remover 500 measures the actual thermal noise power by removing an error signal of a as illustrated in fig4 from the measurement signal the controller 511 reflects the thermal noise power measurement received from the remover 500 in current thermal noise power and controls the power of the reverse link for the non silence period based on the updated thermal noise power value the controller 511 generally has information about the non silence period and the silence period therefore the silence period control signal provided from the controller 511 to the remover 500 indicates the start and end of the silence period upon receipt of the silence period information the remover 500 outputs the power measurement from which the error is removed a description will now be made of how the remover 500 removes the error the time t varying power measurement error a for the silence period as illustrated in fig4 varies with the time constant of the average calculator 302 that is an integrator hence the time constant of the average calculator 302 can be determined in advance and is denoted by t the power value measured at the end time of the non silence period is represented by p1 dbm and the power value output from the average calculator 302 in the silence period is represented by p2 dbm as illustrated in fig4 p2 varies with time using p1 and p2 the rots of the silence period and the non silence period rot silence and rot non silence are computed by rot silence ue89e db rot non ue89e ue89e silence rot non ue89e ue89e silence u00b7 exp ue8a0 t t ue89e p1 p2 rot.