Repeater Early Synchronization for Radio Call Connect Time

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Solution Overview

Problem

In asynchronous digital two-way radio communication systems, the current method of establishing calls is inefficient due to the need for repeated transmission of time and frequency synchronization information, which significantly extends the call connect time.

Innovation Solution

The solution involves early synchronization of a repeater by having it listen to the synchronization information during the initial attempt at direct talk-around mode between the originator and target radios, allowing the repeater to be ready for use if the direct mode is not successful, thereby reducing the need for resending synchronization information and shortening the call connect time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the repeater acquires synchronization information from the originator radio after the direct talk-around mode fails, then the repeater can relay the call, but the call connect time is significantly extended

Engineering Contradiction:
Improvecall connection reliabilityVSAvoidcall connect time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The repeater performs preliminary synchronization by acquiring time and frequency synchronization information from the originator radio during the initial direct talk-around attempt, before the repeater is actually needed. This preliminary action allows the repeater to be ready for immediate use if the direct mode fails, eliminating the need to acquire synchronization information later and thus reducing call connect time

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the originator radio sends synchronization information to both the target radio and the repeater, then the repeater can relay the call, but the synchronization information is sent twice extending call connect time

Engineering Contradiction:
Improvecall relay capabilityVSAvoidcall connect time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The synchronization information sent from the originator radio serves dual purposes: it enables the target radio to communicate in direct mode and simultaneously provides the repeater with the necessary synchronization information to relay the call. This multi-functionality eliminates the need for separate synchronization transmissions to the repeater, reducing call connect time while maintaining full relay capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of time

If the repeater is synchronized in advance during direct talk-around mode, then call connect time is reduced, but repeater loading increases

Engineering Contradiction:
Improvecall connect timeVSAvoidrepeater loading
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The repeater performs self-synchronization by autonomously acquiring synchronization information from the originator radio during the initial direct talk-around attempt without requiring additional signaling or control from other system components. This self-service approach reduces call connect time while avoiding increased system complexity or additional loading on other system elements

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2371177B1Method and apparatus for establishing a call in a digital radio communication system
Publication Date: 2015.08.26 MOTOROLA SOLUTIONS INC
  • EP2371177B1 patent drawingFigure 1~2
  • EP2371177B1 patent drawingFigure 3
  • EP2371177B1 patent drawingFigure 4

AI summary

A digital radio communication system (200) uses a repeater (216) to relay calls which can not be completed in a direct talk-around mode between two radios. The repeater (216) establishes early synchronization in advance of a pending call by listening to an originator radio (204) attempt to make a direct talk-around call to a target radio (210). Asynchronous digital two-way radio communication systems can benefit from the reduction in voice call connect time.