Maximum Likelihood Sequence Estimation for Randomly Dispersive Channels

Receiver designs for maximum likelihood sequence estimation of digital data transmission through randomly dispersive channels are developed. The random channels are constrained to have finite memory of duration in the sense that the casual minimum mean square error estimate of the channel output at any given time is a function of only the most recent seconds of observations. Examples of the channels included are the time varying Rayleigh, Rician and lognormal fading channels whose covariance functions have finite support, phase unsynchronized channels which satisfy the finite-memory constraint and point process channels. The information sequence may be either a stream of independent, equally-likely symbols of binary or -ary alphabets or the output sequence of a trellis or convolutional encoder.