Abstract: A modem for use in Digital Subscriber Line communications transmits and receives data over the local subscriber loop in common with voice information over the loop, while avoiding the need for voice/data splitters. The modem responds to disruptions associated with “disturbance events” such as on-hook to off-hook transitions and the like by rapidly switching between pre-stored channel parameter control sets defining communications over the loop under varying conditions. In addition to changing parameter control sets responsive to a disturbance event, the modem may also change transmission power levels and other system parameters such as frequency domain equalizer characteristics. Further, provisions are made for reduced bandwidth communications under selected conditions.

Abstract: Data is distributed among the channels of an asynchronous data subscriber loop (ADSL) communications system in accordance with an adaptive algorithm which from time to time measures the signal to noise ratio of the various channels and finds a margin for each channel dependent on achievement (where possible) of a given bit error rate and a desired data transmission rate. The margin distribution is achieved by augmenting the constellation signal to noise ratio to enhance computational efficiency and allow redetermination of bit allocation tables during transmission as necessary. Pairs of bit allocation tables are maintained at the transmitter and receiver and one table of each pair at the transmitter and receiver is updated while the other pair is in use for controlling communication.

Abstract: A system and method for supporting multiple applications are described. A digital subscriber line system includes two transceivers in communication over a communication channel using multicarrier modulation. Application profiles are defined for characterizing transmission of information over the communication channel. Each application profile is a parameter set that is associated with a unique set of one or more applications that may become active between the transceivers and specifies the transmission requirements for such applications. Each transceiver stores the application profiles and transmits information over the communication channel according to the one of the stored application profiles. When a change in a number of applications active between the transceivers occurs, a second one of the application profiles is retrieved. The transceivers then transition to transmitting information over the communication channel according to the second application profile.

Abstract: A Discrete Multitone Modulation (DMT) system and method with the capability to adapt the system bit rate on-line in a seamless manner. The DMT system provides a robust and fast protocol for completing this seamless rate adaptation. The DMT system also provides a framing and encoding method with reduced overhead compared to conventional DMT systems. The DMT system and method provide seamless rate adaptation with the provision of different power levels. This framing and encoding method enables a system with seamless rate adaptation capability. The system and method of the invention can be implemented in hardware, or alternatively in a combination of hardware and software.

Abstract: A DMT system and method with the capability to adapt the system bit rate on-line in a seamless manner. The DMT system provides a robust and fast protocol for completing this seamless rate adaptation. The DMT system also provides a framing and encoding method with reduced overhead compared to conventional DMT systems. The DMT system and method provide seamless rate adaptation with the provision of different power levels. This framing and encoding method enables a system with seamless rate adaptation capability. The system and method of the invention can be implemented in hardware, or alternatively in a combination of hardware and software.

Abstract: A technique is provided that may be employed in multicarrier communications to improve the efficiency of error correction using symbol-oriented error correction methodologies, by reducing the number of error correction code symbols (102, 104 . . . ) that are received in error that result from a single channel error. More specifically, in this technique, bits from the symbols are allocated among the channels in such a way as to minimize the number of respective channels that are allocated bits belonging to more that one respective symbol during a respective transmission period.

Abstract: Through the use of a variable state length initialization, both the transmitter and the receiver can have control of the length of one or more initialization states. For example, a transmitter can send information, such as a message, to the receiver at the commencement of, during initialization or prior to entering a variable length initialization state. The information can specify, for example, a minimum length of an initialization state as needed by the transmitter.

Abstract: A method for initializing modems in a multicarrier transmission system to establish a communication link between the transmitter and the receiver. An exemplary embodiment includes the steps of providing a predetermined parameter value that approximates a corresponding actual parameter value of the communication link, establishing a data communication link between a first transceiver and a second transceiver using the predetermined parameter value to allow the transmission of data, determining the actual parameter value, and seamlessly increasing the data rate of the established data communication link by using the determined actual parameter value to provide an steady state communication link with an updated data rate.

Abstract: A modem for use in Digital Subscriber Line communications transmits and receives data over the local subscriber loop in common with voice information over the loop, while avoiding the need for voice/data splitters. The modem responds to disruptions associated with “disturbance events” such as on-hook to off-hook transitions and the like by rapidly switching between pre-stored channel parameter control sets defining communications over the loop under varying conditions. In addition to changing parameter control sets responsive to a disturbance event, the modem may also change transmission power levels and other system parameters such as frequency domain equalizer characteristics. Further, provisions are made for reduced bandwidth communications under selected conditions.

Abstract: A Discrete Multitone Modulation (DMT) system and method with the capability to adapt the system bit rate on-line in a seamless manner. The DMT system provides a robust and fast protocol for completing this seamless rate adaptation. The DMT system also provides a framing and encoding method with reduced overhead compared to conventional DMT systems. The DMT system and method provide seamless rate adaptation with the provision of different power levels. This framing and encoding method enables a system with seamless rate adaptation capability. The system and method of the invention can be implemented in hardware, or alternatively in a combination of hardware and software.

Abstract: A transceiver and method for communicating over a communications channel having a plurality of subchannels are described. In particular, the transceiver is capable of dynamically switching between communicating data for a first active application set and communicating data for a second different active application set. An active application set is defined as the set of one or more active applications for which the transceiver is currently communicating data. As part of communicating data for the first active application set, the transceiver allocates the subchannels to the one or more applications in the first application set. The transmission requirements of the first active application set defines a first communication state of the transceiver. When the transceiver dynamically transitions to communicating data for the second different application set, the transceiver reallocates the subchannels to the one or more applications in the second different application set.

Abstract: A modem for use in Digital Subscriber Line communications transmits and receives data over the local subscriber loop in common with voice information over the loop, while avoiding the need for voice/data splitters. The modem responds to disruptions associated with “disturbance events” such as on-hook to off-hook transitions and the like by rapidly switching between pre-stored channel parameter control sets defining communications over the loop under varying conditions. In addition to changing parameter control sets responsive to a disturbance event, the modem may also change transmission power levels and other system parameters such as frequency domain equalizer characteristics. Further, provisions are made for reduced bandwidth communications under selected conditions.