KR-20260064122-A - BASE STATION TRANSMISSION LAYER DELAY REDUCTION CONTROL DEVICE AND METHOD

Abstract

The present invention controls the base station to set the target BLER low to reduce delay caused by retransmission when the transmission layer of the base station is in the slow start phase of the slow start algorithm, and controls the base station to operate in a mode where the base station pre-allocates uplink resources to reduce non-congestion delay.

Inventors

• 박세웅
• 이굳솔
• 이진명

Assignees

• 서울대학교산학협력단

Dates

Publication Date

20260507

Application Date

20241031

Claims (6)

1. A method performed in a computing device comprising one or more processors and memory storing a set of program instructions executable by said processors, A flow information receiving step of receiving flow information from a base station, including the amount of downlink direction data entering the base station, the size of the transport layer congestion window (CWND), the state of the transmit buffer, and the acknowledgment rate (ACK rate); A slow start determination step that determines whether the base station transport layer is in a slow start operation state on a slow start algorithm based on received flow information; A first control message transmission step in which, if the base station transport layer is in a slow start operation state, a target BLER is determined according to the amount of data of flow information, and a first control message is transmitted so that the base station can set the base station's transport layer to the corresponding target BLER; A base station transmission layer delay reduction control method including
2. In Article 1, A second control message transmission step in which, if the base station transport layer is determined to be in a slow start operation state and the acknowledgment response rate of flow information is smaller than a set value, a second control message is transmitted so that the base station can pre-allocate uplink resources; A base station transmission layer delay reduction control method further comprising
3. In Article 1, A third control message transmission step in which the base station transport layer is determined to be in a congestion avoidance operation state, but if the congestion status is determined based on the bandwidth estimated according to the amount of data in flow information and the state of the transmission buffer, and if it is determined to be in a non-congested state, the base station transmits a third control message to cause the base station to transition the base station transport layer to a slow start operation state; A base station transmission layer delay reduction control method further comprising
4. A flow information receiving unit that receives flow information from a base station, including the amount of downlink data entering the base station, the size of the transport layer congestion window (CWND), the state of the transmit buffer, and the acknowledgment rate (ACK rate); A congestion control state determination unit that determines whether the base station transmission layer is in a slow start operation state on a slow start algorithm based on received flow information; A non-congestion delay control unit that, when the base station transport layer is in a slow start operation state, determines a target BLER based on the amount of data in the flow information and then transmits a first control message so that the base station can set the base station's transport layer to the corresponding target BLER; A base station transport layer delay reduction control device including
5. In Article 4, The non-congestion delay control unit transmits a second control message to enable the base station to pre-allocate uplink resources when the base station transport layer is determined to be in a slow start operation state and the acknowledgment response rate of flow information is smaller than a set value. Base station transport layer delay reduction control device.
6. In Article 4, The non-congestion delay control unit determines whether the base station transport layer is in a congestion avoidance operation state based on the bandwidth estimated according to the amount of data in flow information and the state of the transmission buffer, and if it is determined to be in a non-congestion state, transmits a third control message to cause the base station to transition the base station's transport layer to a slow start operation state. Base station transport layer delay reduction control device.

Description

Base Station Transmission Layer Delay Reduction Control Device and Method The present invention relates to wireless communication technology, and more specifically, to a technology for controlling a congestion control algorithm to operate efficiently at the base station transmission layer. In 5G communication, high bandwidth is provided to enable low-latency applications, such as web loading, to achieve low-latency performance. In 5G communication, the slow start algorithm is applied and used as a congestion control algorithm in the transport layer. The slow start algorithm rapidly increases the congestion window size initially to a size adaptively set based on wireless channel conditions when a session is established, and then slowly increases the congestion window size once that size is reached to avoid congestion. However, in the case of 5G communication, there is a problem where the congestion control state is reached before the congestion window size increases sufficiently to match the bandwidth due to non-congestion delays such as retransmission delay and uplink scheduling delay, and the congestion window size is slowly increased. As a result, even though high bandwidth is provided, queuing delay occurs due to the insufficient size of the congestion window, making it impossible to achieve a low latency level. Figure 1 illustrates an exemplary slow start operation performed at the base station transport layer. Figure 2 illustrates an example of entering the congestion avoidance phase from the slow start phase due to an increase in RTT in a 5G wireless network. Figure 3 is a flowchart of the base station transmission layer delay reduction control method of the present invention. Figure 4 illustrates the difference in RTT according to the target BLER setting. Figure 5 illustrates the difference in RTT according to the uplink scheduling method. FIG. 6 is a block diagram of the base station transmission layer delay device of the present invention. FIG. 7 conceptually illustrates the operation of the base station transmission layer delay device of the present invention. The foregoing and additional aspects are embodied in the embodiments described with reference to the attached drawings. It is understood that the components of each embodiment may be combined in various ways within the embodiment unless otherwise stated or contradictory. Each block in the block diagram may represent a physical part in some cases, but in others, it may be a logical representation of a part of the function of a single physical part or a function spanning multiple physical parts. Sometimes, the entity of a block or part thereof may be a set of program instructions. These blocks may be implemented in whole or in part by hardware, software, or a combination thereof. In this specification, "base station" refers to a base station of a mobile communication system that provides various communication services, such as voice, packet data, etc., in particular, in a wireless network. A base station is a device that communicates with devices and encompasses Node-B, eNB, gNB, etc. The term "device" is a comprehensive concept meaning a User Equipment (UE) in a mobile communication system, and includes UEs in WCDMA, LTE, 5G, Machine Type Communication (MTC) devices, Mobile Stations (MS) and User Terminals (UT) in GSM. In this specification, the terms "resource" and "resource" are used interchangeably. Figure 1 illustrates an exemplary slow start operation performed at the base station transport layer. Congestion control is a technique for resolving network congestion caused by the difference between the data transmission speed of a transmitting device and the processing speed of the network; generally, a congestion window utilizing a sliding window method is established and used. Since the congestion window (CWND) is not moved during data transmission, packets that have already been transmitted but have not received an ACK, as well as transmittable packets that have not yet been transmitted, may exist within the CWND. If the CWND is filled with packets that have not received an ACK, data transmission becomes impossible. Congestion control algorithms adjust the size of the congestion window, and the slow start algorithm is a representative example. The slow start algorithm consists of a slow start phase, a congestion control phase, and a fast recovery phase. Figure 1 illustrates, by way of example, that when a TCP session is created or a Retransmission Timeout (RTO) occurs, the Congestion Window (CWND) starts at size 1 and increases during the Slow Start phase and the Congestion Avoidance phase. During the Slow Start phase, the Congestion Window (CWND) increases by 1 each time an ACK is received for a packet transmitted during the Round Trip Time (RTT). Therefore, when ACKs are received for all packets transmitted during the Round Trip Time (RTT), that is, for all packets transmitted up to the size of the Congestion Window (CWND), the size of