Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

ACTIVITY MONITORING METHOD FOR SHARING SPECTRUM BETWEEN LAND-MOBILE VOICE AND SATELLITE DATA SERVICES

IP.com Disclosure Number: IPCOM000009642D
Original Publication Date: 2000-Jan-01
Included in the Prior Art Database: 2002-Sep-06
Document File: 1 page(s) / 61K

Publishing Venue

Motorola

Related People

Michael L. Needham: AUTHOR [+2]

Abstract

Low earth orbit satellite systems for low-speed data communications have been proposed - the so- called "Little Leo" systems. Dam transmissions on the uplink consist of short (400 ms) bursts of data sent in time slots. Each burst is sent on a frequency which is randomly picked from a bank of available frequencies.

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 60% of the total text.

Page 1 of 1

0 M MOlOROLA Technical Developments

 ACTIVITY MONITORING METHOD FOR SHARING SPECTRUM BETWEEN LAND-MOBILE VOICE AND SATELLITE DATA SERVICES

by Michael L. Needham and Allen L. Davidson

  Low earth orbit satellite systems for low-speed data communications have been proposed - the so- called "Little Leo" systems. Dam transmissions on the uplink consist of short (400 ms) bursts of data sent in time slots. Each burst is sent on a frequency which is randomly picked from a bank of available frequencies.

  The Little LEOs have proposed that their sys- tems could share spectrum with existing land- mobile voice communication systems for the uplink, with little or no interference to the existing systems.

  To prevent such interference, the Little LEOs have proposed a scheme whereby the satellite would scan the available channels, then indicate an "OK to send" status to ground units for those channels found to be idle.

  The problem with this approach is that there is no coordination between the two systems - an "OK to send" could be sent just as a land-mobile trans- mission was beginning, resulting in interference at the beginning of voice messages.

  The invention is as follows. By monitoring an ongoing land-mobile transmission, the satellite can reasonably expect a short period of silence on the

channel just after the transmission ends, before another transmission begins on the channel. This is based on the typical "call-response" model of a 2- way communications. A short data burst...