Timing Leader Switching in Digital Mobile Radio

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Solution Overview

Problem

Current Digital Mobile Radio (DMR) systems lack an efficient method to automatically switch the functions of the timing leader radio to another radio on the channel, leading to potential power source longevity issues and lack of seamless synchronization in case the timing leader fails or moves out of range.

Innovation Solution

The method involves radios receiving a timing signal and maintaining values for priority-based selection of a new leading radio, using a table to store radio-specific elements like source subscriber identifier, radio type, and synchronization age, and automatically switching leadership based on these criteria when the current leader can no longer provide control timing messages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the timing leader continuously transmits CT messages, then channel synchronization is maintained, but power source longevity deteriorates

Engineering Contradiction:
Improvechannel synchronizationVSAvoidpower source longevity
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The timing leader transmits CT messages at predefined intervals rather than continuously, reducing power consumption while maintaining synchronization. The periodic transmission allows other radios to maintain synchronization during intervals by using stored timing reference values.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The timing leader transmits timing reference values in advance before they are needed, allowing other radios to store these values and use them during intervals when CT messages are not transmitted, thereby maintaining synchronization without continuous transmission.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If a single timing leader is used, then channel timing control is simplified, but system reliability deteriorates when the leader fails or moves out of range

Engineering Contradiction:
Improvetiming control structureVSAvoidsystem continuity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Other radios maintain stored timing reference values and readiness information in advance, so when the timing leader fails or moves out of range, a backup radio can immediately assume the timing leader role using pre-stored information without interruption to channel synchronization.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system automatically detects when the timing leader is unavailable and self-organizes by selecting a new timing leader from among the radios on the channel, without requiring external intervention or complex centralized control.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If manual timing leader switching is implemented, then flexibility is improved, but operational complexity and response time worsen

Engineering Contradiction:
Improvetiming leader selection flexibilityVSAvoidswitching operation simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system automatically performs timing leader switching based on pre-established selection criteria (such as radio priority values or synchronization age), eliminating the need for manual intervention while maintaining flexibility in leader selection. The radios self-organize and elect a new timing leader when the current one becomes unavailable.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2647258B1Method and system for sending a channel timing message in a digital mobile radio system
Publication Date: 2016.08.17 MOTOROLA SOLUTIONS INC
  • EP2647258B1 patent drawingFigure 1
  • EP2647258B1 patent drawingFigure 2
  • EP2647258B1 patent drawingFigure 3~4

AI summary

A method and apparatus for automatically switching functions associated with a leading radio to another radio on a channel is disclosed. The method includes receiving (410), from a leading radio by at least one other radio operating on a channel, an associated timing signal via at least one control timing message. Other radios use the timing signal to synchronize transmissions made on the channel. The method also includes receiving (420), by the other radios, an indication that the leading radio can no longer provide control timing messages. The method further includes maintaining (430), by each radio on the channel, values for various elements associated with radios operating on the channel and selecting (440) a new leading radio from the other radios based on priorities of the various elements.