改进的变步长比例仿射投影算法

摘要

变步长分割式比例仿射投影算法(VSS-SPAPA)具有收敛快、失调小等优点,但运用到有大量抽头系数需要更新的回波抵消器中时,因计算量较大,限制了其应用.为降低其计算复杂度,基于局部迭代思想提出了一种改进算法.该算法将滤波器系数分成多个系数子集,通过仅更新权系数某一子集的方法,减少了每次迭代中需更新的抽头权系数个数,从而减少了VSS-SPAPA的运算量.理论分析和仿真结果表明:新算法每次迭代更新的抽头权系数只需达到全部系数的一半时,收敛速度和稳态误差均与原算法相当,但所提算法较大程度降低了计算复杂度,从而具备更好的实时性.%Variable step-size segment proportionate affine projection algorithm,namely VSS-SPAPA,incorporates the advantages of fast convergence speed and low mis-adjustment.However,the large number of filter coefficients in echo cancellation applications diminishes the usefulness of this algorithm owing to increased complexity.To deal with this obstacle,a selective par-tial-update method for VSS-SPAPA is proposed which partitions the filter coefficients into multiple subsets and focuses on updating a selected subset per iteration because the computational complexity is proportional to the number of filter coeffi-cients.Echo cancellation simulation results verify that the proposed algorithm can maintain the convergence and tracking performance close to the full update VSS-SPAPA when its updating counts range from around 50% to 100% of the number of updates in standard algorithm.