Dismiss
IP.com applications will be updated on Sunday, March 5, from 11 am to 2 pm ET, to add new functionality and content. You may experience brief service interruptions during this period. We apologize for any inconvenience.
Browse Prior Art Database

PROGRAMMABLE GSM TRAFFIC DATA DEMULTIPLEXOR

IP.com Disclosure Number: IPCOM000007025D
Original Publication Date: 1993-Oct-01
Included in the Prior Art Database: 2002-Feb-19
Document File: 2 page(s) / 91K

Publishing Venue

Motorola

Related People

Julian Singleton: AUTHOR [+3]

Abstract

In a system where subrate multiplexing is used for efficient data transfer, demultiplexing the data in a quick and flexible manner can be very complex and expensive. The GSM Digital Cellular System Transcoder to Channel Coder Interface provides an example where four 16kbit/s data timeslots are packed into a single 64kbit/s timeslot on a 2Mbit/s serial data stream for transfer between the Base Site Con- troller (BSC) and the Base Transceiver Station (BTS).

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 50% of the total text.

Page 1 of 2

MOTOROLA INC. Technical Developments Volume 20 October 1993

PROGRAMMABLE GSM TRAFFIC DATA DEMULTIPLEXOR

by Julian Singleton, Kevan Hobbis and Nigel Elliot

  In a system where subrate multiplexing is used for efficient data transfer, demultiplexing the data in a quick and flexible manner can be very complex and expensive. The GSM Digital Cellular System Transcoder to Channel Coder Interface provides an example where four 16kbit/s data timeslots are packed into a single 64kbit/s timeslot on a 2Mbit/s serial data stream for transfer between the Base Site Con- troller (BSC) and the Base Transceiver Station (BTS).

  In the present Motorola GSM Base Station Sys- tem, 64kbit/s timeslots (with four 16kbit/s embedded subchannels) on a CEPT 2.048Mbit/s serial stream are placed on an 8 bit parallel Time Division Multi- plex (TDM) bus from which the Channel Coder units remove 2 bits per TDM frame (125~~s).

  This system is a simple and cheap method of extracting eight, or more, 16kbit/s data channels from anywhere within a frame of thirty-two 64kbit/s timeslots, and passing each individual subchannel to a programmably selected processing unit. This system can also be used to extract eight, or more, Skbit/s data channels from the data stream as described above making it applicable for Half-Rate GSM Systems.

  Data flows into the circuit in CEPT 2.048Mbit/s format (see Figures 1 and 2). The received stream is fed into both the on-chip Programmable Strobe Gen- erator of the Motorola 68360 Microcontroller and the Bit-Selective Multiplexor. The MC68360 Core

Processor (CPU32) programs the Strobe Generator to generate...