SUBSCRIBER BASED AIR TIME CALCULATION IN TWO WAY COMMUNICATION SYSTEMS
Original Publication Date: 1988-Oct-01
Included in the Prior Art Database: 2001-Nov-05
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.