Uplink Flow Control via Modem Buffer Thresholds

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Solution Overview

Problem

Existing wireless communication systems face inefficiencies in uplink data transmission due to consistently high buffer occupancy at user equipment (UE), leading to increased memory consumption, cache inefficiencies, and packet drops, particularly in 5G NR systems.

Innovation Solution

A method and apparatus at the UE manage the flow of data by identifying uplink grants based on modem buffer size and sending data only when the grant exceeds a threshold, reducing buffer occupancy and maintaining consistent data transmission rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the UE sends uplink grant requests based on data available in the modem buffer, then the buffer occupancy remains consistently high, but this leads to increased memory consumption and cache inefficiencies

Engineering Contradiction:
Improveuplink data transmission rateVSAvoidmemory consumption
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent implements a feedback mechanism where the application processor monitors modem buffer occupancy levels and dynamically adjusts uplink grant requests accordingly. When buffer occupancy exceeds a threshold, the AP sends feedback to reduce or pause data transmission to the modem, preventing buffer overflow and reducing memory consumption while maintaining efficient uplink transmission rates.

Inventive Principle:
Principle #23Feedback

2Power

If the modem buffer is consistently highly occupied, then uplink grants are maximized, but this causes larger fluctuations in flow control and longer buffer emptying times

Engineering Contradiction:
Improveuplink grant utilizationVSAvoidbuffer emptying time
Core Design Contradiction:
PowerVSDuration of action of moving object

Solution Approach 1:

The patent employs periodic monitoring of modem buffer occupancy by the application processor, which sends flow control feedback at regular intervals or when threshold conditions are met. This periodic action prevents continuous high buffer occupancy, maintains steady uplink grant utilization, and reduces the duration buffers remain empty by proactively managing data flow before buffers become overfilled.

Inventive Principle:
Principle #19Periodic action

3Quantity of substance

If the buffers are highly occupied, then more data is available for transmission, but this increases packet drops when the UE cannot empty buffers at sufficient rate

Engineering Contradiction:
Improvedata availability in bufferVSAvoidpacket drop rate
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The application processor performs preliminary assessment of modem buffer occupancy before sending data to the modem. By checking buffer levels in advance and adjusting data transmission accordingly, the system ensures buffers maintain optimal occupancy levels, preventing packet drops while maximizing data availability for uplink transmission.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If the UE maintains high buffer occupancy, then consistent uplink transmission is achieved, but this creates cache inefficiencies at processors

Engineering Contradiction:
Improveuplink transmission consistencyVSAvoidcache management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements feedback control where the application processor monitors modem buffer occupancy and dynamically adjusts data flow to the modem. This feedback mechanism maintains consistent buffer occupancy levels that optimize uplink transmission consistency while preventing excessive buffer filling that would cause cache inefficiencies and processor complexity issues.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4723524A2System and method for flow control and acknowledgement transmission
Publication Date: 2026.04.08 QUALCOMM INC
  • EP4723524A2 patent drawingFigure 1
  • EP4723524A2 patent drawingFigure 2A~2D
  • EP4723524A2 patent drawingFigure 3

AI summary

A configuration to enable a UE to send data to a modem, from an AP, in the absence of an uplink grant from the modem. An apparatus receives data transmissions from a base station. The apparatus stores the data transmissions in a memory of the AP of the apparatus. The apparatus identifies, by the AP, an uplink grant based at least in part on a size of a modem buffer. The apparatus determines, by the application processor, whether to send data to the modem based at least in part on the identified uplink grant. The apparatus sends, by the AP, the data when the identified uplink grant exceeds a threshold.