Electronic device and method for controlling traffic in wireless communication system

Abstract

In embodiments, an electronic device of a lower network node is provided. The electronic device may comprise: a memory for storing instructions; at least one transmission / reception device; and at least one processor. When executed by the at least one processor, the instructions can cause the electronic device to: transmit a first status message including first data amount information for a data radio bearer to an upper network node (a central unit) through the at least one transmission / reception device; receive downlink (DL) data for the data radio bearer from the upper network node through the at least one transmission / reception device; determine second data amount information for the data radio bearer on the basis of a packet loss metric, obtained from the DL data, for the path between the upper network node and a lower network node; and transmit a second status message including the second data amount information to the upper network node through the at least one transmission / reception device.

Description

Electronic device and method for controlling traffic in a wireless communication system

[0001] The present disclosure relates to a wireless communication system. More specifically, the present disclosure relates to an electronic device and method for controlling traffic in a wireless communication system.

[0002] A base station can provide an access network to terminals. To provide the access network, the base station can be implemented in a distributed deployment, with a central unit (CU) configured to perform upper layer functions and a distributed unit (DU) configured to perform lower layer functions, according to communication protocols.

[0003] The above information may be provided as background art to aid in understanding the present disclosure. No claim or determination is made as to whether any of the above-described matters constitute prior art related to the present disclosure.

[0004] In embodiments, an electronic device of a lower network node is provided. The electronic device may include a memory storing instructions, at least one transceiver, and at least one processor. The instructions, when executed by the at least one processor, may cause the electronic device to transmit a first status message including first data amount information for a data radio bearer to an upper network node via the at least one transceiver, receive downlink (DL) data for the data radio bearer from the upper network node via the at least one transceiver, determine second data amount information for the data radio bearer based on a packet loss metric for a path between the upper network node and the lower network node obtained from the downlink data, and transmit a second status message including the second data amount information to the upper network node via the at least one transceiver.

[0005] In embodiments, a method performed by a lower network node may include transmitting a first status message including first data amount information for a data radio bearer to an upper network node, receiving downlink (DL) data for the data radio bearer from the upper network node, determining second data amount information for the data radio bearer based on a packet loss metric for a path between the upper network node and the lower network node obtained from the downlink data, and transmitting a second status message including the second data amount information to the upper network node.

[0006] In embodiments, a non-transitory computer-readable storage medium is provided. The non-transitory computer-readable storage medium may store instructions that, when executed by a processor of a lower network node, cause the lower network node to perform operations including transmitting a first status message including first data amount information for a data radio bearer to an upper network node, receiving downlink (DL) data for the data radio bearer from the upper network node, determining second data amount information for the data radio bearer based on a packet loss metric for a path between the upper network node and the lower network node obtained from the downlink data, and transmitting a second status message including the second data amount information to the upper network node.

[0007] In embodiments, an electronic device of a lower network node is provided. The electronic device may include at least one transceiver including one or more communication circuits and at least one processor including one or more processing circuits. The at least one processor may be configured to transmit a first status message including first data amount information for a data radio bearer to an upper network node via the at least one transceiver. The at least one processor may be configured to receive downlink (DL) data for the data radio bearer from the upper network node via the at least one transceiver. The at least one processor may be configured to determine second data amount information for the data radio bearer based on a packet loss metric for a path between the upper network node and the lower network node obtained from the downlink data. The at least one processor may be configured to transmit a second status message including the second data amount information to the upper network node via the at least one transceiver.

[0008] The above and other aspects, features and advantages of specific embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings.

[0009] Figures 1a and 1b illustrate examples of wireless communication systems.

[0010] Figure 2a shows examples of control planes (C-planes).

[0011] Figure 2b shows examples of user planes (U-planes).

[0012] Figures 3a, 3b, and 3c illustrate examples of function split according to a communication protocol.

[0013] Figure 4a shows an example of signaling between a central unit (CU) and a distributed unit (DU).

[0014] Figure 4b shows an example of signaling between a CU and a DU via a routing node.

[0015] Figure 5 shows the flow of downlink packet processing.

[0016] Figure 6 shows the operation flow of an electronic device for downlink traffic control.

[0017] Figures 7a and 7b show the flow of downlink packet processing according to downlink traffic control.

[0018] Figure 8 shows an example of components of an electronic device for downlink traffic control.

[0019] The terms used in this disclosure are used only to describe specific embodiments and may not be intended to limit the scope of other embodiments. The singular expression may include plural expressions unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by those of ordinary skill in the art described in this disclosure. Terms defined in general dictionaries among the terms used in this disclosure may be interpreted as having the same or similar meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined in this disclosure. In some cases, even if a term is defined in this disclosure, it cannot be interpreted to exclude embodiments of the present disclosure.

[0020] The various embodiments of the present disclosure described below illustrate a hardware-based approach as an example. However, since the various embodiments of the present disclosure include techniques utilizing both hardware and software, the various embodiments of the present disclosure do not exclude a software-based approach.

[0021] In the following description, terms referring to signals (e.g., signal, information, message, signaling), terms referring to data types (e.g., list, set, subset), terms for operational states (e.g., step, operation, procedure), terms referring to data (e.g., packet, user stream, information, bit, symbol, codeword), terms referring to resources (e.g., symbol, slot, subframe, radio frame, subcarrier, resource element (RE), resource block (RB), bandwidth part (BWP), occasion), terms referring to channels, terms referring to network entities, terms referring to components of devices, etc. are examples for convenience of description. Therefore, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used. In addition, the terms '...bu', '...gi', '...mul', '...che', etc. used below may mean at least one shape structure or a unit that processes a function.

[0022] In addition, in the present disclosure, expressions such as "more than" or "less than" may be used to determine whether a specific condition is satisfied or fulfilled, but this is merely a description for expressing an example and does not exclude descriptions such as "more than" or "less than." A condition described as "more than" may be replaced with "more than," a condition described as "less than" may be replaced with "less than," and a condition described as "more than and less than" may be replaced with "more than and less than." In addition, hereinafter, "A" to "B" mean at least one of elements from A (including A) to B (including B). hereinafter, "C" and / or "D" mean at least one of "C" or "D," that is, including {"C", "D", "C" and "D"}.

[0023] Although the present disclosure describes various embodiments using terms used in some communication standards (e.g., 3rd Generation Partnership Project (3GPP), European Telecommunications Standards Institute (ETSI), extensible radio access network (xRAN), open-radio access network (O-RAN), etc.), these are merely examples for explanation. The various embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0024] Figures 1a and 1b illustrate examples of wireless communication systems.

[0025] Referring to FIG. 1A, FIG. 1A illustrates a base station (110) and a terminal (120) as some of the nodes utilizing a wireless channel in a wireless communication system. Although FIG. 1A illustrates only one base station, the wireless communication system may further include other base stations identical or similar to the base station (110).

[0026] The base station (110) is a network infrastructure that provides wireless access to the terminal (120). The base station (110) has coverage defined based on the distance at which a signal can be transmitted. In addition to the base station, the base station (110) may be referred to as an 'access point (AP)', 'eNodeB (eNB)', '5th generation node', 'next generation nodeB (gNB)', 'wireless point', 'transmission / reception point (TRP)', or other terms having equivalent technical meanings.

[0027] The terminal (120) is a device used by a user and communicates with the base station (110) via a wireless channel. The link from the base station (110) to the terminal (120) is referred to as a downlink (DL), and the link from the terminal (120) to the base station (110) is referred to as an uplink (UL). In addition, although not shown in FIG. 1A, the terminal (120) and another terminal may communicate with each other via a wireless channel. In this case, the link between the terminal (120) and another terminal (device-to-device link, D2D) is referred to as a sidelink, and the sidelink may be used interchangeably with the PC5 interface. In some other embodiments, the terminal (120) may be operated without the involvement of a user. In one embodiment, the terminal (120) is a device that performs machine type communication (MTC) and may not be carried by the user. Additionally, according to one embodiment, the terminal (120) may be an NB (narrowband)-IoT (internet of things) device.

[0028] The terminal (120) may be referred to as a terminal, or other terms such as 'user equipment (UE),' 'customer premises equipment (CPE),' 'mobile station,' 'subscriber station,' 'remote terminal,' 'wireless terminal,' 'electronic device,' or 'user device,' or other terms having equivalent technical meanings.

[0029] The base station (110) and the terminal (120) can perform beamforming. The base station (110) and the terminal (120) can transmit and receive wireless signals in a relatively low frequency band (e.g., FR 1 (frequency range 1) of NR). In addition, the base station (110) and the terminal (120) can transmit and receive wireless signals in a relatively high frequency band (e.g., FR 2 (or, FR 2-1, FR 2-2, FR 2-3), FR 3 of NR), millimeter wave (mmWave) band (e.g., 28 GHz, 30 GHz, 38 GHz, 60 GHz)). To improve channel gain, the base station (110) and the terminal (120) can perform beamforming. Here, the beamforming can include transmission beamforming and reception beamforming. The base station (110) and the terminal (120) can impart directionality to the transmitted or received signal. To this end, the base station (110) and the terminal (120) can select serving beams through a beam search or beam management procedure. After the serving beams are selected, subsequent communication can be performed through resources that have a QCL relationship with the resource that transmitted the serving beams.

[0030] The terminal (120) may be configured with cells of the base station (110) and carrier aggregation (CA). CA technology is a technology that increases the frequency usage efficiency of the terminal (120) and the base station (110) by connecting the terminal to a group of homogeneous wireless communication cells having a common radio resource control entity and simultaneously using frequency resources on component carriers of each cell located in different frequency bands for signal transmission and reception. The cells configured for CA may include one PCell (primary cell) and one or more SCells (secondary cells).

[0031] Referring to FIG. 1B, a terminal (120) may be configured in dual connectivity (DC) using a first base station (110-1) and a second base station (110). DC technology is a technology that increases frequency utilization efficiency by allowing a terminal to simultaneously connect to two independent heterogeneous or homogeneous wireless communication cell groups having separate radio resource control entities, and to use frequency resources on component carriers of cells within each cell group located in different frequency bands for signal transmission and reception. The terminal (120) is a technology for connecting to two different radio resource entities (e.g., a first base station (110-1), a second base station (110-2)) and using radio resources allocated by each radio resource entity. In MR-DC, a UE (e.g., terminal 120) in a radio resource control (RRC) connected state (i.e., RRC_CONNCETED) can be configured to utilize radio resources provided by two independent schedulers. Each scheduler can be located in an NG-RAN node (e.g., a first base station (110-1) and a second base station (110-2)). Here, one node is a master node (MN) and the other node is a secondary node (SN). The MN and SN are connected via a network interface, and the MN can be connected to a core network. The SN may or may not be connected to the core network.

[0032] The MN may provide a master cell group (MCG). The MN, in addition to the MN, may be referred to as an M-NODE or an M-NG-RAN node. The MCG may include one or more cells. The MCG may include a PCell (primary cell). The MCG may include multiple aggregated cells. The MCG may include a PCell and one or more secondary cells (SCells). The SN may provide a secondary cell group (SCG). The SN, in addition to the SN, may be referred to as an S-NODE or an S-NG-RAN node. The SCG may include one or more cells. The SCG may include multiple aggregated cells. Like the MCG, the SCG may include a PCell and / or an SCell. A cell functioning as a PCell within the SCG may be referred to as a PSCell (primary secondary cell). The secondary cell group may include a PSCell and one or more SCells. Hereinafter, the term "SpCell" (special cell) may be used to encompass PCell and PSCell. "SpCell" refers to the primary cell of an MCG or SCG. In other words, an MCG SpCell refers to a PCell, and an SCG SpCell refers to an SCell.

[0033] The possible types of DC can be defined as follows:

[0034] 1) EN-DC: Dual connectivity in which the eNB is connected to the evolved packet core (EPC), and the UE is connected to the eNB acting as an MN and the gNB acting as an SN. Here, the gNB may be referred to as an en-gNB, and the en-gNB may or may not be connected to the EPC.

[0035] 2) NGEN-DC: Dual connectivity in which the eNB is connected to the 5GC (5G core), and the terminal is connected to the eNB operating as an MN and the gNB operating as an SN. Here, the eNB may be referred to as ng-eNB.

[0036] 3) NE-DC: Dual connectivity in which the gNB is connected to the 5GC, and the terminal is connected to the gNB operating as an MN and the eNB operating as an SN. Here, the eNB may be referred to as ng-eNB.

[0037] 4) NR-DC: Dual connectivity where gNBs are connected to 5GC, and the UE is connected to a gNB that acts as an MN and a gNB that acts as an SN. NR-DC can also be used when a UE is connected to a single gNB that acts as both an MN and SN and configures both an MCG and an SCG.

[0038] The terminal (120) can support MR (multi-radio)-DC. The terminal (120) can be connected to a first base station (110-1) and a second base station (110-2). The first base station (110-1) is an MN, and the second base station (110-2) is an SN, and can be connected to the terminal. With the CA (carrier aggregation) provided by each base station, the DC technology can provide higher data rates. The first base station (110-1) and the second base station (110-2), as MN and SN, respectively, can transmit downlink traffic to the terminal (120) or receive uplink traffic from the terminal (120).

[0039] Figure 2a shows examples of control planes (C-planes).

[0040] Referring to FIG. 2a, in the C-plane, the UE (110) and the AMF (235) can perform NAS (non-access stratum) signaling. In the C-plane, the UE (110) and the gNB (120) can perform communication according to protocols specified in the RRC layer, the PDCP layer, the RLC layer, the MAC layer, and the PHY layer, respectively.

[0041] The main functions of the RRC layer may include at least some of the following functions:

[0042] - Broadcasting of AS (Access Stratum) and NAS-related system information

[0043] - Paging initiated by 5GC (5G Core) or NG-RAN (Next Generation-Radio Access network)

[0044] - Establishment, maintenance and release of RRC connection between UE and NG-RAN, including control over RLC, MAC and PHY, specifically:

[0045] - Adding, modifying, and disabling carrier aggregation

[0046] - Add, modify and disable dual connectivity between NR or E-UTRA and NR.

[0047] - Security features including key management;

[0048] - Setup, configuration, maintenance, and release of SRB (Signaling Radio Bearer) and DRB (Data Radio Bearer).

[0049] - Movement features including:

[0050] - Handover and context transfer;

[0051] - UE cell selection and reselection and cell selection and reselection control;

[0052] - Inter-RAT mobility.

[0053] - QoS (quality of service) management function;

[0054] - UE measurement reporting and reporting control;

[0055] - Detection and recovery of radio link failures

[0056] - Sending messages from / to UE to / from NAS.

[0057] The main functions of the PDCP layer may include at least some of the following functions:

[0058] - Header compression and decompression (ROHC only)

[0059] - User data transfer function

[0060] - In-sequence delivery of upper layer PDUs

[0061] - Out-of-sequence delivery of upper layer PDUs

[0062] - PDCP PDU reordering for reception

[0063] - Duplicate detection of lower layer SDUs

[0064] - Retransmission function (Retransmission of PDCP SDUs)

[0065] - Encryption and decryption functions (Ciphering and deciphering)

[0066] - Timer-based SDU discard in uplink.

[0067] The main functions of the RLC layer may include at least some of the following functions:

[0068] - Data transfer function (Transfer of upper layer PDUs)

[0069] - In-sequence delivery of upper layer PDUs

[0070] - Out-of-sequence delivery of upper layer PDUs

[0071] - ARQ function (Error Correction through ARQ)

[0072] - Concatenation, segmentation and reassembly of RLC SDUs

[0073] - Re-segmentation of RLC data PDUs

[0074] - Reordering of RLC data PDUs

[0075] - Duplicate detection function

[0076] - Protocol error detection

[0077] - RLC SDU discard function

[0078] - RLC re-establishment function

[0079] The MAC layer can be connected to multiple RLC layer devices configured in one terminal, and the main functions of the MAC can include at least some of the following functions.

[0080] - Mapping between logical channels and transport channels

[0081] - Multiplexing / demultiplexing of MAC SDUs

[0082] - Scheduling information reporting function

[0083] - Error correction through HARQ

[0084] - Priority handling between logical channels of one UE

[0085] - Priority handling between UEs by means of dynamic scheduling

[0086] - MBMS service identification function

[0087] - Transport format selection function

[0088] - Padding function

[0089] The physical layer can perform operations such as channel coding and modulating upper layer data, converting it into OFDM symbols and transmitting it over a wireless channel, or demodulating and channel decoding OFDM symbols received over a wireless channel and transmitting them to the upper layer.

[0090] Figure 2b shows examples of user planes (U-planes).

[0091] Referring to FIG. 2b, in the U-plane, the UE (110) and the gNB (120) can perform communication according to protocols specified in each of the SDAP layer, PDCP layer, RLC layer, MAC layer, and PHY layer. For the PDCP layer, RLC layer, MAC layer, and PHY layer, excluding the SDAP layer, the description for FIG. 2a may be referred to.

[0092] The SDAP layer can provide QoS flows for 5GC. A single SDAP protocol entity can be configured for each individual PDU session, and the SDAP layer's functionality can include at least some of the following functions:

[0093] - Mapping between QoS flows and data radio bearers;

[0094] - Display QoS flow ID (QFI) in both DL and UL packets.

[0095] Figures 3a, 3b, and 3c illustrate examples of function split according to communication protocols. A base station (e.g., base station (110)) may operate as an eNB or gNB depending on the radio access technology (RAT) provided. For example, the base station may be referred to as an NG-RAN node. The base station may be implemented in a distributed deployment according to a centralized unit (CU) configured to perform functions of upper layers of an access network (e.g., packet data convergence protocol (PDCP), radio resource control (RRC)) and a distributed unit (DU) configured to perform functions of lower layers.

[0096] Referring to FIG. 3A, in the control plane, the CU (310) may be connected to one or more DUs (e.g., DU (320)) and may be responsible for functions of a higher layer than the DU. For example, the CU (310) may be responsible for functions of the RRC layer (311) and the PDCP layer (312). The CU (310) may transmit or receive messages to or from the DU (320) through the F1 interface (340). In the control plane, the DU (320) may be responsible for functions of the RLC layer (321), the MAC layer (322), and the PHY layer (323). For a description of the functions of the RRC layer (311) of the CU (310), reference may be made to the description of the RRC layer of FIG. 2A. For a description of the functions of the PDCP layer (312) of the CU (310), reference may be made to the description of the PDCP layer of FIG. 2A. For a description of the functions of the RLC layer (321) of the DU (320), reference may be made to the description of the RLC layer of FIG. 2A. For a description of the functions of the MAC layer (322) of the DU (320), reference may be made to the description of the MAC layer of FIG. 2A. For a description of the functions of the PHY layer (323) of the DU (320), reference may be made to the description of the PHY layer of FIG. 2A. The DU (320) may perform an operation of channel coding and modulating upper layer data through the physical layer (323), converting it into an OFDM symbol and transmitting it through a wireless channel, or demodulating and channel decoding an OFDM symbol received through a wireless channel and transmitting it to a higher layer.

[0097] Referring to FIG. 3b, in the user plane, a CU (310) may be connected to one or more DUs (e.g., DU (320)) and may be responsible for functions of a higher layer than the DU. For example, the CU (310) may be responsible for functions of the SDAP layer (361) and the PDCP layer (362). The CU (310) may transmit messages to or receive messages from the DU (320) through the F1 interface (350) (e.g., F1-U). The CU (310) may be referred to as a node hosting a PDCP entity for the PDCP layer (362) in terms of performing functions for the PDCP layer (362). The DU (320) may be referred to as a node that interacts with the node hosting the PDCP entity for flow control. In the user plane, the DU (320) may be responsible for the functions of the RLC layer (371), the MAC layer (372), and the PHY layer (373). For a description of the functions of the SDAP layer (361) of the CU (310), reference may be made to the description of the SDAP layer in FIG. 2B. For a description of the functions of the PDCP layer (362) of the CU (310), reference may be made to the description of the PDCP layer in FIG. 2B. For a description of the functions of the RLC layer (321) of the DU (320), reference may be made to the description of the RLC layer in FIG. 2B. For a description of the functions of the MAC layer (322) of the DU (320), reference may be made to the description of the MAC layer in FIG. 2B. For a description of the functions of the PHY layer (323) of the DU (320), reference may be made to the description of the PHY layer in FIG. 2B.

[0098] Referring to FIG. 3C, an example of the protocol layers of the user plane in dual connectivity is illustrated. Different DUs (e.g., DU 320 and DU 330) may be connected to a single CU (310). DU (330) may include an RLC entity for an independent RLC layer (381) and a MAC entity for a MAC layer (382), separate from DU (320). DU (330) may also provide a UE (e.g., terminal (120)) with an access network distinct from the access network of DU (320). From the UE perspective, two separate MAC entities (e.g., a first MAC entity for the MAC layer (372) and a second MAC entity for the MAC layer (382)) may represent dual connectivity for the UE.

[0099] Although FIGS. 3A, 3B, and 3C illustrate that a DU (e.g., DU (320)) is responsible for a physical layer (e.g., physical layer (323), physical layer (373)), embodiments of the present disclosure are not limited thereto. According to an implementation example, the DU (320) may perform some functions of the physical layer (high PHY), and an RU connected to the DU (320) may be responsible for the remaining functions of the physical layer (low PHY). In addition, as an example, a DU (digital unit) may be included in a DU (distributed unit) (320) according to a distributed deployment implementation of a base station. As a non-limiting example, a DU (digital unit) may also refer to an entity that includes a CU and a DU (distributed unit) in a structure in which a CU, a DU (distributed unit), and an RU are deployed in that order.

[0100] In the present disclosure, a distributed arrangement may be utilized when describing network nodes that transmit or receive data packets. As components for the distributed arrangement, an upper network node and a lower network node may be utilized. The upper network node may be configured to perform functions of a higher layer (e.g., RRC, PDCP, SDAP) among communication protocol layers. For example, the upper network node may be a CU (e.g., CU (310)). The lower network node may be configured to perform functions of a lower layer (e.g., RLC, MAC) among communication protocol layers. For example, the lower network node may be a DU (e.g., DU (320)). Hereinafter, the upper network node is described as CU (310) and the lower network node is DU (320) as an example, but it is to be understood that other types of network nodes may be utilized depending on other functional separation options.

[0101] Figure 4a illustrates an example of signaling between a central unit (CU) (e.g., CU 310) and a distributed unit (DU) (e.g., DU 320). Figure 4a illustrates examples of messages on the F1 interface (350) (e.g., F1-U) between the CU (310) and the DU (320) in the user plane (U-plane). Like reference numerals may represent like descriptions.

[0102] Referring to FIG. 4a, CU (310) can transmit a status message (410) to DU (320).

[0103] 1. Sending status messages

[0104] The CU (310) may transmit a status message (410) to the DU (320) via the F1 interface (350) (e.g., F1-U). In one embodiment, the status message (410) may be used to provide downlink data delivery status (DDDS) to the CU (310). The procedure for transmitting the status message (410) may enable the CU (310) to control the downlink user data flow of each data radio bearer (DRB) by providing feedback from the DU (320) to the CU (310). The procedure for transmitting the status message (410) may be used to provide feedback from the DU (320) to the CU (310) to allow the CU (310) to control the successful delivery of downlink control data. As a non-limiting example, the DU (320) may also transmit uplink user data of a related data radio bearer to the CU (310) via a status message (410). In this case, the data radio bearer of the uplink user data and the radio bearer of the status message (410) may be associated with the same protocol data unit (PDU).

[0105] The status message (410) may include various information. For example, in RLC AM (acknowledged mode), the status message (410) may include the highest NR PDCP PDU sequence number that has been successfully and sequentially delivered to the UE among the PDCP PDUs received from the CU (310). Here, retransmitted NR PDCP PDUs may be excluded from the PDUs. For example, the status message (410) may include information about a desired buffer size for the corresponding data radio bearer or multicast / broadcast service radio bearer (MRB). The desired buffer size may be indicated in bytes. For example, the status message (410) may optionally include information about a desired data rate associated with a specific data radio bearer configured for the UE or MRB. The desired data rate may be indicated in bytes. The value indicated in bytes above may represent the amount of data transmitted per unit time (e.g., 1 second). For example, the status message (410) may include information about NR-U packets that have been declared "lost" and have not yet been reported to the CU (310) within the status message (410) (e.g., a downlink data forwarding status (DDDS) frame of Table 1). For example, the status message (410) may include information about the NR PDCP PDU sequence number associated with the highest NR-U sequence number among the retransmitted NR PDCP PDUs successfully delivered to the UE in the order of NR-U sequence numbers, if a retransmitted NR PDCP PDU has been delivered.For example, the status message (410) may include information about the NR PDCP PDU sequence number associated with the highest NR-U sequence number among the retransmitted NR PDCP PDUs transmitted to the lower layer in the order of NR-U sequence numbers when a retransmitted NR PDCP PDU is transmitted to the lower layer. For example, the status message (410) may include information about the highest NR PDCP PDU sequence number transmitted to the lower layer among the NR PDCP PDUs received from the CU (310). Here, the retransmitted NR PDCP PDU may be excluded from the PDUs. For example, in RLC AM, the status message (410) may include information about the NR PDCP PDU sequence number that was successfully delivered to the UE out of order among the NR PDCP PDUs received from the CU (310). Here, the retransmitted NR PDCP PDU may be excluded from the PDUs.

[0106] The status message (410) may be triggered based on an event. For example, when the DU (320) detects successful random access channel (RACH) access of a UE (e.g., terminal (120)) to the corresponding data radio bearer, the DU (320) may transmit the status message (410) to the CU (310). The CU (310) may initiate downlink data transmission before receiving the status message (410). For example, the status message (410) may have the following format, referred to as a downlink data forwarding status (DDDS) frame.

[0107] BitsNumber of Octets76543210PDU Type (=1)Highest Transmitted NR PDCP SN IndHighest Delivered NR PDCP SN IndFinal Frame Ind.Lost Packet Report1SpareFeedback Delay Ind.NR-U SN Ind.Delivered NR PDCP SN Range IndData rate Ind.Retransmitted NR PDCP SN IndDelivered Retransmitted NR PDCP SN IndCause ReportDesired buffer size for the data radio bearer4Desired Data Rate0 or 4Number of lost NR-U Sequence Number ranges reported0 or 1Start of lost NR-U Sequence Number range0 or (6* Number of reported lost NR-U SN ranges)End of lost NR-U Sequence Number rangeHighest successfully delivered NR PDCP Sequence Number0 or 3Highest transmitted NR PDCP Sequence Number0 or 3Cause Value0 or 1Successfully delivered retransmitted NR PDCP Sequence Number0 or 3Retransmitted NR PDCP Sequence Number0 or 3Number of successfully delivered out of sequence PDCP Sequence Number range0 or 1Start of successfully delivered out of sequence PDCP Sequence Number range0 or (6* Number of successfully delivered out of sequence PDCP Sequence Number range)End of successfully delivered out of sequence PDCP Sequence Number rangeNR-U Sequence Number of Polling Frame0 or 3Feedback Delay Result0 or 4Padding0-3.

[0108] Referring to Table 1, when the status message (410) is the last downlink status report, the status message (410) may include a separate indicator (e.g., Final Frame Ind.). Upon receiving the indicator, the CU (310) may consider that no further UL or DL ​​data transmission is expected between the DU (320) and the terminal (120). The status message (410) may include a detected indicator of a radio link outage or radio link resume for the relevant data radio bearer. For example, a specific value of a parameter (e.g., "Cause Value") may indicate a radio link outage (e.g., a value of '1' of the parameter indicates a radio link outage) or a radio link resume (e.g., a value of '2' of the parameter indicates a radio link resume). For example, through the value of the above parameter, a wireless link interruption or wireless link resumption can be indicated by both the downlink and the uplink, by the downlink only, or by the uplink only.

[0109] Referring to Table 1, 'Desired buffer size for the data radio bearer' can indicate the requested buffer size in bytes for the related data radio bearer. 'Desired buffer size for the data radio bearer' is a 4-octet structure, and is 0 to 2. 32 -1 value. For example, 'Desired Data Rate' represents the amount of data in bytes desired to be received during a specific time period (e.g., 1 second). 'Desired Data Rate' is a 4-octet structure, and can be 0 to 2. 32 It can have a value of -1.

[0110] The CU (310) can receive a status message (410) from the DU (320). The CU (310) can determine a desired buffer size (e.g., 'Desired buffer size for the data radio bearer') and a data rate (e.g., 'Desired Data Rate') as the amount of data to be transmitted from the CU (310). If the value of the desired buffer size is 0, the CU (310) can stop data transmission of the corresponding bearer. If the value of the desired buffer size is greater than 0, the CU (310) can transmit data up to the amount of data indicated by the desired buffer size per bearer. For example, the data may include data to be retransmitted. The above data may include, in addition to the retransmitted data, new data starting from the last "highest successfully delivered NR PDCP sequence number" (e.g., 'Highest successfully delivered NR PDCP Sequence Number') for RLC AM or starting from the last "highest transmitted NR PDCP sequence number" (e.g., 'Highest transmitted NR PDCP Sequence Number') for RLC UM. The value of the requested data rate indicates the amount of data desired to be received for about 1 second. Information about the requested buffer size and information about the requested data rate may be valid until the next status message is received.

[0111] 2. Transmission of user data

[0112] DU (320) can transmit user data (420) to CU (310). The purpose of the transmission procedure of user data (420) is to provide NR-U specific sequence number information when transmitting user data (420) carrying DL NR PDCP PDU from CU (310) to DU (320). In downlink, NR user plane protocol instance using the transmission procedure of user data (420) can be associated with only a single radio bearer. CU (310) can assign consecutive NR-U sequence numbers to each transmitted NR-U packet. A retransmitted NR PDCP PDU must be assigned a new NR-U sequence number. CU (310) can inform DU (320) whether this NR-U packet is a retransmission of an NR PDCP PDU. The CU (310) may also instruct the DU (320) to discard all NR PDCP PDUs up to and including the defined DL discard NR PDCP PDU SN or to discard one or more downlink NR PDCP PDU blocks.

[0113] For example, user data (420) may have the following format.

[0114]

[0115] Referring to Table 2, for example, 'NR-U Sequence Number' represents the NR-U sequence number allocated by CU (310). 'NR-U Sequence Number' is a 3-octet structure, and is 0 or more and 2 24 -1 value. For example, 'DL discard NR PDCP PDU SN' can indicate the SN when PDUs up to NR PDCP PDU SN are discarded. 'DL discard NR PDCP PDU SN' is a 3-octet structure, 0 to 2. 18It can have a value of -1. For example, 'DL discard Number of blocks' represents the downlink blocks to be discarded. 'DL discard Number of blocks' is a 1-octet structure and can have a value greater than or equal to 1 and less than or equal to 244. For example, 'DL discard NR PDCP PDU SN start' represents the starting SN of the block to be discarded, and 'Discarded Block size' represents the number of PDCP PDUs to be discarded from the starting SN.

[0116] In Fig. 4a, NR PDCP PDU is described as an example as a downlink packet, but embodiments of the present disclosure are not limited thereto. PDCP PDUs on the W1 interface between eNB-DU and eNB-CU may also be applied to embodiments of the present disclosure. In other words, downlink packets include PDCP PDUs in an LTE network, and CU (310) and DU (320) may correspond to eNB-CU and eNB-DU constituting an eNB, respectively. The following description of the F1 interface (350) (e.g., F1-U) may also be equally applied to the W1 interface between eNB-CU and eNB-DU.

[0117] Figure 4b illustrates an example of signaling between a CU (e.g., CU (310)) and a DU (e.g., DU (320)) via a routing node. Like reference numbers may represent like descriptions.

[0118] Referring to FIG. 4b, at least one routing node (e.g., routing node (444)) (which may be referred to as a router, relay node, node, and / or equivalent technical terminology other than a routing node) may be placed between the CU (310) and the DU (320). In terms of a communication protocol, the CU (310) and the DU (320) communicate via the F1 interface, but data transmitted from the CU (310) to the DU (320) may be provided to the DU (320) via at least one routing node between the CU (310) and the DU (320). Similarly, data transmitted from the DU (320) to the CU (310) may be provided to the DU (320) via at least one routing node between the CU (310) and the DU (320). For example, the DU (320) can transmit a status message (410) to the CU (310) via the routing node (444). For example, the DU (320) can transmit the status message (410) to the routing node (444) via a first uplink path (410a). The routing node (444) can transmit the status message (410) to the CU (310) via a second uplink path (410b). The DU (320) can transmit user data (420) to the DU (320) via the routing node (444). For example, the CU (310) can transmit user data (420) to the routing node (444) via a first downlink path (420a). The routing node (444) can transmit user data (420) to the DU (320) via the second downlink path (420b).

[0119] The presence of the routing node (444) may cause a difference between the desired data rate at the DU (320) and the actual data rate provided from the CU (310). For example, the DU (320) may request downlink packets corresponding to a data rate of about 3 Gbps via a status message (410). The CU (310) may receive the status message (410). The CU (310) may determine the amount of downlink packets to be allocated per unit time from the status message (410). The CU (310) may determine the data rate. For example, the CU (310) may determine a data rate of about 3 Gbps. The CU (310) may transmit downlink packets to the DU (320) according to the determined data rate. The CU (310) may transmit the downlink packets to the routing node (444) via the first downlink path (420a). The routing node (444) may decide to transmit the downlink packets to the DU (320). However, the performance of the second downlink path (420b) between the routing node (444) and the DU (320) may be different from the performance of the first downlink path (420a) between the CU (310) and the routing node (444). For example, the cable of the first downlink path (420a) between the CU (310) and the routing node (444) may support up to about 10 Gbps, whereas the cable of the second downlink path (420b) between the routing node (444) and the DU (320) may only support up to a maximum of 1 Gbps. Therefore, the cable performance of the second downlink path (420b) between the routing node (444) and the DU (320) may have difficulty in guaranteeing a speed of about 3 Gbps between the CU (310) and the routing node (444). Speed ​​mismatches can occur due to differences in performance between paths (e.g., differences in performance between cables).Since the routing node (444) provides downlink packets to the DU (320) only at a speed of about 1 Gbps, the DU (320) may not be able to receive packets corresponding to the remaining about 2 Gbps. Even if downlink packets stored through a buffer in the routing node (444) are provided to the DU (320), if the capacity of the buffer is not sufficient to compensate for the speed difference, packet loss may occur in the routing node (444). In other words, a mismatch between the speed performance of the first downlink path (420a) and the speed performance of the second downlink path (420b) may cause packet loss. These lost packets may be difficult to sufficiently recover even through a retransmission algorithm (e.g., ARQ (automatic repeat request)). Due to the lost packets, the UE (e.g., terminal (120)) may experience service interruption. A specific example of packet loss is described through FIG. 5.

[0120] Figure 5 illustrates the flow of downlink packet processing. Identical reference numbers may represent identical descriptions.

[0121] Referring to FIG. 5, the CU (310) can transmit downlink packets corresponding to user data (420) to the routing node (444) via the first downlink path (420a). The downlink packets can include a first downlink packet (501), a second downlink packet (502), a third downlink packet (503), a fourth downlink packet (504), and a fifth downlink packet (505). For example, the first downlink path (420a) can process 10 downlink packets per unit time. The CU (310) can transmit up to a total of 10 downlink packets during the unit time. Accordingly, the CU (310) can transmit the first downlink packet (501), the second downlink packet (502), the third downlink packet (503), the fourth downlink packet (504), and the fifth downlink packet (505) to the routing node (444) within the unit time.

[0122] The second downlink path (420b) can process one downlink packet per unit time. The routing node (444) can only transmit one downlink packet per unit time. Therefore, the routing node (444) can transmit the first downlink packet (501) to the DU (320) within the unit time. The routing node (444) can include a buffer (544). For example, the buffer (544) can store three downlink packets. The routing node (444) can store the second downlink packet (502), the third downlink packet (503), and the fourth downlink packet (504). However, the routing node (444) may have difficulty storing the fifth downlink packet (505) due to the limitation of the capacity of the buffer (544). Since the routing node (444) cannot process the fifth downlink packet (505), the fifth downlink packet (505) may be discarded or lost. In fact, if packet loss occurs, recovery may be performed through packet retransmission, but the higher the buffer usage at the network level, the more difficult it may be to recover packets such as the fifth downlink packet (505).

[0123] When downlink packets are allocated in bursts, the amount of data in the downlink path increases rapidly, which may increase the possibility of packet loss occurring in the backhaul section between the CU (310) and the DU (320). To address and / or mitigate the above-described problem, the present disclosure describes a technique for detecting expected packet loss and adaptively controlling downlink traffic based on the degree of detected packet loss. Specifically, the DU (320) may control downlink traffic from the CU (310) through parameters related to the requested amount of data (e.g., information on the desired buffer size ('Desired buffer size for the data radio bearer') and information on the desired data rate ('Desired Data Rate') among the parameters included in the status message (410) (e.g., the downlink data forwarding status (DDDS) frame of Table 1).

[0124] Figure 6 shows the operation flow of an electronic device (e.g., DU (320)) for downlink traffic control.

[0125] Referring to FIG. 6, in operation (601), an electronic device (e.g., DU (320)) may transmit a first status message (e.g., status message (410), DDDS frame of Table 1) including first data amount information for a data radio bearer to the CU (310). For example, the first data amount information may indicate a desired buffer size for the data radio bearer. As an example, the first data amount information may correspond to 'Desired buffer size for the data radio bearer' of Table 1. As another example, the first data amount information may indicate an amount of data desired to be received within a specified time (e.g., 1 second). As an example, the first data amount information may correspond to 'Desired Data Rate' of Table 1.

[0126] In operation (603), an electronic device (e.g., DU (320)) may receive downlink data (e.g., user data (420)). The electronic device may obtain downlink packets (e.g., PDCP PDUs) corresponding to the downlink data received from the CU (310). The electronic device may determine a packet loss index between the CU (310) and the DU (320) from the downlink packets. For example, the electronic device may determine a packet loss rate as the packet loss index. The electronic device may determine the packet loss rate based on a sequence number for each packet of the downlink packets. Specifically, the electronic device may check the sequence number of each received downlink packet. By obtaining the sequence numbers, the electronic device may check the number of at least one lost packet. The electronic device may determine the packet loss rate based on the total number of transmitted packets and the number of at least one lost packet. For example, the electronic device can determine the number of lost packets as the packet loss indicator. The electronic device can determine the number of lost packets based on a sequence number for each packet of the downlink packets. Specifically, the electronic device can check the sequence number of each received downlink packet. By obtaining the sequence numbers, the electronic device can check at least one lost packet. For example, the electronic device can determine the capacity size of delayed packets (or lost packets) as the packet loss indicator. The electronic device can determine the capacity size of delayed packets through the difference between the data amount requested through the first status message of operation (601) and the data amount of downlink data actually received.For example, the electronic device may request about 275 megabytes of data from the CU (310) via the first status message. If the electronic device receives about 125 megabytes of data per unit time (e.g., 1 second), the electronic device may determine that a delay of about 150 megabytes of data has occurred.

[0127] In operation (605), the electronic device (e.g., DU (320)) may determine second data volume information based on a packet loss indicator. A higher packet loss indicator may indicate that a relatively larger number of packets are lost, and a higher packet loss indicator may indicate that a relatively smaller number of packets are lost. As described in operation (603), the packet loss indicator may be determined through at least one of various methods (e.g., a packet loss rate, a number of lost packets, and / or a delayed packet capacity (or lost packet capacity)).

[0128] The electronic device can compare the packet loss indicator with at least one threshold. Traffic control according to the threshold can be performed in various ways. For example, the traffic control can be performed in three stages of 'up', 'maintain', and 'down'. The first data amount information indicated through the first status message in operation (601) can have a first value. The electronic device can determine a second value as the second data amount information. When the packet loss indicator is less than the first threshold, the electronic device can determine a second value greater than the first value. Since the number of lost packets is small, the electronic device can request the CU (310) to transmit a larger amount of downlink data than the amount of data requested in the first data amount information. When the packet loss indicator is greater than or equal to the first threshold and less than the second threshold, the electronic device can determine a second value equal to the first value. Since the number of lost packets is within a certain range, the electronic device can request the CU (310) to transmit the same amount of data in order to maintain the current data rate. If the packet loss indicator is equal to or greater than a second threshold, the electronic device can determine the second value, which is smaller than the first value, as the second data amount information. If the number of lost packets is large, the electronic device can request the CU (310) to transmit a smaller amount of downlink data than the amount of data requested in the first data amount information. For another example, the traffic control can be configured in two stages of 'up' and 'down'. The first data amount information indicated through the first status message in operation (601) can have a first value. The electronic device can determine the second value as the second data amount information. If the packet loss indicator is less than a threshold, the electronic device can determine the second value, which is larger than the first value.The electronic device may determine a second value smaller than the first value when the packet loss indicator is greater than or equal to the threshold value.

[0129] The electronic device can control the traffic speed of downlink data from the CU (310) by determining the second data amount information. The unit for controlling the second data amount information (hereinafter, referred to as a control unit) can be performed in units of absolute packet capacity (e.g., xx bytes) or ratio (e.g., yy%). For example, in case of lowering the data amount due to a packet loss index above a threshold value, the electronic device can determine a value lowered by about 5% from the first value of the first data amount information as the second value. In another example, in case of increasing the data amount due to a packet loss index below a threshold value, the electronic device can determine a value higher by about 100 megabytes from the first value of the first data amount information as the second value. According to one embodiment, the control unit can be fixedly set. According to a predefined value, the electronic device can increase or decrease the data amount to be requested from the CU (310). According to another embodiment, the control unit can be set according to a previous control type. When the number of requested packets is gradually increased, the control unit may gradually increase. For example, when the packet loss index continues to be lower than the threshold value and the requested buffer size is continuously increased, the control unit for increasing the requested buffer size may gradually increase. The electronic device may determine a data amount (e.g., a second data amount) that is approximately 1% greater than the previous data amount during the first traffic control. The electronic device may determine a data amount (e.g., a third data amount) that is approximately 3% greater than the previous data amount (e.g., a second data amount) during the second traffic control. The electronic device may determine a data amount (e.g., a fourth data amount) that is approximately 10% greater than the previous data amount (e.g., a third data amount) during the third traffic control.

[0130] The type of the second data amount information may correspond to the type of the first data amount information. For example, the second data amount information may indicate a desired buffer size for the data radio bearer. As an example, the second data amount information may correspond to 'Desired buffer size for the data radio bearer' in Table 1. As another example, the second data amount information may indicate an amount of data desired to be received within a specified time (e.g., 1 second). As an example, the second data amount information may correspond to 'Desired Data Rate' in Table 1. As a non-limiting example, even if the type of the second data amount information is different from the type of the first data amount information, if the type of the second data amount information can be provided to the CU (310) for the purpose of controlling a traffic rate, the second data amount information using the type may be understood as an embodiment of the present disclosure. For example, the first data amount information may indicate a desired buffer size, and the second data amount information may indicate a desired data rate.

[0131] In operation (607), an electronic device (e.g., DU (320)) may transmit a second status message (e.g., status message (410), DDDS frame of Table 1) including second data amount information for a data radio bearer to the CU (310). The electronic device may adjust the data amount of downlink packets for the same data radio bearer through the second data amount information.

[0132] As described through FIG. 6, if the packet loss indicator between the CU (310) and the DU (320) is higher than a certain level (e.g., a threshold), the DU (320) reduces the packet transmission amount through a status message (e.g., a DDDS frame), and if the loss rate between the CU (310) and the DU (320) is lower than a certain level, the traffic speed between the CU (310) and the DU (320) can be adaptively adjusted by reducing the packet transmission amount of the status message (e.g., a DDDS frame). When at least one node (e.g., routing node (444)) is located between the CU (310) and the DU (320), the difference between the data capacity between the DU (320) and the routing node (444) and the data capacity between the CU (310) and the routing node (444) may cause a speed mismatch. The data capacity may represent an available data rate. For example, the data rate between the DU (320) and the routing node (444) may be lower than the available data rate between the CU (310) and the routing node (444). Therefore, the DU (320) may control the data rate or data amount of downlink traffic from the CU (310) to prevent packet loss due to the speed mismatch.

[0133] As a factor for determining a packet loss index, a sequence number of a packet may be used. To identify lost packets, the DU (320) may check the sequence number of each packet. According to one embodiment, the DU (320) may determine a packet loss index by checking the NR-U sequence number of the frame of each received packet (e.g., the format of Table 2). According to another embodiment, the DU (320) may determine a packet loss index by checking the sequence number of the GTP-U header of each packet. For example, the GTP-U header may have the following format.

[0134]

[0135] (*) This bit is a spare bit. It shall be sent as '0'. The receiver shall not evaluate this bit.

[0136] 1) This field shall only be evaluated when indicated by the S flag set to 1.

[0137] 2) This field shall only be evaluated when indicated by the PN flag set to 1.

[0138] 3) This field shall only be evaluated when indicated by the E flag set to 1.

[0139] 4) This field shall be present if and only if any one or more of the S, PN and E

[0140] As a non-limiting example, the N-PDU number field and / or the Next Extension Header Type field may be omitted within the GTP-U header.

[0141] Figures 7a and 7b illustrate the flow of downlink packet processing according to downlink traffic control. Like reference numbers may indicate like descriptions. Figures 7a and 7b illustrate a situation in which traffic control is performed by DU (320) after the packet loss of Figure 5.

[0142] Referring to FIG. 7A, the DU (320) may transmit a status message (710) (e.g., status message (410), DDDS frame) including data amount information adjusted through traffic control to the CU (310). The DU (320) may transmit the status message (710) to the CU (310) via the routing node (444). For example, the status message (710) may include a parameter indicating a data amount that is less than the data amount previously provided to the CU (310). As an example, the status message (710) may include information indicating a desired data buffer size ('Desired buffer size for the data radio bearer') that is less than the desired data buffer size provided to the CU (310). As an example, the status message (710) may include information indicating a desired data rate ('Desired Data Rate') that is lower than the desired data rate provided to the CU (310). According to one embodiment, the DU (320) may determine the amount of data information to be included in the status message (710) based on the capacity of the buffer (544) of the routing node (444) and the transmission capacity of the second downlink path (420b). The DU (320) may determine the amount of data to be transmitted from the CU (310) using the capacity of the buffer (544) as well as the data rate on the second downlink path (420b). The DU (320) may determine the amount of data to be transmitted from the CU (310) through the second downlink path (420b) and the buffer (544) so ​​as to prevent downlink packets from being lost. For example, the DU (320) may determine the amount of data information representing four downlink packets per unit time. As a non-limiting example, when a large amount of traffic continuously occurs, the risk of packet loss increases, so the DU (320) can set thresholds for traffic control (e.g., a first threshold, a second threshold, a threshold for comparison with a packet loss indicator) based on a margin to an acceptable limit.

[0143] The CU (310) can adjust the amount of downlink data to be transmitted in response to the status message (710). The CU (310) can transmit downlink packets corresponding to user data (420) to the routing node (444) via the first downlink path (420a). The downlink packets can include a first downlink packet (701), a second downlink packet (702), a third downlink packet (703), and a fourth downlink packet (704). For example, the first downlink path (420a) can process 10 downlink packets per unit time. The CU (310) can transmit up to a total of 10 downlink packets during the unit time. Accordingly, the CU (310) can transmit the first downlink packet (701), the second downlink packet (702), the third downlink packet (703), and the fourth downlink packet (704) to the routing node (444) within the unit time. The second downlink path (420b) can process two downlink packets per unit time. The routing node (444) can transmit only two downlink packets during the unit time. Accordingly, the routing node (444) can transmit the first downlink packet (701) and the second downlink packet (702) to the DU (320) within the unit time. The routing node (444) can include a buffer (544). For example, the capacity of the buffer (544) can be larger than the size of two downlink packets. The buffer (544) can store two downlink packets. The routing node (444) can store the third downlink packet (703) and the fourth downlink packet (704).

[0144] Referring to FIG. 7B, the DU (320) may transmit a status message (710) (e.g., status message (410), DDDS frame) including data amount information adjusted through traffic control to the CU (310). The DU (320) may transmit the status message (710) to the CU (310) via the routing node (444). For example, the status message (710) may include a parameter indicating a data amount that is less than the data amount previously provided to the CU (310). As an example, the status message (710) may include information indicating a desired data buffer size ('Desired buffer size for the data radio bearer') that is less than the desired data buffer size provided to the CU (310). As an example, the status message (710) may include information indicating a desired data rate ('Desired Data Rate') that is lower than the desired data rate provided to the CU (310). According to one embodiment, the DU (320) may determine the amount of data information to be included in the status message (710) based on the transmission capacity of the second downlink path (420b). The capacity of the buffer (544) may not be sufficient, or it may not be easy to identify the margin of the buffer (544). The DU (320) may determine the amount of data to be transmitted from the CU (310) based on the data rate in the second downlink path (420b). The DU (320) may determine the amount of data to be transmitted from the CU (310) so that downlink packets are not lost due to the limitation of the transmission capacity of the cable of the second downlink path (420b) (e.g., 1 Gbps). For example, the DU (320) may determine the amount of data information representing two downlink packets per unit time.

[0145] The CU (310) can adjust the amount of downlink data to be transmitted in response to the status message (710). The CU (310) can transmit downlink packets corresponding to user data (420) to the routing node (444) via the first downlink path (420a). The downlink packets can include a first downlink packet (701) and a second downlink packet (702). For example, the first downlink path (420a) can process 10 downlink packets per unit time. The CU (310) can transmit up to 10 downlink packets in total during the unit time. Accordingly, the CU (310) can transmit the first downlink packet (701) and the second downlink packet (702) to the routing node (444) within the unit time. The second downlink path (420b) can process two downlink packets per unit time. The routing node (444) can transmit only two downlink packets per unit time. Therefore, the routing node (444) can transmit the first downlink packet (701) and the second downlink packet (702) to the DU (320) within the unit time.

[0146] The CU (310) may transmit downlink packets based on a first data amount (e.g., a requested buffer size). If there is no traffic control, such as transmission of a status message (710) from the DU (320), the CU (310) transmits downlink packets based on a previously received status message. Therefore, even if packet loss occurs on the path between the CU (310) and the DU (320), the requested buffer size of the first data amount may be maintained the same as the previous value. Due to the transmission capacity between the DU (320) and the routing node (444) and the capacity limit of the buffer (544) of the routing node (444), not all lost packets may be recovered. Due to packet loss, a service interruption may occur at the terminal. Therefore, by providing the CU (310) with a second data amount (e.g., a requested buffer size) that is lower than the first data amount through the status message (710), the packet loss rate can be reduced. If the loss rate is lower than a certain level, in order to increase the data rate again, the DU (320) can transmit information to the CU (310) indicating an increased amount of data (e.g., a requested buffer size larger than the second amount of data) compared to before. The DU (320) can reduce the packet loss rate in the F1-U section below a certain level by adjusting the rate of downlink data (or the amount of downlink data) to be transmitted from the CU (310) through a status message (710) (e.g., status message (410), DDDS frame). As the packet loss rate is reduced below a certain level, the service interruption experience at the terminal can be reduced, and the overall throughput through the network can be increased.

[0147] Although the present disclosure describes an example in which a single routing node is arranged between the CU (310) and the DU (320), the embodiments of the present disclosure are not limited thereto. In a situation in which a plurality of nodes are arranged between the CU (310) and the DU (320), packet loss occurring due to a speed difference between the nodes can also be resolved through the embodiments of the present disclosure. For example, if the data speed between the nodes among the plurality of nodes or the data speed between the DU (320) and a node (the node is a node connected to the DU (320)) is lower than the data speed between the CU (310) and a node (the node is a node connected to the CU (310)), the DU (320) can reduce the packet loss rate for the path between the CU (310) and the DU (320) by adjusting the amount of data (e.g., required buffer size, required data speed).

[0148] Fig. 8 illustrates an example of components of an electronic device (e.g., DU (320)) for downlink traffic control. The configuration illustrated in Fig. 8 can be understood as a configuration of a network entity (e.g., DU (320)) that functions as at least a part of a base station (e.g., base station (110)). Terms such as "...unit" and "...unit" used hereinafter mean a unit that processes at least one function or operation, and this can be implemented by hardware or a combination of hardware and software.

[0149] Referring to FIG. 8, the electronic device (800) may include a transceiver (810), a memory (820), and a processor (830).

[0150] The transceiver (810) may perform functions for transmitting and receiving signals in a wired communication environment. The transceiver (810) may include a wired interface for controlling direct connections between devices via a transmission medium (e.g., copper wire, optical fiber). For example, the transceiver (810) may transmit electrical signals to other devices via copper wire, or perform conversion between electrical signals and optical signals. The DU (220) may communicate with a centralized unit (CU) (e.g., CU (310)) via the transceiver (810). The transceiver (810) may also perform functions for transmitting and receiving signals in a wireless communication environment. For example, the transceiver (810) may perform a conversion function between a baseband signal and a bitstream according to the physical layer specifications of the system. For example, when transmitting data, the transceiver (810) generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the transceiver (810) restores a reception bit stream by demodulating and decoding a baseband signal. In addition, the transceiver (810) may include multiple transmission and reception paths. According to an implementation example, the electronic device (800) may perform communication with a UE (e.g., terminal (120)) directly through a wireless access network as a DU (220) or may perform communication with a UE (e.g., terminal (120)) through a radio unit (RU).

[0151] The transceiver (810) transmits and receives signals as described above. Accordingly, all or part of the transceiver (810) may be referred to as a "communication unit," a "transmitter," a "receiver," or a "transmitter-receiver unit." Furthermore, in the following description, transmission and reception performed via a wireless channel are used to mean that processing as described above is performed by the transceiver (810). Although only the transceiver (810) is illustrated in FIG. 8, the electronic device (800) may include two or more transceivers according to other implementation examples.

[0152] The memory (820) stores data such as basic programs, application programs, and setting information for the operation of the electronic device (800). The memory (820) may be referred to as a storage unit. The memory (820) may be configured as volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. In addition, the memory (820) may provide stored data upon request of the processor (830). The memory (820) is a functional component and represents a storage space. For example, the memory (820) may be understood not only to represent a memory (e.g., a hard disk, flash memory, RAM) arranged as a component within the electronic device (800), but also to represent a space for storing instructions and / or programs.

[0153] The processor (830) controls the overall operations of the electronic device (800). The processor (880) may be referred to as a control unit. For example, the processor (830) transmits and receives signals through the transceiver (810) (or through the backhaul communication unit). In addition, the processor (830) records and reads data in the memory (820). In addition, the processor (830) may perform functions of the protocol stack required by the communication standard (e.g., functions according to the protocols of FIGS. 2A, 2B, 3A, 3B, and 3C). Although only the processor (830) is illustrated in FIG. 8, the electronic device (800) may include two or more processors according to other implementation examples.

[0154] The configuration of the electronic device (800) illustrated in FIG. 8 is merely an example, and the examples of components of the electronic device performing the embodiments of the present disclosure are not limited to the configuration illustrated in FIG. 8. In some embodiments, some configurations may be added, deleted, or changed.

[0155] Burstiness of packet authorization can be prevented through traffic control of a DU (e.g., DU (320)) according to embodiments of the present disclosure. By reducing packet loss that may occur in the F1-U section due to the difference in transmission capacity between DU (320) and the routing node and between CU (310) and the routing node, DU (320) can provide smooth downlink traffic to the terminal.

[0156] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0157] In embodiments, an electronic device of a lower network node is provided. The electronic device may include a memory storing instructions, at least one transceiver, and at least one processor. The instructions, when executed by the at least one processor, may cause the electronic device to transmit a first status message including first data amount information for a data radio bearer to an upper network node via the at least one transceiver, receive downlink (DL) data for the data radio bearer from the upper network node via the at least one transceiver, determine second data amount information for the data radio bearer based on a packet loss metric for a path between the upper network node and the lower network node obtained from the downlink data, and transmit a second status message including the second data amount information to the upper network node via the at least one transceiver.

[0158] For example, the downlink data may be received from the upper network node via a routing node. The available data rate between the routing node and the lower network node may be lower than the available data rate between the upper network node and the routing node.

[0159] For example, each of the first status message and the second status message may correspond to a downlink data delivery status frame. Each of the first data amount information and the second data amount information may include a parameter indicating a required buffer size for the data radio bearer.

[0160] For example, each of the first status message and the second status message may correspond to a downlink data delivery status frame. Each of the first data amount information and the second data amount information may include a parameter indicating the amount of data desired to be received within a specified time for the data radio bearer.

[0161] For example, the downlink data may be received from the upper network node via downlink user data (DL user data) frames. The packet loss indicator may indicate a packet loss rate for a path between the upper network node and the lower network node, determined based on a sequence number for each packet of the downlink user data frames.

[0162] For example, the first data amount information may indicate a first value, and the second data amount information may indicate a second value. The instructions, when executed by the at least one processor, may cause the electronic device to determine the second value greater than the first value when the packet loss indicator is less than a first threshold value, determine the second value equal to the first value when the packet loss indicator is greater than or equal to the first threshold value and less than a second threshold value, and determine the second value less than the first value when the packet loss indicator is greater than or equal to the second threshold value.

[0163] For example, the first data amount information may indicate a first value, and the second data amount information may indicate a second value. The instructions, when executed by the at least one processor, may cause the electronic device to determine the second value greater than the first value when the packet loss indicator is less than a threshold value, and to determine the second value less than the first value when the packet loss indicator is greater than or equal to the threshold value.

[0164] For example, the second data amount information may be determined based on the size of the available buffer for the data radio bearer of the routing node and the size of the packet loss indicator.

[0165] For example, the downlink data may be received from the upper network node via a plurality of nodes. The plurality of nodes may include a first node connected to the upper network node and a second node connected to the lower network node. An available data rate between the second node and the lower network node or an available data rate between two nodes among the plurality of nodes may be lower than an available data rate between the upper network node and the first node.

[0166] For example, the upper network node may include a central unit (CU) configured to perform functions of the packet data convergence protocol (PDCP) layer. The lower network node may include a distributed unit (DU) configured to perform functions of the radio link layer (RLC) layer and the medium access control (MAC) layer.

[0167] In embodiments, a method performed by a lower network node may include transmitting a first status message including first data amount information for a data radio bearer to an upper network node, receiving downlink (DL) data for the data radio bearer from the upper network node, determining second data amount information for the data radio bearer based on a packet loss metric for a path between the upper network node and the lower network node obtained from the downlink data, and transmitting a second status message including the second data amount information to the upper network node.

[0168] For example, the downlink data may be received from the upper network node via a routing node. The available data rate between the routing node and the lower network node may be lower than the available data rate between the upper network node and the routing node.

[0169] For example, each of the first status message and the second status message may correspond to a downlink data delivery status frame. Each of the first data amount information and the second data amount information may include a parameter indicating a required buffer size for the data radio bearer.

[0170] For example, each of the first status message and the second status message may correspond to a downlink data delivery status frame. Each of the first data amount information and the second data amount information may include a parameter indicating the amount of data desired to be received within a specified time for the data radio bearer.

[0171] For example, the downlink data may be received from the upper network node via downlink user data (DL user data) frames. The packet loss indicator may indicate a packet loss rate for a path between the upper network node and the lower network node, determined based on a sequence number for each packet of the downlink user data frames.

[0172] For example, the first data amount information may indicate a first value, and the second data amount information may indicate a second value. The operation of determining the second data amount information may include: when the packet loss indicator is less than a first threshold value, determining the second value greater than the first value; when the packet loss indicator is greater than or equal to the first threshold value but less than a second threshold value, determining the second value equal to the first value; and when the packet loss indicator is greater than or equal to the second threshold value, determining the second value less than the first value.

[0173] For example, the first data amount information may indicate a first value, and the second data amount information may indicate a second value. The operation of determining the second data amount information may include an operation of determining the second value greater than the first value when the packet loss indicator is less than a threshold value, and an operation of determining the second value less than the first value when the packet loss indicator is greater than or equal to the threshold value.

[0174] For example, the second data amount information may be determined based on the size of the available buffer for the data radio bearer of the routing node and the size of the packet loss indicator.

[0175] For example, the downlink data may be received from the upper network node via a plurality of nodes. The plurality of nodes may include a first node connected to the upper network node and a second node connected to the lower network node. An available data rate between the second node and the lower network node or an available data rate between two nodes among the plurality of nodes may be lower than an available data rate between the upper network node and the first node.

[0176] For example, the upper network node may include a central unit (CU) configured to perform functions of the packet data convergence protocol (PDCP) layer. The lower network node may include a distributed unit (DU) configured to perform functions of the radio link layer (RLC) layer and the medium access control (MAC) layer.

[0177] In embodiments, a non-transitory computer-readable storage medium is provided. The non-transitory computer-readable storage medium may store instructions that, when executed by a processor of a lower network node, cause the lower network node to perform operations including transmitting a first status message including first data amount information for a data radio bearer to an upper network node, receiving downlink (DL) data for the data radio bearer from the upper network node, determining second data amount information for the data radio bearer based on a packet loss metric for a path between the upper network node and the lower network node obtained from the downlink data, and transmitting a second status message including the second data amount information to the upper network node.

[0178] In embodiments, an electronic device of a lower network node is provided. The electronic device may include at least one transceiver including one or more communication circuits and at least one processor including one or more processing circuits. The at least one processor may be configured to transmit a first status message including first data amount information for a data radio bearer to an upper network node via the at least one transceiver. The at least one processor may be configured to receive downlink (DL) data for the data radio bearer from the upper network node via the at least one transceiver. The at least one processor may be configured to determine second data amount information for the data radio bearer based on a packet loss metric for a path between the upper network node and the lower network node obtained from the downlink data. The at least one processor may be configured to transmit a second status message including the second data amount information to the upper network node via the at least one transceiver.

[0179] For example, the first data amount information may indicate a first value, and the second data amount information may indicate a second value. The at least one processor may be configured to determine the second data amount information, such that when the packet loss indicator is less than a first threshold, the second value is determined to be greater than the first value, when the packet loss indicator is greater than or equal to the first threshold but less than a second threshold, the second value is determined to be equal to the first value, and when the packet loss indicator is greater than or equal to the second threshold, the second value is determined to be less than the first value.

[0180] For example, the first data amount information may indicate a first value, and the second data amount information may indicate a second value. The at least one processor may be configured to determine the second data amount information by determining the second value greater than the first value when the packet loss indicator is less than a threshold value, and by determining the second value less than the first value when the packet loss indicator is greater than or equal to the threshold value.

[0181] For one or more embodiments, at least one of the components described in one or more of the preceding drawings may be configured to perform one or more operations, techniques, processes, and / or methods as described herein. For example, a processor (e.g., a baseband processor) described herein with respect to one or more of the preceding drawings may be configured to operate according to one or more examples described herein. For another example, circuitry associated with a user equipment (UE), a base station, a network element, and the like, as described above with respect to one or more of the preceding drawings, may be configured to operate according to one or more examples described herein.

[0182] Any of the embodiments described above may be combined with any other embodiment (or combination of embodiments) unless explicitly stated otherwise. The foregoing description of one or more implementations provides examples and descriptions, but is not intended to be exhaustive or limit the scope of the embodiments to the precise forms disclosed. Modifications and variations are possible in light of the above teachings or may be learned from practicing various embodiments.

[0183] The various embodiments of this document and the terminology used therein are not intended to limit the technical features described in this document to specific embodiments, but should be understood to include various modifications, equivalents, or substitutes of the embodiments. In connection with the description of the drawings, similar reference numerals may be used for similar or related components. The singular form of a noun corresponding to an item may include one or more of the items, unless the context clearly indicates otherwise. In this document, each of the phrases "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" can include any one of the items listed together in the corresponding phrase among those phrases, or all possible combinations thereof. Terms such as "first," "second," or "first" or "second" may be used merely to distinguish one component from another, and do not limit the components in any other respect (e.g., importance or order). When a component (e.g., a first component) is referred to as "coupled" or "connected" to another component (e.g., a second component), with or without the terms "functionally" or "communicatively," it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or through a third component.

[0184] The term "module" used in various embodiments of this document may include a unit implemented in hardware, software, or firmware, and may be used interchangeably with terms such as logic, logic block, component, or circuit. A module may be an integral component, or a minimum unit or part of such a component that performs one or more functions. For example, according to one embodiment, a module may be implemented in the form of an application-specific integrated circuit (ASIC).

[0185] Various embodiments of the present document may be implemented as software including one or more instructions stored in a storage medium (e.g., memory (820)) readable by a machine (e.g., DU (320), an electronic device operating as DU (320)). For example, a processor (e.g., processor (830)) of the machine (e.g., DU (320), an electronic device operating as DU (320)) may call at least one instruction among the one or more instructions stored from the storage medium and execute it. This enables the machine to operate to perform at least one function according to the at least one called instruction. The one or more instructions may include code generated by a compiler or code executable by an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Here, 'non-transitory' simply means that the storage medium is a tangible device and does not contain signals (e.g., electromagnetic waves), and the term does not distinguish between cases where data is stored semi-permanently or temporarily on the storage medium.

[0186] The 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.

[0187] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured to be executed by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure. The one or more programs may be provided as a computer program product. The computer program product may be traded between a seller and a buyer as a commodity. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or may be distributed online (e.g., downloaded or uploaded) through an application store (e.g., Play Store™) or directly between two user devices (e.g., smart phones). In the case of online distribution, at least a portion of the computer program product may be temporarily stored or temporarily created in a device-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or an intermediary server.

[0188] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), 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, or may be stored in memories formed by a combination of some or all of these. In addition, each configuration memory may include multiple copies.

[0189] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present disclosure.

[0190] In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0191] According to embodiments, one or more of the components or operations of the aforementioned components may be omitted, or one or more other components or operations may be added. Alternatively or additionally, a plurality of components (e.g., modules or programs) may be integrated into a single component. In such a case, the integrated component may perform one or more functions of each of the plurality of components identically or similarly to those performed by the corresponding component among the plurality of components prior to the integration. According to embodiments, the operations performed by a module, program, or other component may be executed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.

[0192] Meanwhile, although the detailed description of the present disclosure has described specific embodiments, it is obvious that various modifications are possible within the scope of the present disclosure.

Claims

1. In the electronic devices of the lower network nodes, Memory that stores instructions; at least one transceiver; and comprising at least one processor, The above instructions, when executed by the at least one processor, cause the electronic device to: Transmitting a first status message including first data amount information for a data radio bearer to an upper network node through at least one transceiver, Receiving downlink (DL) data for the data radio bearer from the upper network node through the at least one transceiver, Based on a packet loss metric for a path between the upper network node and the lower network node obtained from the downlink data, second data volume information for the data radio bearer is determined, Causing a second status message including the second data amount information to be transmitted to the upper network node via the at least one transceiver; Electronic devices.

2. In claim 1, The above downlink data is received from the upper network node through a routing node (via), The available data rate between the above routing node and the lower network node is lower than the available data rate between the upper network node and the routing node. Electronic devices.

3. In claim 1, Each of the above first status message and the above second status message corresponds to a downlink data delivery status frame, Each of the first data amount information and the second data amount information includes a parameter indicating a requested buffer size for the data radio bearer. Electronic devices.

4. In claim 1, Each of the above first status message and the above second status message corresponds to a downlink data delivery status frame, Each of the first data amount information and the second data amount information includes a parameter indicating an amount of data desired to be received within a specified time for the data radio bearer. Electronic devices.

5. In claim 1, The above downlink data is received from the upper network node via downlink user data (DL user data) frames, The above packet loss indicator indicates a packet loss rate for a path between the upper network node and the lower network node, which is determined based on a sequence number for each packet of the downlink user data frames. Electronic devices.

6. In claim 1, The first data amount information indicates a first value, and the second data amount information indicates a second value. The above instructions, when executed by the at least one processor, cause the electronic device to: If the above packet loss indicator is less than the first threshold, determine the second value greater than the first value, If the above packet loss indicator is greater than or equal to the first threshold and less than the second threshold, a second value equal to the first value is determined, If the packet loss indicator is greater than or equal to the second threshold value, causing the second value to be determined to be less than the first value, Electronic devices.

7. In claim 1, The first data amount information indicates a first value, and the second data amount information indicates a second value. The above instructions, when executed by the at least one processor, cause the electronic device to: If the above packet loss indicator is less than the threshold value, the second value is determined to be greater than the first value, If the above packet loss indicator is greater than or equal to the threshold value, causing the second value to be determined to be less than the first value, Electronic devices.

8. In claim 1, The second data amount information is determined according to the size of the available buffer for the data radio bearer of the routing node and the size of the packet loss indicator. Electronic devices.

9. In claim 1, The above downlink data is received from the upper network node through multiple nodes (via), The above plurality of nodes include a first node connected to the upper network node and a second node connected to the lower network node, The available data rate between the second node and the lower network node or the available data rate between two nodes among the plurality of nodes is lower than the available data rate between the upper network node and the first node. Electronic devices.

10. In claim 1, The above upper network node includes a CU (central unit) configured to perform functions of the PDCP (packet data convergence protocol) layer, The above lower network node includes a DU (distributed unit) configured to perform functions of the RLC (radio link layer) layer and the MAC (medium access control) layer. Electronic devices.

11. In a method performed by a sub-network node, An operation of transmitting a first status message including first data amount information for a data radio bearer to an upper network node, An operation of receiving downlink (DL) data for the data radio bearer from the upper network node, An operation of determining second data amount information for the data radio bearer based on a packet loss metric for a path between the upper network node and the lower network node obtained from the downlink data; Including an operation of transmitting a second status message including the second data amount information to the upper network node. method.

12. In claim 11, The above downlink data is received from the upper network node through a routing node (via), The available data rate between the above routing node and the lower network node is lower than the available data rate between the upper network node and the routing node. method.

13. In claim 11, Each of the above first status message and the above second status message corresponds to a downlink data delivery status frame, Each of the first data amount information and the second data amount information includes a parameter indicating a requested buffer size for the data radio bearer. method.

14. In claim 11, Each of the above first status message and the above second status message corresponds to a downlink data delivery status frame, Each of the first data amount information and the second data amount information includes a parameter indicating an amount of data desired to be received within a specified time for the data radio bearer. method.

15. In a non-transitory computer-readable storage medium, When executed by a processor of a sub-network node, said sub-network node: Transmitting a first status message including first data amount information for a data radio bearer to a central unit of an upper network node, Receiving downlink (DL) data for the data radio bearer from the upper network node, Determining second data volume information for the data radio bearer based on a packet loss metric for a path between the upper network node and the lower network node obtained from the downlink data; Storing instructions that cause operations to be performed, including transmitting a second status message including the second data amount information to the upper network node; A non-transitory computer-readable storage medium.

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