A system and method for augmenting the data capacity of pre-existing communications channels is provided. In one example, a subcarrier waveform of the system can be dithered based on data generated by an additional source and then transmitted. The dithered subcarrier can be passed through a plurality of matched filters so as to ascertain which dither pattern was used, thus ultimately allowing for the demodulation of the additional data source. The system and methods provided herein can be implemented with minimal impact to legacy users of the system as implementation of the dithering scheme can have minimal impact to the performance of receivers that are not equipped to demodulate the dithered waveforms.