Date of Award


Document Type


Degree Name

Master of Science (MS)

Legacy Department

Electrical Engineering

Committee Member

Dr. Daniel L. Noneaker, Committee Chair

Committee Member

Dr. Harlan B. Russell

Committee Member

Dr. Kuang-Ching Wang


The standard Gaussian approximation is extended to the performance analysis of direct-sequence code-division multiple-access (DS-CDMA) systems using binary con-volutional coding, quaternary modulation with quaternary direct-sequence spreading and Viterbi decoding. Using the standard Gaussian approximation, the random variables mod-eling the multiple-access interference in the receiver statistics are replaced by an equivalent additive Gaussian noise term with the same variance as the actual multiple-access interfer-ence term. The Gaussian approximation is shown to result in an accurate approximation to the probability of code-word error at the receiver. The accuracy is demonstrated by compar-ing simulation results for the actual multiple-access system and a model using the standard Gaussian approximation. Both are compared with two previously developed closed-form bounds on the performance: the concave-first-event bound and the concave-integral bound.