message includes an indication ULCongestionDectection IE used to enable UE 501 to detect the UL congestion status. In an embodiment, the ULCongestionDectection IE indicates the criteria of UL congestion status. The criteria of the congestion status may include:
(1) the packet discard count, for example, the packet discard count in N period, wherein N =1, …n, and n >1, or
(2) buffer size of a LCH of the DRB or a LCG (logical channel group) including the LCH of the DRB, or legacy buffer size of a LCG including the LCID of the DRB, for example, the packet discard count in N period, wherein N =1, …n, and n >1.
In operation 514, UE 501 monitors the UL congestion status according to the UL congestion detection configuration or based on UE 501’s implementation.
1) If UE 501 detects the UL congestion status is high or not low, UE 501 activates the 2^nd discard timer for the PDU set type on a DRB. For example, if UE 501 counts that the discarding packet number is equal to or above the packet discard count, it is considered as high.
2) If UE 501 detects the UL congestion status is not high or low, UE 501 deactivates the 2^nd discard timer for the PDU set type on a DRB. For example, if UE 50 counts that the discarding packet number is below the packet discard count, it is considered as low.
Embodiment 1-4
Different from Embodiment 1-1, Embodiment 1-2, and Embodiment 1-3, Embodiment 1-4 assumes that only one PDCP discard timer is configured via an RRC message. For instance:
1) An additional (2^nd) PDCP discard timer value may be predefined in a standard specification, e.g. 0ms; or the predefined rate relative to the 1^st discard timer value, e.g. 50%, value = a length of the 1^st discard timer value *0.5; or the predefined offset relative to the 1^st discard timer value, e.g. 5ms, value = 1^st discard timer value -5.
2) The above information may be indicated by the dynamic signaling to UE 501.
In Embodiment 1-4, the above pre-configuration information may be predefined by a standard specification, for example, the specific PDU set type (s) to dynamically apply the 2^nd discard timer (s) may be predefined by a standard specification or configured in an RRC message. The PSI level (s) to apply the 2^nd discard timer (s) may be predefined by a standard specification.
In Embodiment 1-4, UE 501 may apply the predefined 2^nd discard timer value to the specific PDU set type by performing the same operations as those in Embodiment 1-1 and Embodiment 1-2, for example:
(1) if UE 501 receives a dynamic activation command from BS 504;
(2) if UE 501 determines the UL congestion status which is detected at UE 501;
(3) if UE 501 receives an UL high congestion status indication or command from BS 504.
In Embodiment 1-4, UE 501 may apply or resume the 1^st discard timer value to the specific PDU set type if receiving the deactivation command as specified in Embodiment 1-1.
Embodiment 2
Embodiment 2 assumes that the transmitting PDCP entity default uses different discard timers for different PDU set types based on RRC configuration information, and a UE may handle the PDCP discard timer value for the specific PDU set type according to a dynamic update command. In Embodiment 2, a UE may update the discard timer value of a PDU set type based on a command from a network node. In Embodiment 2, operations 511-516 may be performed.
In operation 511, CU 503 may transmit the PDCP discard timer configuration for a DRB to UE 501 in an RRC message, which may include a (i.e. 1^st) PDCP discard timer (e.g. discard timer #a as described in the embodiments of FIG. 3) and an additional (i.e. 2^nd) PDCP discard timer (e.g. discard timer #b as described in the embodiments of FIG. 3) . The 2^nd PDCP discard timer may be configured by network or predefined by a standard specification (e.g. timer length value = 0) .
For example, UE 501 may apply the 1^st discard timer to PDU set type #1 the DRB. UE 501 may apply the 2^nd discard timer to PDU set type #2 of the DRB. PDU set type #1 refers to an important PDU set, and PDU set type #2 refers to a less important PDU set.
In an embodiment, both 1^st and 2^nd discard timers are used to PDU set discard handling. If the 1^st discard timer of one PDCP SDU in a PDU set expires, UE 501 may discard all the remaining data of the PDU set. If the 2^nd discard timer of one PDCP SDU in a PDU set expires, UE 501 may discard all the remaining data of the PDU set.
In operation 513, DU 502 may transmit a dynamic discard timer update command to UE 501, which is used to update a length of the 1^st discard timer and/or a length of the 2^nd discard timer.
In case of CU and DU split, CU 503 optionally preconfigures the discard timer command allowed indication to DU 502 via F1AP message, e.g. in operation 512.
In an example, when BS 504 detects that the UL congestion is high or not low, BS 504 may determine to send the discard timer update command to UE 501 to set the lower value of the 2^nd discard timer (e.g. 0) .
In an example, when BS 504 detects that the UL congestion is high or not low, BS 504 may determine to send the update command for a DRB to UE 501 to set the higher value of the 1^st discard timer.
For example, the update command indicates UE 501 to update the discard timer for the specific PDU set type for a DRB via an MAC CE, which includes at least one of the following:
(1) Information used to indicate which DRB.
(2) Information used to indicate a (new) length of the 2^nd discard timer, an offset value, or a rate relative value. For example:
a) UE 501 determines that the new length of the 2^nd discard timer = a length of the 2^nd discard timer in RRC message +/-the offset value.
b) UE 501 determines that the new length of the 2^nd discard timer = a length of the 2^nd discard timer in RRC message *the rate relative value.
(3) Information used to indicate which PDU set type or which importance level to use the 2^nd discard timer.
(4) Information used to indicate a PDCP SN or a PDU set ID, from which UE 501 applies the 2^nd discard timer to the specific PDU set.
For example, the update command indicates UE 501 to update the discard timer for the specific PDU set type for a DRB via PDCP control PDU, which includes at least one of:
(1) Information used to indicate a (new) length of the 2^nd discard timer or an offset value or a rate relative value. For example:
a) UE 501 determines the new length of the 2^nd discard timer = a length of the 2^nd discard timer in RRC message +/-the offset value.
b) UE 501 determines the new length of the 2^nd discard timer = a length of the 2^nd discard timer in RRC message *the rate relative value.
(2) Information used to indicate which PDU set type or which importance level to use 2^nd discard timer.
(3) Information used to indicate PDCP SN or PDU set ID, from which UE 501 start applying the 2^nd discard timer to the specific PDU set.
In case of CU-DU split, DU 502 needs to send the recommended discard timer value to CU 503, and then, CU 503 generates the PDCP control PDU according to the recommended discard timer value.
In operation 514, after UE 501 receives the update command from DU 502 to update the 1^st or 2^nd discard timer for a DRB, UE 501 may determine the new 1^st or 2^nd discard timer value and apply the new 1^st or 2^nd discard timer value to the data of specific PDU set type on the DRB according to the command.
For example, if receiving the discard command for a DRB via an MAC CE, the MAC entity notifies the activation command to the PDCP entity of the DRB.
The PDCP entity may apply the new 2^nd discard timer to the PDCP SDU available for transmission of the PDU set (s) according to at least one of: the running status of the old 2^nd discard timer, the submission status of the whole PDU set to the RLC layer, the submission status of part of the PDU set to the RLC layer, the running status of the old 2^nd discard timer of the PDCP SDU in the PDU set, and/or the submission status of the PDCP SDU in the PDU set to the RLC layer.
For examples of receiving the 2^nd discard timer command, the PDU set (s) may include at least one of:
(1) Future arriving PDU set (s) .
a) Referring to FIG. 7, if receiving the command at t1, UE 501 applies the new 2^nd discard timer to the data of the PDU set to be received after or at t1, e.g. PDU Set SN = 1.
(2) No data in PDU set (s) already in the buffer of UE 501 has started the old 2^nd discard timer, i.e. it is running.
a) Referring to FIG. 7, if receiving the command at t2 and the PDCP entity has not started the old 2^nd discard timer for any one of data in the PDU set, UE 501 applies the new 2^nd discard timer to the data of the PDU set, e.g. PDCP Set SN = 1.
(3) Partial data of the PDU set already in the buffer of UE 501 has started the 2^nd discard timer, i.e. it is running.
a) Referring to FIG. 7, if receiving the command at t3 and the PDCP entity has started the 2^nd discard timer for some data (PDCP SN = 1) in the PDU set SN = 1, UE 501 applies the new 2^nd discard timer to the data (e.g. PDCP SN = 2, 3, 4) of the PDU set SN = 1, which has not started the old 2^nd discard timer.
b) Referring to FIG. 7, if receiving the command at t3 and the PDCP entity has started the old 2^nd discard timer for some data (e.g. PDCP SN = 1) in the PDU set (e.g. PDCP Set SN = 1) , UE 501 applies the new 2^nd discard timer to the all data (e.g. PDCP SN = 1, 2, 3, 4) of the PDU set (e.g. PDCP Set SN =1) , regardless of the running status of the old 2^nd discard timer of the data. For the PDCP SN = 1, UE 501 may reset or stop the old 2^nd discard timer if running associated with the data and starts the new 2^nd discard timer associated with the data.
c) Optionally, if the new 2^nd discard timer value is equal to 0 or the new 2^nd discard timer value is smaller than the old 2^nd discard timer value, UE 501 may reset or stop the old 2^nd discard timer and starts the 2^nd discard timer for the PDU SDU or the PDU set.
d) Optionally, if the buffer delay of a PDCP SDU or a PDU set is equal to or larger than the new 2^nd discard timer value, UE 501 considers the new 2^nd discard timer expires for the PDU SDU or the PDU set, i.e. UE 501 does not start the new 2^nd discard timer.
e) Optionally, if the buffer delay of a PDCP SDU or a PDU set is equal to or smaller than the new 2^nd discard timer value, UE 501 may reset or stop the running 2^nd discard timer and set (2^nd discard timer value –buffer delay) to the 2^nd discard timer and starts the new 2^nd discard timer for the PDU SDU or the PDU set.
f) Optionally, if the remaining time of the running discard timer is equal to or smaller than the new 2^nd discard timer value, UE 501 does not reset or stop the old 2^nd discard timer and does not start the new 2^nd discard timer for the PDU SDU or the PDU set, just leaving the old 2^nd discard timer running till expiration. If the remaining time of the running discard timer is equal to or larger than the new 2^nd discard timer value, UE 501 may reset or stop the running old 2^nd discard timer and starts the new 2^nd discard timer for the PDU SDU or the PDU set.
(4) The whole PDU set has not been submitted to the RLC entity.
(5) The part of the PDU set has not been submitted to the RLC entity.
The PDCP entity applies the new 1^st discard timer to the PDCP SDU available for transmission of the PDU set (s) according to at least one of: the running status of the old 1^st discard timer, the submission status of the whole PDU set to the RLC layer, the submission status of part of the PDU set to the RLC layer, the running status of the old 1^st discard timer of the PDCP SDU in the PDU set, the submission status of the PDCP SDU in the PDU set to the RLC layer.
For examples, the PDU set (s) may include at least one of:
(1) Future arriving PDU set (s) .
a) Referring to FIG. 7, if receiving the command at t1, UE 501 applies the new 1^st discard timer to the data of the PDU set to be received after or at the t1, e.g. PDU Set SN = 1, i.e. the next PDU set available for transmission to be expected from the upper layer.
(2) No data in PDU set (s) has started the old 1^st discard timer, i.e. the timer is not running.
a) Referring to FIG. 7, if receiving the command at t2 and the PDCP entity has not started the old 1^st discard timer for any one of data in the PDU set, UE 501 applies the new 1^st discard timer to the data of the PDU set, e.g. PDCP Set SN = 1.
(3) Partial data of the PDU set has already started the 1^st discard timer, i.e. it is running.
a) Referring to FIG. 7, if receiving the command at t3 and the PDCP entity has started the1^st discard timer for some data (PDCP SN = 1) in the PDU set SN = 1, UE 501 applies the new 1^st discard timer to the data (e.g. PDCP SN =2, 3, 4) of the PDU set SN = 1, which has not started the old 1^st discard timer. i.e. the next PDCP SDU available for transmission to start new 1^st discard timer associated with the data.
b) Referring to FIG. 7, if receiving the command at t3 and the PDCP entity has started the old 1^st discard timer for some data (e.g. PDCP SN = 1) in the PDU set (e.g. PDCP Set SN = 1) , UE 501 applies the new 1^st discard timer to the all data (e.g. PDCP SN = 1, 2, 3, 4) of the PDU set (e.g. PDCP Set SN = 1) or the PDU set, regardless of the running status of the old 1^st discard timer of the data or the whole PDU set including the data. For PDCP SN = 1 or for PDU set SN = 1, UE 501 may reset or stop the old 1^st discard timer if running and starts the new 1^st discard timer associated with the data. UE 501 may reset or stop the old 1^st discard timer if running associated with the data and starts the new 1^st discard timer associated with the data.
c) Optionally, if the buffer delay of a PDCP SDU or a PDU set is equal to or smaller than the new 1^st discard timer value or the new 1^st timer value is larger than the old 1^st timer value, UE 501 may reset or stop the old 1^st discard timer if running and starts the new 1^st discard timer for the PDU SDU or the PDU set.
d) Optionally, if the buffer delay of a PDCP SDU or a PDU set is equal to or smaller than the new 1^st discard timer value or the new 1^st timer value is larger than the old 1^st timer value, UE 501 may reset or stop the old 1^st discard timer if running and set (1^st discard timer value –buffer delay) to the 1^st discard timer and starts the new 1^st discard timer for the PDCP SDU or the PDU set.
e) Optionally, if the buffer delay of a PDCP SDU or a PDU set is larger than the new 1^st discard timer value, UE 501 may consider the new 1^st discard timer or the running 1^st discard timer as expired for the PDU SDU or the PDU set, i.e. UE 501 does not reset or stop the new 1^st discard timer associated with the data.
f) Optionally, if the remaining time of the running discard timer is equal to or smaller than the new 1^st discard timer value, UE 501 may reset or stop the old 1^st discard timer and starts the new 1^st discard timer for the PDU SDU or the PDU set, otherwise just leaving the old 1^st discard timer running till expiration.
(4) The whole PDU set has not been submitted to the RLC entity.
(5) The part of the PDU set has not been submitted to the RLC entity.
(6) From the specified PDU set SN or PDCP SN, from the next SN of the specified PDU set SN or PDCP SN.
BS 504 transmits a dynamic PDCP discard timer update command to UE 501.
In case of CU and DU split, CU 503 optionally preconfigures the discard timer command allowed indication to DU 502 via F1AP message, e.g. in operation 512.
In an example, when BS 504 detects the UL congestion is not high or low and determines to sends the update command for a DRB to UE 501 to set the normal/lower value of 1^st discard timer.
In an example, when BS 504 detects the UL congestion is not high or low and determines to sends the update command for a DRB to UE 501 to set the normal/higher value of 2^nd discard timer.
For example, the command indicates UE 501 to update the 1^st discard timer for the specific PDU set type for a DRB via MAC CE, which includes at least one of: (1) Information used to indicate which DRB.
(2) Information used to indicate a (new) length of the 1^st discard timer or offset value or rate relative value. For example:
a) UE 501 determines the new length of the 1^st discard timer = a length of the 1^st discard timer in RRC message +/-the offset value.
b) UE 501 determines the new length of the 1^st discard timer = a length of the 1^st discard timer in RRC message *the rate relative value.
(3) Information used to indicate which PDU set type or importance level to use the 1^st discard timer.
(4) Information used to indicate PDCP SN or PDU set ID, from which UE 501 start applying the 1^st discard timer to the specific PDU set.
For example, the command indicates UE 501 to update the 1^st discard timer for the specific PDU set type for a DRB via PDCP control PDU, which includes at least one of:
(1) Information used to indicate a (new) length of the 1^st discard timer or offset value or rate relative value. For example:
a) UE 501 determines the new length of the 1^st discard timer = a length of the 1^st discard timer in RRC message +/-the offset value.
b) UE 501 determines the new length of the 1^st discard timer = a length of the 1^st discard timer in RRC message *the rate relative value.
(2) Information used to indicate which PDU set type or importance level to use 1^st discard timer
(3) Information used to indicate PDCP SN or PDU set ID, from which UE 501 start applying the 1^st discard timer to the specific PDU set.
After UE 501 receives the dynamic PDCP discard timer update command from BS 504 to update the 1^st or 2^nd discard timer for a DRB, UE 501 may determine the new 1^st or 2^nd discard timer value and apply the new 1^st or 2^nd discard timer value to the data of specific PDU set type on the DRB.
If the old 1^st discard timer has started for some PDCP SDU (s) of the PDU set upon reception of the indication according to at least one of: the running status of the old 1^st discard timer, the submission status of the whole PDU set to the RLC layer, the submission status of part of the PDU set to the RLC layer, the running status of the old 1^st discard timer of the PDCP SDU in the PDU set, and/or the submission status of the PDCP SDU in the PDU set to the RLC layer.
For examples, the PDU set (s) may include at least one of:
(1) Future arriving PDU set (s) .
a) Referring to FIG. 7, if receiving the command at t1, UE 501 applies new the 1^st discard timer to the data of the PDU set to be received after or at the t1, e.g. PDU Set SN = 1, 2.
(2) No data in PDU set (s) already in the buffer of UE 501 has started the old 1^st discard timer, i.e. it is running.
a) Referring to FIG. 7, if receiving the command at t2 and the PDCP entity has not started the old 1^st discard timer for any one of data in the PDU set, UE 501 applies the new 1^st discard timer to the data of the PDU set, e.g. PDCP Set SN = 1.
(3) Partial data of the PDU set already in the buffer of UE 501 has started the old 1^st discard timer, i.e. it is running.
a) Referring to FIG. 7, if receiving the command at t3 and the PDCP entity has started the old 1^st discard timer for some data (PDCP SN = 1) in the PDU set SN= 1, UE 501 applies the new 1^st discard timer to the data (e.g. PDCP SN =2, 3, 4) of the PDU set SN = 1, which has not started the old 1^st discard timer.
b) Referring to FIG. 7, if receiving the command at t3 and the PDCP entity has started the old 1^st discard timer for some data (e.g. PDCP SN = 1) in the PDU set (e.g. PDCP Set SN = 1) , UE 501 applies the new1^st discard timer to the all data (e.g. PDCP SN = 1, 2, 3, 4) of the PDU set (e.g. PDCP Set SN = 1) or the PDU set, regardless of the running status of the old 1^st discard timer of the data or the PDU set including the data. UE 501 may reset or stop the old 1^st discard timer if running associated with the data and starts the new 1^st discard timer associated with the data. UE 501 starts the new 1^st discard timer associated with the data if having not started the old 1^st discard timer associated with the data.
c) Optionally, if the buffer delay of a PDCP SDU or a PDU set is equal to or smaller than the new1^st discard timer value or the new 1^st timer value is smaller than the old 1^st timer value, UE 501 may reset or stop the 1^st discard timer and starts the 1^st discard timer for the PDU SDU or the PDU set.
d) Optionally, if the buffer delay of a PDCP SDU or a PDU set is equal to or smaller than the 1^st discard timer value or the new 1^st timer value is smaller than the old 1^st timer value, UE 501 may reset or stop the 1^st discard timer and set (1^st discard timer value –buffer delay) to the 1^st discard timer and starts the 1^st discard timer for the PDU SDU or the PDU set.
e) Optionally, if the buffer delay of a PDCP SDU or a PDU set is equal to or larger than the 1^st discard timer value, UE 501 may consider the 1^st discard timer expires for the PDU SDU or the PDU set, i.e. UE 501 does not reset or stop the 1^st discard timer.
f) Optionally, if the remaining time of the running discard timer is equal to or smaller than the new 1^st discard timer value, UE 501 does not reset or stop the old 1^st discard timer and start the new 1^st discard timer for the PDU SDU or the PDU set, just leaving the old 1^st discard timer running till expiration. If the remaining time of the running discard timer is equal to or larger than the new 1^st discard timer value, UE 501 may reset or stop the running 1^st discard timer and starts the new 1^st discard timer for the PDU SDU or the PDU set.
(4) The whole PDU set has not been submitted to the RLC entity.
(5) The part of the PDU set has not been submitted to the RLC entity.
If the old 2^nd discard timer has started for some PDCP SDU (s) of the PDU set upon reception of the indication according to at least one of: the running status of the old 2^nd discard timer, the submission status of the whole PDU set to the RLC layer, the submission status of part of the PDU set to the RLC layer, the running status of the old 2^nd discard timer of the PDCP SDU in the PDU set, the submission status of the PDCP SDU in the PDU set to the RLC layer.
For examples, the PDU set (s) may include at least one of:
(1) Future arriving PDU set (s) .
a) Referring to FIG. 7, if receiving the command at t1, UE 501 applies the new 2^nd discard timer to the data of the PDU set to be received after or at the t1, e.g. PDU Set SN = 1, i.e. the next PDU set available for transmission to be expected from the upper layer.
(2) No data in PDU set (s) has started the new 2^nd discard timer, i.e. the timer is not running.
a) Referring to FIG. 7, if receiving the command at t2 and the PDCP entity has not started the 2^nd discard timer for any one of data in the PDU set, UE 501 applies the 2^nd discard timer to the data of the PDU set, e.g. PDCP Set SN =1.
(3) Partial data of the PDU set has already started the old 2^nd discard timer, i.e. it is running.
a) Referring to FIG. 7, if receiving the command at t3 and the PDCP entity has started the old 2^nd discard timer for some data (PDCP SN = 1) in the PDU set SN = 1, UE 501 applies the new 2^nd discard timer to the data (e.g. PDCP SN =2, 3, 4) of the PDU set SN = 1, which has not started the 2^nd discard timer, i.e. the next PDCP SDU available for transmission to start a discard timer.
b) Referring to FIG. 7, if receiving the command at t3 and the PDCP entity has started the old 2^nd discard timer for some data (e.g. PDCP SN = 1) in the PDU set (e.g. PDCP Set SN = 1) , UE 501 applies the new 2^nd discard timer to the all data (e.g. PDCP SN = 1, 2, 3, 4) of the PDU set (e.g. PDCP Set SN =1) , regardless of the running status of the 2^nd discard timer of the data. For PDCP SN = 1 or for PDU set SN = 1, UE 501 may reset or stop the old 2^nd discard timer if running associated with the data and starts the new 2^nd discard timer. UE 501 starts the new 2^nd discard timer if having not started associated with the data and starts the new 2^nd discard timer associated with the data.
c) Optionally, if the buffer delay of a PDCP SDU or a PDU set is equal to or smaller than the new 2^nd discard timer value or the new 2^nd timer value is equal to or larger than the old 2^nd timer value, UE 501 may reset or stop the2^nd discard timer if running and starts the 2^nd discard timer for the PDU SDU or the PDU set.
d) Optionally, if the buffer delay of a PDCP SDU or a PDU set is equal to or smaller than the new 2^nd discard timer value or the new 2^nd timer value is equal to or larger than the old 2^nd timer value, UE 501 may reset or stop the old 2^nd discard timer and set (new 2^nd discard timer value –buffer delay) to the 2^nd discard timer and starts the 2^nd discard timer for the PDU SDU or the PDU set.
e) Optionally, if the buffer delay of a PDCP SDU or a PDU set is equal to or larger than the new 2^nd discard timer value, UE 501 considers the new 2^nd discard timer expires for the PDU SDU or the PDU set, i.e. does not start the new 2^nd discard timer.
f) Optionally, if the remaining time of the running discard timer is equal to or smaller than the new 2^nd discard timer value, UE 501 does not start the new 2^nd discard timer for the PDU SDU or the PDU set, just leaving the old 2^nd discard timer running till expiration. If the remaining time of the running discard timer is equal to or larger than the new 2^nd discard timer value, UE 501 may reset or stop the running 2^nd discard timer and starts the new 2^nd discard timer for the PDU SDU or the PDU set.
(4) The whole PDU set has not been submitted to the RLC entity.
(5) The part of the PDU set has not been submitted to the RLC entity.
(6) From the specified PDU set SN or PDCP SN, from the next SN of the specified PDU set SN or PDCP SN.
FIG. 8 illustrates a block diagram of an exemplary apparatus 800 in accordance with some embodiments of the present application. As shown in FIG. 8, the apparatus 800 may include at least one processor 806 and at least one transceiver 802 coupled to the processor 806. Although in this figure, elements such as the at least one transceiver 802 and processor 806 are described in the singular, the plural is contemplated unless a limitation to the singular is explicitly stated. In some embodiments of the subject application, the transceiver 802 may be divided into two devices, such as a receiving circuitry and a transmitting circuitry. In some embodiments of the subject application, the apparatus 800 may further include an input device, a memory, and/or other components.
In some embodiments of the subject application, the apparatus 800 may be a UE or a network node (e.g. a BS) . The transceiver 802 and the processor 806 may interact with each other so as to perform the operations with respect to the UE or the network node described above, for example, in any of FIGS. 1-7.
In some embodiments of the subject application, the apparatus 800 may further include at least one non-transitory computer-readable medium. For example, in some embodiments of the present disclosure, the non-transitory computer-readable medium may have stored thereon computer-executable instructions to cause the processor 806 to implement the method with respect to a UE or a network node (e.g. a BS) as described above. For example, the computer-executable instructions, when executed, cause the processor 806 interacting with transceiver 802 to perform the operations with respect to the UE or the network node described in FIGS. 1-7.
Those having ordinary skill in the art would understand that the operations or steps of a method described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. Additionally, in some aspects, the operations or steps of a method may reside as one or any combination or set of codes and/or instructions on a non-transitory computer-readable medium, which may be incorporated into a computer program product.
In this document, the terms "includes, " "including, " or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "a, " "an, " or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element. Also, the term "another" is defined as at least a second or more. The term "having" and the like, as used herein, are defined as "including" . Expressions such as "A and/or B" or "at least one of A and B" may include any and all combinations of words enumerated along with the expression. For instance, the expression "A and/or B" or "at least one of A and B" may include A, B, or both A and B. The wording "the first, " "the second" or the like is only used to clearly illustrate the embodiments of the subject application, but is not used to limit the substance of the subject application.

Claims

A user equipment (UE) , comprising:

a transceiver; and

a processor coupled to the transceiver, wherein the processor is configured to cause the UE to:

determine a discard timer for data of a protocol data unit (PDU) set type of a data radio bearer (DRB) ; and

handle the discard timer for the data of the PDU set type of the DRB.
The UE of Claim 1, wherein the processor is configured to cause the UE to handle the discard timer for the data of the PDU set type of the DRB based on an uplink (UL) congestion status or a first indication or pre-configuration information.
The UE of Claim 1 or Claim 2, wherein the processor is configured to cause the UE to:

receive first configuration information, wherein the first configuration information includes the first indication, and the discard timer is determined based on the first configuration information.
The UE of Claim 2, wherein the first indication indicates at least one of the following:

information to indicate the DRB;

information to indicate a timer length of the discard timer of the DRB;

activated or deactivated status of the discard timer;

information to indicate a PDU set type to activate or deactivate the discard timer;

information to indicate an importance level to activate or deactivate the discard timer; or

information to indicate a packet data convergence protocol (PDCP) sequence number (SN) or a PDU set ID according to which the discard timer is activated or deactivated.
The UE of Claim 2, wherein the processor is configured to cause the UE to:

activate the discard timer in response to that the UL congestion status is high or not low; or

deactivate the discard timer in response to that the UL congestion status is low or not high.
The UE of Claim 1, to handle the discard timer, the processor is further configured to cause the UE to:

apply the discard timer to the data of the PDU set type if the discard timer is activated for the PDU set type of the DRB.
The UE of Claim 1 or Claim 6, if the discard timer for the PDU set type is activated, the processor is configured to cause the UE to apply the discard timer to the data of the PDU set type based at least on:

upon receiving the data of the PDU set type from an upper layer;

running status of a first discard timer associated with the data of the PDU set type or associated with a PDU set of the PDU set type including the data;

submission status of the data of the PDU set type to a radio link control (RLC) layer; or

submission status of the PDU set including the data to the RLC layer.
The UE of any of Claims 1, 6, and 7, if the discard timer for the PDU set type is activated, the processor is configured to cause the UE to:

determine whether buffer delay of the data is equal to or greater than a timer length of the discard timer or whether a timer length of the discard timer is equal to zero; and

in response to the buffer delay of the data being equal to or greater than the timer length of the discard timer or in response to the timer length of the discard timer being equal to zero, consider the discard timer or the first discard timer as expired.
The UE of Claim 1, to handle the discard timer, the processor is further configured to cause the UE to:

apply a first discard timer associated with the data of the PDU set type if the discard timer is deactivated for the PDU set type of the DRB.
The UE of Claim 1 or Claim 9, if the discard timer for the PDU set type is deactivated, the processor is configured to cause the UE to apply the first discard timer to the data of the PDU set type based at least on:

upon receiving the data of the PDU set type from an upper layer;

running status of the discard timer associated with the data of the PDU set type or associated with a PDU set of the PDU set type including the data;

submission status of the data of the PDU set type to a radio link control (RLC) layer; or

submission status of the PDU set including the data to the RLC layer.
A network node, comprising:

a transceiver; and

a processor coupled with the transceiver, wherein the processor is configured to cause the network node to:

receive capability information of a user equipment (UE) , wherein the capability information includes handling a discard timer for data of a protocol data unit (PDU) set type of a data radio bearer (DRB) ; and

transmit, to the UE, first configuration information for the UE handling the discard timer for the data of the PDU set type of the DRB.
The network node of Claim 11, wherein the processor is configured to cause the network node to transmit second configuration information to the UE, and the second configuration information indicates at least one of the following:

information to indicate a timer length of the discard timer of the DRB;

activated or deactivated status of the discard timer;

information to indicate a PDU set type to activate or deactivate the discard timer; or

information to indicate an importance level to activate or deactivate the discard timer.
The network node of Claim 11, wherein the first configuration information is a first indication or uplink (UL) congestion detection configuration information.
The network node of Claim 13, wherein the first indication indicates at least one of the following:

information to indicate the DRB;

activated or deactivated status of the discard timer;

information to indicate a PDU set type to activate or deactivate the discard timer;

information to indicate an importance level to activate or deactivate the discard timer; or

information to indicate a packet data convergence protocol (PDCP) sequence number (SN) or a PDU set ID according to which the discard timer is activated or deactivated.
A method performed by a network node, comprising:

receiving capability information of a user equipment (UE) , wherein the capability information includes handling a discard timer for data of a protocol data unit (PDU) set type of a data radio bearer (DRB) ; and

transmitting, to the UE, a first configuration information for the UE handling the discard timer for the data of the PDU set type of the DRB.