Blind estimation of signal in periodic long-code DSSS communications

This paper discusses blind estimation of periodic long-code (PLC) direct sequence spread spectrum (DSSS) signal. We model a PLC DSSS signal as equivalent to a multiuser short-code DSSS system. This enables us to exploit second-order statistics (SOS) to estimate users´ spreading codes up to an inherent ambiguity matrix. Using the structure of the spreading codes of these virtual users and without further restricting assumptions, we will show that the ambiguity matrix can be estimated which would lead us to the extraction of spreading codes. Exploiting similar ideas, we will extend the proposed algorithm to blind estimation of the PLC DSSS signal in multipath environment. Finally, simulations are presented to demonstrate the superior performance of the proposed algorithm.