A simple constant envelope modulation scheme for orthogonal multicode CDMA system

We propose a simple linear transformation technique to alleviate the signal envelope fluctuation in an orthogonal multicode CDMA system. This method is capable of converting the multilevel transmitted signals of multicode CDMA into a constant envelope signal, which then allows the use of efficient nonlinear power amplifiers. This feature leads to significant cost-reduction in the implementation of multicode CDMA systems in the uplink. The error performance and the overall complexity of this technique is shown to be very similar to that of a conventional orthogonal multicode CDMA system.