Layered modulation for digital signals

A receiver for compatibly receiving a transmission signal having a legacy upper layer signal receivable by a plurality of legacy receivers and a plurality of layered modulation receivers and a lower layer signal non-coherently layered over the legacy upper layer signal, the lower layer signal receivable by the layered modulation receivers and not receivable by the legacy receivers, the receiver comprising:

• a first demodulator for demodulating the legacy upper layer signal to produce a demodulated signal;
• a first layer decoder, coupled to the first layer demodulator, for decoding the demodulated signal to produce legacy upper layer signal symbols;
• a remodulator, coupled to the first layer decoder, for remodulating the first signal symbols to produce a remodulated legacy upper layer signal;
• a subtracter, coupled to the first demodulator and the remodulator, for subtracting the remodulated legacy upper layer signal from the demodulated signal to produce the lower layer signal;
• a second layer demodulator, coupled to the subtracter, the second layer demodulator for demodulating the lower layer signal to produce a second demodulator output;
• and
• a second layer decoder, coupled to the second layer demodulator, the second layer decoder for decoding the second layer demodulated output to produce lower layer signal symbols.

A method of receiving a transmission signal having a legacy upper layer signal compatibly receivable by a plurality of legacy receivers and a plurality of layered modulation receivers and a lower layer signal non-coherently layered over the upper layer signal, the lower layer signal receivable by the layered modulation receivers and not receivable by the legacy receivers, the method comprising:

• demodulating the legacy upper layer signal of the transmission signal to produce a demodulated signal;
• decoding the demodulated signal to produce legacy upper layer symbols;
• remodulating the legacy upper layer symbols;
• subtracting the remodulated legacy upper layer symbols from the demodulated signal to produce the lower layer signal;
• demodulating the lower layer signal;
• and
• decoding the demodulated lower layer signal to produce second decoded symbols.