Hi Mahdiyar,

CDMA spreading sequences will spread out the spectrum of narrowband interference while crosscorrelating the local sequence with the received sequence.

The "measure of goodness" or robustness in CDMA is called the "Jamming Margin"

In approximate terms, it is the ration of the effective RF bandwidth of the spreading sequence when applied to an RF carrier to the effective information bandwith of the unspread signal. If you have an unspread signal bandwidth of 10KHz and a spreading bandwith of 1000KHz, the jamming margin is 100 or 20 dB.

Good luck