ADSL-VDSL interference mitigation for the fiber to the cabinet architecture using adaptive filtering and the longitudinal signal as a reference

Abstract

With architectures such as fiber to the cabinet, the possible combination of shorter lines deployed from the cabinet with longer lines deployed from the Central Office in the same bundle can cause the far-end crosstalk from the transmitters located at the cabinet to severely degrade the performance of the long lines. External interference (including crosstalk) mostly couples to the twisted-pair line as a longitudinal signal, and then leaks to differential mode because of the lack of ideal line balance. This thesis offers a possible solution to mitigate crosstalk impairments worsened by the fiber to the cabinet architecture. This thesis uses the longitudinal signal as a reference to an adaptive wideband crosstalk canceller, aiming to decrease the crosstalk in the corrupted differential signal. Simulations show that the canceller can substantially reduce the crosstalk in the differential signal and evaluates three distinct adaptive algorithms for convergence speed and complexity.