Method and apparatus for managing a reordering report in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate than that of a 4G communication system such as LTE. According to one embodiment, a method performed by a receiving packet data convergence protocol (PDCP) device in a wireless communication system comprises the steps of: recording event information associated with a reordering report; receiving a reordering report request from a transmitting PDCP device; and transmitting the event information associated with the reordering report to the transmitting PDCP device on the basis of the reordering report request.

Description

Method and device for managing reordering reports in a wireless communication system

[0001] The present disclosure relates to a wireless communication system, and more specifically, to a method and apparatus for establishing a reordering report between a radio access network (RAN) and a terminal.

[0002] Looking back at the evolution of wireless communication through successive generations, technologies have been developed primarily for human-oriented services, such as voice, multimedia, and data. Following the commercialization of 5G (5th-generation) communication systems, connected devices, which have been increasing explosively, are expected to be connected to communication networks. Examples of networked objects include vehicles, robots, drones, home appliances, displays, smart sensors installed in various infrastructures, construction machinery, and factory equipment. Mobile devices are expected to evolve into various form factors, such as augmented reality glasses, virtual reality headsets, and holographic devices. In the 6G (6th-generation) era, efforts are underway to develop improved 6G communication systems to connect hundreds of billions of devices and objects to provide diverse services. For this reason, 6G communication systems are being referred to as "beyond 5G" systems.

[0003] In the 6G communication system predicted to be realized around 2030, the maximum transmission speed is tera (i.e., 1,000 gigabit) bps, and the wireless latency is 100 microseconds (μsec). In other words, compared to the 5G communication system, the transmission speed in the 6G communication system is 50 times faster, and the wireless latency is reduced to one-tenth.

[0004] To achieve such high data transmission speeds and ultra-low latency, 6G communication systems are being considered for implementation in the terahertz band (e.g., the 95 GHz to 3 terahertz (3 THz) band). In the terahertz band, due to more severe path loss and atmospheric absorption compared to the millimeter wave (mmWave) band introduced in 5G, the importance of technology capable of guaranteeing signal reach, or coverage, is expected to increase. As key technologies to ensure coverage, radio frequency (RF) devices, antennas, new waveforms that offer better coverage than orthogonal frequency division multiplexing (OFDM), beamforming, and multi-antenna transmission technologies such as massive multiple-input and multiple-output (massive MIMO), full-dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas must be developed. In addition, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing technology using orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS) are being discussed to improve coverage of terahertz band signals.

[0005] In addition, to improve frequency efficiency and system network, development is underway in 6G communication systems for full duplex technology, in which uplink and downlink simultaneously utilize the same frequency resources at the same time; network technology that integrates satellites and HAPS (high-altitude platform stations); network structure innovation technology that supports mobile base stations and enables network operation optimization and automation; dynamic spectrum sharing technology through collision avoidance based on spectrum usage prediction; AI-based communication technology that utilizes AI (artificial intelligence) from the design stage and internalizes end-to-end AI support functions to realize system optimization; and next-generation distributed computing technology that realizes services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high performance communication and computing resources (mobile edge computing (MEC), cloud, etc.). In addition, attempts are continuing to further strengthen connectivity between devices, further optimize networks, promote the softwareization of network entities, and increase the openness of wireless communication through the design of new protocols to be used in 6G communication systems, the implementation of hardware-based security environments, the development of mechanisms for the safe utilization of data, and the development of technologies regarding privacy maintenance methods.

[0006] Due to the research and development of such 6G communication systems, it is expected that a new dimension of hyper-connected experience will become possible through the hyper-connectivity of 6G communication systems, which encompasses not only connections between objects but also connections between people and objects. Specifically, it is projected that 6G communication systems will enable the provision of services such as truly immersive extended reality (truly immersive XR), high-fidelity mobile holograms, and digital replicas. Furthermore, services such as remote surgery, industrial automation, and emergency response, which are provided through 6G communication systems with enhanced security and reliability, will be applied in various fields including industry, healthcare, automotive, and home appliances.

[0007] Meanwhile, with the introduction of 5G NR (new radio) DC (dual connectivity) technology in wireless network systems, the efficiency and stability of data transmission are being improved as User Equipment (UE) devices are simultaneously connected to multiple base stations. However, when traffic data is branched in a DC environment, the reception order of data is not guaranteed, which may lead to data loss or delay. In particular, in NR-based communication environments, reordering management following traffic branching is required to support high-speed data transmission. Therefore, technical improvements are needed for the efficient reordering management of traffic.

[0008] The present disclosure proposes a method and apparatus for establishing a reorder report between a terminal and a base station by transmitting information regarding a reorder delay or the expiration of a reorder timer to a transmitting PDCP device when a dual connectivity (DC) connection is established between a terminal and a base station.

[0009] According to one embodiment of the present disclosure, a method performed by a receiving PDCP (packet data convergence protocol) device in a wireless communication system may include: recording event information related to a reorder report; receiving a reorder report request from a transmitting PDCP device; and transmitting the event information related to the reorder report to the transmitting PDCP device based on the reorder report request.

[0010] According to one embodiment of the present disclosure, a method performed by a transmitting PDCP (packet data convergence protocol) device in a wireless communication system may include: transmitting a reorder report request to a receiving PDCP device; and receiving event information related to the reorder report from the receiving PDCP device based on the reorder report request.

[0011] In a receiving PDCP (packet data convergence protocol) device in a wireless communication system according to one embodiment of the present disclosure, the device comprises: a transmitting and receiving unit; and at least one processor; wherein the at least one processor records event information related to a reorder report, receives a reorder report request from a transmitting PDCP device, and transmits the event information related to the reorder report to the transmitting PDCP device based on the reorder report request.

[0012] In a wireless communication system according to one embodiment of the present disclosure, a transmitting PDCP (packet data convergence protocol) device comprises: a transmitting and receiving unit; and at least one processor; wherein the at least one processor transmits a reordering report request to a receiving PDCP device and receives event information related to the reordering report from the receiving PDCP device based on the reordering report request.

[0013] The various embodiments of the present disclosure described above are merely some of the preferred embodiments of the present disclosure, and various embodiments reflecting the technical features of the various embodiments of the present disclosure can be derived and understood by those skilled in the art based on the detailed description to be described below.

[0014] By means of the method and apparatus according to the embodiment of the present disclosure, a reordering report between a base station and a terminal is established, and the transmitting PDCP device can divert traffic in a direction that reduces the frequency of reordering occurrences or reordering delay time, thereby preventing an increase in end-to-end delay or a degradation in transmission speed quality.

[0015] The 5G gNB-CU can handle reordering delay by receiving feedback information related to the reordering delay.

[0016] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0017] FIG. 1 is a diagram illustrating an example of a block diagram showing a DC (dual connectivity) connection between a base station and a terminal in a wireless communication system.

[0018] Figure 2 is a diagram illustrating an example of a block diagram showing the reordering delay in a dual connectivity (DC) connection between a transmitting PDCP (packet data convergence protocol) device and a receiving PDCP device in a wireless communication system.

[0019] Figure 3 is a diagram illustrating an example of a block diagram illustrating the handling of packet loss due to reordering timer expiration in a dual connectivity (DC) connection between a transmitting PDCP (packet data convergence protocol) device and a receiving PDCP device in a wireless communication system.

[0020] FIG. 4 is a diagram illustrating an example of a realignment report setting operation between a base station and a terminal according to one embodiment of the present disclosure.

[0021] FIG. 5 is a diagram illustrating a realignment operation process according to one embodiment of the present disclosure.

[0022] FIGS. 6a and 6b illustrate an example of a structure in which a poll bit field is added to a packet data unit (PDU) of a packet data convergence protocol (PDCP) data when a reordering report request is transmitted according to one embodiment of the present disclosure.

[0023] FIGS. 7a and 7b illustrate an example of a structure in which an on / off indication bit field is added to a packet data unit (PDU) of a packet data convergence protocol (PDCP) when a reordering report request is transmitted according to one embodiment of the present disclosure.

[0024] FIG. 8 is a diagram illustrating an example of a reorder report transmission operation when a polling-based reorder report request is received according to one embodiment of the present disclosure.

[0025] FIG. 9 is a diagram illustrating an example of a reorder report transmission operation when a reorder report request based on an on / off indication according to one embodiment of the present disclosure is received.

[0026] FIG. 10 is a diagram illustrating an example of a PDCP data PDU (packet data unit) format included in a reorder report transmission according to one embodiment of the present disclosure.

[0027] FIG. 11 is a diagram illustrating a change in the data PDU (packet data unit) branching policy of a transmitting PDCP (packet data convergence protocol) device by a reordering report according to one embodiment of the present disclosure.

[0028] FIG. 12 is a drawing illustrating the structure of a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0029] FIG. 13 is a drawing illustrating the structure of a base station in a wireless communication system according to one embodiment of the present disclosure.

[0030] The drawings are included as reference examples to aid in understanding the invention and are not limited to specific embodiments of the invention. The specific details depicted in the drawings are intended to supplement the overall technical background and context of the invention and may provide technical information beneficial to the invention even if not directly specified in the claims.

[0031] Hereinafter, embodiments of the present disclosure will be described in detail together with the accompanying drawings.

[0032] In describing the embodiments, technical details that are well known in the technical field to which this disclosure belongs and are not directly related to this disclosure are omitted. This is intended to convey the essence of this disclosure more clearly without obscuring it by omitting unnecessary explanations.

[0033] For the same reason, some components in the attached drawings have been emphasized, omitted, or depicted schematically. Additionally, the dimensions of each component do not fully reflect their actual dimensions. Identical or corresponding components in each drawing have been assigned the same reference numbers.

[0034] The advantages and features of the present disclosure and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to make the disclosure of the present invention complete and to fully inform those skilled in the art of the scope of the invention, and the present disclosure is defined only by the scope of the claims. Throughout the specification, like reference numerals refer to like components.

[0035] At this time, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the computer also creates means for the instructions executed through the processor of other programmable data processing equipment to perform the functions described in the flow diagram block(s). Since these computer program instructions can also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the function in a specific way, the instructions stored in such computer-available or computer-readable memory can also produce a manufactured item containing means of instruction that perform the function described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0036] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specified logical function(s). It should also be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For instance, two blocks described in succession may actually be executed substantially simultaneously, or the blocks may be executed in reverse order according to their corresponding functions.

[0037] In this embodiment, the term "part" refers to a software or hardware component, such as an FPGA or ASIC, and the "part" performs certain roles. However, the meaning of "part" is not limited to software or hardware. The "part" may be configured to reside in an addressable storage medium or configured to operate one or more processors. Accordingly, as an example, the "part" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and "parts" may be combined into a smaller number of components and "parts" or further separated into additional components and "parts." Furthermore, the components and "parts" may be implemented to operate one or more CPUs within a device or secure multimedia card.

[0038] In the present disclosure, each of the phrases such as “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B or C,” “at least one of A, B and C,” and “at least one of A, B, or C” may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof. Terms such as “first,” “second,” or “first” or “second” may be used simply to distinguish a corresponding component from another corresponding component and do not limit the corresponding components in other aspects (e.g., importance or order).

[0039] Hereinafter, a base station is an entity that performs resource allocation for terminals and may be at least one of a gNode B (gNB), eNode B (eNB), Node B, BS (Base Station), wireless access unit, base station controller, or a node on a network. A terminal may include a UE (User Equipment), MS (Mobile Station), cellular phone, smartphone, computer, or a multimedia system capable of performing communication functions. In this disclosure, a downlink (DL) refers to a wireless transmission path of a signal transmitted by a base station to a terminal, and an uplink (UL) refers to a wireless transmission path of a signal transmitted by a terminal to a base station. Furthermore, while LTE, LTE-A, or 5G systems may be described as examples below, embodiments of this disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, 5th generation mobile communication technology (5G, new radio, NR) developed after LTE-A may be included therein, and the 5G below may be a concept that includes existing LTE, LTE-A, and other similar services. In addition, the present disclosure may be applied to other communication systems with some modifications made at the discretion of a person with skilled technical knowledge, without significantly departing from the scope of the present disclosure.

[0040] Hereinafter, various embodiments are described in detail with reference to the attached drawings. It should be noted that in the attached drawings, identical components are indicated by the same reference numerals whenever possible. Furthermore, it should be noted that the drawings of the present disclosure attached below are provided to aid in understanding the present disclosure, and the present disclosure is not limited to the forms or arrangements exemplified in the drawings. Additionally, detailed descriptions of known functions and configurations that may obscure the essence of the present disclosure will be omitted. It should be noted that in the following description, only the parts necessary for understanding the operation according to the various embodiments of the present disclosure are described, and descriptions of other parts will be omitted so as not to distract from the essence of the present disclosure.

[0041] FIG. 1 is a diagram illustrating an example of a block diagram showing a DC (dual connectivity) connection between a base station and a terminal in a wireless communication system.

[0042] FIG. 1(a) illustrates an example of EN-DC (evolved non-standalone dual connectivity) connection between a base station and a terminal, and FIG. 1(b) illustrates an example of NR-DC (new radio dual connectivity) connection between a base station and a terminal.

[0043] The 5G NR (new radio) wireless network system supports dual connectivity (DC) technology. When the packet data convergence protocol (PDCP) of a transmitting device splits traffic, it determines the transmission path of each packet between the master cell group (MCG) and the secondary cell group (SCG) based on its own policies and various information. The packets split to the MCG and SCG may arrive at the receiving device's PDCP at different times due to various reasons, such as scheduling delays. If the bearer of the receiving device's PDCP is not configured for out-of-order delivery, packets with differing arrival times are reordered at the receiving PDCP device according to the PDCP alignment value (PDCP count). When the receiving PDCP device receives the PDCP alignment value (PDCP count) sequentially, it immediately forwards it to the upper layer. However, if reordering begins because the PDCP alignment value (PDCP count) is not received sequentially, a reordering timer starts operating. If packets containing alignment values ​​that were waiting are received before the reorder timer expires, the reorder timer stops and is reset. If packets containing alignment values ​​that were waiting until the reorder timer expires are not received, the packets containing alignment values ​​received sequentially before the reorder timer expires are forwarded to the upper layer, and the receiving window is moved. Therefore, the receiving PDCP device treats packets containing alignment values ​​that were not received as lost even if they arrive after the reorder timer expires.

[0044] In a 5G system, user equipment can select two of 4G LTE (long term evolution), 5G FR1 (frequency range 1), and 5G FR2 (frequency range 2) to connect simultaneously.

[0045] The above DC connection can be determined as any one of EN-DC (evolved non-standalone dual connectivity), NE-DC (NR E-UTRA dual connectivity), and NR-DC (new radio dual connectivity) depending on the connection method.

[0046] EN-DC uses 4G EPC (evolved packet core) in the core network (CN or core network) and can simultaneously connect 4G LTE and 5G FR1 or 4G LTE and 5G FR2 in the radio access network (RAN or radio access network).

[0047] NE-DC uses 5G's 5GC (5G core network) in the core network and can simultaneously connect 4G LTE and 5G FR1 or 4G LTE and 5G FR2 in the radio access network (RAN).

[0048] NR-DC uses 5GC (5G core network) in the core network and can simultaneously connect 5G FR1 and 5G FR2 in the radio access network (RAN).

[0049] In 5G DC connections, bidirectional traffic branching and merging occur at the Packet Data Convergence Protocol (PDCP) layer. Downlink (DL) direction traffic can be branched from the RAN device's PDCP layer and merged at the terminal's PDCP layer, while uplink (UL) direction traffic can be branched from the terminal's PDCP layer and merged at the RAN device's PDCP layer. That is, when processing DL direction traffic, the RAN PDCP acts as the transmitting PDCP device and the terminal PDCP acts as the receiving PDCP device, and when processing UL direction traffic, the terminal PDCP acts as the transmitting PDCP device and the RAN PDCP acts as the receiving PDCP device.

[0050] When a transmitting PDCP device splits traffic in a 5G DC connection, the transmission path of each packet can be determined between the MCG (master cell group) and SCG (secondary cell group) based on the transmitting PDCP device's own policy and various information.

[0051] Referring to FIG. 1, when a DC connection is established between a core network (EPC (evolved packet core) (101), 5GC (5G core) (111)) and a terminal (106, 116) in a wireless communication system, the layers included in the DC connection can be identified. In the DC connection, the termination point may refer to the termination point of a protocol layer, or the termination point of a physical link or a logical session. For example, the termination point may refer to the point where the PDCP layer terminates data transmission and processing. For example, the termination point may refer to the point where the RLC (radio link control) layer terminates the data flow and passes the data to an upper layer. In the DC connection, the bearer type refers to the type of path or logical channel for data transmission in a wireless network such as 4G LTE or 5G.

[0052] Referring to FIG. 1(a), in the case of a DC connection using the EN-DC connection method, the base station side core network (EPC, evolved packet core, 101) can be connected to a terminal (106) through a MeNB (master cell group - evolved node B, 104) of a 4G LTE wireless network. For example, in the case of a DC connection using the EN-DC connection method, the base station side core network (101) can be connected to a terminal (106) through a SgNB (secondary cell group - generation node B) of a 5G NR wireless network. The SgNB may include a CU (central unit, 103) at the PDCP layer and a DU (distributed unit, 105) at the RLC layer. For example, when the base station side core network (101) is connected to a terminal (106), it can be connected via the path from the core network (101) - PDCP layer of the SgNB CU (103) - RLC layer of the MeNB (104) - terminal (106). For example, when the base station side core network (101) is connected to a terminal (106), it can be connected via the path from the core network (101) - PDCP layer of the SgNB CU (103) - RLC layer of the SgNB DU (105) - terminal (106).

[0053] Referring to FIG. 1(b), in the case of a DC connection of the NR-DC connection method, the base station side core network (5GC, 5G core network, 101) can be connected to a terminal (116) through a master cell group (evolved node B) of the 5G wireless network. The MgNB may include a central unit (CU, 112) at the PDCP layer and a distributed unit (DU, 114) at the RLC layer.

[0054] For example, in the case of a DC connection of an NR-DC connection method, the base station side core network (111) can be connected to a terminal (116) through a SgNB (secondary cell group - generation node B) of a 5G NR wireless network. The SgNB may include a CU (central unit, 113) at the PDCP layer and a DU (distributed unit, 115) at the RLC layer.

[0055] For example, when the base station side core network (111) is DC connected to the terminal (116), the DC connection can be connected through the path of core network (111) - PDCP layer of MgNB CU (112) - RLC layer of MgNB (114) - terminal (116).

[0056] For example, when the base station side core network (111) is DC connected to the terminal (116), the DC connection can be connected through the path of core network (111) - PDCP layer of MgNB CU (112) - RLC layer of SgNB (115) - terminal (116).

[0057] For example, when the base station side core network (111) is DC connected to the terminal (116), the DC connection can be established through the path of the core network (111) - PDCP layer of the SgNB CU (113) - RLC layer of the MgNB (114) - terminal (116). For example, when the base station side core network (111) is DC connected to the terminal (116), the DC connection can be established through the path of the core network (111) - PDCP layer of the SgNB CU (113) - RLC layer of the SgNB (115) - terminal (116).

[0058] Figure 2 is a diagram illustrating an example of a block diagram showing the reordering delay in a dual connectivity (DC) connection between a transmitting PDCP (packet data convergence protocol) device and a receiving PDCP device in a wireless communication system.

[0059] FIG. 2 illustrates the operations of a transmitting PDCP device (Tx PDCP, 201) transmitting a data packet in an EN-DC connection to a receiving PDCP device (Rx PDCP, 207).

[0060] In a wireless communication system supporting dual connectivity (DC) technology, packets branched into master cell group (MCG) and secondary cell group (SCG) may arrive at a receiving PDCP (packet data convergence protocol, 207) device at different times due to various reasons, such as scheduling delays. If the bearer is not configured for out-of-order delivery, packets with different arrival times may be reordered at the receiving PDCP device (207) according to an order value (count). (The above count is defined in the standard document 3GPP TS38.323.) If the receiving PDCP device receives packets containing an order value (count) sequentially, the receiving PDCP device (207) can immediately forward the received packets to the upper layer. If the receiving PDCP device (207) fails to receive packets containing an order value (count) sequentially and reordering begins, a reordering timer on the receiving PDCP device side may start operating. If packets containing a waiting alignment value (count) are received before the reorder timer on the receiving PDCP device side expires, the reorder timer on the receiving PDCP device side may stop operation and be initialized.

[0061] Referring to FIG. 2, the transmitting PDCP device (201) can transmit packet 1 to the eNB (203) on the MCG (master cell group) side and packet 2 to the gNB-DU (205) on the SCG (secondary cell group) side. If the receiving PDCP device (207) receives packet 2 first from the gNB-DU (205) on the SCG side, the reordering timer on the receiving PDCP device side may start operating, and a reordering delay may occur while waiting for packet 1. If packet 1 is received from the eNB (203) on the MCG (master cell group) side before the reordering timer on the receiving PDCP device (207) side expires, the reordering timer on the receiving PDCP device (207) side may stop operating and be initialized, and the receiving PDCP device (207) may transmit packet 1 and packet 2 to the upper layer. If the receiving PDCP device (207) first receives packet 2 from the SCG-side gNB-DU (205), and packet 2 is a ping test packet, the ping latency may increase.

[0062] Figure 3 is a diagram illustrating an example of a block diagram illustrating packet loss processing due to reordering timer expiration in a dual connectivity (DC) connection between a transmitting PDCP (packet data convergence protocol) device and a receiving PDCP device in a wireless communication system.

[0063] FIG. 3 illustrates the operations of a transmitting PDCP device (Tx PDCP, 301) transmitting a data packet in an EN-DC connection to a receiving PDCP device (Rx PDCP, 307).

[0064] Referring to FIG. 3, if a receiving PDCP device (307) fails to receive packets sequentially and reordering begins, a reordering timer on the receiving PDCP device side may start operating. (For example, the reordering timer on the receiving PDCP device side may be set to wait for packets that have not been received for 300ms.) When the reordering timer on the receiving PDCP device side starts operating, if the reordering timer on the receiving PDCP device (307) side expires without receiving packet 1 from the eNB (303) on the MCG (master cell group) side even though packet 2 and packet 3 have been received from the gNB-DU (305) on the SCG (secondary cell group) side, the receiving PDCP device (307) can only transmit packet 2 and packet 3 to the upper layer. If packet 1 is received from the eNB (303) on the MCG (master cell group) side after the reordering timer on the receiving PDCP device side has expired, the receiving PDCP device (307) may discard the late-arriving packet 1. If packet loss occurs due to discarding packet 1, a decrease in the transmission control protocol (TCP) throughput of the wireless network system may occur.

[0065] Accordingly, to solve this problem, the present disclosure proposes a method in which a receiving PDCP device transmits information regarding the occurrence of a reordering delay or the expiration of a reordering timer to a transmitting PDCP device when a DC connection is established in a wireless network system. By transmitting the information regarding the occurrence of a reordering delay or the expiration of a reordering timer to the transmitting PDCP device, the present disclosure proposes a reordering reporting setting procedure that enables the transmitting PDCP device to branch traffic in a direction that reduces the frequency of reordering occurrences or the reordering delay time.

[0066] FIG. 4 is a diagram illustrating an example of a realignment report setting operation between a base station and a terminal according to one embodiment of the present disclosure.

[0067] FIG. 4 illustrates a method for setting up a reorder report during operations related to network setup between a terminal (401) and a base station (RAN, radio access network, 403).

[0068] Referring to FIG. 4, when a terminal (401) connects to a network, it can transmit to a base station (403) whether it supports reordering reports by including the terminal's capability information (user equipment (UE) capability information) in the terminal's capability information message. The base station can transmit to the terminal (401) settings related to the reordering operation by including them in a radio resource control (RRC) reconfiguration message.

[0069] In one embodiment, the capability information of the terminal may include 'SupportOfReorderingReport', which is an information element (IE) that supports reordering reports. In one embodiment, the 'SupportOfReorderingReport' may be configured in the same format as other information elements (IEs) within UECapabilityInformation already defined in the 3GPP TS38.331 specification document.

[0070] In operation 410, the terminal (401) can transmit a terminal capability information (UE capability information) message to a base station (RAN, radio access network, 403). The terminal capability information may include the following information elements (IE).

[0071] - supportOfReorderingReport-r19

[0072] The above supportOfReorderingReport-r19 can be used by the base station (RAN) to determine whether the terminal PDCP device supports a reordering report.

[0073] When the terminal (401) supports reorder reporting and sets up a bearer that is not out-of-order delivery, the base station (403) may set reorder reporting related values ​​for use by itself. In one embodiment, the reorder reporting related values ​​for use by the base station may include at least one of the following.

[0074] -t-ReorderingReportPollRetransmitRAN

[0075] - pollPDURAN

[0076] - pollByteRAN

[0077] -t-ReorderingReportProhibitRAN

[0078] - reorderingDelayThresholdRAN

[0079] - reorderingReportListRAN

[0080] - t-ReorderingReportRAN

[0081] The above t-ReorderingReportPollRetransmitRAN can be set to a timer value that causes the base station PDCP device to request a reordering report from the terminal PDCP device.

[0082] The above pollPDURAN can be set to the number of PDUs (packet data units) that cause the base station PDCP device to request a reordering report from the terminal PDCP device.

[0083] The above pollByteRAN can be set to a byte that causes the base station PDCP device to request a reorder report from the terminal PDCP device.

[0084] The above t-ReorderingReportProhibitRAN can be set as a timer that stops the base station PDCP device from reporting reordering to the terminal PDCP device.

[0085] The above reorderingDelayThresholdRAN can be set to an uplink reordering delay threshold counted by the base station PDCP device.

[0086] The above reorderingReportListRAN can be set as a list of values ​​that the base station must include in the reordering report.

[0087] The above t-ReorderingReportRAN can be set as the base station's reordering report cycle.

[0088] In operation 420, the base station (RAN, radio access network, 403) can transmit a radio resource control (RRC, reconfiguration) message to the terminal (401).

[0089] The base station (403) may include settings related to a reorder operation in a bearer configuration message and transmit it to the terminal (401). The terminal's capability information (UE capability information) and the bearer configuration message may be configured in any form and are not limited to a specific message. In one embodiment, the base station (403) may include settings related to a reorder operation in a radio resource control (RRC) reconfiguration message and transmit it to the terminal (401), and the RRC reconfiguration message may include settings related to a reorder report. In one embodiment, the settings related to a reorder report may include at least one of the following information elements (IE).

[0090] - reorderingReport-r19

[0091] -t-ReorderingReportPollRetransmitUE

[0092] - pollPDUUE

[0093] - pollByteUE

[0094] -t-ReorderingReportProhibitUE

[0095] - reorderingDelayThresholdUE

[0096] - reorderingReportListUE

[0097] - t-ReorderingReportUE

[0098] The above reorderingReport-r19 can be used to configure reordering report support for terminal PDCP devices.

[0099] The above t-ReorderingReportPollRetransmitUE can be set to a timer value that causes the terminal PDCP device to request a reordering report from the base station PDCP device.

[0100] The above pollPDUUE can be set to the number of PDUs (packet data units) that cause the terminal PDCP device to request a reordering report from the base station PDCP device.

[0101] The above pollByteUE can be set to a byte of data that causes the terminal PDCP device to request a reordering report to the base station PDCP device.

[0102] The above t-ReorderingReportProhibitUE can be set as a timer that stops the terminal PDCP device from reporting reordering to the base station PDCP device.

[0103] The above reorderingDelayThresholdUE can be set to a downlink reordering delay threshold counted by the terminal PDCP device.

[0104] The above reorderingReportListUE can be set as a list of values ​​that the terminal must include in the reordering report.

[0105] The above t-ReorderingReportUE can be set as the terminal's reordering report cycle.

[0106] The information elements (IEs) described above can be added in the same format as other information elements (IEs) included in the RRCReconfiguration already defined in the 3GPP TS38.331 specification document.

[0107] FIG. 5 is a diagram illustrating a realignment operation process according to one embodiment of the present disclosure.

[0108] When bidirectional traffic branching and merging occur in a 5G DC (dual connectivity) connection of a wireless communication system, packets with different arrival times at the receiving PDCP device may be reordered according to the PDCP alignment value (count). (The alignment value (count) defined in the standard document 3GPP TS38.323 may be applied.)

[0109] When the receiving PDCP device receives packets containing a sort value (count) sequentially, it immediately forwards them to the upper layer. If the receiving PDCP device fails to receive packets containing a sort value (count) sequentially and reordering begins, a reordering timer (500) may operate. If packets containing unreceived sort values ​​(count) are received before the reordering timer expires, the reordering timer may stop and be reset.

[0110] If the receiving PDCP device fails to receive packets containing unreceived alignment values ​​(counts) even by the time the reordering timer expires, it may forward the packets containing alignment values ​​(counts) received sequentially until the timer expires to the upper layer and shift the receiving window. Subsequently, the receiving PDCP device may treat packets containing unreceived alignment values ​​(counts) as lost even if they arrive after the reordering timer has expired.

[0111] Detailed reordering operations and definitions for RX_DELIV, RX_RECORD, RX_NEXT, and Window_Size are described in 3GPP TS38.323.

[0112] Hereinafter, FIGS. 6a, FIGS. 6b, FIGS. 7a, and FIGS. 7b illustrate PDCP data packets included in a reordering report request transmitted by a transmitting PDCP device to a receiving PDCP device.

[0113] The present disclosure proposes the following two methods for a transmitting PDCP device to request a realignment report from a receiving PDCP device when a realignment report setting between a base station and a terminal is completed.

[0114] Method 1. A method for the transmitting PDCP device to request a reordering report from the receiving PDCP device whenever necessary.

[0115] Method 2. Method for the transmitting PDCP device to change the on / off status of the receiving PDCP device's periodic realignment report.

[0116] FIGS. 6A and 6B illustrate examples of the packet data convergence protocol (PDCP) data PDU (packet data unit) structure for the above method 1.

[0117] Figures 7a and 7b describe examples of PDCP (packet data convergence protocol) data PDU (packet data unit) for the above method 2.

[0118] FIGS. 6a and 6b illustrate an example of a structure in which a poll bit field is added to a packet data unit (PDU) of a packet data convergence protocol (PDCP) data when a reordering report request is transmitted according to one embodiment of the present disclosure.

[0119] FIG. 6a illustrates an example in which a poll bit field is added to a 12-bit packet data convergence protocol (PDCP) data packet data unit (PDU) when transmitting a reordering report request according to one embodiment of the present disclosure.

[0120] FIG. 6b illustrates an example in which a poll bit field is added to an 18-bit packet data convergence protocol (PDCP) data packet data unit (PDU) when transmitting a reordering report request according to one embodiment of the present disclosure.

[0121] When the reordering report setting is completed between the transmitting PDCP device and the receiving PDCP device, the transmitting PDCP device can request a reordering report from the receiving PDCP device.

[0122] As in Method 1 above, when the transmitting PDCP device requests a reordering report from the receiving PDCP device whenever necessary, the transmitting PDCP device may send a polling packet to the receiving PDCP device. The polling packet may be defined by modifying the header of the PDCP data packet (PDCP data PDU) defined in the standard document 3GPP TS38.323.

[0123] In one embodiment, the header of the PDCP data PDU format (610, 620) illustrated in FIGS. 6a and 6b may be modified. For example, a transmitting PDCP device may designate one of the unused R (reserved bit) fields of the PDCP data PDU as a P field (poll bit field, 605, 615). In one embodiment, when the transmitting PDCP device transmits the PDCP data PDU to a receiving PDCP device, the P field may be marked as 0 if no reorder report is requested, and the P field may be marked as 1 if a reorder report is requested.

[0124] In one embodiment, the condition under which a transmitting PDCP device transmits a polling packet (a packet in which the header of a PDCP data PDU is modified to a P field) may vary depending on the reordering report setting between the base station and the terminal, and the setting may be any one of the following three cases.

[0125] 1. The transmitting PDCP device periodically sends polling packets according to the timer

[0126] A. If a bearer is configured, the polling timer can be initialized. The base station PDCP device can use t-ReorderingReportPollRetransmitRAN as the polling timer. The terminal PDCP device can use t-ReorderingReportPollRetransmitUE as the polling timer.

[0127] B. When the above polling packet transmission begins, the transmitting PDCP device may start the polling timer applied during the reorder report setting.

[0128] C. When the polling timer expires, the transmitting PDCP device may transmit a polling packet with the P field of the header marked as 1 during the next PDCP data PDU transmission.

[0129] D. If the polling packet of step C above is transmitted, the polling timer can be initialized and restarted.

[0130] 2. The transmitting PDCP device sends polling packets at regular intervals of the PDCP SN (packet data convergence protocol sequence number).

[0131] A. When a bearer is configured, the transmitting PDCP device may not mark the P field as 1 and may initialize PDU_WITHOUT_POLL, a variable value representing the number of packets transmitted, to 0.

[0132] B. The transmitting PDCP device can increase the PDU_WITHOUT_POLL value by 1 for every PDCP data PDU transmitted.

[0133] C. When PDU_WITHOUT_POLL is greater than or equal to the pollPDURAN value applied during reorder reporting settings or greater than or equal to the pollPDUUE value, the transmitting PDCP device may transmit a polling packet with the P field of the header marked as 1 during the next PDCP data PDU transmission. In one embodiment, the base station PDCP device may use pollPDURAN. In one embodiment, the terminal PDCP device may use pollPDUUE.

[0134] D. If the polling packet of step C above is transmitted, PDU_WITHOUT_POLL may be initialized to 0.

[0135] 3. Send polling packets at regular intervals based on the number of bytes transmitted by the transmitting PDCP device.

[0136] A. When a bearer is configured, the transmitting PDCP device may not mark the P field as 1 and may initialize BYTE_WITHOUT_POLL, a variable value representing the number of bytes transmitted, to 0.

[0137] B. For every PDCP data PDU transmitted, the transmitting PDCP device may add to BYTE_WITHOUT_POLL an amount equal to the size of the data byte (byte) included.

[0138] C. If BYTE_WITHOUT_POLL becomes greater than or equal to the pollByteRAN value applied when reordering report settings or greater than or equal to the pollByteUE value, the transmitting PDCP device may transmit a polling packet with the P field of the header marked as 1 during the next PDCP data PDU transmission. In one embodiment, the base station PDCP device may use pollByteRAN. In one embodiment, the terminal PDCP device may use pollByteUE.

[0139] D. If the polling packet of step C above is transmitted, BYTE_WITHOUT_POLL may be initialized to 0.

[0140] FIGS. 7a and 7b illustrate an example of a structure in which an on / off indication bit field is added to a packet data unit (PDU) of a packet data convergence protocol (PDCP) when a reordering report request is transmitted according to one embodiment of the present disclosure.

[0141] FIG. 7a illustrates an example in which an on / off indication field is added to a 12-bit packet data convergence protocol (PDCP) data packet data unit (PDU) when transmitting a reordering report request according to one embodiment of the present disclosure.

[0142] FIG. 7b illustrates an example in which an on / off indication field is added to an 18-bit packet data convergence protocol (PDCP) data packet data unit (PDU) when transmitting a reordering report request according to one embodiment of the present disclosure.

[0143] In order to change the on / off status of the transmitting PDCP device by reporting periodic reordering of the receiving PDCP device as in Method 2 above, the transmitting PDCP device may transmit an on / off indication packet to the receiving PDCP device. The on / off indication packet may be defined by modifying the header of the PDCP data packet (PDCP data PDU) defined in the standard document 3GPP TS38.323.

[0144] In one embodiment, the header of the PDCP data PDU format (710, 720) disclosed in FIG. 7a and 7b may be modified. For example, a transmitting PDCP device may designate one of the unused R (reserved bit) fields of the PDCP data PDU as an I field (indication bit field, 705, 715). In one embodiment, when the transmitting PDCP device transmits the PDCP data PDU to a receiving PDCP device, the I field may be marked as 0 if the receiving PDCP device does not want to change the periodic reordering report status, and the I field may be marked as 1 if the receiving PDCP device wants to change the periodic reordering report status.

[0145] In one embodiment, when a transmitting PDCP device transmits an on / off indicator packet (a packet in which the header of a PDCP data PDU has been modified to the I field), it may be any one of the following two cases.

[0146] 1. If the transmitting PDCP device needs to receive a reordering report packet while the receiving PDCP device's periodic reordering report status is off, the transmitting PDCP device sends an on / off indicator packet by marking the I field of the PDCP data PDU header as 1 when transmitting the PDCP data PDU.

[0147] 2. If the transmitting PDCP device needs to stop receiving periodic reordering report packets while the receiving PDCP device's periodic reordering report status is on, the transmitting PDCP device sends an on / off indicator packet by marking the I field of the PDCP data PDU header as 1 when transmitting the PDCP data PDU.

[0148] Hereinafter, FIGS. 8 and 9 illustrate the operation in which, when a receiving PDCP device receives a reordering report request from a transmitting PDCP device, the receiving PDCP device performs a reordering report to the transmitting PDCP device through a PDCP control packet for reordering reporting. FIGS. 8 and 9 illustrate the receiving PDCP device as a terminal and the transmitting PDCP device as a base station, but this is merely illustrative, and even if the receiving PDCP device is a base station and the transmitting PDCP device is a terminal, the operation can be performed as described below.

[0149] FIG. 8 is a diagram illustrating an example of a reorder report transmission operation when a polling-based reorder report request is received according to one embodiment of the present disclosure.

[0150] FIG. 8 illustrates the operation in which a terminal (801) transmits a reorder report (820) to the base station (803) when the base station (RAN, radio access network) (803) transmits a reorder report request (a polling packet in which the P field of the PDCP data PDU header is marked as 1) to the terminal (801). When the terminal (801) transmits a reorder report to the base station (803), a PDCP control packet (PDCP control PDU) for the reorder report may be transmitted (820). In one embodiment, the PDCP control packet for the reorder report may be defined by modifying a portion of the PDCP control packet (PDCP control PDU) defined in the standard document 3GPP TS38.323. A description of the PDCP control packet (PDCP control PDU) for the reorder report will be provided later in FIG. 10.

[0151] In operation 810, the terminal (801) may receive a reorder report request (polling packet) from the base station (803). In operation 810, the base station (803) may transmit the reorder report request through a data packet in which a poll bit is added to the PDCP data PDU as described in FIG. 6a and FIG. 6b.

[0152] In operation 820, the terminal (801) may transmit a reordering report packet to the base station (803). The reordering report packet may consist of a PDCP control packet (PDCP control PDU) for reordering reporting. A description of the PDCP control packet (PDCP control PDU) for reordering reporting is provided later in FIG. 10.

[0153] In one embodiment, the terminal (i.e., receiving PDCP device) (801) may transmit the reordering report packet to the base station (i.e., transmitting PDCP device) (803) when any one of the following three cases is satisfied.

[0154] 1. When a PDCP data packet is received with the P field marked as 1 while the reordering report stop timer has expired. In one embodiment, the base station PDCP device may set t-ReorderingReportProhibitRAN as the reordering report stop timer. In one embodiment, the terminal PDCP device may set t-ReorderingReportProhibitUE as the reordering report stop timer.

[0155] 2. When a polling packet (PDCP data PDU with the P field marked as 1) is received while the reordering report stop timer is in operation, and the reordering report stop timer expires. In one embodiment, the base station PDCP device may set t-ReorderingReportProhibitRAN as the reordering report stop timer. In one embodiment, the terminal PDCP device may set t-ReorderingReportProhibitUE as the reordering report stop timer.

[0156] 3. When the reordering report stop timer expires while the reordering report stop timer is expired. In one embodiment, the base station PDCP device may set t-ReorderingReportProhibitRAN as the reordering report stop timer and t-ReorderingReportRAN as the reordering report timer. In one embodiment, the terminal PDCP device may set t-ReorderingReportProhibitUE as the reordering report stop timer and t-ReorderingReportUE as the reordering report timer.

[0157] When the terminal (801) transmits a reordering report packet in the above operation 820, the t-ReorderingReportProhibitUE and t-ReorderingReportUE of the terminal (801) and the t-ReorderingReportProhibitRAN and t-ReorderingReportRAN of the base station (803) can all be initialized.

[0158] FIG. 9 is a diagram illustrating an example of a reorder report transmission operation when a reorder report request based on an on / off indication according to one embodiment of the present disclosure is received.

[0159] FIG. 9 illustrates the operation in which a terminal (901) transmits a reordering report (920) to the base station (903) when the base station (RAN, radio access network) (903) transmits an on / off indication packet (910) to the terminal (901), which is an on / off indication packet with the I field of the PDCP data PDU header marked as 1. When the terminal (901) transmits a reordering report to the base station (903), it may transmit a PDCP control packet (PDCP control PDU) for the reordering report (920). The PDCP control packet for the reordering report may be defined by modifying a portion of the PDCP control packet (PDCP control PDU) defined in the standard document 3GPP TS38.323. An explanation of the PDCP control packet for the reordering report (PDCP control PDU) is provided later in FIG. 10.

[0160] In one embodiment, when a bearer is established between a terminal (i.e., a receiving PDCP device) (901) and a base station (i.e., a transmitting PDCP device) (903), the receiving PDCP device may be set to an on or off state for periodic reordering reports. When the receiving PDCP device receives an on / off indicator packet (PDCP data PDU with the I field marked as 1) while in the off state for periodic reordering reports, it may transmit a reordering report packet.

[0161] In one embodiment, when the receiving PDCP device transmits a reordering report packet, the receiving PDCP device may change to a reordering report on state and start a reordering report timer operation. In one embodiment, if the receiving PDCP device is a terminal, the reordering report timer may be set to t-ReorderingReportUE. In one embodiment, if the receiving PDCP device is a base station, the reordering report timer may be set to t-ReorderingReportRAN.

[0162] In one embodiment, when the reorder report timer expires, the receiving PDCP device may repeat the operation of transmitting a reorder report packet and initializing and restarting the reorder report timer.

[0163] In one embodiment, when the receiving PDCP device receives an on / off indicator packet with the I field marked as 1 while the periodic reordering report is on, the receiving PDCP device may initialize and stop the reordering report timer. When the receiving PDCP device receives an on / off indicator packet with the I field marked as 1 while the periodic reordering report is on, the receiving PDCP device may stop transmitting the reordering report packet.

[0164] The method by which the receiving PDCP device records reorder timer expiration and reorder delay events is as follows.

[0165] 1. The receiving PDCP device creates variables with an initial value of 0 to record reorder timer-related events when creating a bearer. In one embodiment, the variables are as follows.

[0166] - NUM_T_EXP: Number of reordering timer expirations

[0167] The initial value is 0, and the 16-bit variable standard range is 0 to 65,535.

[0168] - NUM_D_EXC: Number of times the reordering delay has exceeded a predefined threshold

[0169] The initial value is 0, and the 16-bit variable standard range is 0 to 65,535.

[0170] - NUM_S_EX: Sum of the above NUM_T_EXP and the above NUM_D_EXC

[0171] The initial value is 0, and the 16-bit variable standard range is 0 to 65,535.

[0172] 2. The variables generated above are increased by 1 for each related event. In one example, the related events are as follows.

[0173] - NUM_T_EXP increases by 1 each time the reorder timer expires. When the above NUM_T_EXP reaches the maximum value of the variable range (65,535), it does not increase further.

[0174] - NUM_D_EXC increases by 1 whenever the reordering delay reaches a predefined threshold (reorderingDelayThreshold). When NUM_D_EXC reaches the maximum value of the variable range (65,535), it does not increase further.

[0175] - NUM_S_EX: NUM_S_EX increases by 1 for every NUM_T_EXP and NUM_D_EXC increase by 1. When NUM_S_EX reaches the maximum value of the variable range (65,535), it does not increase further.

[0176] 3. When the receiving PDCP device sends a reordering report packet to the transmitting PDCP device, the above variables may be initialized to 0.

[0177] FIG. 10 is a diagram illustrating an example of a PDCP data PDU (packet data unit) format included in a reorder report transmission according to one embodiment of the present disclosure.

[0178] When the receiving PDCP device transmits a reordering report to the transmitting PDCP device, it transmits a PDCP control packet (PDCP control PDU, 1000) for the reordering report, and FIG. 10 illustrates the PDCP control packet.

[0179] In one embodiment, each field of the PDCP control packet (PDCP control PDU, 1000) can be defined as follows.

[0180] - D / C = 0 (Control PDU)

[0181] - PDU Type = 101

[0182] The above 'PDU Type = 101' may represent a PDCP control PDU format for reordering reporting. In one embodiment, the PDU Type format defined in the standard document 3GPP TS 38.323 may be changed as shown in the following [Table 1].

[0183] BitDescription0PDCP status report1Interspersed ROHC feedback10EHC feedback11UDC feedback100PDCP SN gap report101PDCP reordering report110-111Reserved

[0184] - TI (1001): Indicates the presence of the NUM_T_EXP field

[0185] - DI (1003): Indicates whether the NUM_D_EXC field exists

[0186] - SI (1005): Indicates whether the NUM_S_EX field exists

[0187] - NUM_T_EXP (1011)

[0188] Defined as the number of reordering timer expirations. The above NUM_T_EXP (1011) can be composed of 16 bits (range of 16-bit variables: 0 to 65,535).

[0189] - NUM_D_EXC (1013)

[0190] The reordering delay is defined as the number of times it reaches a predefined threshold value. The above NUM_D_EXC (1013) can be composed of 16 bits (16-bit variable range: 0 to 65,535).

[0191] - NUM_S_EX (1015)

[0192] It is defined as the sum of the above NUM_T_EXP (1011) and the above NUM_D_EXC (1013).

[0193] In one embodiment, the PDCP control packet (PDCP control PDU, 1000) for the reordering report may include at least one of the NUM_T_EXP (1011), the NUM_D_EXC (1013), and the NUM_S_EX (1015).

[0194] FIG. 11 is a diagram illustrating a change in the data PDU (packet data unit) branching policy of a transmitting PDCP (packet data convergence protocol) device by a reordering report according to one embodiment of the present disclosure.

[0195] FIG. 11 illustrates that when a transmitting PDCP device (1011, 1111) and a receiving PDCP device (1107, 1117) are connected via dual connectivity (DC), the transmitting PDCP device (1011, 1111) modifies the packet transmission path as shown in FIG. 11 (b) as the receiving PDCP device (1107, 1117) makes a reordering report in the event of a packet reception delay in FIG. 11 (a).

[0196] A transmitting PDCP device (1011, 1111) can determine a branch path of a reorder report packet based on information contained in the reorder report packet (e.g., a PDCP control PDU for reorder reporting according to one embodiment of FIG. 10). In one embodiment, if at least one of NUM_T_EXP, NUM_D_EXC, or NUM_S_EX contained in the reorder report packet received by the transmitting PDCP device is greater than or equal to a predefined value, the reorder report packet can be transmitted only through one of the paths of MCG or SCG without dividing it into MCG (master cell group) and SCG (secondary cell group), thereby reducing the amount of packets transmitted.

[0197] Referring to FIG. 11 (a), when the transmitting PDCP device (1101) transmits packet 1 to the eNB (1103) of the MCG path and packets 2 and 3 to the gNB-DU (1105) of the SGC path, there may be a delay in the receiving PDCP device (1107) receiving packet 1. The receiving PDCP device (1107) may transmit a reordering report (1109) to the transmitting PDCP device (1101).

[0198] Referring to FIG. 11 (b), the transmitting PDCP device (1101) can transmit all of packets 1, 2, and 3 through the gNB-DU (1105) of the SCG path without branching the packet transmission path to the eNB (1103) of the MCG path, and the receiving PDCP device (1107) can receive all of packets 1, 2, and 3 from the gNB-DU (1105).

[0199] In one embodiment, when the packet branching policy of the transmitting PDCP device (1101) is changed by a reordering report from the receiving PDCP device (1107), the transmitting PDCP device (1101) may perform the following operations.

[0200] - Return timer operation

[0201] - PDU_WITH_EX increases by 1 for every packet transmitted through the DC connection.

[0202] - BYTE_WITH_EX increases by the number of bytes of data included for every packet transmitted through the DC connection.

[0203] In one embodiment, the transmitting PDCP device (1101) can restore the packet branching policy prior to receiving the reorder report packet from the receiving PDCP device (1107) if the following conditions are satisfied.

[0204] - If at least one of NUM_T_EXP, NUM_D_EXC, or NUM_S_EX of the above reorder report packet decreases below a predefined number

[0205] - Return timer expires

[0206] - When PDU_WITH_EX reaches a predefined value of exPDU or higher

[0207] - When BYTE_WITH_EX reaches a predefined value of exByte or more

[0208] FIG. 12 is a drawing illustrating the structure of a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0209] Referring to FIG. 12, the terminal may include at least one of a transceiver (1210) referring to a receiver and a transmitter, a memory (1220), and a processor (1230, or a terminal control unit or a processing unit). According to the communication method of the terminal described above, the transceiver (1210), memory (1220), and terminal processor (1230) of the terminal may operate. However, the components of the terminal are not limited to the examples described above.

[0210] In one embodiment, the terminal may include more or fewer components than the aforementioned components. In addition, the transceiver, memory, and processor may be implemented in the form of a single chip.

[0211] The transceiver can transmit and receive signals with a base station. Here, the signal may include control information and data. To this end, the transceiver may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is merely one embodiment of the transceiver, and the components of the transceiver are not limited to an RF transmitter and an RF receiver.

[0212] In addition, the transceiver receives a signal through a wireless channel and outputs it to a processor, and can transmit the signal output from the processor through a wireless channel.

[0213] Memory can store programs and data necessary for the operation of the terminal. Additionally, memory can store control information or data included in signals transmitted or received by the terminal. Memory may be composed of storage media or combinations of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. Additionally, there may be multiple memories.

[0214] The processor can control a series of processes to enable the terminal to operate according to the embodiments of the present disclosure described above. The processor may be one or more, and the processor may perform component control operations of the terminal by executing a program stored in memory.

[0215] In one embodiment, in a method performed by a receiving PDCP (packet data convergence protocol) device in a wireless communication system, the receiving PDCP device can record event information related to a reordering report.

[0216] In one embodiment, the receiving PDCP device may receive a reordering report request from the transmitting PDCP device.

[0217] In one embodiment, the receiving PDCP device may transmit event information related to the reorder report to the transmitting PDCP device based on the reorder report request.

[0218] In one embodiment, when the receiving PDCP device is a terminal (user equipment, UE) and the transmitting PDCP device is a base station, the receiving PDCP device may transmit terminal capability information (UE capability information) including reordering report support information to the base station, which is the transmitting PDCP device.

[0219] In one embodiment, when the receiving PDCP device is a terminal (user equipment, UE) and the transmitting PDCP device is a base station, the receiving PDCP device may receive a message containing reordering report setting information from the base station, which is the transmitting PDCP device.

[0220] In one embodiment, the message may include at least one of information regarding the reordering report support setting of the terminal, a timer for the terminal to trigger a reordering report request to the base station, the number of PDUs for the terminal to trigger a reordering report request to the base station, bytes for the terminal to trigger a reordering report request to the base station, a timer for the terminal to stop reordering reporting to the base station, a reordering delay threshold counted by the terminal, a list of values ​​included in the reordering report by the terminal, and a reordering report period for the terminal.

[0221] In one embodiment, the message may include a radio resource control (RRC) reconfiguration message.

[0222] In one embodiment, the event information related to the reordering report may include at least one of the number of timer expirations that cause the transmitting PDCP device to request a reordering report from the receiving PDCP device, the number of times a reordering delay threshold is reached that is counted by the transmitting PDCP device, and the sum of the number of timer expirations that cause the transmitting PDCP device to request a reordering report from the receiving PDCP device and the number of times a reordering delay threshold is reached that is counted by the transmitting PDCP device.

[0223] In one embodiment, the receiving PDCP device can receive a polling packet in which a specified header field is set to a specific value among the PDCP data packets transmitted by the transmitting PDCP device.

[0224] In one embodiment, the receiving PDCP device may receive a polling packet in which a specified header bit is set to 1 among the PDCP data packets transmitted by the transmitting PDCP device. In one embodiment, the specified header field of the polling packet may be set to a specific value based on at least one of a reorder report request timer value, a transmitted PDU count value, or a transmitted byte value.

[0225] In one embodiment, the polling packet may set a specified bit to 1 based on at least one of a reorder report request timer value, a transmitted PDU count value, or a transmitted byte value.

[0226] In one embodiment, the receiving PDCP device may receive a packet among the PDCP data packets transmitted by the transmitting PDCP device in which a specified periodic reordering report setting header field is set to a specific value.

[0227] In one embodiment, a receiving PDCP device may receive a packet in which a specified periodic reordering report setting header bit is set to 0 or 1 among the PDCP data packets transmitted by the transmitting PDCP device. The receiving PDCP device may maintain a periodic reordering report state when the periodic reordering report setting bit is 0, and change the periodic reordering report state when the periodic reordering report setting bit is 1.

[0228] In one embodiment, the receiving PDCP device may transmit event information related to the reordering report in any one of the following cases: when the receiving PDCP device receives a polling packet in which a designated header field is set to a specific value among the PDCP data packets transmitted by the transmitting PDCP device while the timer for stopping the reordering report (t-ReorderingReportProhibit) has expired; when the timer for stopping the reordering report expires after receiving a polling packet in which a designated header field is set to a specific value among the PDCP data packets transmitted by the transmitting PDCP device while the timer for stopping the reordering report is operating; or when the reordering report cycle for the transmitting PDCP device has expired while the timer for stopping the reordering report has expired.

[0229] In one embodiment, the receiving PDCP device may transmit event information related to the reorder report in either case where the reorder report cycle for the transmitting PDCP device expires while the reorder report is on, or where the receiving PDCP device receives a packet in which a designated periodic reorder report setting header field is set to a specific value among the PDCP data packets transmitted by the transmitting PDCP device while the reorder report is off, and the reorder report cycle for the transmitting PDCP device expires.

[0230] FIG. 13 is a drawing illustrating the structure of a base station in a wireless communication system according to one embodiment of the present disclosure.

[0231] Referring to FIG. 13, a base station may include at least one of a transceiver (1310), which refers to a receiver and a transmitter, a memory (1320), and a processor (1330, or a base station control unit or processing unit). According to the communication method of the base station described above, the transceiver (1310), memory (1320), and memory (1330) of the base station may operate. However, the components of the base station are not limited to the examples described above. For example, the base station may include more components or fewer components than the components described above. Furthermore, the transceiver, memory, and processor may be implemented in the form of a single chip.

[0232] The transceiver can transmit and receive signals with a terminal. Here, the signal may include control information and data. To this end, the transceiver may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts its frequency. However, this is merely one embodiment of the transceiver, and the components of the transceiver are not limited to an RF transmitter and an RF receiver.

[0233] In addition, the transceiver can receive a signal through a wireless channel and output it to a processor, and transmit the signal output from the processor through a wireless channel.

[0234] Memory can store programs and data necessary for the operation of the base station. Additionally, memory can store control information or data included in signals transmitted and received by the base station. Memory can be composed of storage media or combinations of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. Additionally, there may be multiple memories.

[0235] In addition, the processor can control a series of processes to enable the base station to operate according to the aforementioned embodiment. There may be one or more processors, and the processor can perform control operations on the components of the base station by executing a program stored in memory.

[0236] In one embodiment, in a method performed by a transmitting PDCP (packet data convergence protocol) device in a wireless communication system, the transmitting PDCP device may transmit a reordering report request to a receiving PDCP device.

[0237] In one embodiment, the transmitting PDCP device may receive event information related to the reorder report from the receiving PDCP device based on the reorder report request.

[0238] In one embodiment, when the transmitting PDCP device is a base station and the receiving PDCP device is a terminal, the transmitting PDCP device can receive terminal capability information (UE capability information) including reordering report support information from the terminal, which is the receiving PDCP device.

[0239] In one embodiment, when the transmitting PDCP device is a base station, the method further includes the step of setting a bearer based on the reordering report support information; and when setting the bearer, at least one of a timer for which the base station causes a reordering report request to the terminal, a number of PDUs for which the base station causes a reordering report request to the terminal, a byte for which the base station causes a reordering report request to the terminal, a timer for which the base station stops reordering reporting to the terminal, a reordering delay threshold counted by the base station, a list of values ​​included in the reordering report by the base station, and a reordering report period for the base station may be set.

[0240] In one embodiment, when the transmitting PDCP device is a base station and the receiving PDCP device is a terminal, a message including reordering report setting information can be transmitted to the terminal, which is the receiving PDCP device.

[0241] In one embodiment, a message including reordering report setting information to the terminal may include at least one of: information regarding the reordering report support setting of the terminal; a timer for the terminal to trigger a reordering report request to the base station; the number of PDUs for the terminal to trigger a reordering report request to the base station; a byte for the terminal to trigger a reordering report request to the base station; a timer for the terminal to stop reordering reporting to the base station; a reordering delay threshold counted by the terminal; a list of values ​​included in the reordering report by the terminal; and a reordering report period for the terminal.

[0242] In one embodiment, a message to the terminal containing reordering report setting information may include a radio resource control (RRC) reconfiguration message.

[0243] In one embodiment, the event information related to the reordering report may include at least one of the number of timer expirations that cause the transmitting PDCP device to request a reordering report from the receiving PDCP device, the number of times a reordering delay threshold is reached that is counted by the transmitting PDCP device, and the sum of the number of timer expirations that cause the transmitting PDCP device to request a reordering report from the receiving PDCP device and the number of times a reordering delay threshold is reached that is counted by the transmitting PDCP device.

[0244] Methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software. When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute the methods according to the embodiments described in the claims or specification of the present disclosure.

[0245] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, ROM (Read Only Memory), Electrically Erasable Programmable Read Only Memory (EEPROM), magnetic disc storage devices, Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0246] Additionally, the above program may be stored on an attachable storage device that can be accessed via a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), or Storage Area Network (SAN), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. Additionally, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

[0247] In the specific embodiments of the present disclosure described above, the components included in the invention are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed of a singular form, or even if a component is expressed in the singular form, it may be composed of a plural form.

[0248] Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, it is understood that various modifications are possible within the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof.

Claims

In a method performed by a receiving PDCP (packet data convergence protocol) device in a wireless communication system, Step of recording event information related to reordering reports; A step of receiving a reordering report request from a transmitting PDCP device; and A method comprising the step of transmitting event information related to the reorder report to the transmitting PDCP device based on the reorder report request. In paragraph 1, where the receiving PDCP device is a terminal (user equipment, UE) and the transmitting PDCP device is a base station, A method further comprising the step of transmitting to the base station above terminal capability information (UE capability information) including reordering report support information. In paragraph 1, where the receiving PDCP device is a terminal (user equipment, UE) and the transmitting PDCP device is a base station, The method further includes the step of receiving a message containing reordering report setting information from the base station; and The above message is, Information regarding the reordering report support settings of the above terminal, A timer that causes the terminal to request a reordering report to the base station, The number of PDUs that cause the above terminal to request a reordering report to the above base station, A byte that causes the terminal to request a reordering report to the base station, A timer that stops the terminal from reporting realignment to the base station. The reordering delay threshold counted by the above terminal, A list of values ​​included in the reorder report by the above terminal, and It includes at least one of the reordering reporting cycles for the above terminal, and A method comprising a radio resource control (RRC) reconfiguration message. In paragraph 1, the event information related to the above realignment report is, The number of timer expirations that cause the transmitting PDCP device to request a reordering report to the receiving PDCP device, The number of times the reordering delay threshold is reached or more, counted by the transmitting PDCP device, and A method comprising at least one of the sum of the number of timer expirations that cause the transmitting PDCP device to request a reordering report to the receiving PDCP device and the number of times the transmitting PDCP device reaches a reordering delay threshold. In paragraph 1, the step of receiving the reordering report request is, A method comprising the step of receiving a polling packet in which a specified header field is set to a specific value among the PDCP data packets transmitted by the transmitting PDCP device. In paragraph 5, the polling packet is, A method in which a specified header field is set to a specific value based on at least one of a reorder report request timer value, a transmitted PDU count value, or a transmitted byte value. In paragraph 1, the step of receiving the reordering report request is, A method comprising the step of receiving a packet in which a specified periodic reordering report setting header field is set to a specific value among the PDCP data packets transmitted by the transmitting PDCP device. In paragraph 1, the step of transmitting event information related to the reordering report is, When the timer (t-ReorderingReportProhibit) that stops reordering reporting has expired, the transmitting PDCP device receives a polling packet in which a specified header field among the PDCP data packets it transmits is set to a specific value, If the timer for stopping the reordering report expires after receiving a polling packet in which a designated header field among the PDCP data packets transmitted by the transmitting PDCP device is set to a specific value while the timer for stopping the reordering report is operating, or A method for transmitting event information related to the reorder report in any one of the cases where the reorder report cycle for the transmitting PDCP device expires while the timer for stopping the reorder report has expired. In paragraph 1, the step of transmitting event information related to the reordering report is, If the reordering report cycle for the transmitting PDCP device expires while the reordering report is on, or A method for receiving a packet in which a specified periodic reordering report setting header field is set to a specific value among PDCP data packets transmitted by the transmitting PDCP device in the reordering report off state, and transmitting event information related to the reordering report in any of the cases where the reordering report period for the transmitting PDCP device has expired. In a method performed by a transmitting PDCP (packet data convergence protocol) device in a wireless communication system, A step of transmitting a reordering report request to a receiving PDCP device; and A method comprising the step of receiving event information related to the reorder report based on the reorder report request from the receiving PDCP device. In Clause 10, where the transmitting PDCP device is a base station and the receiving PDCP device is a terminal, A step of receiving terminal capability information (UE capability information) including reordering report support information from the above terminal; and The method further includes the step of setting a bearer based on the above-mentioned reordering report support information; When setting the above bearer, A timer that causes the base station to request a reordering report from the terminal, The number of PDUs that cause the base station to request a reordering report from the terminal, A byte that causes the base station to request a reordering report from the terminal, A timer at which the base station stops reporting realignment to the terminal, The reordering delay threshold counted by the above base station, A list of values ​​included in the realignment report by the above base station, and A method for setting at least one of the reordering reporting cycles for the above base station. In Clause 10, where the transmitting PDCP device is a base station and the receiving PDCP device is a terminal, The method further includes the step of transmitting a message containing reordering report setting information to a terminal, and The above message is, Information regarding the reordering report support settings of the above terminal, A timer that causes the terminal to request a reordering report to the base station, The number of PDUs that cause the above terminal to request a reordering report to the above base station, A byte that causes the terminal to request a reordering report to the base station, A timer that stops the terminal from reporting realignment to the base station. The reordering delay threshold counted by the above terminal, A list of values ​​included in the reorder report by the above terminal, and It includes at least one of the reordering reporting cycles for the above terminal, and A method comprising a radio resource control (RRC) reconfiguration message. In Item 10, the event information related to the above realignment report is, The number of timer expirations that cause the transmitting PDCP device to request a reordering report to the receiving PDCP device, The number of times the reordering delay threshold is reached or more, counted by the transmitting PDCP device, and A method comprising at least one of the sum of the number of timer expirations that cause the transmitting PDCP device to request a reordering report to the receiving PDCP device and the number of times the transmitting PDCP device reaches a reordering delay threshold. In a receiving PDCP (packet data convergence protocol) device in a wireless communication system, Transmitter / receiver; and It includes at least one processor; and the at least one processor, Record event information related to reordering reports, and Receive a reordering report request from the transmitting PDCP device, and A receiving PDCP device that transmits event information related to the reorder report to the transmitting PDCP device based on the reorder report request. In a transmitting PDCP (packet data convergence protocol) device in a wireless communication system, Transmitter / receiver; and It includes at least one processor; and the at least one processor, Send a reordering report request to the receiving PDCP device, and A transmitting PDCP device that receives event information related to the reorder report based on the reorder report request from the receiving PDCP device.

Images