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A METHOD TO ALLOW SUBSCRIBER SCAN OPERATION IN AN INTEGRATED VOICE/DATA WIRELESS SYSTEM

IP.com Disclosure Number: IPCOM000008726D
Original Publication Date: 1998-Jun-01
Included in the Prior Art Database: 2002-Jul-05
Document File: 2 page(s) / 102K

Publishing Venue

Motorola

Related People

Mark Chapman: AUTHOR

Abstract

Today's conventional integrated voice and data radio systems allow subscriber radios to utilize scan operation for voice alone. A radio may be programmed to listen to a list of channels and pause on any given channel when it receives a call which matches its programmed squelch parameters, Each outbound call is of course an asynchronous event. The consequence to the voice user is then limited to the possible late entry to a conversation. With voice this is a relatively benign condition that has long been accepted by the radio user. The question in an integrated voice/data system then becomes what methods can be used to allow data reception under similar circumstances.

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A METHOD TO ALLOW SUBSCRIBER SCAN OPERATION IN AN INTEGRATED VOICE/DATA WIRELESS SYSTEM

by Mark Chapman

INTRODUCTION SOLUTION

  Today's conventional integrated voice and data radio systems allow subscriber radios to utilize scan operation for voice alone. A radio may be programmed to listen to a list of channels and pause on any given channel when it receives a call which matches its programmed squelch parameters, Each outbound call is of course an asynchronous event. The consequence to the voice user is then limited to the possible late entry to a conversation. With voice this is a relatively benign condition that has long

been accepted by the radio user. The question in an integrated voice/data system then becomes what methods can be used to allow data reception under similar circumstances.

  In order to solve the above problems we must attack the root cause, the unsolicited nature of the outbound calls. This can be done in the following fashion.

I) The data controller is to be programmed with the ID's of those units which use scan. In this way it can use a different style of operation for these units without impacting the normal operation used by non-scanning units.

PROBLEM(S) TO BE RESOLVED

  In a packet data service each data packet is formatted with a header containing destination addressing and control information, followed by the user data and usually a packet CRC. Unlike voice data does not permit a late entry condition. If any portion of the header is missed then the packet is not received. Given that each outbound data packet is perceived by the receiving radio as an unsolicited asynchronous event and that the radio is cycling through a scan list of channels, it becomes readily apparent that the chances of the radio accidentally being ready to receive at just the right moment or a particular data packet are very slim. The conse- quence to a system with a large number of data using scan mode subscribers can be even worse. With most packets now being missed, an avalanche of retries can result which may bring down normal data traffic on the channel. For this reason previous systems have simply forbidden data reception while the subscribe...