Soft decision decoding of block codes using received signal envelopes in fading channels

The word-error-rate (WER) performance of noncoherent FSK (frequency-shift keying) with soft-decision decoding of block codes using D. Chase´s (1972) second algorithm is investigated in a Rayleigh fading channel. The received signal envelope is sampled and used as channel measurement information. The theoretical upper and lower bounds of the WER are derived assuming independent Rayleigh envelope samples in a received block. The effects of bit interleaving on the WER performance when fading envelope variation is slow compared with the bit rate are investigated through computer simulations. The theoretical analysis was supported by laboratory experiments