Multicast Acknowledgment Method for Wireless Multi-Hop Networks

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Solution Overview

Problem

In wireless multi-hop networks, existing methods for acknowledging receipt of broadcast or multicast communications often lead to network overload and prolonged reaction times, especially when using flooding, as all network participants send acknowledgments simultaneously, causing collisions and delays.

Innovation Solution

The method involves repeatedly sending the communication only to network participants that have not acknowledged receipt, with each iteration step using a data structure to track acknowledged participants and setting a shorter expiry time to reduce network load and increase acknowledgment efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all network participants send acknowledgments simultaneously after receiving a broadcast or multicast communication, then the originating network subscriber can confirm receipt from all participants, but network overload and collisions occur leading to prolonged reaction times

Engineering Contradiction:
Improveconfirmation of receipt from all participantsVSAvoidreaction time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the acknowledgment process into multiple rounds. In each round, only a subset of participants (those who have not yet acknowledged) send acknowledgments. This is achieved by maintaining a list of unacknowledged participants and processing them in batches, thereby avoiding simultaneous transmissions from all participants and reducing network collisions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements periodic acknowledgment rounds with defined intervals. Between rounds, the system waits for a specified duration to allow acknowledgments to be transmitted and received. This periodic structure prevents continuous network traffic and allows the network to recover from congestion between rounds.

Inventive Principle:
Principle #19Periodic action

2Object-affected harmful factors

If random delay times are used for acknowledgment transmission, then collision resolution is improved, but the reaction time becomes too long for practical use in networks with many participants

Engineering Contradiction:
Improvecollision resolutionVSAvoidreaction time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

Instead of using long random delays for all participants, the patent segments participants into groups and assigns shorter, structured delay intervals between groups. Each group transmits acknowledgments in sequence with controlled timing, reducing overall reaction time while maintaining collision avoidance through the segmented structure.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the originating network subscriber waits for all acknowledgments before considering transmission successful, then reliable delivery is ensured, but network overload occurs especially in large networks

Engineering Contradiction:
Improvesuccessful transmission confirmationVSAvoidnetwork load
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies partial action by processing acknowledgments in rounds rather than requiring all acknowledgments to be received simultaneously. In each round, a portion of the remaining unacknowledged participants are processed. This partial processing approach reduces the instantaneous network load while still ensuring eventual reliable delivery through multiple rounds.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system uses periodic acknowledgment collection rounds with defined waiting periods between rounds. This periodic approach spreads the acknowledgment processing over time, preventing network overload that would occur if all acknowledgments were expected simultaneously, while still ensuring reliable delivery through repeated rounds.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3176971B1Method for transmitting reception confirmations in broad or multicast communication
Publication Date: 2021.02.24 INSTA ELEKTRO GMBH
  • EP3176971B1 patent drawingFigure 1
  • EP3176971B1 patent drawingFigure 2
  • EP3176971B1 patent drawingFigure 3

AI summary

This document describes a method for transmitting acknowledgments of receipt in a broadcast or multicast communication within a multi-hop network, particularly a wireless one. In this method, each network participant sends an acknowledgment after a randomly chosen delay. A key feature of this method is that the originating network participant sending the broadcast or multicast communication retransmits the communication in at least one iteration step, with a time interval after the initial transmission, if the originating network participant (TU) has not yet received acknowledgments of receipt from all designated network participants (T1-T7) within a specified timeframe.