Exploiting data and code interactions to reduce the power variance for CDMA sequences

This paper investigates the effect of interactions between the Walsh codes and data sequences on the statistical moments of the forward-link CDMA signal. Of primary interest is the normalized fourth-order moment, which is referred to as the “power variance”. Several techniques for reducing the power variance of the CDMA signal are discussed that are based on Walsh code selection and data encoding. Certain groupings of Walsh codes, referred to as “active quadruples”, are shown to be useful in predicting the potential of each technique. Results demonstrate the reduction in the power variance afforded by two novel approaches referred to as “channel hopping” and “data reversal”