An Improved LSL Interpolator to Suppress Narrow-Band Interference forDirect-Sequence Spread-Spectrum Systems

An improved interpolator based on QR-decomposition is proposed to suppress narrow-band interference (NBI) in direct-sequence spread-spectrum (DS/SS) systems. This interpolator is based on the discrepancy in the predictability between NBI and the spread spectrum signal (SS), and then uses a linear interpolation of the received signal to estimate NBI. Because of QR-decomposition operation instead of inverting the correlation matrix and a novel variable with a small dynamic range, the performances of QRD-LSL interpolators outperform ones of LSL predictors and LSL interpolators. It was shown that the QRD-LSL interpolators can obtain more 4 dB processing gain than LSL predictors and LSL predictors, and its total computational complexity scales linearly with the interpolation order.