Dynamic Timeout Control for Wireless Packet Retransmission

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Solution Overview

Problem

In wireless communications networks, especially those with virtualized environments, the traditional timeout mechanisms for data packet transmissions are prone to generating unnecessary timeouts due to the store and forward mechanism, leading to incorrect bandwidth adjustments and slow retransmissions.

Innovation Solution

A method to dynamically control the timeout value of the retransmission timer by observing the round-trip time (RTT) and adjusting it based on available RTT measurements, including increasing the timeout value when necessary to avoid unnecessary timeouts and decreasing it to prevent slow retransmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the timeout value is set to a small value to enable fast retransmission, then retransmission speed is improved, but unnecessary timeouts occur due to store and forward mechanism delays

Engineering Contradiction:

Improveretransmission speedVSAvoidtimeout accuracy

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent implements dynamic adjustment of the timeout value based on observed RTT measurements. Instead of using a fixed timeout value, the system continuously adapts the timeout parameter according to actual network conditions and measured RTT values, allowing it to respond to varying network latency caused by store and forward operations while maintaining fast retransmission when appropriate

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent performs preliminary RTT measurements and observations before finalizing the timeout value setting. By pre-observing RTT behavior and patterns in the virtualized network environment, the system can establish an appropriate baseline timeout value that accounts for expected store and forward delays, preventing unnecessary timeouts before they occur

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the timeout value is increased to avoid unnecessary timeouts, then timeout accuracy is improved, but retransmission delay increases when packets are actually lost

Engineering Contradiction:

Improvetimeout accuracyVSAvoidretransmission delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system dynamically adjusts the timeout value based on observed RTT measurements and network conditions. When RTT measurements indicate stable, low latency, the timeout value is reduced to enable fast retransmission. When RTT variability increases or store and forward delays are detected, the timeout value is increased to prevent unnecessary timeouts, thus optimizing both responsiveness and accuracy

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the timeout parameter based on observed network behavior and RTT measurements. By monitoring RTT patterns and adjusting the timeout parameter accordingly, the system can maintain high timeout accuracy while minimizing retransmission delays, adapting to the specific characteristics of virtualized network environments

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If traditional timeout mechanisms are used in virtualized networks, then implementation simplicity is maintained, but unnecessary bandwidth reduction occurs due to false timeout detection

Engineering Contradiction:

Improvetimeout mechanism complexityVSAvoidbandwidth utilization

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent implements a feedback mechanism where RTT measurements are continuously observed and fed back to adjust the timeout value. This feedback loop allows the system to distinguish between genuine packet loss and delays caused by store and forward operations, preventing false timeout detection and unnecessary bandwidth reduction while maintaining reasonable implementation complexity

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces the traditional fixed-threshold timeout mechanism with an adaptive system based on RTT measurement and observation. Instead of using a static timeout value that causes false positives in virtualized environments, the system substitutes a dynamic, measurement-based approach that accurately distinguishes between real packet loss and virtualization-induced delays

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11785499B2Controlling timeout events for data packet transmissions

Publication Date: 2023.10.10 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

The present disclosure relates to a method of controlling a timeout event for a data packet transmission in a wireless communications network, and a node performing the method. In an aspect, a method of controlling a timeout event for a data packet transmission in a wireless communications network is provided, wherein a data packet retransmission timer initially is set to a timeout value indicating the maximum allowed round-trip time (RTT) for the data packet transmission and a timeout event occurs upon the retransmission timer expiring. The method includes observing the RTT for the data packet transmission over a connection in the network, increasing, upon the retransmission timer expiring before a measured value is available for the observed RTT, the timeout value for the retransmission timer, and determining whether a currently set timeout value for the retransmission timer is to be decreased or not.