Abstract: A system and device for, and method of, detecting, characterizing, and mitigating deterministic distortion in a communication system. An exemplary communication system includes a digital adaptor for sending octets on to a backbone of a PSTN, which then sends, and potentially distorts the octets, received by a line interface. The line interface converts the octets to baseband signals received by an analog adaptor. Several mechanisms and methods are described in which the analog and digital adaptor cooperate to detect the presence of distortion, in particular, robbed bit signaling, on the communication system. The characterization may then be used to mitigate the effects of the distortion. Several receive constellations are provided, each constructed in view of the transmit constellation and in view of the manner in which the deterministic distortion will distort signals transmitted over the system. The receive constellations differ from the transmit constellation.

Abstract: A transmitter for transmitting a sequence of octets over a digital network which digital network converts the octets into a sequence of levels for transmission over an analog channel to a receiver, the levels producing an analog signal having a predefined spectral shape, the transmitter including: a mapping device which receives at its input groups of data bits to be transmitted and outputs for each group an equivalence class of one or more levels, wherein at least one equivalence class contains more than one level; a level selector, operably coupled to the mapping device, for selecting the level in the equivalence class to represent the group of data bits to be transmitted; a filter device, operably coupled to the level selector and having a filter response corresponding to the predefined spectral shape, which receives at its input previously selected levels and provides its output to the level selector, wherein the level selector selects the level to be transmitted based on the output of the filter device;

Abstract: The present invention provides a device (200, 300), system (400, 500) and method for real-time streaming of a multimedia file stored in a remote server over a packet network to a multimedia client connected to the same network via a low-speed access link such as an analog telephone line. The invention operates to provide significantly improved QoS with respect to both quality and delay.

Abstract: The present invention provides a device and method in multi-access communications system for reliably receiving burst transmissions from users in the presence of narrow band interference. The adaptive interference suppresser incorporates adaptive elements that are updated using a predetermined adaptation algorithm. These adaptive elements are stored in memory at the end of the burst transmission for reuse in receiving a next burst transmission.

Abstract: The present invention provides a device (200, 300, 400) and method (500) in multi-access communications system for reliably receiving burst transmissions from users in the presence of distortion and interference. The signal detector of the invention incorporates separate modules (280, 290; 302, 304; 402, 404) for distortion cancellation and interference suppression. This allows efficient tracking of distortion and interference characteristics.

Abstract: The present invention provides a device, method, and system for, in an entry node of a packet communication network, transcoding a received constant bit-rate video bitstream to a variable bit-rate video bitstream, packetizing the variable bit-rate video bitstream into video packets for efficient transport of a video signal over a packet-switched network.

Abstract: The present invention provides a transcoder for transcoding of digitally encoded bit streams produced by predictive encoders. The transcoder of this invention is less complex than previously known transcoders in terms of both computational and storage requirements. This efficiency is achieved by combining decoding and re-encoding steps into one step. This one-step transcoding is accomplished by modifying the originally quantized vectors and then requantizing and noiseless encoding these vectors into a bit stream in accordance with a predetermined objective.

Abstract: A device (100) and method (400) are set forth that provide a parity check that utilizes a nonlinear dependence upon bits other than the parity bit alone. The 4D 16-state Wei trellis code is made transparent to m.multidot.90 degree rotations by utilizing a parity generating unit that generates a parity check bit based on at least a second rotationally significant label bit. The parity check bit allows detection of errors in a first rotationally-significant label bit, i.e., allows for achievement of a rotationally transparent parity check.

Abstract: Multipoint control units are networked utilizing a predetermined number of mixing operations such that delay is reduced while maintaining overall quality. The present invention provides an advantageous system by also substantially reducing communication costs by utilizing efficient networking.

Abstract: A novel precoding technique (900) and device (100) allows transmission of a stream of signal points over a channel h(D) to provide efficient data transfer in the presence of intersymbol interference and noise at data rates approaching channel capacity. This new technique may be combined with trellis-coded modulation and works with any signal constellation. In addition, the present invention allows decoupling signal constellation shaping, a significant improvement over prior precoding techniques. Thus, the present invention simplifies shaping and allows signaling at fractional rates without constellation switching.

Abstract: An improved precoding technique (700) and device (100) allows transmission of a signal point sequence over a channel h(D) to provide efficient data transfer in the presence of intersymbol interference and noise at data rates approaching channel capacity. This improved technique works with trellis-coded modulation and with any signal constellation. Thus, the present invention simplifies shaping and allows signaling at fractional rates without constellation switching. A key advantage of the present invention over prior art is its ability to achieve reduced dither loss by selecting the output components of a mapper based on past components of a channel output sequence.

Abstract: The device (100) and method (700) of the present invention provides for detecting and correcting loss of frame synchronization in a communication system with multi-level trellis coding without additional allocation of channel capacity for such detection and correction.

Abstract: A device and method utilize a linear feedback/feedforward configuration to estimate and cancel a listener echo wherein equalizer (202) and listener echo cancellation (204 and 208) units are jointly updated, allowing determination of an error signal (204 and 208), in place of the former method of separate error signal determination for each of an equalizer and a listener echo canceller. An improved phase-correction scheme is utilized to compensate the frequency offset in the listener echo. The relationship between the listener echo and talker far echo is utilized to facilitate the listener echo cancellation.

Abstract: A device and method utilize a linear feedback/feedforward configuration to estimate and cancel a listener echo wherein equalizer (202) and listener echo cancellation (204 and 208) units are jointly updated, allowing determination of an error signal once (204 and 208), in place of the former method of separate error signal determination for each of an equalizer and a listener echo canceller. An improved phase-correction scheme is utilized to compensate the frequency offset in the listener echo. The relationship between the listener echo and talker far echo is utilized to facilitate the listener echo cancellation.

Abstract: A device (400) and method (1200) include interleaved trellis precoding to provide a low probability of error in the presence of bursty noise. The use of interleaving and shaping, particularly in a trellis precoded system, provide for improved burst error bit correction.

Abstract: The device and method provide precoding and symbol-rate transmitter spectral shaping of signals representative of digital information. The invention improves reliability of reception in the presence of non-Gaussian channel noise. The present invention also provides a flexible way of choosing between linear equalization, precoding without spectral shaping, and precoding with spectral shaping.

Abstract: A signal weighting system for associating a confidence level with portions of a communication signal transmitted upon a multipath channel and received by a receiver. A signal received by the receiver is equalized by an equalizer circuit, such as a maximum likelihood sequence estimator, and the equalized signal generated thereby is supplied to an adaptive filter which is synthesizes portions of the multipath channel. The signal received by the receiver is altered responsive to values of a filtered, equalized signal generated by the adaptive filter.