Multi-Hop Content Distribution With Feedback-Based Block Forwarding

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Solution Overview

Problem

In multi-hop networks, the use of erasure correction codes for content distribution leads to inefficiencies due to increased packet collisions, power consumption, and retransmissions when reception stations cannot directly communicate with the transmission station, necessitating data transfers that increase packet numbers.

Innovation Solution

A content distribution system that employs erasure correction coding, where each distribution apparatus transmits selected encoded and redundant blocks with identifiers, and only transmits additional blocks based on reception responses indicating successful receptions, reducing unnecessary transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all reception stations transfer received data in multi-hop networks, then content distribution reaches distant nodes, but packet collisions increase and communication efficiency deteriorates

Engineering Contradiction:

Improvecontent distribution reachVSAvoidcommunication efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements selective data transfer where only specific reception stations that have successfully decoded the content or possess critical intermediate data transfer the encoded blocks to the next hop. This local differentiation based on decoding success and position optimizes the network by avoiding redundant transmissions from all nodes, thereby reducing packet collisions while maintaining distribution reach.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent performs preliminary decoding attempts at each reception station before forwarding data. Stations that successfully decode the content identify themselves and do not forward, while those that fail but have useful intermediate data are selected to forward. This preliminary action prevents unnecessary transmissions and reduces packet collisions in the network.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If erasure correction coding is applied to ensure reliable content distribution, then data loss is corrected, but the number of packets increases leading to more collisions

Engineering Contradiction:

Improvedata loss correctionVSAvoidpacket collisions

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies erasure correction coding but only transmits a subset of the encoded blocks rather than all of them. Reception stations attempt decoding with the received subset, and only request or forward additional blocks if necessary. This partial action approach maintains the reliability benefits of erasure correction while reducing the total packet count and associated collisions.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent implements feedback mechanisms where reception stations inform transmission stations about their decoding status and which encoded blocks they have successfully received. This feedback allows the system to adaptively transmit only the necessary additional blocks, avoiding unnecessary transmissions that would increase packet collisions while still achieving reliable content distribution.

Inventive Principle:

Principle #23Feedback

3Reliability

If reception stations transfer data to next hop stations, then multi-hop content distribution is enabled, but electric power consumption increases

Engineering Contradiction:

Improvemulti-hop distribution capabilityVSAvoidelectric power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent enables reception stations to autonomously determine whether they should forward data based on their decoding status and network position. Stations that successfully decode the content self-identify as complete and do not forward, while those needing to forward do so autonomously without requiring continuous control signaling, reducing energy consumption.

Inventive Principle:

Principle #25Self-service

Data Source

PatentEP4683257A1Content distribution system, content distribution method, and content distribution program

Publication Date: 2026.01.21 MITSUBISHI ELECTRIC CORP

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AI summary

A subject distribution apparatus, which is a content distribution apparatus, includes a transmission unit (121). The transmission unit (121) transmits K2 pieces of blocks selected from among K1 pieces of encoded blocks (132) and M pieces of redundant data blocks (133) based on erasure correction coding, together with a transmission source identifier, as wireless signals. Further, when a destination identifier indicated in a reception response received from each content distribution apparatus is consistent with an apparatus identifier of the subject distribution apparatus, the transmission unit (121) transmits K2-Rmin pieces of blocks selected from among blocks that have not been transmitted among the K1 pieces of encoded blocks (132) and the M pieces of redundant data blocks (133), as wireless signals, where the relatively small number of blocks among the number of blocks that have succeeded to be received as indicated in each received reception response is denoted as Rmin.