Proposed triple correlation receiver for CDMA

Conventional intercept receivers based on second order signal processing are generally ineffective in detecting direct sequence spread spectrum signals if the spreading sequences are unavailable. Also the capacity of direct sequence code division multiple access is limited by multiple access interference. Previous work has shown that the triple correlation function is used to implement triple correlation receiver to detect direct sequence spread spectrum signals. In this receiver, the received signal is auto-triple-correlated at a particular lag such that the transmitted code acts as its own reference. In this paper, we study the conventional direct sequence CDMA system, the cross-correlation between codes of length 127. The study has been extended to calculate the triple correlation function for the same code. A proposed triple correlation receiver to detect the pervious codes is presented. Finally, a detailed study of triple correlation receiver in multiuser environment for direct sequence CDMA has been performed. The study ended with a comparison between conventional and triple correlation receivers with numerical examples illustrated.