How do I get the value of "Length of the analysis of the Window"

Wireless Connectivity Ultra-Wideband
1

The APS006-Part3 , we can get Luep = Number of peaks above the new low threshold / Maximum possible peaks in the analysis window;the Maximum possible peaks in the analysis window is got:
Maximum possible peaks in the analysis window =( Length of the analysis Window -1 ) / 2.

Well,I want to know “Length of the analysis Window” from which register?How do I get this value???

Thank You!!