The Joint Anti-jamming of Superimposed Spread Spectrum and SP in DS MIMO System

As the direct spread (DS) combined with multiple input multiple output (MIMO) space time block codes has multiple access interference, and the performance will be degraded with strong jamming especially wideband jamming. The superimposed spread spectrum was presented to eliminate multiple access interference. The method of subspace projection (SP) was adopted to suppress wideband jamming which the channel and receiving matrix were projected with the subspace of jamming and noise to set up effective matrix for decoding. Thereinto, the maximal ratio combining was simplified to reduce the complexity of space time block codes. The theoretical analysis and system simulation shown that the anti-jamming scheme can improve the ability that DS system combat against narrow-band jamming, and achieve wideband jamming rejection and multiple access interference suppression absolutely.