Repeater Rest Channel Identity Broadcast for Trunked Radio

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In trunked radio systems, subscribers face high latency during call setup due to the need to scan for an idle channel, especially when trying to initiate a new call while already participating in an active communication, as they do not initially know the identity of the current rest channel.

Innovation Solution

A method where a repeater transmits the identity of the rest channel during an active communication, allowing a subscriber unit to leave the current call and initiate a new communication on that rest channel, leveraging the European Telecommunications Standards Institute (ETSI) Digital Mobile Radio (DMR) specification's Common Announcement Channel (CACH) for channel access information, thus eliminating the need for a dedicated control channel and reducing access time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a decentralized trunked radio system is used where subscriber units determine channel assignment autonomously, then system complexity is reduced and no dedicated control channel is needed, but call setup time increases significantly due to scanning delays

Engineering Contradiction:
Improvesystem complexityVSAvoidcall setup time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The repeater pre-identifies and designates a rest channel before subscribers need to initiate calls. By maintaining a known rest channel identity that subscribers can access without scanning, the system eliminates the time-consuming channel search process while keeping the overall system structure simple and decentralized.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If subscriber units scan for idle channels to initiate calls, then channel allocation is flexible and decentralized, but access time increases due to scanning requirements

Engineering Contradiction:
Improvechannel allocation flexibilityVSAvoidaccess time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The repeater acts as an intermediary that provides subscribers with rest channel identity information. Instead of subscribers directly scanning for channels, they receive the rest channel identity from the repeater, which then forwards this information to the rest channel. This intermediary mechanism maintains decentralized channel allocation while eliminating scanning delays.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If a centralized trunked radio system with a control channel is used, then channel assignment is efficient and coordinated, but system complexity increases and requires dedicated control infrastructure

Engineering Contradiction:
Improvechannel assignment efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention extracts the control function from a dedicated control channel and integrates it into the rest channel framework. The repeater performs channel assignment coordination on the rest channel itself, eliminating the need for separate control infrastructure while maintaining efficient channel management. This reduces system complexity by removing redundant control channel hardware and protocols.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2425675B1Method for initiating a communication while participating in another communication
Publication Date: 2015.05.20 MOTOROLA SOLUTIONS INC
  • EP2425675B1 patent drawingFigure 1
  • EP2425675B1 patent drawingFigure 2
  • EP2425675B1 patent drawingFigure 3

AI summary

Within a two way radio frequency communication system, a repeater transmits an identity of a rest channel when transmitting during an active communication call on a channel other than the rest channel. A subscriber unit communicating within the active communication, receives the identity of the rest channel, leaves the active communication; and initiates a new communication on the rest channel.