AM RLC Timer Consolidation for ARQ Status Report Triggering

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Solution Overview

Problem

The existing scheme for triggering status reports by an Acknowledged Mode Radio Link Control (AM RLC) entity in wireless communication systems requires setting a timer for each missing RLC PDU, leading to inefficient use of radio resources and potential false NACK reports due to multiple timers and retransmissions.

Innovation Solution

A method where only one timer is activated at a time for detecting gaps in RLC PDU serial numbers, with new timers set only if gaps are detected after the initial timer has expired, reducing the number of timers and messages needed for status reports.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a timer is set for every RLC PDU corresponding to the SN at the gap, then the receiver can accurately detect missing PDUs and trigger status reports, but the number of timers and messages increases, occupying much radio resources and leading to low efficiency

Engineering Contradiction:
Improveaccuracy of missing PDU detectionVSAvoidnumber of timers and messages
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple individual timers (one for each missing PDU) into a single unified timer that tracks the oldest missing PDU. This consolidation reduces the number of timers from multiple to one, thereby reducing radio resource occupation and improving efficiency while maintaining accurate detection of missing PDUs through the single timer's expiration event.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple timers are set for every RLC PDU, then status reports can be triggered accurately, but the radio resources are occupied and efficiency is reduced

Engineering Contradiction:
Improvestatus report accuracyVSAvoidradio resource efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent combines multiple timer functions into a single timer that manages the status report triggering for all missing PDUs. This single timer expires when the oldest missing PDU should have been received, triggering a unified status report that covers all missing PDUs, thereby maintaining accuracy while significantly improving radio resource efficiency.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If timers are set for every RLC PDU, then false NACK reports can be avoided, but the system complexity and resource consumption increase

Engineering Contradiction:
Improveavoidance of false NACK reportsVSAvoidtimer management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple timer instances into a single timer that tracks the oldest missing PDU. This single timer approach maintains the ability to avoid false NACK reports by waiting for the timer expiration to confirm missing PDUs, while dramatically reducing timer management complexity from multiple independent timers to one unified timer.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2175582B2A method for triggering status report of automatic repeat request
Publication Date: 2017.01.25 ZTE CORP
  • EP2175582B2 patent drawingFigure 1
  • EP2175582B2 patent drawingFigure 2

AI summary

The present invention discloses a method for triggering a status report of automatic repeat request. When a receiver acknowledged mode radio link control entity detects that received radio link control layer PDUs are missing, a timer T1 is set. When the timer T1 is running, new timer is not set even if a new missing radio link control layer PDU is detected. When the timer T1 is running, if the receiver acknowledged mode radio link control entity has received all missing radio link control layer PDUs which are detected before setting T1, the timer T1 is stopped. When the timer T1 times out, the receiver acknowledged mode radio link control entity triggers the status report. The method of the present invention effectively decreases the number of timers used for triggering the status report of receiver AM RLC entity ARQ, the number of messages used for feeding back the status reports and the number of message packets. And the method also could improve the efficiency and the system performance of wireless resource.