rate if the calculated rab set time is not greater than 0 rotc as a calculated value for a load degree of reverse link is calculated s 15 rotc is calculated by finding a ratio of reception pilot power vs total reception power for each reception data rate and by multiplying a total of f datarate value of all access terminals in a sector by ecp io i e average energy per chip of pilot channel in antenna vs psd power spectral density of total reception signals the calculated rotc is compared to a specific threshold rotc_th s 17 if rotc is greater than rotc_th rab is set to decrease reverse data rate s 18 if rotc is smaller than rotc_th rab is unset to increase reverse data rate s 19 in one embodiment of the present invention for example after rab has been set using rotm rotc is complementarily considered to set rab rotc is used as a method of correcting unstable measurement accuracy in this case rotm_th and rotc_th may differ and may not be equal to each other in certain embodiments referring to fig2 a base station system 200 includes a reception processing unit 21 a rot measurement unit 22 a rot set time calculation unit 23 a rotc calculation unit 24 a first comparison unit 25 a second comparison unit 26 a rab generation unit 27 and a transmission processing unit 28 numeral u2018 29 u2019 in the drawing indicates a reception antenna and numeral u2018 30 u2019.