On the second-order cyclostationarity properties of long-code DS-SS signals

In this letter, the cyclostationarity properties of a general class of long-code direct-sequence spread-spectrum (DS-SS) signals are analyzed, and it is shown that these properties can be exploited in long-code DS code-division multiple-access systems. Specifically, it is shown that a continuous-time DS-SS signal exhibits cyclostationarity at cycle frequencies related to both the symbol rate and the chip rate. Moreover, it is pointed out that the discrete-time signal obtained by uniformly sampling a continuous-time long-code DS-SS signal exhibits cyclostationarity, provided that at least two samples per chip are taken. Finally, it is shown how such a cyclostationarity can be suitably exploited for blind signal-parameter estimation.