Systems and methods for bidirectional communication are provided. In one embodiment, a multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system comprises: a plurality of remote units, a host unit; wherein the host sends an adjustment signal to a remote instructing the remote to adjust the timing of transmissions from the remote to improve orthogonality of the OFDM waveform received at the host, wherein the host sends an adjustment signal to a remote instructing the remote to adjust the frequency of transmissions from the remote to improve orthogonality of the OFDM waveform received at the host, wherein payload data is transmitted between a remote and the host over a first orthogonal tone within the OFDM communication system during a first time interval, and wherein control data is transmitted between a remote and the host over the first orthogonal tone within the OFDM communication system during a second time interval.