  In this work we develop the maximum likelihood detection (MLD) algorithm for
noncoherent amplitude shift keying (NCASK) systems in additive white Gaussian
noise (AWGN) channels. The developed algorithm was used to investigate the
performance of the NCASK system with convolutional coding and soft-decision
Viterbi decoding. Tight and simple upper bounds have been derived to describe
the system performance; simulation results have shown that the derived upper
bounds are within 0.1 dB of the simulated points.
