An adaptive cancellation of direct wave interference using a new variable-step-size NLMS algorithm

The adaptive cancellation techniques of direct wave interference in passive bistatic pulse radar were developed in this paper. When the scatter signal was mixed with the direct wave, and can not be separated by the time window technique, a new variable-step-size normalized LMS (new VSSNLMS) algorithm was proposed to implement the adaptive cancellation of direct wave interference, on the basis of the analyses of the conventional LMS algorithm, normalized LMS algorithm, and variable-step-size LMS algorithm. The superiority of the algorithm was proved by the computer simulation. The proposed algorithm was applied to adaptive cancellation of direct wave interference in passive bistatic pulse radar. The theoretical analysis and simulation results show that a faster convergence rate as well as a smaller output error are obtained by the new VSSNLMS algorithm than the conventional LMS, NLMS, and MSVSLMS algorithm.