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: In the present invention, the overhead data transmission rate in a multicarrier communication system (1) may be changed and/or selected. More specifically, this rate may be selected during an initial negotiation process and/or during a steady state mode of operation.

Abstract: A muticarrier transceiver is provided with a sleep mode in which it idles with reduced power consumption when it is not needed to transmit or receive data. The full transmission and reception capabilities of the transceiver are quickly restored when needed, without requiring the full (and time-consuming) initialization commonly needed to restore such transceivers to operation after inactivity.

Abstract: A muticarrier transceiver is provided with a sleep mode in which it idles with reduced power consumption when it is not needed to transmit or receive data. The full transmission and reception capabilities of the transceiver are quickly restored when needed, without requiring the full (and time-consuming) initialization commonly needed to restore such transceivers to operation after inactivity.

Abstract: Using DSL modems as data collectors, the modems processes the data to, for example, allow easier interpretation of the line characteristics. In particular, the modems postprocess the data including calibration, filter compensation, determination of the SNR medley from the bits and gains tables and rate conversion. The interpretation process uses the postprocessed data and determines loop characterization, interferer detection, a data reduction estimation and a data rate estimation. The outputs of these determinations least allow for the characterization of the line conditions between the two modems.

Abstract: An alternative approach to coping with the ever increasing demand for faster communications hardware is to design modems that are capable of operating its speeds at a higher data rate than a speed required for a single port of the standard communication rate for that modem. Basically, by utilizing a resource manager, that directs the data in and out of the various portions of the modem in an orderly manner, keeping track of which of the ports is being operated at any given point in time, a standard single port modem can be reconfigured, for example, at an over clocked rate, to manipulate the data input and output of a modem.

Abstract: An information distribution system distributes information over a distributed network in a multi-phase manner. In particular, the information distribution system provides, for example, to an end user, a model for determining a particular output. Then, as a user requests the most current output of the model, a parameter set is forwarded to the user and introduced to the model. This parameter set, with the cooperation of the model, allows for determining, for example, a current merchants pricing information for a plurality of goods and/or services. By using this model based approach, the entire set of information need not be distributed to the user every time an update is made. To the contrary, only a sub-set of information, i.e., the parameters, will be forwarded to the user for updating of information at a user device.

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 communication system for sending a sequence of symbols on a communication link. The system includes a transmitter for placing information indicative of the sequence of symbols on the communication link and a receiver for receiving the information placed on the communication link by the transmitter. The transmitter includes a clock for defining successive frames, each of the frames including M time intervals, where M is an integer greater than 1. A modulator modulates each of M carrier signals with a signal related to the value of one of the symbols thereby generating a modulated carrier signal corresponding to each of the carrier signals. The modulated carriers are combined into a sum signal which is transmitted on the communication link. The carrier signals include first and second carriers, the first carrier having a different bandwidth than the second carrier.

Abstract: A communication system for transmitting data comprising first and second data streams on a communication link having a communication channel of fixed bandwidth. The first and second data streams have first and second error tolerances, respectively, the first error tolerance being greater than the second error tolerance. The communication system includes a transmitter and a receiver, the transmitter transmitting data on the communication link for receipt by the receiver. The transmitter includes circuitry for dividing the communication channel into a plurality of sub-bands. In the preferred embodiment of the present invention, each sub-band has a bandwidth chosen such that distortions introduced by the communication link in the sub-band may be represented by an attenuation coefficient and phase shift.

Abstract: An improvement in a data communication link between a server site and a client site. The server site transfers data packets to the client site, each data packet causing an acknowledgment packet to be sent from the client site to the server site. Denote the ratio of the average number of bits in the data packets to the average number of bits in the acknowledgment packets by R. The communication link includes a multi-channel communication link having a plurality of data channels. Each data channel provides communication in one direction between the server site and the client site, each of the channels having a data carrying capacity characteristic of that data channel.

Abstract: A decoder and an encoder for extracting a subset of symbols from, or inserting a subset of symbols into, a communication channel in which M symbols are transmitted as the amplitudes of M sinusoidal carriers. The decoder recovers K symbols, S.sub.p . . . S.sub.p+K-1, from an analog signal generated by modulating M sinusoidal carriers for a frame period. Each carrier is modulated with an amplitude proportional to the value of one of M symbols, the i.sup.th carrier being modulated by symbol S.sub.i. The K symbols are a contiguous subset of the M symbols. The decoder includes a down-converter for down-converting to the modulated signal on the communication channel to generate a down-converted signal in which the carriers corresponding to S.sub.p . . . S.sub.p+K-1 occupy frequencies starting from 0. An analog-digital converter generates K time-domain samples in each frame period from the down-converted signal. These time-domain samples are converted to K frequency-domain values representing the symbols S.sub.p . .

Abstract: A communication system for sending a sequence of symbols on a communication link. The transmitter receives a sequence of symbols and groups the symbols into a block of symbols for which transmission is to be initiated in a following frame. Each symbol is used to modulate a different carrier. At the receiver, the signal from the communication link is decoded by a plurality of finite impulse response (FIR) filters that are matched to the waveforms modulated by the symbols in the transmitter. Errors arising from synchronization errors between the transmitter and receiver are corrected by forming weighted sums of the symbols decoded by the FIR filters for the current frame and frames received prior to and/or after the current frame. The weights are determined by training samples sent on the communication link prior to the actual transmissions.

Abstract: A communication system having a modulation system for transmitting a symbol set via a single side-band modulated carrier and a demodulation system for recovering the in-phase and quadrature signals from the modulated carrier. The modulation circuit receives M symbol values and generates M time domain samples for each of the in-phase and quadrature signals. The in-phase and quadrature signals can then be combined to generate the single side-band modulated carrier. The modulation circuit includes a transform circuit for generating M transformed symbol values by computing the transform of the M symbol values. A polyphase filter bank having 2M FIR filters is used to process the output of the transform circuit. Each filter has g taps, where g is an integer greater than 1. The outputs of the polyphase filters are combined with the outputs of the polyphase filters generated from a previously received set of M symbols to generate the M time-domain signal values of the in-phase signal.

Abstract: A multi-carrier data transmission system utilizing lapped transforms. Information to be transmitted is divided into a plurality of channels that are coded using a transform that places information into narrow bandwidth channels. The system makes use of the superior properties of filter banks constructed with narrow-band lapped transforms to provide improved signal isolation between the data channels. A new form of lapped transformation that provides both narrow-band filtering and phase information is described. The transform utilizes two components to provide information on phase changes induced by errors on the communication link. The improved transform provides a means for correcting for phase shifts that occur on the communication link. The system has superior burst noise immunity compared to systems based on FFT's.