Browse Prior Art Database

BROADCAST CALL FOR A TRUNKED RADIO SYSTEM

IP.com Disclosure Number: IPCOM000009661D
Original Publication Date: 2000-Jan-01
Included in the Prior Art Database: 2002-Sep-09
Document File: 4 page(s) / 200K

Publishing Venue

Motorola

Related People

Gary Aitkenhead: AUTHOR

Abstract

This article describes a method of operation for broadcast calls in a radio communications system. The method attempts to maintain ongoing calls so that ongoing communication can continue once the broadcast ends.

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Technical MOTOROLA @ Developments

BROADCAST CALL FOR A TRUNKED RADIO SYSTEM

by Gary Aitkenhead

ABSTRACT

  This article describes a method of operation for broadcast calls in a radio communications system. The method attempts to maintain ongoing calls so that ongoing communication can continue once the broadcast ends.

INTRODUCTION

  Trunked radio systems (such as Motorola's SmartZone) have a broadcast call feature which allows a console dispatcher to broadcast an announcement to all system users at one or more sites in the system. This call is a one-way commu- nication to which no radio users can respond. Therefore, it is generally used to convey general information relevant to all system users in a particu- lar area. In fact, the call may even be sent out across the entire system. SmartZone calls this fea- ture "site-wide" or "system-wide" cab. Throughout this article, the generic term, "broadcast call" shall be used to refer to all such cases.

  4. at the end of the broadcast call, users can be pulled back into group calls via late entry but pri- vate call users need to re-initiate the call to continue the conversation.

  This article proposes a new operation for broad- cast call which overcomes these limitations and pro- vides a more elegant operation without the need to clear down ongoing calls and reinitiate them at the end of the broadcast.

PROPOSED SOLUTION TO THE PROBLEMS

  When a broadcast call starts at a site, a channel is allocated for the call and all subscriber units which are currently idle (i.e. not involved in any call and monitoring the main control channel), move to the allocated trtic channel for the call. Instead of clearing ongoing private calls and leaving any users in interconnect calls out of the broadcast, the fol- lowing operation is proposed by this article. The group call operation is also described.

PROBLEMS TO BE SOLVED PRIVATE CALLS

  There are several shortcomings with the current implementations of broadcast call. These are:

  1. In order to ensure that all users hear the broadcast, other on-going dispatch calls are first cleared at those sites to be included in the broadcast. For group calls, the call can continue at other sites not involved in the broadcast while private calls are cleared even if only one user is to be included in the broadcast call.

  2. any currently transmitting users do not hear the broadcast call signaling.

  3. any users in telephone interconnect calls do not hear the broadcast call at all.

  The channel allocated for the private call remains allocated but the conversation is interrupted with a tone or recorded announcement followed by the broadcast audio. If the user at the other end of the call is not involved in the broadcast (due to being outside of the broadcast area), a tone or announcement indicates that the call is temporarily suspended due to a broadcast call. The broadcast audio may even be routed to this user so that they know when they will be able to continue the private call agai...