Forward error correction of FSK alphabets for wireless noncoherent transmissions

We show that several coding schemes, and in particular turbo encoding, dramatically improve the performance of a noncoherently detected frequency shift-keying modulation with correlated signals. The a posteriori probabilities (APP) decoding scheme based on bit-by-bit decisions proves to be better than a classical block decisions decoding scheme when the bit mapping is not optimized. Moreover, the choice of the FSK modulation tone spacing is important. Finally, high latency and low latency systems are compared