US Patent 7496153 Modulating signals for coherent and differentially coherent receivers

A system incorporates time-hopped and transmitted-reference transceivers in the same wireless network. A transmitter modulates a sequence of bits in a wireless communications network by generating a reference waveform and a data waveform of a waveform pair for each current bit. The phase of the reference waveform depends on a previous modulated bit, and a difference in phase between the reference waveform and the data waveform pair depend on the current bit.