Research And Implementation Of Narrow-Band Interference Suppression Technology Based On DSSS Communication System

Direct Sequence Spread Spectrum (DSSS), as the most widely used spread spectrum system, has a good performance of interference suppressing ability. But the ability (interference tolerance) depends on the processing gain of DSSS system. If the processing gain is large enough, the DSSS system can suppress all the interferences. But, if the processing gain is limited and the power of Narrow Band Interference (NBI) exceeds some restrictions, the system performance is dramatically degraded; even the communication process is intermitted. For suppressing the strong NBI thoroughly on the condition that the processing gain will not be increased, it is often necessary to supplement the innate processing gain by introducing the NBI suppression technologies.Firstly, through analyzing and comparing all the NBI suppression arithmetic briefly, two arithmetic which to be implemented in engineering easily are put forward and implement the arithmetic based on FPGA. In time domain, a kind of adaptive notch is designed based on FIR filter according to the characteristic of DSSS communication system. In frequency domain, FFT calculation is a "bottle-neck" for implementing the NBI suppression. Therefore, an all-parallel pipeline arithmetic is put forward, which to implement the FFT calculation in real time and avoid the "bottle-neck".