Abstract: A composite spread spectrum signal including modulator and demodulator therefor is disclosed. The composite signal having a multi-dimensional signal space, comprising a pulse position modulation dimension generated by varying starting positions of cyclically repeated chipping sequences, a frequency shift key dimension generated by varying a carrier frequency between a plurality of frequencies, code shift keyed dimensions generated by selecting the chipping sequences from among a plurality of orthogonal sequences, and amplitude shift key dimensions generated by selecting amplitudes of each subcarrier for each message bundle. This signal may further comprise a phase shift key dimension generated by assigning a phase relationship of the orthogonal subcarriers.