Journal of Xi'an Jiaotong Universtity

Fast Adaptive Trans-Propagation Least Mean Square Algorithm Based on Principle of Alternative Projection
Wang Teng¹, Yan Guirong¹, Zhang Xinwu²
(School of Architectural Engineering and Mechanics, Xi'an Jiaotong University, Xi'an 710049, China;
2ª±China Academy of Engineering Physics, Mianyang 621900, China)

Abstract: A new fast adaptive algorithm, the TPLMS (Trans-Propagation Least Mean Square algorithm), was proposed for long finite impulse response(FIR) filters. Based on the iterative of alternative projection of two convex sets, a long FIR filter is decomposed into several sets of short sub-filters, and the iteration process is performed repeatedly from the set with the shortest sub-filters to the original filter. At each moment, the least mean square algorithm is performed sequentially in every set of sub-filters. Since the length of sub-filters is shorter than the original filter, the convergence rate is higher than the standard least mean square algorithm even by using a larger permissible iteration step-size. With the increase of the length of sub-filters step by step, the iteration step-size is reduced accordingly, which leads to a lower misadjustment. The simulation results indicate that the proposed TPLMS algorithm can remarkably speed up convergence rate, and is particularly suitable for long FIR filters.
Keywords: least mean square algorithm; alternative projection; long finite impulse response filter; trans-propagation least mean square algorithm