Network capacity and queue aspects of USPS electronic message systems

A geostationary orbit satellite communications network is developed parametrically for a 125 station application to USPS Electronic Message Service. The satellite is based on the Atlas-Centaur launch vehicle with a 9-zone antenna coverage of the continental U.S. Other multiple zone configurations are considered. Earth stations with 5.0 meter diameter antennas are assumed to have a total average traffic load of 91,312,000 messages/day. The queueing analysis is based on 4th order Erlangian arrival and service statistics with an average bits/message considered parametrically up to 1,200,000. Message delays are presented parametrically so that results for networks up to 123 stations and traffic loads up to 100,000,000 messages/day may be evaluated. For 123 stations and 617,000 bits/messages, a nearly state-of-the-art single satellite network appears feasible to support a 91,312,000 messages/day traffic load with average message transmission delays of 2.5 seconds/message or less.