Convergence performance analysis of an affine projection algorithm in the presence of narrowband interference

In the presence of narrowband interference, non-Wiener effects have been observed for the normalized least-mean-square (NLMS) algorithm and the affine projection algorithm (APA). The convergence performance of the affine projection algorithm (APA) is analyzed in the presence of strong narrowband interference. Firstly, the relationship between the APA and the NLMS algorithm is derived, with the help of decorrelation of the input signal. Then, the statistical properties of the decorrelated input signals are derived, from which we can see that the convergence performance of the APA is almost not affected by the strong narrowband interference. The computer simulation results support the theoretical analysis.