Multi-channel signal processing for data communications in the presence of crosstalk

The authors consider transmission of data over multiple coupled channels, such as bundles of twisted-pair cables in the local subscriber loop, and between central offices in the public switched telephone network. Transceiver designs for such channels typically treat the crosstalk between adjacent cables as random noise uncorrelated with the transmitted signal. A transmitter/receiver pair is proposed which compensated for crosstalk by treating an entire bundle of cables as a single multi-input/multioutput channel with a (slowly varying) matrix transfer function. One attribute of the proposed transceiver is the use of a multichannel adaptive FIR (finite-impulse response) filter to cancel near-end crosstalk. Results of numerical simulations, including plots of mean squared error vs. time, and eye diagrams, are presented assuming a standard transmission line mode for the channel. These results indicate that data rates over coupled channels can be significantly increased by exploiting the multidimensional character of the channel