Demodulation of amplitude information in differentially modulated OFDM signals

摘要

Where the additional data throughput is added using an amplitude offset or a combination of phase and amplitude offset, the legacy differential demodulator (602) does not recover the amplitude information. The present invention provides a method for demodulating amplitude offsets in a differential modulation system in order to recover the amplitude information. The amplitude information may be used to demodulate the additional Level 2 data transmitted as an amplitude offset or combination phase and amplitude offset across adjacent OFDM symbols and/or adjacent frequency subcamers (612).