Browse Prior Art Database

DIGITAL SAT SIGNALLING

IP.com Disclosure Number: IPCOM000005661D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2001-Oct-24
Document File: 1 page(s) / 73K

Publishing Venue

Motorola

Related People

Steve Levine: AUTHOR [+2]

Abstract

The following is a description of a method for providing continuous signalling over cellular radio-telephone voice channels. The current U.S. cellular system blanks the audio for 100 msec to send 10K bibsec data messages. Increasing the capacity by splitting the channels would require the data rate to be reduced. This increases the blank time and places more of the data transmission spectrum in the audio band. Therefore, continuous signalling provides a fundamental advantage in the quest for improved spectrum efficiency.

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MOTOROLA Technical Developments Volume 7 October 1987

DIGITAL SAT SIGNALLING by Steve Levine and Larry Puhl The following is a description of a method for providing continuous signalling over cellular radio-telephone voice channels. The current U.S. cellular system blanks the audio for 100 msec to send 10K bibsec data messages. Increasing the capacity by splitting the channels would require the data rate to be reduced. This increases the blank time and places more of the data transmission spectrum in the audio band. Therefore, continuous signalling provides a fundamental advantage in the quest for improved spectrum efficiency.

The current U.S. cellular system uses the three Supervisory Audio Tone (SAT) frequencies (A, B & C) as follows:

                  A = 5970 Hz, B = 6000 Hz, C = 6030 Hz DIGITAL SAT SIGNALLING replaces the three SAT frequencies by the following three combinations of fre- quency pairs, providing an FSK digital data signalting capability while still keeping three signalling formats distinguishable from each other.

DIGITAL SAT 1 = A & B FREQ. DIGITAL SAT 2 = B & C FREQ. DIGITAL SAT 3 = A & C FREQ. Digital SAT is determined by which frequency pair is used to transmit the continuous digital FSK modulated signalling between the base-site and mobile. Noncoherent FSK detection would provide a 30 BPS unencoded data thruput.

   During call set up a dotting sequence such as ABABABAB. .is transmitted between the base-site and mobile to facilitate a quick detection of the signalling frequency pairA&B. Before handoffs, the mobile is ordered via Digital SAT FSK signalling to start transmitting ABABAB.. .dotting for easier scan board detection.

An alternative to the ABABAB. .dotting, is to name a primary frequency for,each digital SAT pair; DI...