Exact expression for Prabhu upper bound for digital communication systems with noise and interference

The authors first present an exact expression for the Prabhu general upper bound on error probability of the canonical binary system with noise and interference in terms of a modified Bessel function. This bound is tighter than the modified Chernoff bound and simpler than a recent approximation. Secondly, the new expression is used to evaluate the error rate of an optically preamplified direct-detection optical receiver and is shown to provide tighter estimates of the error probability than either the Chernoff or modified Chernoff bounds for amplifier gains of practical interest