Method and device for managing network congestion state

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate beyond a 4G communication system such as LTE. A method performed by a terminal according to an embodiment of the present disclosure may comprise the steps of: identifying first congestion information measured by a communication processor (CP); measuring a change amount of application processor (AP) information; acquiring, on the basis of the first congestion information and the change amount of the AP information, second congestion information on which compensation for the first congestion information has been performed; calculating an explicit congestion notification (ECN) marking probability by using the second congestion information; and configuring, according to the ECN marking probability, an ECN bit in a packet to be transmitted.

Description

Method and device for managing network congestion

[0001] The present disclosure relates to L4S (Low Latency, Low Loss, Scalable Throughput) technology, and specifically, to a method and apparatus for managing network congestion by compensating for congestion information within a terminal to maintain data packet transmission efficiency and network performance.

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

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

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

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

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

[0007] A method of a terminal in a wireless communication system according to one embodiment of the present disclosure may be provided. The method of the terminal may include: a step of identifying first congestion information measured in a Communication Processor (CP); a step of measuring a change in Application Processor (AP) information; a step of obtaining second congestion information in which compensation for the first congestion information is performed based on the first congestion information and the change in AP information; a step of calculating an Explicit Congestion Notification (ECN) marking probability using the second congestion information; and a step of setting an ECN bit in a packet to be transmitted according to the ECN marking probability.

[0008] A method of an Application Processor (AP) within a terminal in a wireless communication system according to one embodiment of the present disclosure may be provided. The method of the AP may include: receiving first congestion information measured by a Communication Processor (CP); measuring a change in AP information within the AP; obtaining second congestion information in which compensation for the first congestion information is performed based on the first congestion information and the change in AP information; calculating an Explicit Congestion Notification (ECN) marking probability using the second congestion information; and setting an ECN bit in a packet to be transmitted according to the ECN marking probability.

[0009] A terminal may be provided in a wireless communication system according to one embodiment of the present disclosure. The terminal may include a transceiver and at least one processor coupled to the transceiver. The at least one processor may identify first congestion information measured by a Communication Processor (CP), measure a change in Application Processor (AP) information, obtain second congestion information in which compensation for the first congestion information is performed based on the first congestion information and the change in AP information, calculate an Explicit Congestion Notification (ECN) marking probability using the second congestion information, and set an ECN bit in a packet to be transmitted according to the ECN marking probability.

[0010] An Application Processor (AP) within a terminal may be provided in a wireless communication system according to one embodiment of the present disclosure. The AP receives first congestion information measured by a Communication Processor (CP), measures a change in AP information within the AP, obtains second congestion information in which compensation for the first congestion information is performed based on the first congestion information and the change in AP information, calculates an Explicit Congestion Notification (ECN) marking probability using the second congestion information, and sets an ECN bit in a packet to be transmitted according to the ECN marking probability.

[0011] A computer-readable recording medium disclosed as a technical means for achieving the above-described technical task may store a program for executing at least one of the embodiments of the disclosed method on a computer.

[0012] Other technical features can be easily made clear to a person skilled in the art from the following drawings, descriptions, and claims.

[0013] FIG. 1 is a drawing for explaining the technical field of the present disclosure.

[0014] Figure 2 is a diagram illustrating how L4S technology is applied in a 5G system.

[0015] Figure 3 is a diagram illustrating the current status of L4S service support by 5G operators.

[0016] Figures 4a to 4c are diagrams illustrating a method of applying L4S technology inside a terminal.

[0017] FIG. 5 is a diagram illustrating a method for compensating L2 congestion information received from a CP by an AP inside a terminal in one embodiment of the present disclosure.

[0018] FIG. 6 is a diagram illustrating a method for compensating L2 congestion information received from a CP by an AP inside a terminal in one embodiment of the present disclosure.

[0019] FIGS. 7a and 7b are drawings illustrating a method for compensating for L2 congestion information received from a CP by an AP inside a terminal using a change in TCP RTT in one embodiment of the present disclosure.

[0020] FIGS. 8a and 8b are drawings for explaining a method for compensating for L2 congestion information received by an AP inside a terminal from a CP using a change in the ratio between the number of packets on the network and the TCP throughput in one embodiment of the present disclosure.

[0021] FIG. 9 is a diagram for explaining the reason for considering the time difference between TCP RTT and L2 congestion information in the process of compensating for L2 congestion information using the amount of change in TCP RTT in one embodiment of the present disclosure.

[0022] FIG. 10 is a flowchart illustrating a process for compensating for L2 congestion information by calculating the change in TCP RTT in a way that specifies a TCP segment in a CP inside a terminal in an embodiment of the present invention.

[0023] FIG. 11 is a diagram illustrating a process for compensating for L2 congestion information by calculating a change in TCP RTT in a way that specifies a TCP segment in a CP inside a terminal in an embodiment of the present disclosure.

[0024] FIG. 12 is a flowchart illustrating a process for compensating for L2 congestion information by calculating the change in TCP RTT in a specific way for a TCP segment in an AP inside a terminal in an embodiment of the present invention.

[0025] FIG. 13 is a diagram illustrating a process of compensating for L2 congestion information by calculating a change in TCP RTT in a way that specifies a TCP segment in an AP inside a terminal in an embodiment of the present disclosure.

[0026] FIG. 14 is a diagram illustrating the background of a proposed method for compensating L2 congestion information using the change in the ratio between the number of packets on a network and TCP throughput in one embodiment of the present disclosure.

[0027] FIG. 15 is a flowchart illustrating a process for compensating for L2 congestion information using the change in the ratio between the number of packets on the network and the TCP throughput in one embodiment of the present disclosure.

[0028] FIG. 16 is a diagram illustrating a process for compensating for L2 congestion information using the change in the ratio between the number of packets on the network and the TCP throughput in one embodiment of the present disclosure.

[0029] FIG. 17 is a diagram illustrating a method for a terminal to compensate for L2 congestion information based on the amount of AP information change in one embodiment of the present disclosure.

[0030] FIG. 18 is a diagram illustrating a method for compensating L2 congestion information received by an AP in a terminal from a CP in one embodiment of the present disclosure.

[0031] FIG. 19 is a drawing illustrating the structure of a terminal according to one embodiment of the present disclosure.

[0032] The present disclosure is subject to various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, FIGS. 1 through 19 discussed below and the various embodiments used to explain the principles of the present disclosure in this specification are merely illustrative and should not be construed as limiting the scope of the present disclosure in any way. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any appropriately arranged system or device. Furthermore, those skilled in the art will understand that the principles of the present disclosure may be implemented in any appropriately configured wireless communication system.

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

[0034] In addition, numbers used in the description process of the specification (e.g., 1st, 2nd, etc.) are merely identifiers to distinguish one component from another.

[0035] The advantages and features of the present disclosure, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components. Furthermore, in describing the present disclosure, if it is determined that a detailed description of a related function or configuration might unnecessarily obscure the essence of the present disclosure, such detailed description is omitted. Additionally, the terms described below are defined considering their functions in the present disclosure, and these may vary depending on the intentions or conventions of the user or operator. Therefore, their definitions should be based on the content throughout the specification.

[0036] Hereinafter, a base station (BS) is an entity that performs resource allocation for terminals and may be at least one of an NG-RAN, gNode B, eNode B, Node B, or xNode B (where x is an alphabet including g and e), a radio access unit, a base station controller, a satellite, an airborn, or a node on a network. A distributed base station may be separated into a centralized unit (CU) and a distributed unit (DU). The CU provides support for higher protocol layers such as SDAP (service data adaptation protocol), RRC (radio resource control), and PDCP (packet data convergence protocol), and the DU may provide support for lower protocol layers such as RLC (radio link control), MAC (medium access control), and PHY (physical layer). A single CU may exist for each gNodeB, and multiple DUs may be connected to each CU. The DU includes both baseband processing and RF functions and can support various mobility scenarios.

[0037] Hereinafter, the terminal (user equipment, UE) may include a Mobile Station (MS), a Vehicle, a Satellite, an Airborne, a Cellular Phone, a Smartphone, a Computer, or a Multimedia System capable of performing communication functions.

[0038] In addition, while LTE, LTE-A, or 5G systems may be described below as examples, embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, 5G-Advance or NR-Advance or 6th generation mobile communication technology (6G) developed after 5G mobile communication technology (or new radio, NR) may be included, and the 5G below may be a concept that includes existing LTE, LTE-A, and other similar services. Furthermore, the present disclosure may be applied to other communication systems with some modifications made at the discretion of a person with skilled technical knowledge, without significantly departing from the scope of the present disclosure.

[0039] At this point, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means to perform the functions described in the flow diagram block(s). Since these computer program instructions can also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the function in a specific way, the instructions stored in computer-available or computer-readable memory can also produce a manufactured item containing instruction means to perform the function described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0040] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specified logical function(s). It should also be noted that in some alternative practices, the functions mentioned in the blocks may occur out of order. For example, two blocks described in succession may actually be executed substantially simultaneously, or the blocks may be executed in reverse order according to their corresponding functions.

[0041] In this embodiment, the term "part" refers to a software or hardware component such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), and the "part" performs certain roles. However, the meaning of "part" is not limited to software or hardware. The "part" may be configured to reside in an addressable storage medium or configured to run one or more processors. Thus, as an example, the "part" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and "parts" may be combined into a smaller number of components and "parts" or further separated into additional components and "parts." In addition, the components and 'parts' may be implemented to utilize one or more CPUs within the device or secure multimedia card. Also, in the embodiments, 'parts' may include one or more processors.

[0042] Terms used in the following description to refer to broadcast information, control information, communication coverage, state changes (e.g., events), network entities, messages, and device components are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

[0043] For the convenience of the following explanation, the present invention uses terms and names defined in the LTE and NR specifications, which are the most recent standards defined by the 3GPP (The 3rd Generation Partnership Project) among currently existing communication standards. However, the present invention is not limited by the above terms and names and can be applied in the same way to systems conforming to other standards.

[0044] FIG. 1 is a drawing for explaining the technical field of the present disclosure.

[0045] The present disclosure relates to L4S (Low Latency, Low Loss, Scalable Throughput) technology. L4S technology is designed to simultaneously achieve ultra-low latency, low loss, and high scalable throughput by detecting network congestion. To achieve this, L4S technology can manage network congestion and improve data transmission quality by utilizing a feedback mechanism between a transmitting side and a receiving side based on Explicit Congestion Notification (ECN).

[0046] Referring to Fig. 1, the operating principle of a conventional L4S system will be explained in detail.

[0047] When transmitting data, the transmitter (101) can set an ECN field to efficiently manage network congestion. More specifically, the value of the 2-bit ECN field included in the IP header of the data packet can be defined as follows.

[0048] - '00': Non-ECN Capable Transport (Does not support ECN)

[0049] - '10': [ECT(0) - ECN Capable Transport]

[0050] - '01': ECT(1) - ECN Capable Transport

[0051] - '11': CE (Congestion Experienced)

[0052] Here, the ECT (1) bit (102) with the value of the ECN field set to '01' can be set, thereby indicating that the data packet is for ECN-based congestion management for L4S service support purposes.

[0053] A data packet with the ECT (1) bit (102) set can be transmitted from a transmitter (101) to a router or switch. At this time, an Active Queue Management (AQM) (103) can operate on a router or switch operating in network equipment. For example, the AQM (103) can be a Probabilistic Inference 2 (PI2) or a DualQ Coupled AQM (RFC 9332). The AQM (103) can monitor in real time the extent to which data packets received from the transmitter (101) accumulate in a queue. At this time, if the length of the queue exceeds a threshold, the AQM (103) can determine that the network has entered a congested state.

[0054] At this time, the AQM (103) can dynamically adjust the CE marking probability (p) according to the degree of network congestion. Here, the CE marking probability may refer to the probability that the AQM (103) modifies the ECN field of a data packet from the ECT (1) bit (102) to the CE bit (104). For example, if the AQM (103) determines that congestion is severe, it can increase the CE marking probability (p) to set the CE bit (104) on more data packets, and if the congestion is determined to be mild, it can decrease the CE marking probability (p) to reduce the proportion of data packets that set the CE bit (104).

[0055] AQM (103) can be set by modifying the ECN field of a data packet from the ECT (1) bit (102) to the CE bit (104) according to the CE marking probability (p). Specifically, AQM (103) can indicate that the data packet has experienced congestion by marking the value of the ECN field of the data packet from "10" to "11" according to the CE marking probability (p).

[0056] A data packet with a CE bit (104) set can be transmitted from a router or switch supporting AQM (103) to a receiver (105). When the receiver (105) detects that the CE bit (104) is set in the ECN field of the data packet, it can recognize that the data packet has experienced a congested state. Accordingly, the receiver (105) can convey congestion information to the transmitter (101) by including ECN feedback (106) in the ACK (Acknowledgment) for the data packet. For example, the ECN feedback (106) may include the ratio or probability of data packets with a CE bit (104) set among the data packets received by the receiver (105) during a specific period, and / or the duration of the congested state.

[0057] When the transmitter (101) receives an ACK containing ECN feedback (106) from the receiver (105), it can control the transmission speed of data packets using a Scalable Congestion Control Algorithm (Scalable CCA). Examples of Scalable CCA include DCTCP (Data Center TCP), BBRv2 (Bottleneck Bandwidth and RTT Version 2), and Prague.

[0058] Figure 2 is a diagram illustrating how L4S technology is applied in a 5G system.

[0059] Referring to FIG. 2, when a terminal (201) transmits a data packet to a server (204) within a 5G system, L4S technology may be applied. Here, the terminal (201) may correspond to the transmitter (101) of FIG. 1, and the server (204) may correspond to the receiver (105) of FIG. 1.

[0060] FIG. 2(a) describes an embodiment in which the base station (202) performs the role of the AQM (103) of FIG. 1. A terminal (201) can transmit to the base station (202) by setting the ECN field of the IP header of the data packet to an ECT (1) bit. The base station (202) that receives the data packet can determine the network congestion status by monitoring the buffer status in real time. The base station (202) can adjust the CE marking probability (p) according to the degree of network congestion, and can modify and set the ECN field of the data packet from an ECT (1) bit to a CE bit according to the CE marking probability (p). The base station (202) can transmit the data packet with the CE bit set to the server (204) via the UPF (203), and the server (204) can generate ECN feedback by checking the CE bit within the data packet. The generated ECN feedback is transmitted to the terminal (201), and the terminal (201) can adjust the transmission speed of the data packet using Scalable CCA.

[0061] FIG. 2(b) describes an embodiment in which the role of the AQM (103) of FIG. 1 is performed by the UPF (User Plane Function) (203). A terminal (201) can transmit to a base station (202) by setting the ECN field of the IP header of a data packet to an ECT (1) bit. The base station (202) that receives the data packet can determine the network congestion status by monitoring the buffer status in real time. The base station (202) can include information indicating the network congestion level in the GTP (GPRS Tunneling Protocol) header and transmit it to the UPF (203). The UPF (203) can adjust the CE marking probability (p) based on the network congestion level included in the GTP header received from the base station (202), and can modify the ECN field of the data packet from an ECT (1) bit to a CE bit according to the CE marking probability (p). UPF (203) can transmit a data packet with a CE bit set to a server (204), and the server (204) can generate ECN feedback by checking the CE bit in the data packet. The generated ECN feedback is transmitted to a terminal (201), and the terminal (201) can adjust the transmission speed of the data packet using Scalable CCA.

[0062] Figure 3 is a diagram illustrating the current status of L4S service support by 5G operators.

[0063] In order to practically implement L4S technology within a 5G system, base stations that support Active Queue Management (AQM) are essential. However, in the current 5G network structure, there may be a problem in that base stations supporting such AQM functions are very limited.

[0064] Referring to Figure 3, approximately 82% of current 5G operators operate LTE or 5G NSA (Non-Standalone) base stations. In other words, only 18% of operators operate 5G Standalone (SA) base stations, and among them, even fewer base stations are capable of supporting L4S functions of 3GPP Rel. 18. This means that the network infrastructure for providing L4S services is not currently sufficiently equipped.

[0065] Accordingly, the present disclosure proposes various embodiments for performing a part of the AQM function within the terminal by managing L4S congestion information (L2 congestion information) in real time within the terminal and adjusting the data transmission speed of the transmitter by calculating the CE marking probability based thereon.

[0066] Figures 4a to 4c are diagrams illustrating a method of applying L4S technology inside a terminal.

[0067] Queue delays occurring at the L2 (link layer) within the terminal act as bottlenecks in data transmission, which can degrade the quality of data transfer between the terminal and the network. To address this, a method is required to effectively manage L2 queue delays within the terminal. By performing congestion management within the terminal, queue delays can be reduced, ultra-low latency and low-loss performance can be maintained, and high throughput achieved.

[0068] With reference to FIG. 4a, the process of implementing ECN-based L4S technology by the Communication Processor (410) and Application Processor (420) inside the terminal cooperating with each other will be explained in more detail. At this time, the CP (410) may be a processor responsible for handling physical communication between the terminal and the network, and the AP (420) may be a processor responsible for upper-layer tasks and application execution of the terminal.

[0069] CP (410) monitors the status of data packets in the terminal's L2 buffer and can measure the queue delay of data packets occurring in the L2 buffer in real time. Specifically, CP (410) can measure the data transmission rate (Egress Rate) based on information provided by the MAC (Medium Access Control) layer, and can measure the queue delay value of the L2 buffer based on the measured data transmission rate (Egress Rate) and the length of the queue accumulated in the L2 buffer. Below, the queue delay value of the L2 buffer will be described as the L2 queue delay value.

[0070] CP (410) can generate L2 congestion information based on the measured L2 queue delay value and can transmit the generated L2 congestion information to AP (420). At this time, CP (410) can periodically (period of t, t) It can be transmitted to AP(420) in the form of an L4S Metric.

[0071] AP (420) receives L4S Metric from CP (410) and can identify sampled L2 congestion information based on it. AP (420) can analyze the sampled L2 congestion information to quantitatively determine the degree of congestion in data transmission. AP (420) can calculate the CE marking probability (p) based on the degree of congestion in the network. Here, the CE marking probability (p) may mean the probability of setting the ECN field of a data packet by modifying it from the ECT (1) bit to the CE bit.

[0072] Specifically, graph data or mapping information indicating the correlation between the L2 queue delay value and the CE marking probability (p) may be stored within the AP (420). The AP (420) can determine the L2 queue delay value by analyzing the sampled L2 congestion information, and can calculate the CE marking probability (p) based on the determined L2 queue delay value and the stored graph data or mapping information.

[0073] AP (420) can set the ECN field of a data packet by modifying it from the ECT (1) bit to the CE bit according to the calculated CE marking probability (p). A data packet with the CE bit set can be transmitted from AP (420) to CP (410) and finally transmitted to a server through an L2 buffer. The server receives the data packet and can transmit it to the terminal, including ECN feedback in an ACK for the data packet. When the terminal receives an ACK containing ECN feedback from the server, it can control the transmission speed of the data packet using Scalable CCA.

[0074] Here, the length of the period during which CP (410) transmits L2 congestion information to AP (420) t) can act as a significant problem in the implementation of L4S technology. Although the CP (410) generates L2 congestion information by analyzing the state of the L2 buffer in real time, modifying the CP (410) chipset to immediately transmit this information to the AP (420) may result in additional costs and design complexity. Furthermore, if the CP (410) transmits L2 congestion information to the AP (420) frequently, the power consumption of the terminal may increase rapidly, which can negatively affect the terminal's continuous usage time, especially in mobile environments where battery performance is critical. Accordingly, the CP (410) can transmit L2 congestion information to the AP (420) at a preset interval (e.g., 500ms to 1000ms). This may be a relatively long interval compared to the interval (e.g., 10ms) at which congestion status is measured and responded to via AQM in existing networks.

[0075] Referring to Figures 4b and 4c, we will explain the problems that arise when CP (410) transmits L2 congestion information to AP (420) over a relatively long period.

[0076] Referring to Figure 4b, the longer the period for transmitting L2 congestion information from CP (410) to AP (420), the more significantly L4S performance may degrade.

[0077] If the period for transmitting L2 congestion information from CP (410) to AP (420) is 10ms, L2 mixing information (401) measured at CP (410) can be sampled every 10ms and transmitted to AP (420). At this time, the L2 mixing information (402) sampled every 10ms received by AP (420) can have high correspondence with L2 mixing information (401). AP (420) can calculate the CE marking probability (404) based on the sampled L2 mixing information (402). For example, AP (420) can extract an L2 queue delay value from the sampled L2 mixing information (402) and calculate the CE marking probability (404) in the time interval (t1 to t2) where the value exceeds a threshold value (403). In this way, since the AP (420) can adjust the transmission speed by reflecting the L2 mixing information (401) measured by the CP (410) in near real-time, the L2 queue delay value over time can be stabilized.

[0078] On the other hand, if the period for transmitting L2 congestion information from CP (410) to AP (420) is extended to 500ms, the L2 mixing information (405) measured at CP (410) can be sampled every 500ms and transmitted to AP (420). At this time, the L2 mixing information (406) sampled every 500ms received by AP (420) may have low correspondence with the L2 mixing information (405). Therefore, the time interval during which the L2 queue delay value identifiable by the L2 mixing information (405) measured at the actual CP (410) exceeds the threshold value (403) is from t3 to t5, but the time interval during which the L2 queue delay value identifiable by the sampled L2 mixing information (406) exceeds the threshold value (403) may be from t4 to t6. AP (420) can calculate the CE marking probability (407) in the time interval t4 to t6. Here, the CE marking probability (407) calculated by AP (420) is a value that does not properly reflect the actual congestion state, so transmission speed and congestion management may be performed inaccurately.

[0079] Regarding the change in L4S performance according to the period (Δt) of transmitting L2 congestion information in the L4S system, we will explain with reference to Figure 4c.

[0080] Referring to Figure 4c, the x-axis represents the cycle of transmitting L2 congestion information from CP (410) to AP (420), the left side of the y-axis represents the L2 queue delay (L2 queue delay (ms)), and the right side of the y-axis represents the throughput (Throughput (Mbps)).

[0081] When the cycle of transmitting L2 congestion information from CP (410) to AP (420) is 5ms, the L2 queue delay remains very low on average (e.g., 20ms or less), and the throughput can have the highest performance at approximately 13.11Mbps. This may be because the L2 congestion information is transmitted frequently from CP (410) to AP (420), allowing AP (420) to accurately calculate the CE marking probability (p) based on the latest information and manage congestion appropriately.

[0082] If the cycle for transmitting L2 congestion information from CP (410) to AP (420) is 500ms, L2 queue latency may increase (e.g., 20ms) and variability may increase. As a result, throughput may decrease to about 11.12Mbps. If the cycle for transmitting L2 congestion information from CP (410) to AP (420) is 1000ms, L2 queue latency may increase further (e.g., more than 20ms) and variability may increase further, and throughput may decrease further to about 9.39Mbps.

[0083] This may be because, as the period of transmitting L2 congestion information from CP (410) to AP (420) becomes longer, AP (420) is unable to reflect the congestion status measured by CP (410) in real time, and consequently, the calculation of the CE marking probability (p) becomes inaccurate.

[0084] To solve the problem that occurs as the period of transmitting L2 congestion information from CP (410) to AP (420) becomes longer, a technology may be needed to compensate for L2 congestion information transmitted at a relatively long period (500ms to 1000ms) at AP (420) to improve the performance of the L4S system.

[0085] FIG. 5 is a diagram illustrating a method for compensating L2 congestion information received from a CP by an AP inside a terminal in one embodiment of the present disclosure.

[0086] Referring to FIG. 5, in one embodiment of the present disclosure, the CP may start measuring the L2 congestion state at step 501. Measuring the L2 congestion state may include monitoring the state of data packets in the L2 buffer of the terminal and measuring the queue delay value of the L2 buffer.

[0087] In one embodiment of the present disclosure, a CP may generate L2 congestion information based on the L2 congestion status measurement result in step 502 and transmit the L2 congestion information to an AP. The L2 congestion information transmitted by the CP to the AP may include at least one of the following or a combination thereof.

[0088] - L2 Queue Latency (d): The time difference between when a data packet enters the queue and when it leaves the queue at the L2 layer.

[0089] - L2 Queue Length (bs): Total size of data packets accumulated in the L2 queue (buffer status)

[0090] - L2 Data Transmission Rate (Egress Rate) (R): The speed at which data packets leave the queue and are transmitted at the L2 layer.

[0091] - CE Marking Probability (p): The probability that the ECN (Efficient Congestion Notification) flag is set to CE

[0092] - Wireless Information: Information about the wireless connection status (e.g., signal strength, bandwidth, channel quality, etc.)

[0093] In one embodiment of the present disclosure, the AP may update the L2 congestion status in step 503. Updating the L2 congestion status may include the process of the AP storing L2 congestion information initially received from the CP or changing previously received L2 congestion information to L2 congestion information newly received from the CP.

[0094] In one embodiment of the present disclosure, the AP can compensate for L2 congestion information in steps 504 to 505. In one embodiment of the present disclosure, the AP can identify (estimate) a change in information measurable within the AP (AP information change amount) in step 504. The information measurable within the AP may include at least one of the following or a combination thereof.

[0095] - TCP (Transmission Control Protocol) RTT (Round Trip Time): The round-trip time from the transmission of a data packet to the reception of an ACK packet in a TCP session.

[0096] - TCP throughput: The speed of data successfully transmitted through a TCP session.

[0097] - IP egress rate: The speed at which data is transmitted at the IP layer

[0098] - : Ratio between the number of TCP packets on the network and TCP throughput

[0099] - : The ratio between the number of TCP packets on the network and the data transmission rate at the IP layer

[0100] - : Ratio between TCP congestion window size and TCP throughput

[0101] - : Ratio between TCP congestion window size and data transmission rate at the IP layer

[0102] In one embodiment of the present disclosure, the AP can reflect and update the amount of change in AP information as the amount of change in L2 congestion state at step 505. For example, the AP can compensate for L2 congestion information based on the amount of change in AP information.

[0103] Compensated L2 congestion information within the AP It can be calculated as shown in the following mathematical formula 1.

[0104]

[0105] Here, is L2 congestion information received from the CP (e.g., L2 queue latency (d)), and can be the amount of change in AP information.

[0106] In one embodiment of the present disclosure, the CP may transmit L2 congestion information to the AP in step 506. The timing of transmitting the L2 congestion information in step 506 is a specific transmission period (L2 congestion information transmission period, or L4S metric interval) at the time of transmitting the L2 congestion information in step 502 described above. It could be after ))

[0107] In one embodiment of the present disclosure, the CP may update the L2 congestion status in step 507. Updating the L2 congestion status may include the process of the AP changing the L2 congestion information updated and stored in step 503 to the L2 congestion information received in step 506. The L2 congestion information compensation procedure described above may be repeated thereafter.

[0108] FIG. 6 is a diagram illustrating a method for compensating L2 congestion information received from a CP by an AP inside a terminal in one embodiment of the present disclosure.

[0109] According to one embodiment of the present disclosure, CP (610) monitors the status of data packets in the L2 buffer of a terminal and can measure the queue delay of data packets occurring in the L2 buffer in real time. Specifically, CP (610) can measure the data transmission rate (Egress Rate) based on information provided by the MAC layer, and can measure the queue delay value of the L2 buffer based on the measured data transmission rate (Egress Rate) and the length of the L2 buffer. Hereinafter, the queue delay value of the L2 buffer will be described as the L2 queue delay value.

[0110] According to one embodiment of the present disclosure, CP (610) can generate L2 congestion information (601) based on a measured L2 queue delay value and can transmit the generated L2 congestion information (601) to AP (620). At this time, CP (610) can periodically (period of t, It can be transmitted to AP (620) in the form of an L4S Metric.

[0111] According to one embodiment of the present disclosure, the AP (620) receives an L4S Metric from the CP (610) and can identify sampled L2 congestion information (602) based thereon.

[0112] According to one embodiment of the present disclosure, the AP (620) can obtain compensated L2 congestion information (603) by compensating for the sampled L2 congestion information (602). At this time, the amount of change in AP information may be used to compensate for the sampled L2 congestion information (602). The AP (620) can collect information measurable within the AP (620) in real time (e.g., TCP RTT, TCP throughput, IP egress rate, inflight in TCP, congestion window). The AP (620) can filter data that reflects the L2 congestion state from the collected AP information. The AP (620) can measure the amount of change per hour of the filtered data (amount of change in AP information) and can obtain compensated L2 congestion information (603) by summing the amount of change in AP information to the sampled L2 congestion information (602) received from the CP (610).

[0113] According to one embodiment of the present disclosure, the AP (620) can quantitatively determine the degree of congestion in data transmission based on compensated L2 congestion information (603). The AP (620) can calculate the CE marking probability (p) (604) based on the degree of congestion in the network. Here, the CE marking probability (p) (604) may mean the probability of setting the ECN field of the data packet by modifying it from the ECT (1) bit to the CE bit.

[0114] AP (620) can set the ECN field of a data packet by modifying it from the ECT (1) bit to the CE bit according to the calculated CE marking probability (p) (604). A data packet with the CE bit set can be transmitted from AP (620) to CP (610) and finally transmitted to a server via an L2 buffer. The server receives the data packet and can transmit it to the terminal, including ECN feedback in an ACK for the data packet. When the terminal receives an ACK containing ECN feedback from the server, it can control the transmission speed of the data packet using Scalable CCA.

[0115] FIGS. 7a and 7b are drawings illustrating a method for compensating for L2 congestion information received from a CP by an AP inside a terminal using a change in TCP RTT in one embodiment of the present disclosure.

[0116] As described above in FIGS. 5 and 6, the AP inside the terminal can use the amount of change in information measurable within the AP (amount of change in AP information) to compensate for L2 congestion information received from the CP.

[0117] Below, with reference to FIG. 7a, a method for compensating for L2 congestion information using the change in TCP (Transmission Control Protocol) RTT (Round Trip Time) among the changes in AP information will be explained in detail.

[0118] According to one embodiment of the present disclosure, the CP can monitor the status of data packets in the L2 buffer of a terminal and measure the queue delay of data packets (L2 queue delay) occurring in the L2 buffer in real time. At this time, the L2 queue delay can be calculated as shown in the following Equation 2.

[0119]

[0120] Here, is the L2 queue delay, and is the length of the queue accumulated in the L2 buffer, and can be the data transmission rate (Egress rate) of the L4S traffic bearer. In this case, the data transmission rate of the L4S traffic bearer can be measured based on information tracked and measured at the MAC layer.

[0121] According to one embodiment of the present disclosure, a CP can generate L2 congestion information (701) based on a measured L2 queue delay value and can transmit the generated L2 congestion information (701) to an AP. The CP can periodically (period of t, It can be transmitted to the AP in the form of an L4S Metric. At this time, the L4S Metric transmitted to the AP contains L2 congestion information (701) sampled at intervals of t. (702) may be included.

[0122] According to one embodiment of the present disclosure, the AP receives an L4S Metric from the CP, and based thereon (702) can be identified. (702) is a value obtained by sampling the L2 congestion information (701) at intervals of t, so it may be a value that does not properly reflect the L2 congestion information (701). Therefore, A process of compensation may be required so that (702) can properly reflect L2 congestion information (701).

[0123] According to one embodiment of the present disclosure, AP is from CP From the point in time after receiving the L4S Metric containing (702), the amount of change in TCP RTT can be measured. Referring to FIG. 7b, since the amount of change in TCP RTT can reflect the amount of change in L2 queue delay, the AP, based on the measured amount of change in TCP RTT, (702) can be compensated.

[0124] Specifically, TCP RTT can be the round-trip time from the transmission of a data packet to the reception of an ACK packet in a TCP session. TCP RTT can be composed of various delay elements such as propagation delay, processing delay, queue delay, and transmission delay. Among these, propagation delay, processing delay, and processing delay have relatively fixed values ​​and low variability, whereas queue delay can be a value that fluctuates significantly in real time depending on network congestion. Therefore, based on the change in TCP RTT corresponding to the change in queue delay over time, A method to compensate (702) can be proposed.

[0125] According to one embodiment of the present disclosure, the amount of change in TCP RTT measured within the AP Reflected in (702) for one period (t) Compensation for (702) can be performed. Compensated L2 congestion information within the AP (703) can be calculated as shown in the following mathematical formula 3.

[0126]

[0127] Here, may be the amount of change in TCP RTT measured within the AP.

[0128] According to one embodiment of the present disclosure, AP is L2 congestion information compensated by summing the change in TCP RTT in (702) (703) can be obtained.

[0129] According to one embodiment of the present disclosure, AP is Based on (703), the degree of congestion in data transmission can be quantitatively determined. Graph data or mapping information (704) showing the correlation between the L2 queue delay value and the CE marking probability (p) may be stored within the AP. The AP A CE marking probability (p) (705) can be calculated based on (703) and stored graph data or mapping information (704). Here, the CE marking probability (p) (705) may mean the probability of setting the ECN field of the data packet by modifying it from the ECT (1) bit to the CE bit.

[0130] AP can set the ECN field of a data packet by modifying it from the ECT (1) bit to the CE bit according to the calculated CE marking probability (p) (705). A data packet with the CE bit set can be transmitted from AP to CP and finally transmitted to the server through the L2 buffer. The server receives the data packet and can transmit it to the terminal, including ECN feedback in an ACK for the data packet. When the terminal receives an ACK containing ECN feedback from the server, it can control the transmission rate of the data packet using Scalable CCA.

[0131] FIGS. 8a and 8b are drawings for explaining a method for compensating for L2 congestion information received by an AP inside a terminal from a CP using a change in the ratio between the number of packets on the network and the TCP throughput in one embodiment of the present disclosure.

[0132] As described above in FIGS. 5 and 6, the AP inside the terminal can use the amount of change in information measurable within the AP (amount of change in AP information) to compensate for L2 congestion information received from the CP.

[0133] In the following, with reference to FIG. 8a, the ratio between the number of TCP packets on the network and the TCP throughput among the AP information change amounts ( We will specifically explain how to compensate for L2 congestion information using the change in ).

[0134] According to one embodiment of the present disclosure, the CP monitors the status of data packets in the L2 buffer of the terminal and can measure the queue delay of data packets (L2 queue delay) occurring in the L2 buffer in real time. At this time, the L2 queue delay can be calculated as shown in the following Equation 4.

[0135]

[0136] Here, is the L2 queue delay, and is the length of the queue accumulated in the L2 buffer, and can be the data transmission rate (Egress rate) of the L4S traffic bearer. In this case, the data transmission rate of the L4S traffic bearer can be measured based on information tracked and measured at the MAC layer.

[0137] According to one embodiment of the present disclosure, a CP can generate L2 congestion information (801) based on a measured L2 queue delay value and can transmit the generated L2 congestion information (801) to an AP. The CP can periodically (period of t, It can be transmitted to the AP in the form of an L4S Metric. At this time, the L4S Metric transmitted to the AP contains L2 congestion information (801) sampled at intervals of t. (802) may be included.

[0138] According to one embodiment of the present disclosure, the AP receives an L4S Metric from the CP, and based thereon (802) can be identified. (802) is a value obtained by sampling L2 congestion information (801) at intervals of t, so it may be a value that does not properly reflect L2 congestion information (801). Therefore, A process of compensation may be required so that (802) can properly reflect L2 congestion information (801).

[0139] According to one embodiment of the present disclosure, AP is from CP From the point in time after receiving the L4S Metric containing (802), the ratio between the number of TCP packets on the network and the TCP throughput ( The amount of change of ) can be measured. Referring to Fig. 8b, Since the change in can reflect the change in L2 queue delay, AP is the measured Based on the amount of change of (802) can be compensated.

[0140] Specifically, This can refer to the total amount of data packets transmitted in a TCP session but for which an ACK has not yet been received, and It can refer to the total amount of data successfully transmitted per unit of time (TCP throughput). In the event of network congestion, The value increases It may show a decreasing tendency. In other words, when the degree of network congestion is high It may increase, and if network congestion is alleviated It can be reduced. Network congestion can consist of various delay factors such as propagation delay, processing delay, queue delay, and transmission delay. Among these, propagation delay, packet transmission delay, and processing delay have relatively fixed values ​​and low variability, whereas queue delay can be a value that fluctuates significantly in real time depending on network congestion conditions. Therefore, the amount of change in queue delay over time is It can correspond to the amount of change of, Based on the amount of change of A method to compensate (802) can be proposed.

[0141] According to one embodiment of the present disclosure, measured within AP The amount of change of Reflected in (802) one cycle ( ) during Compensation for (802) can be performed. Compensated L2 congestion information within the AP (803) can be calculated as shown in the following mathematical formula 5.

[0142]

[0143] Here, is measured within the AP It can be the amount of change.

[0144] According to one embodiment of the present disclosure, AP is (802) L2 congestion information compensated by summing the changes in (803) can be obtained.

[0145] According to one embodiment of the present disclosure, AP is Based on (803), the degree of congestion in data transmission can be quantitatively determined. Graph data or mapping information (804) showing the correlation between the L2 queue delay value and the CE marking probability (p) may be stored within the AP. The AP A CE marking probability (p) (805) can be calculated based on (803) and stored graph data or mapping information (804). Here, the CE marking probability (p) (805) may mean the probability of setting the ECN field of the data packet by modifying it from the ECT (1) bit to the CE bit.

[0146] AP can set the ECN field of a data packet by modifying it from the ECT (1) bit to the CE bit according to the calculated CE marking probability (p) (805). A data packet with the CE bit set can be transmitted from AP to CP and finally transmitted to the server through the L2 buffer. The server receives the data packet and can transmit it to the terminal, including ECN feedback in an ACK for the data packet. When the terminal receives an ACK containing ECN feedback from the server, it can control the transmission rate of the data packet using Scalable CCA.

[0147] FIG. 9 is a diagram for explaining the reason for considering the time difference between TCP RTT and L2 congestion information in the process of compensating for L2 congestion information using the amount of change in TCP RTT in one embodiment of the present disclosure.

[0148] Referring to FIG. 9(a), the TCP RTT can reflect the L2 queue delay, and the pattern of change of the TCP RTT over time (902) is similar to the pattern of change of the L2 queue delay (901), but may show a form delayed by t2-t1 on the time axis. Here, time t1 may refer to the time when the CP estimates the L2 queue delay and the AP receives the L4S Metric transmitted from the CP. Time t2 may be the time when the TCP RTT is measured because an ACK for the data packet that experienced the L2 queue delay transmitted from the CP to the AP at time t1 is received. In conclusion, the AP must compensate for the L2 queue delay transmitted at time t1 based on the amount of change in the TCP RTT at time t2.

[0149] With reference to FIG. 9(b), a more detailed explanation will be provided. The CP can measure the L2 queue delay (903) of a data packet occurring in the L2 buffer at time t1 and transmit the measured L2 queue delay (903) to the AP in the form of an L4S Metric. The data packet (904) that will experience the L2 queue delay (903) measured by the CP at time t1 can be transmitted from the CP to the server (905). The server (905) can transmit an ACK (906) for the data packet (904) to the AP. The AP can receive the ACK (906) from the server (905) at time t2 and can measure the TCP RTT based on the received ACK (906).

[0150] Accordingly, in order for the AP to properly compensate for the queue delay measured at time t1, it may need to utilize the change in TCP RTT measured at time t2. If this time difference (e.g., t2-t1) is not taken into account, compensation for L2 congestion information may be inaccurate, which could have a negative impact on network performance.

[0151] Below, we will specifically describe an embodiment that considers the time difference in the process of compensating for L2 congestion information using the change in TCP RTT.

[0152] FIG. 10 is a flowchart illustrating a process for compensating for L2 congestion information by calculating the change in TCP RTT in a way that specifies a TCP segment in a CP inside a terminal in an embodiment of the present invention.

[0153] Referring to Fig. 10, a step-by-step procedure is illustrated for setting a base RTT using TCP ACK to reflect the L2 congestion state in the AP, and then compensating for L2 queue delay by calculating the difference between the measured RTT and the base RTT.

[0154] In step 1001, according to one embodiment of the present disclosure, the CP can monitor the status of data packets in the L2 buffer of the terminal and measure the queue delay of data packets occurring in the L2 buffer (L2 queue delay). The CP can generate L2 congestion information based on the measured L2 queue delay.

[0155] In step 1002, according to one embodiment of the present disclosure, the CP can identify a TCP segment that is determined to experience an L2 queue delay. Specifically, the CP identifies the sequence number of the TCP segment located closest to the L2 buffer among L2 data packets within the CP that have not undergone PDCP ciphering. It can extract.

[0156] In step 1003, according to one embodiment of the present disclosure, CP is L2 congestion information and the sequence number of the extracted TCP segment It can be transmitted to the AP. In this case, the CP contains the generated L2 congestion information and sequence number. It can periodically transmit to the AP in the form of an L4S Metric.

[0157] In step 1004, according to one embodiment of the present disclosure, the AP may stop the compensation operation at the time of receiving the L4S Metric from the CP. Specifically, if the AP is performing an existing compensation operation at the time of receiving the L4S Metric from the CP, the AP may stop the existing compensation operation and change the state of the State Machine to "WAITING". Subsequently, based on the received L4S Metric, the AP [requires] the L2 queue delay and the sequence number of the TCP segment included in the L2 congestion information It can identify.

[0158] In step 1005, according to one embodiment of the present disclosure, the AP may receive a TCP ACK. The TCP ACK may be an ACK for the TCP segment.

[0159] In step 1006, according to one embodiment of the present disclosure, the AP has the ACK number of the received TCP ACK ( ), , and the size of the specified TCP segment ( A base RTT can be set based on ). At this time, the algorithm for setting the base RTT can be defined by the following [Table 1].

[0160]

[0161] Here, the conditions for setting the base RTT can be defined as follows.

[0162] - Condition 1: Number of the received ACK( )go Same as. In this case, since the corresponding TCP ACK can be determined to have been received successfully, the corresponding TCP ACK ( The first RTT measured upon reception can be set as the base RTT.

[0163] - Condition 2: Number of the received ACK( )go Greater than. This is a specific TCP segment ( ) and / or the corresponding TCP segment ( If the ACK for ) is lost, or due to reordering This can occur when a larger TCP ACK arrives first. In this case, a specific TCP segment ( Since ) and the following TCP segment can be expected to experience similar L2 congestion, the corresponding TCP ACK( The first RTT measured upon reception can be set as the base RTT. In this case, the TCP ACK used to set the base RTT ( TCP ACKs with numbers smaller than the number of ) or TCP ACKs for retransmitted TCP segments may not be considered in the compensation process.

[0164] In step 1007, according to one embodiment of the present disclosure, the AP may enable a compensation operation by changing the state of the State Machine to "COMPENSATE" after setting the base RTT. More specifically, the AP may... the difference between the TCP RTT and the base RTT measured after setting the base RTT ( It can calculate ), L2 queue delay received from CP based on Can compensate for ). Compensated L2 queue delay within AP ( ) can be calculated as shown in the following mathematical formula 6.

[0165]

[0166] Here, can be the i-th TCP RTT measured after the base RTT is set, and is a specific TCP segment ( It may be the time when a TCP ACK for ) arrived.

[0167] FIG. 11 is a diagram illustrating a process for compensating for L2 congestion information by calculating a change in TCP RTT in a way that specifies a TCP segment in a CP inside a terminal in an embodiment of the present disclosure.

[0168] According to one embodiment of the present disclosure, CP (1110) can monitor the status of data packets in the L2 buffer of a terminal and measure the queue delay of data packets occurring in the L2 buffer in real time. Specifically, CP (1110) can measure the data transmission rate (Egress Rate, R) based on information provided by the MAC layer, and can measure the L2 queue delay (L2 queue delay, d) based on the measured data transmission rate (Egress Rate) and the length (bs) of the L2 buffer.

[0169] According to one embodiment of the present disclosure, CP (1110) can generate L2 congestion information based on the measured L2 queue delay. Below, a procedure for performing compensation for the L2 queue delay (1101) included in the L2 congestion information will be described.

[0170] According to one embodiment of the present disclosure, a CP (1110) can identify a TCP segment that is determined to experience L2 congestion. Specifically, the CP has the sequence number of the TCP segment located closest to the L2 buffer among L2 data packets within the CP that have not undergone PDCP encryption. (1102) can be extracted.

[0171] According to one embodiment of the present disclosure, CP (1110) includes L2 congestion information including an L2 queue delay (1101) and the sequence number of the extracted TCP segment (1102) can be transmitted to AP (1120). At this time, CP (1110) includes L2 congestion information including L2 queue delay (1101) and periodically (period of t, It can be transmitted to AP (1120) in the form of an L4S Metric.

[0172] According to one embodiment of the present disclosure, AP (1120) receives an L4S Metric from CP (1110), and based thereon, a sampled L2 queue delay (1103) and a sequence number of a TCP segment (1102) can be identified.

[0173] According to one embodiment of the present disclosure, the AP (1120) may receive a TCP ACK (1104). In this case, the TCP ACK (1104) may be a response to a TCP segment transmitted to the server (1130), and the TCP ACK (1104) may include a sequence number of data that the server (1130) expects to receive after the received TCP segment. The AP (1120) may store the received TCP ACK (1104) in an AP storage (AP info.).

[0174] According to one embodiment of the present disclosure, AP (1120) is the ACK number of a TCP ACK (1104) stored in an AP storage (AP info.) ( ), (1102), and the size of the specified TCP segment ( The base RTT (1105) can be set based on ). In this case, the base RTT (1105) can be set through the algorithm and conditions (e.g., condition 1, condition 2) presented in FIG. 10.

[0175] According to one embodiment of the present disclosure, the AP (1120) receives the TCP RTT ( based on the TCP ACK stored in the AP storage (AP info.) )(1106) can be measured. At this time, TCP RTT( )(1106) may be the i-th TCP RTT measured after the base RTT (1105) is set. AP (1120) is the TCP RTT ( The difference between )(1106) and base RTT(1105) It can calculate ), The sampled L2 queue delay (1103) can be compensated based on the above. The compensated L2 queue delay (1107) within the AP can be calculated as Equation 6 of FIG. 10 described above.

[0176] According to one embodiment of the present disclosure, the AP (1120) can quantitatively determine the degree of congestion in data transmission based on compensated L2 congestion information (1107). The AP (1120) can calculate the CE marking probability (p) (1108) based on the degree of congestion in the network. Here, the CE marking probability (p) (1108) may mean the probability of setting the ECN field of a data packet by modifying it from the ECT (1) bit to the CE bit.

[0177] According to one embodiment of the present disclosure, the AP (1120) can modify and set the ECN field of a data packet from the ECT (1) bit to the CE bit according to the calculated CE marking probability (p) (1108). A data packet with the CE bit set can be transmitted from the AP (1120) to the CP (1110) and finally transmitted to the server (1130) through the L2 buffer. The server (1130) receives the data packet and can transmit it to the terminal including ECN feedback in an ACK for the data packet. When the terminal receives an ACK including ECN feedback from the server, it can control the transmission speed of the data packet using a Scalable CCA.

[0178] FIG. 12 is a flowchart illustrating a process for compensating for L2 congestion information by calculating the change in TCP RTT in a specific way for a TCP segment in an AP inside a terminal in an embodiment of the present invention.

[0179] Referring to Fig. 12, a step-by-step procedure is illustrated to set baseRTT using TCP ACK to reflect the L2 congestion state in the AP, and then to compensate for L2 queue delay by calculating the difference between the measured RTT and baseRTT.

[0180] In step 1201, according to one embodiment of the present disclosure, the CP can monitor the status of data packets in the L2 buffer of the terminal and measure the queue delay of data packets occurring in the L2 buffer (L2 queue delay). The CP can generate L2 congestion information based on the measured L2 queue delay value.

[0181] In step 1202, according to one embodiment of the present disclosure, the CP can transmit the generated L2 congestion information to the AP. At this time, the CP can periodically transmit the generated L2 congestion information to the AP in the form of an L4S Metric.

[0182] In step 1203, according to one embodiment of the present disclosure, the AP may stop the compensation operation at the time of receiving the L4S Metric from the CP. Specifically, if the AP is performing an existing compensation operation at the time of receiving the L4S Metric from the CP, it may stop it and change the state of the State Machine to "IDLE". Subsequently, the AP may identify the L2 queue delay included in the L2 congestion information based on the received L4S Metric.

[0183] In step 1204, according to one embodiment of the present disclosure, the AP can identify a TCP segment that is determined to experience an L2 queue delay. Specifically, the AP has the sequence number of a TCP segment passing through the TCP layer within the AP at the time of receiving the L4S Metric. It can extract. Afterwards, AP can change the state of the State Machine to "WAITING".

[0184] At step 1205, according to one embodiment of the present disclosure, the AP may receive a TCP ACK. The TCP ACK may be an ACK for the TCP segment.

[0185] In step 1206, according to one embodiment of the present disclosure, the AP has the ACK number of the received TCP ACK ( ), , and the size of the specified TCP segment ( A base RTT can be set based on ). In this case, the base RTT can be set through the algorithm and conditions (e.g., condition 1, condition 2) presented in FIG. 10.

[0186] In step 1207, according to one embodiment of the present disclosure, the AP may enable a compensation operation by changing the state of the State Machine to "COMPENSATE" after setting the base RTT. More specifically, the AP may... the difference between the TCP RTT and the base RTT measured after setting the base RTT ( It can calculate ), L2 queue delay received from CP based on Can compensate for ). Compensated L2 queue delay within AP ( ) can be calculated as in mathematical formula 6 of Fig. 10 described above.

[0187] FIG. 13 is a diagram illustrating a process of compensating for L2 congestion information by calculating a change in TCP RTT in a way that specifies a TCP segment in an AP inside a terminal in an embodiment of the present disclosure.

[0188] According to one embodiment of the present disclosure, CP (1310) can monitor the status of data packets in the L2 buffer of a terminal and measure the queue delay of data packets occurring in the L2 buffer in real time. Specifically, CP (1310) can measure the data transmission rate (Egress Rate, R) based on information provided by the MAC layer, and can measure the L2 queue delay (L2 queue delay, d) based on the measured data transmission rate (Egress Rate) and the length (bs) of the L2 buffer.

[0189] According to one embodiment of the present disclosure, CP (1310) can generate L2 congestion information based on the measured L2 queue delay. Below, a procedure for performing compensation for the L2 queue delay (1301) included in the L2 congestion information will be described.

[0190] According to one embodiment of the present disclosure, CP (1310) can transmit L2 congestion information including L2 queue delay (1301) to AP (1310). At this time, CP (1310) periodically (period of t, It can be transmitted to AP (1310) in the form of an L4S Metric.

[0191] According to one embodiment of the present disclosure, AP (1310) receives an L4S Metric from CP (1310) and can identify a sampled L2 queue delay (1302) based thereon.

[0192] According to one embodiment of the present disclosure, the AP (1310) can identify a TCP segment that is determined to experience an L2 queue delay. Specifically, the AP (1310) may identify the sequence number of a TCP segment passing through the TCP layer within the AP (1310) at the time of receiving an L4S metric. (1303) can be extracted.

[0193] According to one embodiment of the present disclosure, the AP (1310) may receive a TCP ACK (1304). In this case, the TCP ACK (1304) may be a response to a TCP segment (1303) extracted from the AP (1310), and the TCP ACK (1304) may include an ACK number (ACK Number) containing a sequence number of data that the server (1330) expects to receive next. It may include ). The AP (1310) may store the received TCP ACK (1304) in the AP storage (AP info.).

[0194] According to one embodiment of the present disclosure, AP (1310) is the ACK number of a TCP ACK (1304) stored in an AP storage (AP info.) ( ), (1303), and the size of the specified TCP segment ( The base RTT (1305) can be set based on ). In this case, the base RTT (1305) can be set through the algorithm and conditions (e.g., condition 1, condition 2) presented in FIG. 10.

[0195] According to one embodiment of the present disclosure, the AP (1310) determines the TCP RTT ( based on the TCP ACK stored in the AP storage (AP info.) )(1306) can be measured. At this time, TCP RTT( )(1306) may be the i-th TCP RTT measured after the base RTT (1305) is set. AP (1310) is the TCP RTT ( The difference between )(1306) and base RTT(1305) It can calculate ), The sampled L2 queue delay (1302) can be compensated based on the above. The compensated L2 queue delay (1307) within the AP can be calculated as Equation 6 of FIG. 10 described above.

[0196] According to one embodiment of the present disclosure, the AP (1310) can quantitatively determine the degree of congestion in data transmission based on compensated L2 congestion information (1307). The AP (1310) can calculate the CE marking probability (p) (1308) according to the degree of congestion in the network. Here, the CE marking probability (p) (1308) may mean the probability of setting the ECN field of a data packet by modifying it from the ECT (1) bit to the CE bit.

[0197] According to one embodiment of the present disclosure, the AP (1310) can modify and set the ECN field of a data packet from the ECT (1) bit to the CE bit according to the calculated CE marking probability (p) (1308). A data packet with the CE bit set can be transmitted from the AP (1310) to the CP (1310) and finally transmitted to the server (1330) through an L2 buffer. The server (1330) receives the data packet and can transmit it to the terminal, including ECN feedback in an ACK for the data packet. When the terminal receives an ACK containing ECN feedback from the server, it can control the transmission speed of the data packet using a Scalable CCA.

[0198] FIG. 14 is a diagram illustrating the background of a proposed method for compensating L2 congestion information using the change in the ratio between the number of packets on a network and TCP throughput in one embodiment of the present disclosure.

[0199] FIG. 14 shows the ratio between the number of TCP packets on a network and the TCP throughput ( It visually illustrates the change over time of ) and L2 queue delay.

[0200] The ratio between the number of TCP packets on the network and TCP throughput ( ) can represent the expected RTT of a TCP segment transmitted at the TCP layer. Although this is calculated before the TCP segment transmitted at the TCP layer experiences L2 queue delay, since the delay time until the TCP segment is actually enqueued into the L2 buffer is very short, The temporal change pattern of the L2 queue delay can be nearly identical as shown in Fig. 14.

[0201] Specifically, of the TCP layer It can serve as a leading indicator reflecting the congestion state prior to a TCP segment entering the L2 buffer. In other words, This is a metric that precedes L2 queue delay in terms of time, and corresponds to the time delay until the corresponding TCP segment enters the L2 buffer, i.e., the protocol delay within the terminal; therefore, except for small values, the patterns of the two metrics may appear similar.

[0202] Accordingly, it can be assumed that the relevant TCP segment experiences L2 queue delay, and at the time the AP receives the L4S metric The amount of change can be reflected as the amount of change in the L2 queue delay.

[0203] In the following, An embodiment of the present disclosure that compensates for L2 congestion information using the amount of change will be described in detail.

[0204] FIG. 15 is a flowchart illustrating a process for compensating for L2 congestion information using the change in the ratio between the number of packets on the network and the TCP throughput in one embodiment of the present disclosure.

[0205] Referring to Fig. 15, base information is set at the AP to reflect the L2 congestion status, and subsequently measured The procedure for compensating for L2 queue delay by calculating the difference between and base information is illustrated step-by-step.

[0206] In step 1501, according to one embodiment of the present disclosure, the CP can monitor the status of data packets in the L2 buffer of the terminal and measure the queue delay of data packets occurring in the L2 buffer (L2 queue delay). The CP can generate L2 congestion information based on the measured L2 queue delay.

[0207] In step 1502, according to one embodiment of the present disclosure, the CP can transmit the generated L2 congestion information to the AP. At this time, the CP can periodically transmit the generated L2 congestion information to the AP in the form of an L4S Metric.

[0208] In step 1503, according to one embodiment of the present disclosure, the AP may stop the compensation operation at the time of receiving the L4S Metric from the CP. Specifically, if the AP is performing an existing compensation operation at the time of receiving the L4S Metric from the CP, it may stop it and change the state of the State Machine to "IDLE". Subsequently, the AP may identify the L2 queue delay included in the L2 congestion information based on the received L4S Metric.

[0209] In step 1504, according to one embodiment of the present disclosure, at the time when the AP receives the L4S Metric from the CP, the measured within the AP You can set it as base information.

[0210] In step 1505, according to one embodiment of the present disclosure, after the AP sets the base Info, the AP can activate a compensation operation by changing the state of the State Machine to "COMPENSATE". More specifically, the AP utilizes an internal timer once at a certain period It can calculate, The difference between and base Info ( L2 queue delay received from CP based on ) Can compensate for ). Compensated L2 queue delay within AP ( ) can be calculated as shown in the following mathematical formula 7.

[0211]

[0212] Here, is the i-th measured after base Info is set It could be.

[0213] FIG. 16 is a diagram illustrating a process for compensating for L2 congestion information using the change in the ratio between the number of packets on the network and the TCP throughput in one embodiment of the present disclosure.

[0214] According to one embodiment of the present disclosure, CP (1610) can monitor the status of data packets in the L2 buffer of a terminal and measure the queue delay of data packets occurring in the L2 buffer in real time. Specifically, CP (1610) can measure the data transmission rate (Egress Rate, R) based on information provided by the MAC layer, and can measure the L2 queue delay (L2 queue delay, d) based on the measured data transmission rate (Egress Rate) and the length (bs) of the L2 buffer.

[0215] According to one embodiment of the present disclosure, CP (1610) can generate L2 congestion information based on the measured L2 queue delay. Below, a procedure for performing compensation for the L2 queue delay (1601) included in the L2 congestion information will be described.

[0216] According to one embodiment of the present disclosure, CP (1610) can transmit L2 congestion information including L2 queue delay (1601) to AP (1620). At this time, CP (1610) periodically (period of t, It can be transmitted to AP (1620) in the form of an L4S Metric.

[0217] According to one embodiment of the present disclosure, AP (1620) receives an L4S Metric from CP (1610) and can identify a sampled L2 queue delay (1602) based thereon.

[0218] According to one embodiment of the present disclosure, AP (1620) is measured within AP at the time AP receives L4S Metric from CP. It can be extracted from the AP repository (AP info.), and the L4S Metric measured within the AP at the time of receipt You can set it as base information (base Info) (1603).

[0219] According to one embodiment of the present disclosure, AP (1620) is calculated once at a certain period using an internal timer (1604) can be extracted from the AP storage (AP info.). At this time, (1604) is the i-th measured after base Info (1603) is set It could be. AP(1620) is Difference between (1604) and base Info (1603) The sampled L2 queue delay (1602) can be compensated based on ). The compensated L2 queue delay (1605) within the AP can be calculated as shown in Equation 7 of FIG. 15 described above.

[0220] According to one embodiment of the present disclosure, the AP (1620) can quantitatively determine the degree of congestion in data transmission based on compensated L2 congestion information (1605). The AP (1620) can calculate the CE marking probability (p) (1606) according to the degree of congestion in the network. Here, the CE marking probability (p) (1606) may mean the probability of setting the ECN field of a data packet by modifying it from the ECT (1) bit to the CE bit.

[0221] According to one embodiment of the present disclosure, the AP (1620) can modify and set the ECN field of a data packet from the ECT (1) bit to the CE bit according to the calculated CE marking probability (p) (1606). A data packet with the CE bit set can be transmitted from the AP (1620) to the CP (1610) and finally transmitted to the server (1630) through the L2 buffer. The server (1630) receives the data packet and can transmit it to the terminal including ECN feedback in an ACK for the data packet. When the terminal receives an ACK including ECN feedback from the server, it can control the transmission speed of the data packet using a Scalable CCA.

[0222] FIG. 17 is a diagram illustrating a method for a terminal to compensate for L2 congestion information based on the amount of AP information change in one embodiment of the present disclosure.

[0223] Referring to FIG. 17, the operation of a terminal according to the embodiments of FIG. 1 to FIG. 16 proposed in the present disclosure is illustrated.

[0224] In step S1710, a terminal according to one embodiment of the present disclosure can identify first congestion information measured by a Communication Processor (CP). At this time, the first congestion information may be L2 congestion information generated based on the queue delay of an L2 buffer. The CP can generate L2 congestion information and transmit the L2 congestion information to an AP. The AP inside the terminal can identify the L2 congestion information received from the CP. Step S1710 may operate similarly to steps 501 to 503 of FIG. 5, steps 1001 to 1004 of FIG. 10, steps 1201 to 1203 of FIG. 12, or steps 1501 to 1503 of FIG. 15. Here, descriptions that overlap with the content described in FIG. 5, FIG. 10, FIG. 12, or FIG. 15 are omitted, and reference is made to FIG. 5, FIG. 10, FIG. 12, or FIG. 15.

[0225] In step S1720, a terminal according to one embodiment of the present disclosure can measure the amount of change in AP (Application Processor) information. Specifically, the AP within the terminal can identify (estimate) the amount of change in information measurable within the AP. Step S1720 may operate similarly to step 504 of FIG. 5, steps 1005 to 1007 of FIG. 10, steps 1204 to 1207 of FIG. 12, or steps 1504 to 1505 of FIG. 15. Here, descriptions that overlap with the content described in FIG. 5, FIG. 10, FIG. 12, or FIG. 15 are omitted, and reference is made to FIG. 5, FIG. 10, FIG. 12, or FIG. 15.

[0226] In step S1730, a terminal according to an embodiment of the present disclosure may obtain second congestion information in which compensation for the first congestion information is performed based on the first congestion information and the amount of change in AP information. At this time, the second congestion information may be information in which compensation is performed for L2 congestion information. Step S1730 may operate similarly to step 505 of FIG. 5, step 1007 of FIG. 10, step 1207 of FIG. 12, or step 1505 of FIG. 15. Here, descriptions that overlap with the content described in FIG. 5, FIG. 10, FIG. 12, or FIG. 15 are omitted, and FIG. 5, FIG. 10, FIG. 12, or FIG. 15 are referenced.

[0227] In step S1740, a terminal according to an embodiment of the present disclosure can calculate an Explicit Congestion Notification (ECN) marking probability using second congestion information. The terminal can quantitatively determine the degree of congestion in data transmission based on compensated L2 congestion information. The terminal can calculate an ECN marking probability, which is the probability of marking a CE according to the degree of congestion in the network. Step S1740 may operate similarly to FIG. 6, FIG. 11, FIG. 13, or FIG. 16. Here, descriptions that overlap with those described in FIG. 6, FIG. 11, FIG. 13, or FIG. 16 are omitted, and FIG. 6, FIG. 11, FIG. 13, or FIG. 16 are referenced.

[0228] In step S1750, a terminal according to an embodiment of the present disclosure may set an ECN bit in a packet to be transmitted according to an ECN marking probability. The terminal may set the ECN field of the packet to be transmitted by modifying it from an ECT (1) bit to a CE bit according to an ECN marking probability. Step S1750 may operate similarly to FIG. 6, FIG. 11, FIG. 13, or FIG. 16. Here, descriptions that overlap with those described in FIG. 6, FIG. 11, FIG. 13, or FIG. 16 are omitted, and FIG. 6, FIG. 11, FIG. 13, or FIG. 16 are referenced.

[0229] FIG. 18 is a diagram illustrating a method for compensating L2 congestion information received by an AP in a terminal from a CP in one embodiment of the present disclosure.

[0230] Referring to FIG. 18, the operation of a terminal according to the embodiments of FIG. 1 to FIG. 16 proposed in the present disclosure is illustrated.

[0231] In step S1810, an Application Processor (AP) according to one embodiment of the present disclosure may receive first congestion information measured by a Communication Processor (CP). At this time, the first congestion information may be L2 congestion information generated based on the queue delay of an L2 buffer. The CP may generate L2 congestion information and transmit the L2 congestion information to the AP. The AP inside the terminal may identify the L2 congestion information received from the CP. Step S1810 may operate similarly to steps 501 to 503 of FIG. 5, steps 1001 to 1004 of FIG. 10, steps 1201 to 1203 of FIG. 12, or steps 1501 to 1503 of FIG. 15. Here, descriptions that overlap with those described in FIG. 5, FIG. 10, FIG. 12, or FIG. 15 are omitted, and FIG. 5, FIG. 10, FIG. 12, or FIG. 15 are referenced.

[0232] In step S1820, the AP according to one embodiment of the present disclosure can measure the amount of change in AP (Application Processor) information. Specifically, the AP within the terminal can identify (estimate) the amount of change in information measurable within the AP. Step S1820 may operate similarly to step 504 of FIG. 5, steps 1005 to 1007 of FIG. 10, steps 1204 to 1207 of FIG. 12, or steps 1504 to 1505 of FIG. 15. Here, descriptions that overlap with the content described in FIG. 5, FIG. 10, FIG. 12, or FIG. 15 are omitted, and reference is made to FIG. 5, FIG. 10, FIG. 12, or FIG. 15.

[0233] In step S1830, the AP according to one embodiment of the present disclosure may obtain second congestion information in which compensation for the first congestion information is performed based on the first congestion information and the amount of change in AP information. At this time, the second congestion information may be information in which compensation is performed for L2 congestion information. Step S1830 may operate similarly to step 505 of FIG. 5, step 1007 of FIG. 10, step 1207 of FIG. 12, or step 1505 of FIG. 15. Here, descriptions that overlap with the content described in FIG. 5, FIG. 10, FIG. 12, or FIG. 15 are omitted, and reference is made to FIG. 5, FIG. 10, FIG. 12, or FIG. 15.

[0234] In step S1840, an AP according to one embodiment of the present disclosure can calculate an Explicit Congestion Notification (ECN) marking probability using second congestion information. The AP can quantitatively determine the degree of congestion in data transmission based on compensated L2 congestion information. The AP can calculate an ECN marking probability, which is the probability of marking a CE according to the degree of congestion in the network. Step S1840 may operate similarly to FIG. 6, FIG. 11, FIG. 13, or FIG. 16. Here, descriptions that overlap with those described in FIG. 6, FIG. 11, FIG. 13, or FIG. 16 are omitted, and FIG. 6, FIG. 11, FIG. 13, or FIG. 16 are referenced.

[0235] In step S1850, an AP according to one embodiment of the present disclosure may set an ECN bit in a packet to be transmitted according to an ECN marking probability. The AP may set the ECN field of the packet to be transmitted by modifying it from an ECT (1) bit to a CE bit according to an ECN marking probability. Step S1850 may operate similarly to FIG. 6, FIG. 11, FIG. 13, or FIG. 16. Here, descriptions that overlap with those described in FIG. 6, FIG. 11, FIG. 13, or FIG. 16 are omitted, and FIG. 6, FIG. 11, FIG. 13, or FIG. 16 are referenced.

[0236] FIG. 19 is a drawing illustrating the structure of a terminal according to one embodiment of the present disclosure.

[0237] Referring to FIG. 19, the terminal (1900) may be composed of a transceiver (1910), a processor (1920), and a memory (1930). Depending on the communication method of the terminal (1900) described above, the transceiver (1910), the processor (1920), and the memory (1930) of the terminal (1900) may operate. However, the components of the terminal (1900) are not limited to the examples described above. For example, the terminal (1900) may include more components or fewer components than the components described above. In one embodiment, the transceiver (1910), the processor (1920), and the memory (1930) may be implemented in the form of a single chip. Additionally, the processor (1920) may include one or more processors.

[0238] The transceiver (1910) is a collective term for the receiver and the transmitter of the terminal (1900), and can transmit and receive signals with a network entity including a base station. The signals transmitted and received with the network entity including the base station may include control information and data. To this end, the transceiver (1910) may be composed of an RF transmitter that up-converts and amplifies the frequency of the transmitted signal, and an RF receiver that low-noise amplifies the received signal and down-converts the frequency. However, this is one embodiment of the transceiver (1910), and the components of the transceiver (1910) are not limited to an RF transmitter and an RF receiver. Additionally, the transceiver (1910) may include a wired / wireless transceiver and may include various configurations for transmitting and receiving signals. Additionally, the transceiver (1910) can receive a signal through a wireless channel and output it to a processor (1920), and transmit the signal output from the processor (1920) through a wireless channel. Additionally, the transceiver (1910) can receive a communication signal and output it to a processor, and transmit the signal output from the processor to a network entity through a wired or wireless network.

[0239] The memory (1930) can store programs and data necessary for the operation of the terminal (1900). Additionally, the memory (1930) can store control information or data included in signals obtained from the terminal (1900). The memory (1930) may be composed of a storage medium or a combination of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. Additionally, the memory (1930) may not exist separately but may be configured to be included in the processor (1920). The memory (1930) may be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. Furthermore, the memory (1930) can provide stored data upon the request of the processor (1920).

[0240] The processor (1920) can control a series of processes to enable the terminal (1900) to operate according to the embodiments of the present disclosure described above. For example, the processor (1920) can receive control signals and data signals through the transceiver (1910) and process the received control signals and data signals. The processor (1920) can transmit the processed control signals and data signals through the transceiver (1910). Additionally, the processor (1920) can write or read data to or from memory (1930). The processor (1920) can perform the functions of a protocol stack required by a communication standard. To this end, the processor (1920) may include at least one processor or microprocessor. In one embodiment, a part of the transceiver (1910) or the processor (1920) may be referred to as a communication processor (CP).

[0241] The processor (1920) may be composed of one or more processors. In this case, the one or more processors may be general-purpose processors such as CPUs, APs, and DSPs (Digital Signal Processors), graphics-dedicated processors such as GPUs and VPUs (Vision Processing Units), or artificial intelligence-dedicated processors such as NPUs. For example, if one or more processors are artificial intelligence-dedicated processors, the artificial intelligence-dedicated processors may be designed with a hardware structure specialized for processing a specific artificial intelligence model.

[0242] The processor (1920) can control the overall operation of the terminal according to the embodiment proposed in the present disclosure. For example, the processor (1920) can control the signal flow between each block to perform the operation of FIGS. 1 to 19 described above.

[0243] In one embodiment, the processor (1920) can identify first congestion information measured by a Communication Processor (CP). The processor (1920) can measure the amount of change in Application Processor (AP) information. Based on the first congestion information and the amount of change in AP information, the processor (1920) can obtain second congestion information in which compensation for the first congestion information is performed. The processor (1920) can calculate an Explicit Congestion Notification (ECN) marking probability using the second congestion information. The processor (1920) can set an ECN bit in a packet to be transmitted according to the ECN marking probability.

[0244] In one embodiment, the amount of change in AP information may be the amount of change in TCP (Transmission Control Protocol) RTT (Round Trip Time) measured within the AP from the time when the first congestion information is identified.

[0245] In one embodiment, the amount of change in AP information may be the amount of change in the ratio of the number of TCP packets on the network and the TCP throughput measured within the AP from the time when the first congestion information is identified.

[0246] In one embodiment, the processor (1920) can identify a TCP segment extracted from the CP. The processor (1920) can receive an ACK (Acknowledgment) for the identified TCP segment from the network. The processor (1920) can measure the TCP RTT based on the ACK and set the measured TCP RTT as the base RTT.

[0247] In one embodiment, the amount of change in AP information can be measured based on the TCP RTT and base RTT measured from the time of receiving an ACK for an identified TCP segment.

[0248] In one embodiment, the processor (1920) may extract a TCP segment based on the time when the first congestion information is identified. The processor (1920) may receive an ACK for the extracted TCP segment from the network. The processor (1920) may measure the TCP RTT based on the ACK and set the measured TCP RTT as the base RTT.

[0249] In one embodiment, the amount of change in AP information can be measured based on the TCP RTT and base RTT measured from the time of receiving an ACK for an identified TCP segment.

[0250] In one embodiment, the processor (1920) may set the ratio of the number of TCP packets on the network and the TCP throughput measured within the AP as base information based on the time when the first congestion information is identified.

[0251] In one embodiment, the amount of change in AP information can be measured based on the ratio of the number of TCP packets on the network and the TCP throughput measured since the time when the first congestion information was identified, and base information.

[0252] In the specific embodiments of the present disclosure described above, the components included in the present disclosure are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed in the singular form, or even if a component is expressed in the singular form, it may be composed in the plural form.

[0253] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples provided to facilitate the explanation of the technical content of the present disclosure and to aid in understanding the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to those skilled in the art that other variations based on the technical concept of the present disclosure are possible. Furthermore, each of the above embodiments may be combined and operated as needed. For example, parts of one embodiment of the present disclosure and another embodiment may be combined to operate a base station and a terminal. In addition, the embodiments of the present disclosure are applicable to other communication systems, and other variations based on the technical concept of the embodiments may also be possible. For example, the embodiments may be applied to LTE systems, 5G or NR systems, etc. A device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, 'non-transient storage medium' simply means a tangible device that does not contain a signal (e.g., electromagnetic waves), and the term does not distinguish between cases where data is stored semi-permanently and cases where it is stored temporarily. For example, a 'non-transient storage medium' may include a buffer where data is stored temporarily.

[0254] According to one embodiment, the method according to the various embodiments disclosed herein may be provided by being included in a computer program product. The computer program product may be traded between a seller and a buyer as a product. The computer program product may be distributed in the form of a device-readable storage medium (e.g., compact disc read-only memory (CD-ROM)), or distributed online (e.g., download or upload) through an application store or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product (e.g., downloadable app) may be temporarily stored or temporarily created on a device-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or a relay server.

Claims

1. In a method of operation of a terminal in a wireless communication system, A step of identifying first congestion information measured by a CP (Communication Processor); Step of measuring the amount of change in AP (Application Processor) information; A step of obtaining second congestion information in which compensation for the first congestion information is performed based on the first congestion information and the amount of change in the AP information; A step of calculating the probability of marking an Explicit Congestion Notification (ECN) using the second congestion information above; and A method comprising the step of setting an ECN bit in a packet to be transmitted according to the above ECN marking probability.

2. In Paragraph 1, A method characterized in that the amount of change in the AP information is the amount of change in the TCP (Transmission Control Protocol) RTT (Round Trip Time) measured within the AP from the time when the first congestion information is identified.

3. In Paragraph 1, A method characterized in that the amount of change in AP information is the amount of change in the ratio of the number of TCP packets on the network and the TCP throughput measured within the AP from the time when the first congestion information is identified.

4. In Paragraph 1, A step of identifying a TCP segment extracted from the above CP; A step of receiving an ACK (Acknowledgment) for the identified TCP segment from the network; and The method further includes the step of measuring the TCP RTT based on the ACK and setting the measured TCP RTT as the base RTT. A method characterized in that the amount of change in AP information is measured based on the TCP RTT measured from the time of receiving the ACK for the identified TCP segment and the base RTT.

5. In Paragraph 1, A step of extracting a TCP segment based on the time when the first congestion information is identified; Receiving an ACK for the extracted TCP segment from the network; and The method further includes the step of measuring the TCP RTT based on the ACK and setting the measured TCP RTT as the base RTT. A method characterized in that the amount of change in AP information is measured based on the TCP RTT measured from the time of receiving the ACK for the identified TCP segment and the base RTT.

6. In Paragraph 1, A method further comprising the step of setting the ratio of the number of TCP packets on the network and the TCP throughput measured within the AP as base information based on the time at which the first congestion information is identified.

7. In Paragraph 6, A method characterized in that the above AP information change amount is measured based on the ratio of the number of TCP packets on the network and the TCP throughput measured from the time when the above first congestion information is identified, and the above base information.

8. In a method of operation of an Application Processor (AP) within a terminal in a wireless communication system, A step of receiving first congestion information measured at the CP from the CP (Communication Processor); A step of measuring the amount of change in AP information within the above AP; A step of obtaining second congestion information in which compensation for the first congestion information is performed based on the first congestion information and the amount of change in the AP information; A step of calculating the probability of marking an Explicit Congestion Notification (ECN) using the second congestion information above; and A method comprising the step of setting an ECN bit in a packet to be transmitted according to the above ECN marking probability.

9. In a terminal of a wireless communication system, Transmitter / receiver; and It includes at least one processor coupled to the above-mentioned transmitting and receiving unit, and The above-mentioned at least one processor is, Identifying the first congestion information measured by the CP (Communication Processor), and Measure the amount of change in AP (Application Processor) information, and Based on the first congestion information and the change amount of the AP information, second congestion information is obtained in which compensation for the first congestion information is performed, and Using the above second congestion information, calculate the probability of marking an ECN (Explicit Congestion Notification), and A terminal that sets an ECN bit in a packet to be transmitted according to the above ECN marking probability.

10. In Paragraph 9, A terminal characterized in that the amount of change in the AP information is the amount of change in the TCP (Transmission Control Protocol) RTT (Round Trip Time) measured within the AP from the time when the first congestion information is identified.

11. In Paragraph 9, A terminal characterized in that the above AP information change amount is the change amount of the ratio of the number of TCP packets on the network and the TCP throughput measured within the AP from the time when the above first congestion information is identified.

12. In Paragraph 9, The above-mentioned at least one processor is, Identify the TCP segment extracted from the above CP, and Receive an ACK (Acknowledgment) for the identified TCP segment from the network, and Measuring the TCP RTT based on the above ACK, and setting the measured TCP RTT as the base RTT, A terminal characterized in that the amount of change in AP information is measured based on the TCP RTT measured from the time of receiving the ACK for the identified TCP segment and the base RTT.

13. In Paragraph 9, The above-mentioned at least one processor is, Based on the time when the above first congestion information is identified, a TCP segment is extracted, and Receive an ACK for the extracted TCP segment from the network, and The method involves measuring the TCP RTT based on the above ACK and setting the measured TCP RTT as the base RTT. A terminal characterized in that the amount of change in AP information is measured based on the TCP RTT measured from the time of receiving the ACK for the identified TCP segment and the base RTT.

14. In Paragraph 11, The above-mentioned at least one processor is, Based on the time when the above-mentioned first congestion information is identified, the ratio of the number of TCP packets on the network and the TCP throughput measured within the AP is set as base information. A terminal characterized in that the above AP information change amount is measured based on the ratio of the number of TCP packets on the network and the TCP throughput measured from the time when the above first congestion information is identified, and the above base information.

15. In an Application Processor (AP) within a terminal in a wireless communication system, From the CP (Communication Processor), first congestion information measured by the CP is received, and Measure the amount of change in AP information within the above AP, and Based on the first congestion information and the change amount of the AP information, second congestion information is obtained in which compensation for the first congestion information is performed, and Using the above second congestion information, calculate the probability of marking an ECN (Explicit Congestion Notification), and AP comprising the step of setting an ECN bit in a packet to be transmitted according to the above ECN marking probability.

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