At+t Corp.

Lucent Technologies Inc.

At&t Bell Laboratories

Bell Telephone Laboratories

At&t Intellectual Property I, L.p.

Alcatel Lucent

At&tcorp.

Richard Robert Shively

Robert Raymond Miller, Ii

Ranjan V Sonalkar

Egbert Ammicht

Christopher A Stanziola

Paul David Davis

Howard David Helms

John M Segelken

Allen L Gorin

Patrick A Makofsky

Jesse Eugene Russell

Lawrence Richard Rabiner

Alex Pidwerbetsky

Marc J Beacken

Steve J Nossen

Ronald Eldon Crochiere

Dennis M Romain

Robert N Lewine

Neal C Oliver

Nancy Morton

Lesley J Wu

Lesley J-y Wu

William V Robinson, Jr

Michael J Nossen

Robert Raymond Miller

A codeword synthesizing system and a correlation system for use with a spread spectrum communications system. In one embodiment, the codeword synthesizing system typically associated with a transmitter includes a base sequence generating subsystem, a modifier sequence generating subsystem and a concatenating subsystem. The base sequence generating subsystem is configured to create base sequences having a length less than a synthesized codeword. The modifier sequence generating subsystem is configured to create a modifier sequence, and the concatenating subsystem is configured to produce the synthesized codeword by multiplying each of the base sequences by an element of the modifier sequence. In one embodiment, the correlation system typically associated with a receiver includes a partial correlating subsystem, a memory subsystem and a combining subsystem. The partial correlating subsystem correlates base sequences of a synthesized codeword to a template and derives multiple partially correlated resultants. The memory subsystem temporarily stores the partially correlated resultants, and the combining subsystem sums weighted values of the partially correlated resultants to provide a correlated value of the synthesized codeword.

Codeword synthesizing system and a correlation system, methods of operation thereof and a spread spectrum communications transceiver employing the same

A circuit switched switching system and method includes a plurality of matrix transposition memories. The memories permute the order of incoming and outgoing data, and thereby increase the efficiency of the switch. The switch and matrix transposition memories may be disposed in a satellite. The switch may further include batching circuits for grouping together data from a single terminal device for more efficient transmission through the switch and for more efficient error correction.

Circuit-switched switching system

An improved method is disclosed for the encoding phase for Wavelet-based compression of digital data representing an object or image. Subband decomposition transforms the data into hierarchical tree data. Two terms are precomputed: the highest bit-plane in which any descendant of a node v has a non-zero bit (B(v) and the highest bit-plane in which any indirect descendant (grandchild and beyond) becomes significant (B(v). Node traversal is initiated but its extent is limited by a fixed bit-budget. The number of bits emitted by a node as a function of the bit-plane are counted through to the last bit-plane which exhausts the bit-budget. The user can predetermine the coefficient, bit-plane and specific bit at which the algorithm will halt. The tree structure is read only once, thus greatly accelereating the encoding and reducing the memory reference rate by a factor of 2 or more. Accumulators for each of the stacked bit-planes are provided which are incremented as each said Wavelet coefficient is produced, by the number of bits that the coefficient adds to the relevant bit-plane.

Coefficient computation in image compression using set partitioning in hierarchical trees

A process and apparatus is described for recovering from optical transmission degradation due to scintillation effects in optical free space. A payload bit stream is encoded into Reed-Solomon codewords. These are fragmented and distributed as interleaved segments over a cell matrix of a SDRAM buffer store which is made large enough to correct a burst error occurring over 20 million consecutive bits. The rate imbalance between conventional read vs. write operations for SDRAM devices, which would otherwise obviate their use in this application by preventing real time operation, is overcome by an address remapping that avoids having to changing page addresses each time SDRAM memory is referenced. The remapping facilitates a more nearly equal allocation of READ overhead and WRITE overhead. An optical communications system employs at both the transmit and receive ends, substantially equivalent SDRAM buffer with address remapping capability.

Reducing scintillation effects for optical free-space transmission

A multi-stage wavelet transform of an image signal is implementing using a first processing element to perform computations for a first stage of the transform, and a second processing element operating in a time-multiplexed manner to perform computations for subsequent stages of the transform. The first processing element includes first and second adder trees for implementing horizontal and vertical filtering operations, respectively, and a set of row buffers configured such that the total number of row buffers is only one more than the number of pixels required to generate a given vertically-filtered output. In a four-stage illustrative embodiment in which the first processing element processes image pixel data at a sample rate of f , the multi-stage processing element receives inputs from the first stage processing element at a sample rate of f /4, and generates coefficients for the second, third and fourth stages using sample rates of f /16, f /64 and f /256, respectively. The particular number of stages may be considered a design parameter, and other embodiments may have more or less than four stages. In accordance with the invention, operations performed by the first stage processing element correspond to lowest-level nodes of a binary tree representation of a processing schedule for the multi-stage wavelet transform, and the operations performed by the multi-stage processing element correspond to the remaining nodes of the binary tree representation.

Methods and apparatus for wavelet-based image compression

Circuit switched switching system

Near-end crosstalk between identical discrete multi-tone modems is reduced by aligning the frames of all modems at a central office to each other, aligning the frames transmitted by subscribers' modems with the frames received by those modems, and including a cyclic prefix between the central office and the most distant subscriber to be served. By making adjacent DMT carrier frequencies be orthogonal to each other, the aforementioned modifications will reduce both Near End Cross-Talk and Leakage-Excited Cross-Talk. These benefits apply to modems at both the central office and subscriber ends of the communication path.

Method and apparatus for reducing near-end crosstalk (NEXT) in discrete multi-tone modulator/demodulators

Data compression achieved by set partitioning of hierarchical trees is made more efficient by a family of related traversal schemes which act upon the tree structure and the significance values derived from the tree structure. The tree structure may be traversed in any of a number of sequences. In accordance with significance tests applied to the node data, bits are produced or not. The order in which the bits are produced may be freely chosen. Trees are traversed and bits are emitted which describe the relative magnitude of coefficients in the sub-trees of the current tree-node. The manner of traversal can either be known to the remote decoder or can be derived from the incoming data stream. The encoding scheme typically specifies all bits emitted by a given node v as a function of the traversal of its parents, the bit-plane b, the coefficient value c of v, the significances B (v) and B (v), and whether the parent node p still emits B (p).

Wavelet-based compression of images for storage, transmission and reconstruction using hierarchical subband decomposition

High transmission capacity in a twisted pair signal line, where power is limited by a power spectral-density mask and an aggregate signal power constraint, is obtained by: (1) allocating data to multitone sub-bands according to a lowest marginal power-cost per bit scheme and (2) in an environment where an aggregate power budget remains after all bits have been allocated to all sub-bands with sufficient margins to carry a bit, assigning additional bits to sub-bands with otherwise insufficient power margins to carry a single bit, by frequency-domain-spreading a single bit across several sub-bands at correspondingly reduced power levels, to permit the otherwise unacceptable noise levels to be reduced on average by despreading at the receiving end. Another feature of the invention, applicable in an environment in which multiple interfering channels are employed, provides increased signal throughput by (3) transmitting coherently in a number of multitone sub-bands, identical blocks of data, with the number of multitone sub-bands being equal to a number of interfering channels and multiplying the signal carried by corresponding sub-bands in the separate interfering channels by a different respective vector from an orthonormal basis set so that near-end cross-talk is eliminated upon despreading at the receiving end.

Spread spectrum bit allocation algorithm

The present invention solves the current problem of allowing ad-hoc (manual) voice response by a user to a page received by a paging device. In one aspect of the invention, a paging device includes a digital signal processor for receiving and compressing a voice response to a page prior to transmission back to the paging party. In further aspects of the invention, the speech is first recorded and compressed and then transmitted to a wireless base station for subsequent transmission to the calling party.

Voice-response paging device and method

This invention reduces near-end crosstalk between identical discrete multi-tone (DMT-type) modems by introducing the following modifications to modems at a central office or a subscriber premises. The modifications include: a mechanism for aligning the frames of all modems at the central office (CO), a mechanism for aligning the frames transmitted by the subscribers' modems with the frames received by those modems, and lengthening the DMT frame to include a cyclic prefix. The cyclic prefix to a frame has been made longer than twice the maximum round-trip delay, that is, the delay between the central office and the most distant subscriber to be served. By making adjacent DMT carrier frequencies be orthogonal to each other, the aforementioned modifications will reduce both Near End Cross-Talk (NEXT) and Leakage-Excited Cross-Talk (LEXT). These benefits apply to modems at both the central office (CO) and subscriber ends of the communication path (for example, a high capacity twisted-pair wire).

Method and apparatus for reducing near-end crosstalk (NEXT) in discrete

A method for broadband transmissions through metallic wire in an interference-laden environment. Wideband communication through a wire is achieved in the presence of other wideband signals in the wire or in adjacent wires by applying a modulation schema to the wideband communication signal that forms a signal which is orthogonal or nearly orthogonal to all other signals that are present in the wire, whether directly applied or electromagnetically induced. In accordance with one illustrated embodiment, a CDMA code is applied to the wideband signal that is to be communicated through a given wire, and the code that is employed is orthogonal to the CDMA codes that are applied to other signals that flow through the wire or through other wires which are in the neighborhood of the given wire.

Wideband transmission through wire

Growing community of inventors

Convent Station, NJ, United States of America

Richard Robert Shively