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Browse Prior Art Database

TWO INTERCONNECT CALLS OVER A SINGLE RF CHANNEL

IP.com Disclosure Number: IPCOM000009332D
Original Publication Date: 1999-Jun-01
Included in the Prior Art Database: 2002-Aug-16
Document File: 2 page(s) / 86K

Publishing Venue

Motorola

Related People

Andrew Chu: AUTHOR [+3]

Abstract

In order to preserve battery life in iDEN sub- scriber units, a feature call Discontinuous Transmit (DTx) is used. DTx works by not transmitting speech frames during periods where the voice ener- gy is relatively small. When these frames are not received, the infrastructure will supply "comfort noise" samples in the inbound (PSTN) direction that bridges the periods where the packets are not trans- mitted. The subscriber will only transmit for the purpose of periodically updating certain comfort noise parameters during this DTx period.

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Developments Technical 0 M M61oRoLA

TWO INTERCONNECT CALLS OVER A SINGLE RF CHANNEL

by Andrew Chu, Michael Bychowsky and Michael Kloos

BACKGROUND

  In order to preserve battery life in iDEN sub- scriber units, a feature call Discontinuous Transmit (DTx) is used. DTx works by not transmitting speech frames during periods where the voice ener- gy is relatively small. When these frames are not received, the infrastructure will supply "comfort noise" samples in the inbound (PSTN) direction that bridges the periods where the packets are not trans- mitted. The subscriber will only transmit for the purpose of periodically updating certain comfort noise parameters during this DTx period.

  Circuit data is transmitted in the iDEN system by using an entire RF voice channel (3:l or 6:l). This data is routed through the infrastructure just like a voice packet. The XCDR receives the pack- ets, modifies their format, and sends them to the IWF to be modulated out to the PSTN.

THE PROBLEM

  The RF channel is always allocated the same bandwidth if the subscriber is transmitting or not. This does not fully utilize this expensive medium while a voice call is in progress. Also, in order to make a data call, the voice session must be terminat- ed and set-up again for data. This is a very ineffi- cient use of resources.

THE SOLUTION

  In order to send data simultaneously with voice, the subscriber would notify the infrastructure that it

would like to exchange data during the voice call via a ACP message. Once the request has been received by the system,la second circuit will be establishe...