DRX Retransmission Timer Management for Wireless Packet Loss

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Solution Overview

Problem

In wireless communication systems, particularly in LTE, user equipment (UE) experiences packet loss due to the single DRX retransmission timer managing multiple DL HARQ processes, leading to missed retransmission packets during discontinuous reception.

Innovation Solution

The method involves separately managing retransmission reception timings for each DL HARQ process by assigning a distinct DRX retransmission timer for each process, ensuring that other processes do not stop waiting for their retransmission packets even if one process receives a retransmission, thereby preventing packet loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single DRX retransmission timer is used to manage multiple DL HARQ processes, then device complexity is reduced, but packet loss occurs due to timer conflicts between processes

Engineering Contradiction:
Improvetimer management complexityVSAvoidretransmission packet reception reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent divides the single shared DRX retransmission timer into multiple separate timers, with each timer dedicated to a specific DL HARQ process. This segmentation eliminates timer conflicts between different HARQ processes, ensuring that each process can independently manage its retransmission timing without interfering with others, thereby preventing packet loss while maintaining manageable complexity through systematic organization

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the DRX retransmission timer is restarted for each detected packet, then retransmission detection timing is simplified, but retransmission packets are missed when multiple processes share the same timer

Engineering Contradiction:
Improveretransmission detection timing managementVSAvoidretransmission packet reception reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

By assigning dedicated timers to each HARQ process, the system maintains the simplicity of restarting a timer upon packet detection while eliminating the harmful side effect of timer conflicts. Each process's timer operates independently, ensuring that restarting a timer for one process does not affect the timing of other processes, thus preserving both ease of operation and reliability

Inventive Principle:
Principle #1Segmentation

3Use of energy by moving object

If UE enters standby mode after receiving one retransmission packet, then energy consumption is reduced, but other pending retransmission packets are missed

Engineering Contradiction:
ImproveUE energy consumption during DRXVSAvoidcomplete retransmission packet reception
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent enables the UE to enter standby mode more aggressively by using separate timers for each HARQ process. Since each timer independently tracks its own process's retransmission timing, the UE can confidently enter standby when one timer expires without fearing that other processes will miss their retransmissions. This segmentation thus reduces energy consumption while maintaining complete packet reception reliability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses independent timer feedback for each HARQ process to determine when the UE can safely enter standby mode. Each timer provides feedback about its specific process's timing status, allowing the UE to make informed decisions about when to wake up and when to remain in standby, optimizing energy consumption while ensuring no packets are missed

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2068484B1Method and apparatus for improving discontinuous reception for a wireless communication system
Publication Date: 2016.05.04 INNOVATIVE SONIC LTD
  • EP2068484B1 patent drawingFigure 1
  • EP2068484B1 patent drawingFigure 2
  • EP2068484B1 patent drawingFigure 3

AI summary

A method for improving discontinuous reception for a user equipment of a wireless communication system includes separately managing retransmission reception time limits of a plurality of downlink hybrid automatic repeat request, hereinafter called DL HARQ, processes when the discontinuous reception is used in the plurality of DL HARQ processes.