Optimization method for designing filter bank channelizer of a software defined radio using vertical common subexpression elimination

The most computationally intensive part of wide-band receivers in software defined radios is the channelizer, which extracts individual radio channels from the output of the ADC. The computational complexity of finite impulse response (FIR) filters used in the channelizer is dominated by the number of adders (subtractors) employed in the multipliers. A method for designing channel filters using the minimum number of adders by optimizing vertical common subexpression elimination is presented in this paper. The reduction in number of adders is obtained by eliminating redundant multiplications of common subexpressions that exist among the channel filters of the filter bank channelizer (FBC) with the input signal. Design example of the channel filters employed in the Digital Advanced Mobile Phone System (D-AMPS) show that the proposed method offers considerable reduction in the number of full adders over conventional common subexpression elimination method.