Calculating Error Probabilities for Intersymbol and Cochannel Interference

The probability of error in a binary symmetric channel with intersymbol interference and additive noise is efficiently calculated by numerical quadrature of a Laplace inversion integral along a contour in the complex plane passing through a saddlepoint of the integrand. For Gaussian noise, a bound is set on the truncation error incurred by necessarily restricting the integration to a finite interval. The probability of error resulting from cochannel interference is calculated by a similar technique.