Abstract: A method of far-end crosstalk (FEXT) channel estimation in a digital subscriber line (DSL) system, wherein the DSL system comprises a first subscriber line and a second subscriber line, the method comprising allocating a plurality of time slots, wherein the plurality of time slots comprises a first period and a second period, wherein the first period precedes the second period, and wherein each of the first and second periods comprises at least one time slot, transmitting at least one training symbol in the first period onto the second subscriber line in a downstream direction while no transmission is made on the first subscriber line, receiving at least one feedback symbol in the second period from the first subscriber line in an upstream direction, and estimating a level of downstream FEXT from the second subscriber line into the first subscriber line based on the at least one feedback symbol.

Abstract: An apparatus configured to couple to a plurality of subscriber lines comprising a plurality of transmitters configured to couple to a plurality of physical channels and at least one virtual channel. The number of physical channels equals the number of subscriber lines. A processor is configured to compute a precoder matrix to minimize an error value. The error value accounts for an error on each channel subject to a constraint on power for each channel. A precoder is coupled to the processor and configured to use the precoder matrix to jointly process a plurality of data signals to generate a plurality transmit signals for the plurality of physical channels and the at least one virtual channel.

Abstract: An apparatus for synchronizing a plurality of digital subscriber line access multiplexers (DSLAMs) comprising a reference clock configured to generate a reference clock signal, and an interface configured to transmit the reference clock signal to the DSLAMs, wherein each of the DSLAMs is configured to align its system clock with the reference clock.

Abstract: An apparatus configured to couple to a plurality of subscriber lines comprising a plurality of transmitters configured to couple to a plurality of physical channels and at least one virtual channel, wherein the number of physical channels equals the number of subscriber lines, a processor configured to compute a precoder matrix to minimize an error value, wherein the error value accounts for an error on each channel subject to a constraint on power for each channel, and a precoder coupled to the processor and configured to use the precoder matrix to jointly process a plurality of data signals to generate a plurality transmit signals for the plurality of physical channels and the at least one virtual channel.

Abstract: A method of far-end crosstalk (FEXT) channel estimation in a digital subscriber line (DSL) system, wherein the DSL system comprises a first subscriber line and a second subscriber line, the method comprising allocating a plurality of time slots, wherein the plurality of time slots comprises a first period and a second period, wherein the first period precedes the second period, and wherein each of the first and second periods comprises at least one time slot, transmitting at least one training symbol in the first period onto the second subscriber line in a downstream direction while no transmission is made on the first subscriber line, receiving at least one feedback symbol in the second period from the first subscriber line in an upstream direction, and estimating a level of downstream FEXT from the second subscriber line into the first subscriber line based on the at least one feedback symbol.

Abstract: A processing method and a transceiver for channel changing in a joint transceiving mode are provided. The method includes: performing fault detection for one or more direct channels; after a fault is detected on a direct channel, stopping sending signals on the direct channel; detecting whether the direct channel with fault has been recovered; and when recovery of the direct channel with fault is detected, resuming sending signals on the direct channel.

Abstract: An apparatus for synchronizing a plurality of digital subscriber line access multiplexers (DSLAMs) comprising a reference clock configured to generate a reference clock signal, and an interface configured to transmit the reference clock signal to the DSLAMs, wherein each of the DSLAMs is configured to align its system clock with the reference clock.

Abstract: A method for returning a signal error in a multi-carrier communication system is disclosed. A specific sub-carrier interval is determined. The specific sub-carrier interval is larger than an interval between adjacent sub-carriers in the multi-carrier communication system. A signal error is returned to a central office end on a corresponding frequency in a communication frequency band of the multi-carrier communication system at the specific sub-carrier intervals.

Abstract: A processing method and a transceiver for channel changing in a joint transceiving mode are provided. The method includes: performing fault detection for one or more direct channels; after a fault is detected on a direct channel, stopping sending signals on the direct channel; detecting whether the direct channel with fault has been recovered; and when recovery of the direct channel with fault is detected, resuming sending signals on the direct channel.