Comment on "Maximum likelihood decoding of uncoded and coded PSK signal sequences transmitted over Rayleigh flat-fading channels"

This comment points out some papers published before the paper of Vitetta and Taylor (see ibid., vol.43, no.11, p.2750-58, 1995). These early papers have dealt with the general problem of maximum-likelihood sequence estimation of coded/uncoded phase-shift keying (PSK) and quadrature amplitude modulation (QAM) signals in correlated Rician and Rayleigh-fading channels. These publications did not assume use of interleaving or use of optimal codes, designed for interleaved systems. The statistical properties of the multiplicative fading process have been included in the design of the receivers which were proposed, analyzed, and evaluated. The research contributions documented in these papers have also shown for the first time in the open literature the link between conventional detection techniques and the maximum-likelihood detection of signals in this type of fading channels.