Precoded modulo-precanceling for simultaneous analog FM and digital data

We present techniques for simulcasting low-power digital data and analog FM over fading channels. Our methods have strong connections to "writing on dirty paper" techniques in that a low-power digital data signal is modulo-added to the host analog FM signal, so as to minimize the distortion on the analog FM signal. We develop digital receivers that work reliably over fading channels given partial channel state information. Spread-response preceding is exploited to provide rate-1 temporal diversity benefits and simplify the digital receiver design. Our theoretical and simulation-based performance analysis of the digital receivers and our MSE-based analog FM distortion analysis suggest that the proposed schemes provide higher data rates than existing precanceling strategies at the cost of transmission delay and transceiver complexity.