Spread Spectrum System Using Noise Band Shift Keying

A new spread spectrum technique using band-limited Gaussian noise for transmission and incoherent detection at the receiver has been discussed. The proposed system called noise band shift keying (NBSK) may be considered as a modified form of the frequency-shift keying (FSK) system. In the NBSK system nonoverlapping bandlimited noise is transmitted instead of pure tones as in the FSK system and the center frequency of the noise is chosen on the basis of the binary data signal. For this system, an expression for the probability of error has been derived and it has been shown that its performance under nonfading channel conditions is identical to that of the FSK system with frequency diversity under Rayleigh fading conditions. Compared to the conventional spread spectrum systems, the proposed method is considerably more simple to implement and is attractive where adequate bandwidth is available.