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Browse Prior Art Database

RF UNSELECT OPERATION IN WIDE AREA TAC SYSTEMS

IP.com Disclosure Number: IPCOM000008052D
Original Publication Date: 1997-Mar-01
Included in the Prior Art Database: 2002-May-15
Document File: 2 page(s) / 80K

Publishing Venue

Motorola

Related People

Phil Hargrave: AUTHOR [+2]

Abstract

The present invention relates generally to wide area TACTM systems where the dispatcher needs to hear both subscribers in an RF collision.

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MOTOROLA Technical Developments

RF UNSELECT OPERATION IN WIDE AREA TAC" SYSTEMS

by Phil Hargrave and Keith Eberlein

BACKGROUND/PROBLEM

  The present invention relates generally to wide area TACTM systems where the dispatcher needs to hear both subscribers in an RF collision.

  In radio systems sometimes two subscribers will be transmitting at the same time. This usually hap- pens when two subscribers start transmitting at the same time or when one subscriber anticipates the end of another subscribers transmission but begins transmitting before the first subscriber is finished or when one subscriber tries to preempt another in an emergency.

  In current wide area systems there can be three outcomes of these collisions. The two subscribers can collide and be unreadable in all receivers in the system. In this case neither will be heard. One sub- scriber will capture receivers and the other will not. In this case the subscriber which captures the receivers will be heard. Or each subscriber will cap- ture at least one receiver in the system. In this case one subscriber will be heard at the console and the other will be discarded.

  In the cases where a subscriber can not caputre a receiver the signal is lost at the RF interface. When multiple subscribers capture receivers thee

loosing signals are discarded in the Comparator. Currently there is only one link to the Console

which can carry only one subscriber signal at a time.

In all cases some possibly important communi- catio...