(AR3551A:Mean Number of Busy TCHs (TCHF) (900/850 Cell) + AR3551B:Mean Number of Busy TCHs (TCHF) (1800/1900 Cell) + AR3552A:Mean Number of Busy TCHs (TCHH) (900/850 Cell) + AR3552B:Mean Number of Busy TCHs (TCHH) (1800/1900 Cell))*3600/(CA313:Successful Assignments)