Capacity Estimation of ADSL Line Using Frequency Domain Based SELT Technique

The channel capacity (bit rate) of the Digital subscriber loop depends on the loop topology and the noise Power Spectral Density (PSD). Single Ended Loop Testing (SELT) is the most preferred measurement technique to find out the loop topology due to its cost and operational advantages. A standing wave based new method on frequency domain approach is used to estimate the length and gauge of the loop. Results show good prediction capability of this method for the length range from 300 ft to 25000 ft for both gauge 24 and 26. The channel performance parameters i.e. channel capacity for fixed margin and tone loading profiles are then derived. The capacity estimates obtained in this method with specified noise and signal PSD match real line estimates.