The letter presents a theoretical analysis on a performance index W for cha
otic spreading sequences, which characterizes the multiple access interfere
nce introduced by crosscorrelation of a sequence set in asynchronous DS/CDM
A systems. Using the ergodic theory, W is expressed in terms of ensemble-av
eraged autocorrelation functions and simple explicit formulae for W are obt
ained, under the assumption of independent seeds. Based on this analysis on
e can design chaotic spreading sequences performing better than ideal rando
m sequences with respect to multiple access interference.