UE Flow Control Feedback for Split Bearer Overhead

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Solution Overview

Problem

Current flow control mechanisms for LTE-WLAN split-bearer operation face inefficiencies, particularly in providing timely and efficient feedback to ensure reordered data delivery, due to high overhead in existing PDCP status reporting methods, which are not feasible for frequent updates required in dual connectivity scenarios.

Innovation Solution

A method for UE-based flow-control feedback that includes a PDCP-level reporting format with a reduced overhead, using a Count value format comprising a hyper frame number and PDCP sequence number, and triggers for report creation based on changes in received PDU counts, allowing efficient control of downlink data flow and packet reordering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PDCP status reporting is used for flow control feedback, then data delivery reliability is improved, but reporting overhead increases significantly

Engineering Contradiction:
Improvedata delivery reliabilityVSAvoidreporting overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential flow control information (highest received Count value and optionally missing PDCP PDUs) from the complete PDCP status report, transmitting only this critical subset to the network side. This selective extraction maintains data delivery reliability by providing necessary feedback while dramatically reducing the reporting overhead by eliminating redundant status information.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements partial reporting by transmitting only the most critical flow control parameters (highest received Count value) rather than complete PDCP status information. This partial action approach provides sufficient feedback for the network to adjust downlink data flow while keeping the reporting overhead minimal, avoiding the excessive overhead of full status reporting.

Inventive Principle:
Principle #16Partial or excessive action

2Productivity

If frequent flow control feedback is provided, then data flow control efficiency is improved, but signaling overhead increases

Engineering Contradiction:
Improvedata flow control efficiencyVSAvoidsignaling overhead
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent transmits only the essential highest received Count value and optionally missing PDCP PDU information, providing partial but sufficient feedback for flow control. This allows frequent updates to be sent with minimal signaling overhead, maintaining data flow control efficiency while avoiding excessive signaling burden.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The flow control feedback is segmented into essential components only (highest received Count value, optionally missing PDCP PDUs) rather than transmitting complete PDCP status reports. This segmentation enables frequent feedback transmissions with reduced signaling overhead by including only the critical segments necessary for flow control decisions.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If complete PDCP status reports are transmitted, then packet reordering accuracy is improved, but feedback latency increases

Engineering Contradiction:
Improvepacket reordering accuracyVSAvoidfeedback latency
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the critical highest received Count value and optionally missing PDCP PDU information from complete PDCP status reports. This extraction provides sufficient information for accurate packet reordering at the network side while reducing feedback transmission time, thereby maintaining reordering accuracy while minimizing feedback latency.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3372008B1Flow control feedback from user equipment receiving a split bearer
Publication Date: 2023.01.11 NOKIA TECHNOLOGIES OY
  • EP3372008B1 patent drawingFigure 1~2
  • EP3372008B1 patent drawingFigure 3
  • EP3372008B1 patent drawingFigure 4~5

AI summary

In accordance with the example embodiments of the invention there is at least an apparatus and method to perform triggering creation of a flow control report comprising information of at least one of a highest count value of protocol data units received over a particular wireless link and protocol data units not received so far, wherein the protocol data units not received so far are limited to protocol data units with count values falling within a range of count values determined using preconfigured rules; and communicating the flow control report between a user equipment and a base station.