Self-Reportable RLC Status PDU Segmentation Under Grant Limits

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Solution Overview

Problem

In power-limited or grant-limited conditions, wireless communication networks face challenges in transmitting complete Radio Link Control (RLC) status PDUs due to insufficient bandwidth, leading to failed error recovery procedures in RLC acknowledged mode.

Innovation Solution

Implementing mechanisms for reporting the complete status of an RLC receiving window using multiple self-reportable RLC status reports, allowing segmentation of status information across multiple PDUs to ensure accurate delivery and synchronization between transmitting and receiving devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complete RLC status PDU is transmitted in a single PDU, then error recovery accuracy is improved, but transmission reliability deteriorates under power-limited or grant-limited conditions

Engineering Contradiction:
Improveerror recovery accuracyVSAvoidtransmission reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the complete RLC status PDU into multiple partial status PDUs, each containing status information for a specific portion of the receiver buffer window. This segmentation allows the status information to be transmitted in smaller, more reliable units that can be successfully delivered even under power-limited or grant-limited conditions, while still providing complete error recovery capability when all segments are reassembled at the transmitter.

Inventive Principle:
Principle #1Segmentation

2Reliability

If status information is segmented across multiple PDUs, then transmission reliability is improved, but device complexity increases

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidprotocol processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the transmitter sends an indication to the receiver about which portion of the receiver buffer window the status report covers. This feedback loop enables the receiver to segment status information appropriately and the transmitter to reassemble the complete status by combining multiple partial status PDUs, managing the increased complexity through structured information exchange.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Each partial status PDU is designed to be self-contained with explicit indication of its coverage range within the buffer window. This self-service approach allows the receiver to independently determine which portion of the window each status report addresses, and enables the transmitter to autonomously reassemble the complete status without requiring complex coordination protocols.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If multiple partial status PDUs are transmitted, then complete status delivery is ensured, but loss of time increases due to multiple transmissions

Engineering Contradiction:
Improvestatus delivery accuracyVSAvoidtransmission time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs partial action by transmitting only the necessary portions of status information in separate PDUs rather than attempting to transmit the complete status in a single PDU. This approach accepts multiple transmissions as a trade-off to ensure that status information is successfully delivered even when channel conditions are poor, with each partial transmission having a higher probability of successful delivery.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4097889B1Self-reportable radio link control status protocol data units
Publication Date: 2025.07.23 QUALCOMM INC
  • EP4097889B1 patent drawingFigure 1
  • EP4097889B1 patent drawingFigure 2
  • EP4097889B1 patent drawingFigure 3

AI summary

Wireless communication systems and methods related to radio link control (RLC) transmissions are provided. A first wireless communication device transmits a sequence of protocol data units (PDUs). The first wireless communication device receives a first reception status report for a first portion of a receiver buffer window used for receiving the sequence of PDUs from a second wireless communication device. The first wireless communication device receives a second reception status report for a second portion of the receiver buffer window, the second portion being different from the first portion, from the second wireless communication device.