AbstractAn asynchronous code‐division multiple access (CDMA) system with adaptive transmitters and receivers is considered. It is assumed that the adaptive receiver and transmitter have no knowledge of the signature waveforms and timing of other users. The concept of adaptive transmitter is based on feedback information from the corresponding receiver. The information obtained from the receiver is used to calculate the optimum transmitter signature. The signatures are adaptively adjusted according to the MSE criterion during the training period as well as during data transmission. CDMA systems employing the adaptive transmitters in the presence of multiple access interference achieve the matched filter bound with no interference. The proposed CDMA system are tested by simulation over a channel with multiple access interference and additive white gaussian nois