A new modulation/demodulation method and apparatus are described for use
with RF communication. A transmitter (1001T) modulates information onto a
plurality of carrier signals transmitted simultaneously over a
corresponding plurality of frequencies using cepstral modulation. A
receiver (1003R) receives the plurality of carrier signals and
demodulates the signals utilizing cepstral demodulation. Receiver (1003R)
monitors the carrier signals and in response to predetermined conditions
selects a cepstral constellation to be utilized. Receiver (1003R)
provides the cepstral constellation information to a transmitter (1003T)
that, in turn, transmits the cepstral constellation information to a
receiver (1001R), in turn, provides the cepstral constellation
information to transmitter (100T). Transmitter (1001T) utilizes the
selected cepstral constellation information to modulate the next
transmission of the plurality of carrier signals.