A method is provided which comprises: adjusting a plurality of times a transmit power to vary between a first setting and a second setting on a first Digital Subscriber Line (DSL line) to optimize energy consumption for the first DSL line; measuring or estimating a change in a performance of a second DSL line neighboring the first DSL line caused by a change in crosstalk on the second DSL line generated by the first DSL line in response to adjusting the transmit power of the first DSL line; and identifying one or more DSL lines among a plurality of DSL lines determined to safely operate in a low-power mode by identifying which of the plurality of DSL lines exhibit a crosstalk coupling to neighboring DSL lines below a specified threshold.

A method of operation in an Ethernet transceiver is disclosed. The method includes initiating a training mode of operation, and transmitting Infofield frames to a link partner. Each Infofield frame including a payload field to provide data to the link partner. A flow of the transmitted Infofield frames is controlled such that a new Infofield frame is not transmitted before a previous Infofield frame is received by the link partner.

A method of operation in an Ethernet transceiver is disclosed. The method includes initiating a training mode of operation, and transmitting Infofield frames to a link partner. Each Infofield frame including a payload field to provide data to the link partner. A flow of the transmitted Infofield frames is controlled such that a new Infofield frame is not transmitted before a previous Infofield frame is received by the link partner.

Embodiments of the present invention provide a signal transmission method. The method includes: sequentially rotating phases of to-be-sent signals on a line set 1 by different angles and in relative to phases of to-be-sent signals on a line set 2, and sequentially sending, to a user side, the to-be-sent signals whose phases are rotated. The method also includes receiving a rotation factor that is of a high-quality received signal on the line set 1 and that is fed back by the user side, where the high-quality received signal includes a received signal with a high signal-to-noise ratio or high power. The method also includes using the rotation factor fed back by the user side as a fixed rotation factor, and rotating, according to the fixed rotation factor, a phase of a signal to be subsequently sent on the line set 1.

At least one crosstalk probing sequence out of a set of orthogonal crosstalk probing sequences is assigned to the at least one respective disturber line for modulation at the given carrier frequency of at least one respective sequence of crosstalk probing symbols, and error samples are successively measured by a receiver coupled to the victim line at the given carrier frequency while the at least one sequence of crosstalk probing symbols are being transmitted over the at least one respective disturber line are fed back for crosstalk estimation. The received error samples are next correlated with at least one unassigned crosstalk probing sequence out of the set of orthogonal crosstalk probing sequences for detection of a demapping error in the received error samples.

At least one crosstalk probing sequence out of a set of orthogonal crosstalk probing sequences is assigned to the at least one respective disturber line for modulation at the given carrier frequency of at least one respective sequence of crosstalk probing symbols, and error samples are successively measured by a receiver coupled to the victim line at the given carrier frequency while the at least one sequence of crosstalk probing symbols are being transmitted over the at least one respective disturber line are fed back for crosstalk estimation. The received error samples are next correlated with at least one unassigned crosstalk probing sequence out of the set of orthogonal crosstalk probing sequences for detection of a demapping error in the received error samples.

Embodiments of the present invention provide a power control method, device, and system, and relate to the field of communications technologies. The method is applied to a vectoring system, where the vectoring system includes multiple lines, each line includes multiple subcarriers, and for each subcarrier, a crosstalk channel is formed between the multiple lines, and the method includes: obtaining a closed subcarrier set of the multiple lines according to line crosstalk channel information corresponding to each subcarrier of the multiple subcarriers, where the closed subcarrier set includes a subcarrier set required to be closed on the multiple lines; and sending the closed subcarrier set of the multiple lines to a transceiver, and closing, by the transceiver, a transmit signal on a subcarrier required to be closed on each line.

Embodiments of the present invention provide a power control method, device, and system, and relate to the field of communications technologies. The method is applied to a vectoring system, where the vectoring system includes multiple lines, each line includes multiple subcarriers, and for each subcarrier, a crosstalk channel is formed between the multiple lines, and the method includes: obtaining a closed subcarrier set of the multiple lines according to line crosstalk channel information corresponding to each subcarrier of the multiple subcarriers, where the closed subcarrier set includes a subcarrier set required to be closed on the multiple lines; and sending the closed subcarrier set of the multiple lines to a transceiver, and closing, by the transceiver, a transmit signal on a subcarrier required to be closed on each line.

A system that incorporates teachings of the present disclosure may include, for example, a controller to: determine crosstalk coupling characteristics between a plurality of lines of a digital subscriber line system connected to a plurality of modems based on a transition between a full power mode and one or more other modes, and provide the determined crosstalk coupling characteristics to one or more of the plurality of modems for performance of at least one of pre-coding a transmitted signal and processing a received signal along a line of the plurality of lines, where the pre-coding and processing is performed based at least in part on the determined crosstalk coupling characteristics, and where the pre-coding of the transmitted signal and the processing of the received signal reduce effects of fluctuating crosstalk. Other embodiments are disclosed.

A system that incorporates teachings of the present disclosure may include, for example, a controller to: determine crosstalk coupling characteristics between a plurality of lines of a digital subscriber line system connected to a plurality of modems based on a transition between a full power mode and one or more other modes, and provide the determined crosstalk coupling characteristics to one or more of the plurality of modems for performance of at least one of pre-coding a transmitted signal and processing a received signal along a line of the plurality of lines, where the pre-coding and processing is performed based at least in part on the determined crosstalk coupling characteristics, and where the pre-coding of the transmitted signal and the processing of the received signal reduce effects of fluctuating crosstalk. Other embodiments are disclosed.