A Sliding-Window Kernel RLS Algorithm and its Application to Nonlinear Channel Identification

TitleA Sliding-Window Kernel RLS Algorithm and its Application to Nonlinear Channel Identification
Publication TypeConference Paper
Year of Publication2006
AuthorsVan Vaerenbergh, S., J. Vía, and I. Santamaría
Conference NameIEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2006)
Month PublishedMay
Conference LocationToulouse, France
Keywordskernel adaptive filtering, KRLS
AbstractIn this paper we propose a new kernel-based version of the recursive least-squares (RLS) algorithm for fast adaptive nonlinear filtering. Unlike other previous approaches, we combine a sliding-window approach (to fix the dimensions of the kernel matrix) with conventional -norm regularization (to improve generalization). The proposed kernel RLS algorithm is applied to a nonlinear channel identification problem (specifically, a linear filter followed by a memoryless nonlinearity), which typically appears in satellite communications or digital magnetic recording systems. We show that the proposed algorithm is able to operate in a time-varying environment and tracks abrupt changes in either the linear filter or the nonlinearity.