The Directv Group, Inc.

The Titan Corporation

Samsung Electronics Co., Ltd.

Dtvg Licensing, Inc.

Dennis Lai

Ernest C Chen

Joseph Santoru

Guangcai Zhou

Shamik Maitra

Tung-Sheng Lin

Lin-Nan Lee

Feng-Wen Sun

Adam Von Ancken

Cecilia C Comeaux

Hee-Won Kang

Hoon Huh

Leon J Stanger

Patrick J Loner

William C Lindsey

Lakshmi Iyer, Jr

Donald J Breier

Judith M Wang

Wei-Chung Peng

Jeng-Hong Chen

Asim Loan

Lakshmi Iyer

Joseph A Santoru

Judith Wang

A method and apparatus for adaptively controlling a transmission signal for transmission to at least one receiver in a terrestrial region is disclosed. The method selects a transmission signal mode having a modulation scheme, code scheme, and code rate from a plurality of transmission signal modes according to received information, generates a transmission signal according to the selected mode, and transmits the generated transmission signal to the receiver.

Adaptive coding and modulation for spot beam satellite broadcast

Methods and apparatuses for minimizing co-channel interference in communications systems are disclosed. A method in accordance with the present invention comprises shifting a characteristic of the first signal with respect to a like characteristic of the second signal to mitigate co-channel interference, and transmitting the first signal and the second signal over different channels of the communication system.

Shifted channel characteristics for mitigating co-channel interference

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

Methods and apparatuses for acquiring and demodulating a data stream transmitted in a communication system. A method in accordance with the present invention comprises finding a boundary of a physical layer frame (PLFrame) in the data stream, finding a first 26 bits of a Unique Word (UW) associated with the data stream, finding a scrambling code utilizing the UW, and using a decoding procedure to determine a modulation type and code rate used for desired signals within the data stream.

Blind identification of advanced modulation and coding modes

Methods and apparatuses for determining scrambling codes for minimizing co-channel interference in a communication system. A method in accordance with the present invention comprises defining at least one initial default sequence, generating a scrambling code, scrambling a signal using the generated scrambling code, comparing the scrambled signal with all other scrambled signals meeting a specified criterion, and saving the scrambling code word if the comparison determines that the signal scrambled with the scrambling code also meets the specified criterion. The scrambling codes can be compared with each other for cross-correlation purposes to determine whether they meet the specified criterion based on laboratory testing.

Methods and apparatuses for determining scrambling codes for signal transmission

Systems and methods for characterizing amplifiers. A system for characterizing an amplifier in accordance with the present invention comprises a Gaussian signal source for generating a signal in the frequency domain, a notch filter, coupled to the Gaussian Noise source, wherein the notch filter has a notch at a specified frequency and a frequency bandwidth, the frequency bandwidth encompassing the specified frequency, an Inverse Fast Fourier Transform device, coupled to an output of the notch filter, a normalization device, coupled to the Inverse Fast Fourier Transform device, an amplifier under test, coupled to the normalization device, for amplifying the signal generated by the Gaussian signal source, and a measurement device, coupled to an output of the amplifier, for measuring a power output of the amplifier in the frequency bandwidth and a noise output at the specified notch frequency, and for calculating the ratio between the power output and the noise output.

Optimized uplink efficiencies for transmission of satellite data

Systems for delivering a plurality of broadcast programs where the transmitter and receiver roll-off factors are mismatched. A system in accordance with the present invention comprises a transmitter comprising a modulator, and a plurality of receivers, each receiver in the plurality of receivers receiving the plurality of broadcast programs, each receiver in the plurality of receivers further comprising a demodulator; wherein the modulator has a first root-raised cosine filter having a first roll-off factor and each receiver has a second root-raised cosine filter having a second roll-off factor, the first roll-off factor being smaller than the second roll-off factor.

Reducing spectral roll-off factors to increase spectral efficiency

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 header of the first signal using a first scrambling code, scrambling a second header of the second signal using a second scrambling code, and transmitting the first signal and the second signal with the scrambled first header and the scrambled second header over different channels of the communication system.

Physical layer header scrambling in satellite broadcast systems

A simplified scrambling scheme that unifies all signals of a satellite broadcasting system, including frame header (), frame body () and pilot symbols () with a common reference phase. This results in the simplification and increased flexibility of the receiver front-end design without affecting the overall system performance. In many current communications systems with frame headers and pilot symbols, the phases of frame headers and pilot syrnbols are not designed to be aligned with any constellation points of the modulated data from the frame body. This scrambling scheme takes into account possible impact due to irregular phase changes between frame headers/pilot symbols and modulated data.

Simplified scrambling scheme for satellite broadcasting systems

A ZF joint detection apparatus for a downlink receiver, the apparatus comprising: a channel estimator for estimating a channel impulse response of a multipath fading channel of a received signal; a channel equalizer for estimating a transmission signal by performing channel compensation and removing multipath interference by a deconvolution technique based on the estimated channel impulse response; and a user detector for detecting a symbol-level data sequence transmitted by a specific user by despreading the transmission signal estimated by the channel equalizer with a spreading code for the specific user and a scrambling code.

Method and apparatus for downlink joint detection in a communication system

Each of first and second stations, in communicating with the other station, provides a preamble including forward link parameters and reverse link parameters. The forward link parameters in each preamble for each individual station are provided for each station in accordance with the reverse link parameters previously transmitted to the station in packets from the other station. The reverse link parameters in each preamble in each individual station provide an indication to the other station of the forward link parameters to be provided by the other station in the next transmission of a packet to the individual station from the other station. Data is provided in packets at each station to be transmitted to the other station. Each packet transmitted by each station to the other station includes a preamble and includes data after the preamble.

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Cerritos, CA, United States of America

Dennis Lai