Traffic is measured in terms of traffic intensity. An Erlang is defined as the average number of simultaneous calls.For example, if a base station logs a total usage of 72,000 sec
(1,200 min) between 8:00 A.M. and 9:00 A.M., then the traffic intensity is
72 000 sec/3 600sec = 20 Erlangs
1,200 min/60 min = 20 Erlangs.