Power Line Communication Coexistence via Zero-Crossing Synchronization

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional power line communication systems fail to maintain AV-QoS (Audio Video-Quality of Service) when multiple communication systems with different schemes coexist on the same medium, leading to interference and decreased communication speed due to unsynchronized clocks and phase differences in beacon transmission.

Innovation Solution

A communication apparatus and method that utilize a power reference point, such as the zero-crossing point of the commercial power supply, to synchronize coexistence signals and allocate transmission bands via Time Division Multiplexing (TDM), ensuring that multiple communication systems can coexist without interference by determining transmission timing based on a reference signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple communication systems with different schemes coexist on the same power line medium, then communication coverage and versatility are improved, but interference occurs and communication reliability deteriorates due to unsynchronized clocks and phase differences in beacon transmission

Engineering Contradiction:
Improvecommunication system coexistenceVSAvoidcommunication quality
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies periodic action by synchronizing beacon transmission to the zero-crossing points of the power supply voltage, which occur at regular periodic intervals. This ensures that all communication systems transmit beacons at synchronized periodic moments, eliminating phase differences and interference while maintaining the ability of multiple systems to coexist on the same power line medium.

Inventive Principle:
Principle #19Periodic action

2Device complexity

If conventional power line communication systems transmit beacons without synchronization, then device complexity is reduced, but communication speed decreases and AV-QoS cannot be maintained due to phase differences and interference

Engineering Contradiction:
Improvesynchronization mechanismVSAvoidcommunication speed
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent employs self-service by utilizing the inherently periodic zero-crossing points of the power supply voltage as the synchronization reference. Each communication system automatically aligns its beacon transmission to these naturally occurring reference points without requiring complex external synchronization mechanisms, thereby maintaining simple device architecture while achieving synchronized communication that preserves AV-QoS and communication speed.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP1933485B1Communication apparatus and coexistence method for enabling coexistence of communication systems
Publication Date: 2010.07.28 PANASONIC HOLDINGS CORP
  • EP1933485B1 patent drawingFigure 1
  • EP1933485B1 patent drawingFigure 2A~2B
  • EP1933485B1 patent drawingFigure 2C~3

AI summary

In-home communication systems (110 and 130) andanaccess communication system (120) are caused to coexist by TDM in synchronization with a power cycle, and a communication system which needs to secure AV-QoS assigns transmission timing to a slave station in itself by synchronizing a beacon cycle with a cycle of a power line.