Crosstalk cancellation for hybrid fiber twisted-pair systems

Broadband access over the existing telephone network can be provided by the deployment of hybrid fiber twisted-pair (HFTP) systems. For HFTP the twisted-pair cable has to be modelled as a vector channel with distributed transceivers on the subscriber side. The upstream transmission capacity can be increased by FEXT cancellation based on a 2 dimensional decision feedback equalizer (2-D-DFE). The achievable gain depends on the usable upstream bandwidth as well as on the background noise and can be more than 100 % for the transmission of 27.6 Mbit/s with a 16-QAM. About 15 feedback taps are required per FEXT canceller, resulting in 19000 gates for a gate array implementation in 0.35 /spl mu/m technology.