Asymptotic multiuser efficiency for a two-states CDMA system

The use of CDMA makes third generation wireless systems interference limited rather than noise limited. The research for new methods to reduce interference and increase efficiency lead us to formulate a signaling method where fast impulsive silence states are mapped on zero-energy symbols. The theoretical formulation of the optimum receiver is reported and the asymptotic multiuser efficiency has been derived and applied to the optimum two-states receiver. Numerical comparisons have been performed to show the advantages of the proposed scheme over the traditional single state CDMA transmission. Several operating scenarios have been numerically analyzed and the results are reported in the paper.