PERFORMANCE OF BINARY AND QUATERNARY DIRECT-SEQUENCE SPREAD-SPECTRUM MULTIPLE-ACCESS SYSTEMS WITH RANDOM SIGNATURE SEQUENCES

The performance of synchronous and asynchronous, binary and quaternary (with and without offset) direct-sequence spread-spectrum multiple-access communication systems employing random signature sequences and arbitrary chip waveforms is investigated. The average probability of error at the output of the correlation receiver is evaluated using a characteristic-function approach for all the above systems. Numerical results are presented that illustrate performance comparisons between systems employing random and deterministic signature sequences, synchronous and asynchronous systems, systems with rectangular or sinewave chip waveforms, and binary quaternary systems with the same data rates and bandwidth. In all cases, the accuracy of the Gaussian approximation is also examined.