New structure of affine projection algorithm using a novel subband adaptive system

This paper proposes a new structure of the affine projection algorithm (APA) based on the subband adaptive system (SAS). It is known that the APA can increase the rate of convergence when the input signal is highly correlated. The SAS used in the proposed structure differs from the conventional ones, i.e., it does not include the decimation operations, the adaptive filters in subbands share the same coefficients, and coefficients of analysis filters are determined according to the Hadamard transform. These differences make the proposed structure have some advantages over the conventional structures of the APA, e.g., we can greatly reduce the computational requirement for implementing the APA because the proposed structure does not require the matrix inversion.