Abstract: Embodiments of the present disclosure provide improved techniques for decoding amplitude modulated messages, including those encoded using quadrature amplitude modulation (QAM). For example, a method of decoding amplitude modulation (AM)-encoded messages includes generating a received waveform matrix from a series of receive basis pulses, receiving a multi-dimensional waveform having n AM-encoded messages. The method also includes removing inter-symbol interference from the waveform. In addition, the method includes applying an error-minimizing technique to the received waveform matrix to decode the n AM-encoded messages.