The Directv Group, Inc.

Dtvg Licensing, Inc.

Hughes Electronics Corporation

Hughes Network Systems, LLC

Feng-Wen Sun

Lin-Nan Lee

Mustafa Eroz

Khalid Karimullah

Adam Von Ancken

A Roger Hammons, Jr

Yimin Jiang

Bob Cassagnol

Dan Fraley

Ernest C Chen

Joseph Santoru

Neal David Becker

Guangcai Zhou

Tung-Sheng Lin

Shamik Maitra

Dennis Lai

Lakshmi Iyer, Jr

Kamran Etemad

Douglas M Dillon

Scott D Casavant

Kuriacose Joseph

John Corrigan

Walter Kepley

Lakshmi Iyer

Joseph A Santoru

A Roger Hammons

A system and method for transmitting wideband signals via a radio communication system adapted for transmitting narrow-band signals is described. A base station is used to transmit and receive a plurality of relatively narrow-band and a plurality of relatively wideband signals. The electromagnetic spectrum available to the plurality of narrow-band signals is selectively shared with the electromagnetic spectrum available to the wideband signals by systematically separating the orthogonal codes and the carrier frequencies used for transmission. The prefixes of the orthogonal codes are preferably mutually exclusive and the carrier frequencies are preferably separated by an offset. The offset may be substantially equal to an integer multiple of the narrow-band signal's chip rate. Alternatively, the offset may be substantially equal to an odd multiple of one half the narrow-band signal's chip rate in which case every other bit of the orthogonally encoded data is inverted.

Method and apparatus for orthogonally overlaying variable chip rate spread spectrum signals

Method and apparatus for implementing LDPC codes in an IEEE 802.11 standard system configured to operate in a Multiple-Input, Multiple-Output (MIMO) schema. A method in accordance with the present invention comprises defining a base LDPC code, having a length equal to an integer number of data carriers in an ODFM symbol, transmitting the base LDPC code over a plurality of sub-carriers, wherein the base code is transmitted at an expected phase on sub-carriers specified by the IEEE 802.11 standard system, and transmitting the base LDPC code on other sub-carriers than those specified by the IEEE 802.11 standard system, wherein the base LDPC code on the other sub-carriers is transmit offset in phase from the base LDPC code on the specified sub-carriers.

Code design and implementation improvements for low density parity check codes for wireless routers using 802.11n protocol

An approach is provided for minimizing co-channel interference in a communication system is disclosed. Non-header portions of frames, which are transmitted over the communication system, are scrambled according to respective different scrambling sequences. The above arrangement is particularly suited to a digital satellite broadcast and interactive system.

Method and apparatus for minimizing co-channel interference by scrambling

An approach is provided for distributing multi-media information from a satellite broadcast system. A hub receives a signal from the satellite broadcast system, wherein the signal represents video information and audio information associated with multiple broadcast channels. The hub centrally demodulates and decodes the received signal for distribution to one of a number of access point devices. According to one embodiment of the present invention, the decoded signal represents uncompressed video and audio information corresponding to one of the broadcast channels. The access point devices convert the received decoded signal for output respective displays (e.g., television sets). The hub can also be equipped with an interface to provide access to a public data network, such as the global Internet. Further, the hub can be supplied with a digital video recording capability.

Method and system for providing digital video distribution

A method of interleaving blocks of indexed data of varying lengths is disclosed. The method includes the steps of: providing a set of basic Interleavers comprising a family of one or more permutations of the indexed data and having a variable length; selecting one of the basic Interleavers based upon a desired Interleaver length L; and adapting the selected basic Interleaver to produce an Interleaver having the desired Interleaver length L.

Turbo code interleaver with near optimal performance

Code design and implementation improvements for low density parity check codes for wireless routers using 802.11N protocol

An approach is provided for decoding a low density parity check (LDPC) coded signal. Edge values associated with a structured parity check matrix used to generate the LDPC coded signal are retrieved from memory. The edge values specify the relationship of bit nodes and check nodes, and are stored within memory according to a predetermined scheme that permits concurrent retrieval of a set of the edge values. A decoded signal corresponding to the LDPC coded signal is output based on the retrieved edge values.

Method and system for routing in low density parity check (LDPC) decoders

Methods and apparatuses for minimizing co-channel interference in communications systems are disclosed. A method in accordance with the present invention comprises scrambling a first frame using a first scrambling code, attaching a first header to the first frame to create the first signal, scrambling a second frame using a second scrambling code, attaching a second header to the second frame to create the second signal, and transmitting the first signal and the second signal over different channels of the communication system.

Methods and apparatuses for minimizing co-channel interference

An approach for reliably communicating over a satellite in support of a communication service including, for example, as direct broadcast satellite and data service, is disclosed. An input message is encoded, yielding a structured Low Density Parity Check (LDPC) coded message. The coded message is modulated according to a high order modulation scheme that has a signal constellation representing more than two symbols per signaling point&#x2014;e.g., 8-PSK (Phase Shift Keying) and 16-QAM (Quadrature Amplitude Modulation). The system includes a transmitter configured to propagate the modulated signal over the satellite. The above approach is particularly applicable to bandwidth constrained communication systems requiring high data rates.

Satellite communication system utilizing low density parity check codes

An approach is provided for minimizing co-channel interference in a communication system is disclosed. A header of a first frame is scrambled based on a first unique word. A header of a second frame is scrambled based on a second unique word. The first frame including the corresponding scrambled header and the second frame including the corresponding scrambled header are transmitted, respectively, over adjacent co-channels of the communication system. Each of the frames further includes a payload and a pilot block. The payload and the pilot block of the first frame are scrambled based on a first scrambling sequence. The payload and the pilot block of the second frame are scrambled based on a second scrambling sequence. The above arrangement is particularly suited to a digital satellite broadcast and interactive system.

Method and apparatus for minimizing co-channel interference

Methods include configuring M parallel accumulation engines, accumulating a first information bit at a first set of specific parity bit addresses using the accumulation engines, increasing a parity bit address for each member of the first set of specific parity bit addresses by a pre-determined offset for each new information bit, accumulating subsequent information bits at parity bit addresses that are offset from the specific parity bit addresses by a pre-determined offset until an M+1 information bit is reached, accumulating the next M information bits at a second set of specific parity bit addresses using the accumulation engines, increasing a parity bit address for each member of the second set of specific parity bit addresses by the pre-determined offset for each new information bit; and repeating accumulating and increasing the addresses until the information bits are exhausted. Related systems are described.

Code design and implementation improvements for low density parity check codes for multiple-input multiple-output channels

An approach is providing for supporting broadcast transmission of low density parity check (LDPC) coded signals. A receiver includes a decoder configured to decode an LDPC signal to output a decoded signal. The decoder is further configured to operate as an encoder; as such, interference cancellation can be implemented by the encoder re-encoded the received decoded signal. The above approach has particular applicability to satellite broadcast systems.

Encoding low density parity check (LDPC) codes through an LDPC decoder

A method of interleaving blocks of indexed data of varying length is disclosed. The method includes the steps of: providing a set of basic Interleavers comprising a family of one or more permutations of the indexed data and having a variable length; selecting one of the basic Interleavers based upon a desired Interleaver length L; and adapting the selected basic Interleaver to produce an Interleaver having the desired Interleaver length L.

Growing community of inventors

Germantown, MD, United States of America

Feng-Wen Sun