Direct Sequence Spread Spectrum (DSSS) is a spread spectrum technique whereby the original data signal is multiplied with a pseudo random noise spreading code. This spreading code has a higher chip rate (this the bitrate of the code), which results in a wideband time continiuous scrambled signal. DSSS significantly improves protection against interfering (or jamming) signals, especially narrowband and makes the signal less noticeable. It also provides security of transmission if the code is not known to the public. These reasons make DSSS very popular by the military. In fact, DSSS was first used in the 1940s by the military.
In this project, I have implemented a DSSS spread spectrum modulation technique in GNU Radio and demonstrated its resistance to interference by showing that only the intended receiver is able to decrypt the sent message.
For more information, you can refer to this presentation over here.
The complete implementation of our code can be found over here.