PDU Discard Reporting for ARQ Window Stall Prevention

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In wireless communication systems, particularly 5G NR, PDU discards due to missed deadlines or outdated PDUs can lead to delays in transmitter and receiver ARQ windows, affecting communication reliability.

Innovation Solution

Implementing a method for wireless devices to detect PDUs meeting discard criteria and transmit discard status reports, or indicate sequence number gaps based on PDCP discard timers, to update sliding windows and enhance communication reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PDU discard criteria are implemented to remove outdated PDUs, then communication reliability is improved, but transmission delays occur due to ARQ window stalls

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidtransmission delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The transmitter proactively sends a discard status report indicating which PDUs have been discarded before the receiver's ARQ window stalls. This preliminary notification allows the receiver to advance its ARQ window in advance, preventing transmission delays while maintaining reliability through selective PDU discard.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A feedback mechanism is implemented where the transmitter informs the receiver about discarded PDUs through discard status reports. This feedback loop enables the receiver to adjust its ARQ window accordingly, resolving the contradiction between maintaining reliability through discard and avoiding transmission delays.

Inventive Principle:

Principle #23Feedback

2Productivity

If discard status reports are transmitted to notify PDU discards, then ARQ window advancement is improved, but signaling overhead increases

Engineering Contradiction:

ImproveARQ window advancement efficiencyVSAvoidsignaling overhead

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The discard status report is merged with existing status report structures in the protocol. By combining discard indication with regular status reporting mechanisms, the patent reduces signaling overhead while still providing necessary ARQ window advancement information to the receiver.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The discard status information is extracted as a specific indicator within the status report framework. Rather than creating entirely separate signaling messages, the patent extracts discard information as a component of existing status reports, minimizing additional overhead while improving ARQ window management.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS20260058913A1PDU discard indication in layer-two procedures

Publication Date: 2026.02.26 QUALCOMM INC

AI summary

A method of wireless communication at a first wireless device is disclosed herein. The method includes communicating a plurality of PDUs associated with a DRB with a second wireless device. The method includes detecting that at least one PDU in the plurality of PDUs associated with the DRB meets at least one discard criteria. The method includes transmitting, for the second wireless device, a discard status report associated with the at least one PDU meeting the at least one discard criteria.