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SUBSCRIBER BASED AIR TIME CALCULATION IN TWO WAY COMMUNICATION SYSTEMS

IP.com Disclosure Number: IPCOM000005765D
Original Publication Date: 1988-Oct-01
Included in the Prior Art Database: 2001-Nov-05
Document File: 1 page(s) / 50K

Publishing Venue

Motorola

Related People

Karl R. Weiss: AUTHOR [+2]

Abstract

In two way radio systems, it is sometimes desirable to have a fixed end unit keep track of channel air time usage by the different subscribers. This accounting method is used for billing and general channel manage- ment purposes. In previous binary signalling systems, channel air time for each subscriber was calculated at the fixed end by measuring the time between the unit ID message at the beginning of the transmission (leading packet) and the unit ID message at the end of the transmission (trailing packet). This method of measuring the channel air time depends on the fixed end receiving both the leading and trailing packets correctly. Leading binary packets tend to be subject to collisions due to subscribers trying to access the channel simultaneously.

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MOTOROLA Technical Developments Volume 8 October 1988

SUBSCRIBER BASED AIR TIME CALCULATION IN TWO WAY COMMUNICATION SYSTEMS

by Karl R. Weiss and James R Morris

   In two way radio systems, it is sometimes desirable to have a fixed end unit keep track of channel air time usage by the different subscribers. This accounting method is used for billing and general channel manage- ment purposes. In previous binary signalling systems, channel air time for each subscriber was calculated at the fixed end by measuring the time between the unit ID message at the beginning of the transmission (leading packet) and the unit ID message at the end of the transmission (trailing packet). This method of measuring the channel air time depends on the fixed end receiving both the leading and trailing packets correctly. Leading binary packets tend to be subject to collisions due to subscribers trying to access the channel simultaneously.

A further issue is if a fade occurs, the fixed end will have problems determining when a current transmission has finished. It would be convenient if the fixed end were only dependent on receiving the trailing ID packet to calculate the channel air time usage.

1 By letting the subscriber unit calculate the transmission time and send this information in the trailing binary packet, a much more reliable channel air time calculation can be achieved. This method eliminates the need for the fixed end to receive the leading packet, The probability of the fi...