Robust modem and coding techniques for FM hybrid ICOC DAB

The design of robust modem and FEC (forward error correction) code techniques with application to the transmission of an FM hybrid analog/digital in-band on-channel (IBOC) digital audio broadcast (DAB) signal is presented here. The FEC codes are derived from an original lower rate convolutional code (R=1/3). The original code is segmented into a pair of "complementary" components, which form independent codes, each with a higher rate (less redundancy) than the base code. The exploitation of channel state information (CSI) and special interleaving techniques are described for application to FM hybrid IBOC DAB with its unique interference environment and selective fading due to multipath. Simulation results confirm the robustness of the design.