Exploitation of Far-End Crosstalk in MIMO-OFDM Twisted Pair Transmission Systems

A. Ahrens and C. Lange (Germany)


TwistedPair Cable, OFDM, Power Allocation, Multiple Input MultipleOutput (MIMO) System, Lagrange Multi plier Method, SingularValue Decomposition.


Crosstalk is one of the most limiting factors in local ca ble networks. Often the strong near-end crosstalk (NEXT) disturbance is avoided or suppressed and only the far-end crosstalk (FEXT) remains as crosstalk influence. If FEXT is present, signal parts are transmitted via the FEXT paths from the transmitter to the receiver in addition to the di rect transmission paths. Therefore transmission schemes are of great practical interest, which take advantage of the signal parts transmitted via the FEXT paths. Here an inter esting combination of MIMO-OFDM and power allocation is considered, which is able to take advantage of the FEXT signal path. Based on the Lagrange multiplier method an interesting combination of singular-value decomposi tion (SVD) and power allocation is considered. Contrary to other contributions, here the transmit power is not only adapted to the subchannels but rather to the symbol ampli tudes of the SVD equalized data block individually. As a result it can be seen that the exploitation of FEXT can help to improve the transmission quality in terms of a minimum bit-error rate.

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