Anti-jamming performance of multi-carrier spread spectrum with constant envelope

A special complex sequence, called a complex quadratic sequence, is proposed as the frequency-spreading sequence for multicarrier spread spectrum (MC-SS) modulation scheme. The resulting MC-SS signal has constant envelope in both time and frequency domains. This feature provides flexibility for the MC-SS system to mitigate the effects of both partial-bond jamming and pulse jamming. For partial-band jamming, the MC-SS system with frequency domain detection and combining can outperform DS/SS. for pulse jamming, the MC-SS system with time-domain detection and combining can outperform MC-SS systems. The proposed MC-SS signal has a constant envelope thus reducing linearity requirements on the power amplifier. A simple jammer state estimation scheme for both partial-band and pulse jamming channel is also proposed and analyzed. Furthermore multi-access with the MC-SS system is possible by assigning users with different cyclic-shifts of the complex quadratic sequence. Simulation results are provided to verify our analysis.