Apparatuses and methods for practicing subtractive multi-carrier CDMA techniques are disclosed. A channel is divided into a plurality of contiguous subchannels, wherein in each subchannel an amount of spreading is reduced in accordance with the number of subchannels. The channel can be divided into a Plurality of timeslots and a fraction of the total number of conversations sharing the channel can be allocated to each timeslot. A radio communications device, using such a method, can employ one timeslot for transmission and another time slot for reception.