Mesh Network Relay Node Latency Reduction

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Solution Overview

Problem

Existing mesh network message relay systems suffer from high latency due to path metrics that do not consider processing time or dynamic changes in wireless communication environments, leading to inefficient path establishment and potential retransmissions.

Innovation Solution

A method in a relay node where a timer is started upon receiving a message, and if no other node in the subset transmits it within the timer's waiting time, the relay node alters the message header to transmit it, ensuring that the node closest to the destination initiates transmission first, thereby minimizing latency and avoiding unnecessary retransmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional path metrics (e.g., Airtime Link Metric) are used to establish optimal paths, then radio resource utilization is optimized, but processing time and latency are not considered leading to high overall latency

Engineering Contradiction:
Improveradio resource utilizationVSAvoidmessage relay latency
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent introduces dynamic timer values that adapt based on node characteristics and network conditions. Each relay node calculates a specific timer value considering its processing capabilities and position in the network, allowing the system to dynamically optimize for both resource utilization and latency reduction rather than using static path metrics

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the optimization parameter from purely radio resource-based metrics to a composite metric that includes processing time and latency considerations. By modifying the timer value parameter based on node-specific factors, the system achieves better overall performance by balancing resource usage with speed of delivery

Inventive Principle:
Principle #35Parameter changes

2Speed

If multiple nodes in a subset transmit the same message simultaneously, then message delivery may be faster, but collisions and retransmissions occur increasing overall latency

Engineering Contradiction:
Improvemessage delivery speedVSAvoidmessage transmission reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent implements a preliminary timing mechanism where relay nodes calculate and set specific timer values before actual message transmission. This preliminary action of scheduling transmissions at different times based on pre-calculated timers prevents collisions while maintaining efficient parallel processing, ensuring reliable delivery without sacrificing speed

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The timer mechanism acts as an intermediary that coordinates between multiple relay nodes. By introducing this timing mediator, the system allows multiple nodes to process and forward messages efficiently while the timer ensures they do so at staggered intervals, preventing collisions and retransmissions

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of time

If relay nodes immediately transmit received messages, then processing delay is minimized, but nodes farther from destination may transmit before closer nodes causing inefficiency

Engineering Contradiction:
Improveprocessing delayVSAvoidmessage relay efficiency
Core Design Contradiction:
Loss of timeVSProductivity

Solution Approach 1:

The patent applies local quality by assigning different timer values to different relay nodes based on their specific characteristics and positions in the network. Nodes closer to the destination receive shorter timer values, while nodes farther away receive longer timer values. This localized differentiation ensures that processing delay is minimized for each node while maintaining overall relay efficiency

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces asymmetry in the timer values assigned to different relay nodes. Instead of uniform timing, the system creates an asymmetric timing structure where each node's timer reflects its distance from the destination and its processing capabilities. This asymmetric approach ensures optimal message flow where closer nodes transmit first, improving overall efficiency without excessive processing delay

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3311535B1Reducing latency in a mesh network
Publication Date: 2019.10.02 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3311535B1 patent drawingFigure 1a~1b
  • EP3311535B1 patent drawingFigure 2~3
  • EP3311535B1 patent drawingFigure 4

AI summary

A message (300) that has been transmitted in a mesh network from a source node (102) and intended for reception by a destination node (104) is received by a relay node (125) and also received by a number of other nodes (121,123). A minimized latency can be obtained by the use of a timer such that the message is relayed by the relay node (125) only if no other node has already relayed the message.