A bidirectional communication system is provided. The system includes a first remote unit for communicating with a host unit using orthogonal frequency division multiplexing, the host unit communicatively coupled to a plurality of remote units in a multipoint-to-point, multiple access configuration. The first remote unit is configured to transmit up to a plurality of tones, the up to a plurality of tones modulated with upstream information using orthogonal frequency division multiplexing. The first remote unit is configured to receive information from the host unit to adjust a carrier power of tones transmitted by the first of remote unit, and to adjust the carrier power based on the received information from the host unit so that the tones are orthogonal when received at the host unit.