An improved variable step-size affine projection algorithm for narrowband interference suppression in DSSS systems

In this paper, an improved Variable Step-Size Affine Projection Algorithm (VS-APA) is used in adaptive filters for narrowband interference suppression of direct sequence spectrum spreading (DSSS). Compared with traditional VS-APA and NLMS, this algorithm uses exponential function to vary the step-size, which can estimate NBI more accurately and a better tradeoff between performance and complexity. Computer simulations are shown to verify the analyses and compare the performance of the proposed Narrow-band Interference (NBI) suppression scheme with traditional VS-APA and NLMS adaptive algorithm.