Time-Variant Unit-Norm Tight Frames by Means of Modulated Filter Banks

Unit-norm tight frames (UNTFs) are interesting in the context of robust transmission because of their robustness to erasures. In this correspondence, we show how to convert any finite-dimensional UNTF into an oversampled filter bank which implements a UNTF. The proposed construction uses the vectors of the finite-dimensional frame as modulating functions of a modulated filter bank. Like the usual critically sampled modulated filter banks, the oversampled filter banks obtained by the proposed construction can be made time variant without losing the UNTF condition.