TCP ACK Flow Control Using Adaptive Credit Allocation

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Solution Overview

Problem

There is a need for improved management of Transmission Control Protocol (TCP) acknowledgement (ACK) transmissions in wireless communication systems, particularly in 5G New Radio (NR), to enhance performance and efficiency.

Innovation Solution

Implementing a data flow control mechanism in user equipment (UE) to manage TCP ACK transmissions by determining the amount of data in the memory buffer and generating a data flow control command to ensure sufficient credit for data transmission, thereby optimizing data flow between the host processor and modem.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If TCP ACK transmissions are managed using conventional flow control mechanisms, then data transmission occurs, but latency increases and transmission efficiency decreases due to insufficient credit availability

Engineering Contradiction:
ImprovelatencyVSAvoidtransmission efficiency
Core Design Contradiction:
Loss of timeVSProductivity

Solution Approach 1:

The patent applies preliminary action by proactively monitoring buffer space availability before TCP ACK transmissions are blocked. The system predicts future buffer availability and issues flow control credits in advance, allowing the host processor to prepare and queue ACK packets before actual transmission opportunities arise. This prevents latency spikes caused by waiting for buffer availability while maintaining efficient throughput.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms by continuously monitoring modem buffer status and dynamically adjusting flow control credit allocation. The system uses real-time buffer occupancy information to modulate credit issuance rates, creating a closed-loop control system that adapts to varying traffic conditions. This feedback ensures optimal balance between preventing buffer overflow and maintaining continuous ACK transmission.

Inventive Principle:
Principle #23Feedback

2Productivity

If flow control credits are generously allocated to ensure continuous transmission, then transmission efficiency improves, but buffer overflow risk increases causing data loss

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidbuffer overflow prevention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies dynamics by making flow control credit allocation adaptive rather than static. The system dynamically adjusts credit issuance based on real-time buffer occupancy levels, traffic patterns, and predicted drain rates. When buffer space is abundant, credits are issued more freely to maximize throughput; when buffer levels rise, credit issuance is automatically curtailed to prevent overflow. This dynamic adjustment resolves the contradiction between maintaining high efficiency and ensuring reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of credit allocation from fixed to variable based on buffer conditions. By monitoring buffer occupancy thresholds and adjusting credit quantum sizes accordingly, the system optimizes the balance between transmission efficiency and overflow prevention. The credit allocation parameters are modified in response to changing system states, allowing flexible adaptation to different operational conditions.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If buffer space is strictly monitored and credits issued only when threshold is met, then buffer overflow is prevented, but transmission latency increases due to waiting for threshold conditions

Engineering Contradiction:
Improvebuffer overflow preventionVSAvoidtransmission latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent resolves this contradiction by performing preliminary monitoring and prediction of buffer conditions. Rather than waiting for strict threshold conditions before issuing credits, the system predicts future buffer availability based on current drain rates and traffic patterns. This allows credits to be issued proactively before thresholds are actually met, reducing latency while maintaining overflow prevention through conservative prediction margins.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4189883B1Systems and methods for managing transmission control protocl (TCP) acknowledgement (ACK) transmissions
Publication Date: 2026.04.08 QUALCOMM INC
  • EP4189883B1 patent drawingFigure 1
  • EP4189883B1 patent drawingFigure 2A~2D
  • EP4189883B1 patent drawingFigure 3

AI summary

Some aspects of the present disclosure disclose methods and systems for managing transmission control protocol (TCP) acknowledgements (ACK) transmissions from a host or application processor to a modem of a user equipment. The UE may detect availability of buffer space in a memory buffer of a modem of the UE. Further, the UE may also detect that a host processor of the UE lacks credit sufficient for transmitting data from the host processor to the modem. The UE may then generate and transmit to the host processor a data flow control (DFC) command including credit sufficient for the host processor to transmit at least a portion of the data to the modem. In some instances, in response to the transmission of the DFC command, the at least the portion of the data may be received at the modem from the host processor.