Abstract: Techniques are disclosed for compensating for crosstalk using adaptation of data signals transmitted over respective channels of a communication network. In one example, a method comprises the following steps. Data is transmitted to a communication network device via a communication line during a sequence of periods. For each period of the sequence of periods, a separate value of a measure of crosstalk that was measured at the communication network device is received, each value being an average of measurements at the device of measures of crosstalk for a plurality of communication network signal subcarriers. For each individual signal subcarrier of the plurality, a matrix is updated based on the received values, the matrix being configured to precode data transmissions to the communication network device over the individual signal subcarrier. The communication network may be a DSL system, the signal subcarriers may be DSL tones, and the measure of crosstalk may be a SINR value.

Abstract: Techniques are disclosed that efficiently obtain channel crosstalk estimates in DSL systems and other communication systems that may include unsynchronized channels. For example, a method includes obtaining a first set of estimated measures of crosstalk for a first portion of a plurality of communication channels over which data signals are to be transmitted from a transmitter to a plurality of receivers, and interpolating a second set of estimated measures of crosstalk for a second portion of the plurality of communication channels based on the first set of estimated measures of crosstalk. The first portion of the plurality of communication channels may be a subset of the plurality of communication channels and the second portion of the plurality of communication channels is a remainder of the plurality of communication channels. Each estimated measure of crosstalk may relate to at least one tone associated with at least one of the plurality of communication channels.

Abstract: Techniques are disclosed for compensating for crosstalk using adaptation of data signals transmitted over respective channels of a communication system. For example, a method includes the following steps. A first set of estimated measures of crosstalk is obtained for at least a selected portion of a plurality of communication channels over which data signals are to be transmitted from a transmitter to at least a selected portion of a plurality of receivers. A first set of data signals based on the first set of estimated measures of crosstalk is adapted to generate a first set of adjusted data signals. The first set of adjusted data signals is transmitted to corresponding ones of the plurality of receivers. A second set of estimated measures of crosstalk is obtained for the selected portion of the plurality of communication channels. A second set of data signals for transmission based on the second set of estimated measures of crosstalk is adapted to generate a second set of adjusted data signals.

Abstract: A method for authenticating a mobile device is provided. The method includes receiving a communication request from the mobile device. The mobile device is operable to exchange data over a primary channel. Authentication data is received from the mobile device over a second channel. The secondary channel is a short-range channel operable for exchanging data when the mobile device is within physical proximity. The authentication data is processed to determine whether the mobile device is a trusted device.

Abstract: A multi-channel processing module is arranged in series with multiple channels of a communication system. The processing module synchronizes downstream symbols among the channels, and synchronizes downstream symbols for at least a given one of the channels with upstream symbols for that channel. The synchronization of downstream symbols among the channels and the synchronization of downstream symbols for at least the given channel with upstream symbols for that channel are collectively achieved by adjusting downstream and upstream adjustable delay elements associated with respective downlink and uplink signal paths in the multi-channel processing module. The channels may comprise respective subscriber lines of a DSL communication system.

Abstract: An apparatus includes a transmitter configured to transmit symbols to one or more receivers via a plurality of communication channels of a physical communication link. The transmitter is configured to estimate a phase of one or more off-diagonal elements of a channel matrix for the physical communication link based on values of signal-to-interference-plus-noise ratios at the one or more receivers.

Abstract: A method involves performing a plurality of acts. The acts include transmitting a first signal stream to a first channel of a multi-channel communications medium while transmitting a second signal stream to a different second channel of the medium. The second signal stream is substantially temporally correlated to the first signal stream. The method includes receiving an SINR measured at a receiver configured to receive signals from the first channel. The SINR is measured while the receiver received the first signal stream. The method includes determining a channel matrix element between the first and second channels or a ratio of said channel matrix element to a diagonal element of the channel matrix. The act of determining is based on the received SINR.

Abstract: A multi-channel processing module is arranged in series with multiple channels of a communication system. The processing module synchronizes downstream symbols among the channels, and synchronizes downstream symbols for at least a given one of the channels with upstream symbols for that channel. The synchronization of downstream symbols among the channels and the synchronization of downstream symbols for at least the given channel with upstream symbols for that channel are collectively achieved by adjusting downstream and upstream adjustable delay elements associated with respective downlink and uplink signal paths in the multi-channel processing module. The channels may comprise respective subscriber lines of a DSL communication system.

Abstract: Techniques are disclosed that efficiently obtain channel crosstalk estimates in DSL systems and other communication systems that may include unsynchronized channels. For example, a method includes obtaining a first set of estimated measures of crosstalk for a first portion of a plurality of communication channels over which data signals are to be transmitted from a transmitter to a plurality of receivers, and interpolating a second set of estimated measures of crosstalk for a second portion of the plurality of communication channels based on the first set of estimated measures of crosstalk. The first portion of the plurality of communication channels may be a subset of the plurality of communication channels and the second portion of the plurality of communication channels is a remainder of the plurality of communication channels. Each estimated measure of crosstalk may relate to at least one tone associated with at least one of the plurality of communication channels.

Abstract: A method involves performing a plurality of acts. The acts include transmitting a first signal stream to a first channel of a multi-channel communications medium while transmitting a second signal stream to a different second channel of the medium. The second signal stream is substantially temporally correlated to the first signal stream. The method includes receiving an SINR measured at a receiver configured to receive signals from the first channel. The SINR is measured while the receiver received the first signal stream. The method includes determining a channel matrix element between the first and second channels or a ratio of said channel matrix element to a diagonal element of the channel matrix. The act of determining is based on the received SINR.

Abstract: Techniques are disclosed for compensating for crosstalk using adaptation of data signals transmitted over respective channels of a communication network. In one example, a method comprises the following steps. Data is transmitted to a communication network device via a communication line during a sequence of periods. For each period of the sequence of periods, a separate value of a measure of crosstalk that was measured at the communication network device is received, each value being an average of measurements at the device of measures of crosstalk for a plurality of communication network signal subcarriers. For each individual signal subcarrier of the plurality, a matrix is updated based on the received values, the matrix being configured to precode data transmissions to the communication network device over the individual signal subcarrier. The communication network may be a DSL system, the signal subcarriers may be DSL tones, and the measure of crosstalk may be a SINR value.

Abstract: Techniques are disclosed for compensating for crosstalk using adaptation of data signals transmitted over respective channels of a communication system. For example, a method includes the following steps. A first set of estimated measures of crosstalk is obtained for at least a selected portion of a plurality of communication channels over which data signals are to be transmitted from a transmitter to at least a selected portion of a plurality of receivers. A first set of data signals based on the first set of estimated measures of crosstalk is adapted to generate a first set of adjusted data signals. The first set of adjusted data signals is transmitted to corresponding ones of the plurality of receivers. A second set of estimated measures of crosstalk is obtained for the selected portion of the plurality of communication channels. A second set of data signals for transmission based on the second set of estimated measures of crosstalk is adapted to generate a second set of adjusted data signals.

Abstract: An apparatus includes a transmitter configured to transmit symbols to one or more receivers via a plurality of communication channels of a physical communication link. The transmitter is configured to estimate a phase of one or more off-diagonal elements of a channel matrix for the physical communication link based on values of signal-to-interference-plus-noise ratios at the one or more receivers.

Abstract: An apparatus includes a plurality of DSL modems. Each DSL modem is configured to be connected to a corresponding DSL subscriber line. A first of the DSL modems is configured to transmit a data stream to a DSL subscriber via inter-line cross-talk between the one of the DSL subscriber lines connected to the first of the DSL modems and the one of the DSL subscriber lines connected to a second of the DSL modems.

Abstract: A method and apparatus for using messaging to remotely control access over a network to a subscriber data associated with a mobile device that may be stolen or lost is provided. The method of wireless communication over a network with a mobile device having access to data associated with a subscriber comprises transmitting at least one message to the mobile device over the network for instructing the mobile device to deny access to the data for an unintended use in response to an indication of connectivity to the network for the subscriber. Instead of blocking connectivity of a mobile device which may be stolen or lost to a network, by denying access to data available on a mobile device which may be stolen or lost, at least a portion such vulnerable data stored on the mobile device also becomes inaccessible for malicious usage.

Abstract: A method for authenticating a mobile device is provided. The method includes receiving a communication request from the mobile device. The mobile device is operable to exchange data over a primary channel. Authentication data is received from the mobile device over a second channel. The secondary channel is a short-range channel operable for exchanging data when the mobile device is within physical proximity. The authentication data is processed to determine whether the mobile device is a trusted device.

Abstract: A method is provided of transfer of a service session with a mobile terminal from a first wireless local area network to one of its neighbours in a telecommunications system. According to the method, temporary credentials are provided to the mobile terminal, each being usable for access to a corresponding neighbour. The mobile terminal stores said credentials. The mobile terminal moves to the coverage area of a second network which is one of the neighbours, and detects that it has so moved. The mobile terminal identifies, or is informed of the identity of the second network. The mobile terminal then sends to the second network the temporary credential corresponding to the second network. The second network determines the temporary credential received to be valid, so permits service session transfer.

Abstract: A telecommunications network includes nodes and a controller operative to control levels of best-effort traffic transmitted from those nodes so as to keep bandwidth available for traffic sent with a predetermined quality of service.