Abstract: The present invention provides a method of training a DSL link while transmitting data over a powerline connection. If the powerline connection causes interference on the DSL link then this will be present during the line training, giving a more robust set of line parameters.

Abstract: The present invention provides a method of training a DSL link whilst transmitting data over a powerline connection. If the powerline connection causes interference on the DSL link then this will be present during the line training, giving a more robust set of line parameters.

Abstract: A digital subscriber line arrangement includes a downstream modem, an upstream modem and a copper pair connection between the modems. Each modem includes electrical length estimation function code means which causes the respective modem to measure the attenuation of signals transmitted by the other modem at a plurality of different frequencies, and to combine these measurements, or functions thereof, together to form a combined attenuation measure and to use this combined measure to form an electrical length estimation, KL0bis. The downstream modem is operable to transmit its electrical length estimation to the upstream modem, and the upstream modem is operable to generate a definitive electrical length estimation in dependence upon both the received estimation from the downstream modem and the estimation made by the upstream modem. Having generated a definitive electrical length estimation, the upstream modem is operable to transmit this to the downstream modem.

Abstract: A digital subscriber line arrangement includes a downstream modem, an upstream modem and a copper pair connection between the modems. Each modem includes electrical length estimation function code means which causes the respective modem to measure the attenuation of signals transmitted by the other modem at a plurality of different frequencies, and to combine these measurements, or functions thereof, together to form a combined attenuation measure and to use this combined measure to form an electrical length estimation, KL0bis. The downstream modem is operable to transmit its electrical length estimation to the upstream modem, and the upstream modem is operable to generate a definitive electrical length estimation in dependence upon both the received estimation from the downstream modem and the estimation made by the upstream modem. Having generated a definitive electrical length estimation, the upstream modem is operable to transmit this to the downstream modem.

Abstract: To reduce power consumption and associated heating in a line card of line termination equipment (LTE, 12) employing multiple cub-channel carriers to communicate broadband information to customer premise equipment (CPE, 30) down a wireline communication resource (26, sub-channel carrier transmissions are restricted (58) during periods of CPE inactivity. Power supplies to a power amplifier (30) associated with the line card and wireline resource (26) are reduced, with digital signal processing capabilities of the LTE (12) further restricted (64). When the CPE wishes to re-start communication, the CPE (30) locks (68) to a correct alignment in a transmission scheme using a pilot tone that is transmitted within a simple pattern sent during reduced sub-channel carrier transmissions. Alternatively, should all transmission from the LTE cease during CPE inactivity, then the CPE monitors (80) the transmission environment and sends (82) a wake-up call to the LTE between boundaries of an uplink slot.

Abstract: A method, and related apparatus, for determining symbol alignment in a discrete multi-tone communications system comprising the steps of: receiving a signal on each of at least one selected carrier frequency; for each of a plurality of receiver window alignments with respect to said signals, deriving a measure of received signal power level on each said selected carrier frequency; for each said receiver window alignment and selected carrier frequency deriving a measure of spectral leakage on at least one adjacent carrier frequency; selecting a receiver window alignment responsive to said derived measures.

Abstract: A reduction in a peak-to-mean envelope power ratio of a multicarrier signal, represented as a time domain signal, is achieved by applying (76) an offset, indicative of a difference (74) between a mean signal level and a midpoint level of the time domain signal, to the time domain signal. Alternatively, constellation values of positive and negative frequency components are modified by differing functions to produce a modified data set. Preferably, the negative frequency components are set to a predetermined value (namely zero (124)) to provide an alternate coding scheme Once the multicarrier signal has been converted into a time domain representation, real and imaginary parts (126-128) of the modified data set that consequently only contain positive frequency components and zeros are compared with one another to identify (130) which of the real and imaginary parts has a lower peak-to-average signal ratio (134) for the time domain representation.