In a wireless transmission system that transmits the same information in
parallel using two or more different types of modulation schemes, such as
a satellite-based digital audio transmission system transmitting two TDM
signals and a single OFDM signal, a receiver processes the differently
modulated signals to generate separate demodulated signals that are then
combined to form a single combined signal for further processing (e.g.,
decoding). In one embodiment, the receiver applies a maximal ratio
combining (MRC) technique to generate a single optimal ratio combined
signal from the differently modulated signals. By combining the
differently modulated signals using an MRC technique, the adverse affects
of noise related to inter-symbol interference in the individual signals
can be reduced and the complexity of hardware in the receiver can be
reduced.