Abstract: A multilevel coded modulation scheme is provided in which a first portion of input data is encoded by a first-level code and a second portion of input data is encoded by an second-level code, the second-level code being such that the overall multilevel code exhibits a desired level of time diversity of at least 2 and the minimum distance of the overall code is not increased by virtue of the presence of the second-level code.

Abstract: Advantageous error rate performance, high bandwidth efficiency, low delay and reduced error floor are achieved at an acceptable level of decoding complexity via the use of serial concatenated turbo codes. These are codes for which at least some of the output bits, including at least one redundant bit, provided by a first, outer encoder are, after interleaving, further processed by a second, inner encoder. The resulting data and redundant bits then select a symbol from a predetermined constellation for transmission. In the receiver, the turbo code is decoded using a corresponding number of soft output decoders which operates iteratively in such a way that improved performance as compared to a single encoding can be achieved. The turbo codes can be of various dimensionalities and can be used as a component of a multilevel code to achieve a desired level of bandwidth efficiency.

Abstract: A portion of signal points that appear at predetermined positions in a signal point stream and that benefit less from a particular form of error immunity—e.g., conversion gain—are transmitted in such a way that their robustness against errors is at least as great as that of the signal points that benefit more therefrom. In preferred packet transmission embodiments of the invention, the ending signal points of a packet are transmitted using a signal point constellation that has fewer signal points than the constellation that is used for the other signal points in the packet.

Abstract: Advantageous error rate performance, high bandwidth efficiency, low delay and reduced error floor are achieved at an acceptable level of decoding complexity via the use of serial concatenated turbo codes. These are codes for which at least some of the output bits, including at least one redundant bit, provided by a first, outer encoder are, after interleaving, further processed by a second, inner encoder. The interleaver uses as its interleaved elements the bits associated with a particular symbol interval. The resulting data and redundant bits then select a symbol from a predetermined constellation for transmission. In the receiver, the turbo code is decoded using a corresponding number of soft output decoders which operates iteratively in such a way that improved performance as compared to a single encoding can be achieved. The turbo codes can be of various dimensionalities and can be used as a component of a multilevel code to achieve a desired level of bandwidth efficiency.

Abstract: A process transmits digital data to an A/D converter via an analog channel. The process includes generating a sequence of output signals by precoding a sequence of input signal points to precompensate for ISI in the analog channel. In the precoding is matched to the ISI, at least one of the output signals would be distorted by the ISI to a signal representative of a signal point lying between quantization levels of the A/D converter. If the precoding is matched to the ISI, others of the output signals would be distorted by the ISI to signals representative of signal points that are quantization levels of the A/D converter. A majority of the input signal points are quantization levels of the A/D converter.

Abstract: Advantageous error rate performance, high bandwidth efficiency, low delay and reduced error floor are achieved at an acceptable level of decoding complexity via the use of serial concatenated turbo codes. These are codes for which at least some of the output bits, including at least one redundant bit, provided by a first, outer encoder are, after interleaving, further processed by a second, inner encoder. The resulting data and redundant bits then select a symbol from a predetermined constellation for transmission. In the receiver, the turbo code is decoded using a corresponding number of soft output decoders which operates iteratively in such a way that improved performance as compared to a single encoding can be achieved. The turbo codes can be of various dimensionalities and can be used as a component of a multilevel code to achieve a desired level of bandwidth efficiency.

Abstract: Improved error rate performance of data transmissions systems using both coded and uncoded modulation in the presence of more-than-mild intersymbol interference is achieved in the receiver using M-path joint decision feedback equalizer/decoder in conjunction with a finer partition of the constellation than was used in the transmitter and a refined receiver trellis diagram based on that finer partition.

Abstract: Signal points from a PCM-derived constellation are selected for transmission via a modulation technique which employs different levels of redundancy coding--including the possibility of no redundancy coding--for respective different sub-constellations of the overall PCM-derived constellation. The coding that is employed for at least one of the sub-constellations is carried out independently from any coding that is employed for any of the other sub-constellations. In preferred embodiments, the sub-constellations are non-overlapping portions of the overall PCM-derived constellation, the redundancy codes are trellis codes, and the trellis codes employed in conjunction with sub-constellations having increasingly smaller minimum distance between signal points provide respectively increasing amounts of decibel gain in that minimum distance in order to compensate for that increasingly smaller minimum distance.

Abstract: A path-oriented approach is provided to determine surviving paths in a decoder. The paths that are retained as the surviving paths are some number, M, of the paths which have the smallest path metrics, even if two or more of those paths come into a given state. This approach provides significantly improved performance in at least those applications in which branch metrics are a function of the surviving path from which the branch emanates.

Abstract: Signal points from a PCM-derived constellation are selected for transmission via a modulation technique which employs different levels of redundancy coding--including the possibility of no redundancy coding--for respective different sub-constellations of the overall PCM-derived constellation. The coding that is employed for at least one of the sub-constellations is carried out independently from any coding that is employed for any of the other sub-constellations. In preferred embodiments, the sub-constellations are non-overlapping portions of the overall PCM-derived constellation, the redundancy codes are trellis codes, and the trellis codes employed in conjunction with sub-constellations having increasingly smaller minimum distance between signal points provide respectively increasing amounts of decibel gain in that minimum distance in order to compensate for that increasingly smaller minimum distance.

Abstract: Decision feedback equalization is used in a communication system which employs coded modulation, such as trellis coded modulation. The transmitted stream of signal points includes first signal points that were generated using a particular coded modulation scheme interspersed with second signal points that were generated without the using of coding, and estimated intersymbol interference components for the second signal points are generated in response to tentative decisions as to the first signal points formed by the Viterbi decoder. Rather than forming immediate final decisions as to the second signal points, there is formed a tentative decision for each one of the second signal points associated with each Viterbi decoder state using an estimated intersymbol interference component provided from a decision feedback equalizer associated with that state. Each second-signal-point tentative decision is used to extend the surviving path for the associated state and to also update its path metric.

Abstract: Methods for treating cystic fibrosis are described. The methods involve the administration of a protein enhancing agent, differentiating agent and/or carboxy-compound to a subject afflicted with cystic fibrosis such that mutant cystic fibrosis transmembrane regulator protein present within cystic fibrosis-associated cells becomes functional. Other aspects described include therapeutic compositions and packaged drugs.

Abstract: A method for producing an improved solid phase antigenic reagent useful in an immunoassay for detecting antibodies specific for a virus, such as the human immunodeficiency virus, is disclosed which comprising the addition to a natural viral lysate a synthetic or recombinant viral protein or peptide. Also provided is an improved immunoassay utilizing the solid phase antigenic reagent.

Abstract: A systematic convolutional interleaver arrangement that is obtained by treating the input signals of an associated error correcting encoder as if they had been pre-interleaved in a very particular way so that the order of the input signals of the encoder is not altered when it is transmitted to the channel. By way of example, an interleaver/deinterleaver arrangement is disclosed that uses Reed Solomon code RS(120,116) and employs delay element banks and associated routing to interleave and deinterleave the signals.

Abstract: Coding gain is improved by employing an N-dimensional trellis encoder incorporating an N'-dimensional convolutional encoder where N' is less than N. The additional coding gain is realized as a shaping gain. This unique modulator encodes a digital signal by generating a sequence of N-dimensional symbols as a function of the digital signal using an N'-dimensional convolutional encoder within the trellis encoder more than once (integer N/N' times) during each N-dimensional symbol interval. This allows the trellis encoder to produce an output of higher dimensionality than would normally be expected from the lower dimensionality convolutional encoder. The trellis encoder is applicable to television transmission.

Abstract: Methods and compositions for treating Cystic Fibrosis by mobilizing mutant forms of CFTR, which retain at least some functional activity, to the plasma membrane where they can mediate chloride ion transport are disclosed.

Abstract: A reduced speed equalizer is provided which receives signal samples at a first rate but performs the equalizing operation at a second, lower rate which is below the rate at which symbols are transmitted across the channel. The equalizer is docked to receive samples in a shift register at the first rate. Samples stored in the shift register are clocked into a set of buffers at the second rate. The equalizer coefficients are applied to the samples stored in the buffer set to generate a sequence of equalized symbols at the second rate.

Abstract: An HDTV transmission system includes a Tomlinson precoder in the transmitter in order to compensate for forced intersymbol interference introduced by an NTSC rejection filter used in the receiver. The system employs one of a family of four-dimensional coded modulation schemes based on a six-signal-point, one-dimensional base constellation. The various schemes exhibit different amounts of so-called shaping gain and support respective different payload data rates. The characteristics of the Tomlinson precoder are such as to preserve the substantial portion of the shaping gain. The system may switch its operation among the various coded modulation schemes to account for changes in channel conditions and/or to accommodate different source signal bit rates.

Abstract: A rotationally invariant, multilevel coded modulation scheme is provided by partitioning a constellation, such as an M-PSK or QAM constellation, into several trellis-subsets, each of which is further partitioned into block subsets. The input bits are then encoded to select a signal point from the constellation. A first portion of the input bits are differentially encoded. A second portion of the input bits, together with at least one of the differentially encoded bits, are trellis encoded to select a trellis subset of the constellation. A third portion of the input bits--excluding any differentially encoded bits --are block encoded to select a block subset from the selected trellis subset. A fourth portion of the input bits, together with the remaining differentially encoded bits, are used to select a signal point from the selected block subset.

Abstract: In a modulation scheme involving differential encoding and Reed-Solomon encoding, the differential encoding is performed before the Reed-Solomon encoding in the transmitter. In the receiver, a differential decoding operation is performed after an RS decoding operation. The overall coding scheme and the RS decoding are so arranged as to ensure that the RS decoding will be proper in the presence of phase rotations, notwithstanding the fact that the differential encoding is performed before the RS encoding in the transmitter and the fact that the RS decoding is performed before the differential decoding in the receiver.