Browse Prior Art Database

DIGITAL CELLULAR RELEASE

IP.com Disclosure Number: IPCOM000005660D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2001-Oct-24
Document File: 2 page(s) / 104K

Publishing Venue

Motorola

Related People

Steve Levine: AUTHOR [+3]

Abstract

The following is a description of a new signalling method for implementing a mobile release in a cellular radio-telephone system. The current signalling release protocol has the mobile transmit 1.8 seconds of "signal- ling tone" (10K Hz tone) to the base-site to initiate a release. The mobile then unkeys its transmitter, and upon reception of the 1.8 second signalling tone, the base-site drops the call. This release method can have a prob- lem of the base-site falsing on an interfering channel's signalling tone and inappropriately dropping acall. The new release method utilizes digital confirmation, which significantly reduces the probability of incorrect release. decisions. Consideration was given in its design for efficient retrofit into the current cellular system.

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MmROLA Technical Developments Volume 7 October 1987

DIGITAL CELLULAR RELEASE

by Steve Levine, Larry Puhl and Tom Hull

   The following is a description of a new signalling method for implementing a mobile release in a cellular radio-telephone system. The current signalling release protocol has the mobile transmit 1.8 seconds of "signal- ling tone" (10K Hz tone) to the base-site to initiate a release. The mobile then unkeys its transmitter, and upon reception of the 1.8 second signalling tone, the base-site drops the call. This release method can have a prob- lem of the base-site falsing on an interfering channel's signalling tone and inappropriately dropping acall. The new release method utilizes digital confirmation, which significantly reduces the probability of incorrect release. decisions. Consideration was given in its design for efficient retrofit into the current cellular system.

   The mobile initiates a digital release by transmitting a flash request (400 ms signaling tone). The base station recognizes the flash request, and responds with the following message, which is a modified send called address order.

2 2 2 9 5 3 5 12 BITS TlT2 SCC PSCC RELEASE CODE LOCAL ORDQ ORDER PARITY I

10 11 xx xxxxxxxxx 00000 000 01000 x x

. . .

BASE TO MOBILE RELEASE QUERY

   Standard Forward Voice Channel (FVC) message signalling (11 repeats of a (40,28) BCH encoded word) is used. The initial tone burst is utilized to request the use of the base-site Voice Channel Controller (VCC) data transceiver, which is multiplexed overa number of voice channels. The release code, utilizing the reserved bit field, is a 9 bit word unique to each base site (or reused in a wide pattern). The use of this release code is described below.

   Because the base site does not know if the mobile is requesting a release or a normal flash, the above query message is sent in either case. The mobile responds with the standard called address Reverse Voice Channel (WC) message if it is requesting a normal flash. However, if the mobile is requesting a release, it con- firms this with the following modified WC message.

12 1 5 3 5 2 9 8 12 BITS F NAWC T LOCAL ORDQ ORDER SAT RELEASE CODE RSVD PARITY
1 00 1 00000 000 01000 xx xxxxxxxxx o..o x...x

MOBILE TO BASE RELEASE CONFIRMATION

   This message is sent with standard RVCs...