A Geometric Theory of Intersymbol Interference, Part II: Performance of the Maximum Likelihood Detector

Forney2,3 has detailed the Viterbi algorithm version of the maximum likelihood detector (MLD) of digital sequences in the presence of intersymbol interference. He asserts that the probability of bit error of the MLD in additive white Gaussian noise can be bounded at high S/N ratios in the form where KL and Ku are constants, Q is the Gaussian distribution 1521 1522 T H E B E L L S Y S T E M TECHNICAL JOURNAL, NOVEMBER 1973 function, Q(x) = J" e-'^dy, (2)