Algorithmically engineered fast multichannel adaptive filter based on QR-RLS

A fast version of the multichannel QR algorithm for RLS adaptive filtering, with channel filters of unequal length, is derived. This is achieved by ap plying the techniques of algorithmic engineering to a signal flow graph rep resentation of the basic QR RLS algorithm. By virtue of this graphical appr oach, the derivation is relatively straightforward and circumvents the comp lex and notationally verbose matrix algebra usually involved in the derivat ion of fast RLS algorithms in general and the previously published, unequal -length, multichannel RLS lattice algorithm in particular.