Direct Sequence Spread Spectrum (DSSS) is a Spread Spectrum technique in which a narrowband Signal is spread over a wide Bandwidth by multiplying it with a high-rate PN sequence. Each data bit is replaced by an entire PN sequence, producing a wideband signal whose bandwidth is determined by the Chip rate rather than the data rate.
At the Receiver, correlating against the same PN sequence despreads the signal, recovering the original data while suppressing interference and noise that are uncorrelated with the sequence.