CTHp1-2: Potential Performance of Partial Crosstalk Cancellation in Twisted Pair Cables

This paper presents a method for calculating the reduction in crosstalk power sum obtained by canceling the M strongest interferers in a multi-pair cable. This approach uses Monte Carlo simulations, and it is based on an improved crosstalk model where all individual pair combinations in the cable are modeled separately. All parameters of the model are based on measurements, and an extensive set of crosstalk measurements is necessary in order to describe all relevant pair combinations. The results for far end crosstalk apply to both single carrier and multi- carrier systems. However, the results for near end crosstalk are valid only for multicarrier systems using per sub-channel cancellation. The method has been applied to three cable types of different sizes, which are all based on 10-pair binder groups. The results predict somewhat smaller crosstalk reductions than previously reported for cables containing up to ten pairs. However, it is shown that crosstalk cancellation in larger cables is far more challenging. Our results indicate that it may be difficult to obtain crosstalk reductions of more than 5 - 10 dB for cables of size 100 pairs or more for a realistic number of cancellers (M les 20).