subscribers and subchannel assignment information previously assigned to the respective sss are input to the subchannel assigning apparatus 30 at each preset assignment period the subchannel assigning apparatus 30 sequentially applies an assignment method according to the present invention at each assignment period utilizing the transmission rate required by each subscriber and enables a first second and third assigning units 31 32 and 33 to perform an adaptive assignment of subchannels and the assignment of bits although not shown in fig3 it would be recognized that the bs can be equipped with a receiving unit for receiving the transmission rate and subchannel assignment information required by each user subscriber and for providing the received required transmission rate and subchannel assignment information to the first second and third assigning units 31 32 and 33 since this can be implemented by using the widely known art a detailed description need not be provided herein furthermore subscribers 39 data is assumed transmitted within the same cell that the transmission rate required by a subscriber where the subscribers 39 data is classified non real time data when the transmission rate required by the subscriber has a value of u2018 0 u2019 or a non positive value and real time data.