A simple, accurate method to calculate spread-spectrum multiple-access error probabilities

The exact calculation of error probabilities for direct-sequence spread-spectrum multiple-access (DS/SSMA) systems has been addressed in the literature. The exact calculation is computationally difficult, so emphasis has been on approximations and bounds. One particularly attractive approximation is to just use a signal-to-noise ratio in a Gaussian approximation, the `standard approximation´. Unfortunately, that approximation is not generally accurate enough. An improved Gaussian approximation with good accuracy has recently been presented. The author derives an accurate Gaussian approximation which is also computationally very simple