MSE Analysis of Bi-scale LMS Used for Narrowband Interference Cancellation

Document Type

Conference Proceeding

Publication Date


Publication Title

Proceedings - 2020 IEEE Latin-American Conference on Communications, LATINCOM 2020


Adaptive LMS (Least Mean Square) equalizers are widely used in digital communication systems for their simplicity of implementation. Conventional adaptive filtering theory suggests that the upper bound on performance of such an equalizer is determined by the performance of a Wiener filter of the same structure. However, in the presence of a narrowband interferer the performance of the (normalized) LMS equalizer can be better than that of its Wiener counterpart. The Bi-scale NLMS (BLMS) algorithm enhances this NLMS (Normalized LMS) characteristic by simultaneously using two instantiations of NLMS that run at very different time scales. In this paper, the derivation of a predictive model for the MSE (Mean Square Error) performance of the BLMS equalizer as narrowband interference canceler is shown. The predictive model can be used to adjust canceler parameters on the fly without the delay needed for time-consuming simulations. Simulation results validate the proposed MSE model, which is shown to predict performance of the BLMS equalizer over a wide range of parameters.