Distributed Floor Control via Random Symbol Comparison

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Solution Overview

Problem

In half-duplex communications systems, the lack of a centralized floor control mechanism leads to unsynchronized behavior among subscriber stations, causing disruptions due to differing signal propagation delays and inconsistent floor ownership assignments, which can result in multiple stations granting ownership to different transmitting stations, disrupting data streams.

Innovation Solution

A method where each communication device generates a random symbol and, based on predefined criteria, selects a floor owner from the received symbols, ensuring all devices have an equal opportunity to acquire floor ownership, thereby minimizing conflicts and ensuring consistent selection across the network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a centralized floor control mechanism is used to assign floor ownership, then consistent floor ownership assignment is achieved, but system cost increases

Engineering Contradiction:
Improveconsistent floor ownership assignmentVSAvoidsystem cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system enables subscriber stations to autonomously determine floor ownership through a distributed algorithm. Each station generates a random value, exchanges it with others, and independently determines whether to acquire the floor based on comparing its value with received values, eliminating the need for a centralized controller while maintaining consistent assignment across all stations

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

A random value serves as an intermediary mechanism that enables coordinated floor ownership determination without centralized control. Each station uses its random value and received random values from other stations to make floor acquisition decisions, creating a decentralized mediation system that ensures consistency

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If no centralized floor control mechanism is used, then system cost is reduced, but unsynchronized behavior and communication disruptions occur

Engineering Contradiction:
Improvesystem costVSAvoidsynchronized communication
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Subscriber stations autonomously execute the floor control algorithm, generating random values, exchanging them with peer stations, and independently making floor acquisition decisions based on predetermined comparison rules, achieving synchronized behavior without centralized coordination

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses random values as dynamic parameters that change with each floor request attempt. By comparing these changing parameters across multiple stations, the system achieves synchronized floor ownership determination without requiring centralized parameter management

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If subscriber stations select floor owner based on first received request, then simple selection process is achieved, but inconsistent floor ownership assignment occurs due to differing signal propagation delays

Engineering Contradiction:
Improveselection process simplicityVSAvoidfloor ownership consistency
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Instead of selecting the first received floor request, the system inverts the approach by having each station generate a random value and select based on whether its random value is greater than or equal to received random values from other stations. This inversion eliminates the inconsistency caused by signal propagation delays while maintaining simple selection logic at each station

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP2206286B1Floor control in a communications system
Publication Date: 2016.12.07 MOTOROLA SOLUTIONS INC
  • EP2206286B1 patent drawingFigure 1
  • EP2206286B1 patent drawingFigure 2
  • EP2206286B1 patent drawingFigure 3~5

AI summary

An apparatus (400) and method (600) of implementing floor control in a communications system (100). The method can include receiving (600) a random symbol from each of a plurality of communication devices (104, 106, 108, 110, 112) or network nodes (204, 206, 208, 210, 212). From the plurality of random symbols, a random symbol that satisfies a criteria can be identified (614). Floor ownership can be granted (616) to a selected one of the communication devices associated with the identified random symbol or from which the identified random symbol was received.