Qualcomm Incorporated

Adaptive Spectrum and Signal Alignment, Incorporated

Leland Stanford Junior University

Assia Spe, LLC

Seong Taek Chung

Fuyun Ling

John Matthew Cioffi

Rajiv Vijayan

Georgios Ginis

Wonjong Rhee

Murali Chari

Gordon Kent Walker

Thomas Sun

Vinay Murthy

Bruce Collins

Alok Kumar Gupta

Rajeev Krishnamurthi

Jinxia Bai

Bin Hong Lee

Shusheel Gautam

Krishna Kiran Mukkavilli

Jungwon Lee

Raghvendra Savoor

Zhi Li

Raghuraman Krishnamoorthi

Tao Tian

Bojan Vrcelj

Mark B Flowers

Philip Stanley Bednarz

Peter Joshua Silverman

Murali Ramaswamy Chair

Bin Lee

A video stream DSL analyzer receives at least non-physical layer management data and physical layer management data and in response generates metric information. The generated metric information is used to characterize the performance of the video stream information and diagnose any problems if necessary. In response to the metric information, the video stream DSL analyzer changes one or more DSL configuration(s) in order to improve performance.

Video streaming diagnostics

Estimates of a communication system configuration, such as a DSL system, are based on operational data collected from a network element management system, protocol and users. The operational data collected from the system can include performance-characterizing operational data that typically is available in the OSL system via element-management-system protocols. Generated estimates and/or approximations can be used in evaluating system performance and directly or indirectly dictating/requiring changes or recommending improvements in operation by transmitters and/or other parts of the indication system. Data and/or other information may be collected using internal means or using system elements and components via e-mail and/or other extra means. The likelihood of the models accuracy can be based on various data, information and/or indicators of system performance, such as observed normal operational data, test data and/or prompted operational data that shows operating performance based on stimulation signals.

DSL system estimation

A wireless communication apparatus in a hierarchically coded modulation system can use error control mechanisms generated during decoding of base layer information to predict a probability of successful demodulation of enhancement layer information. Performance in the demodulation of the base layer correlates to performance in the demodulation of the enhancement layer. The receiver can determine whether to attempt demodulation of temporally correlated enhancement layer data based in part on the predicted probability of success. If the receiver determines not to demodulate the enhancement layer, the receiver can power down the enhancement layer demodulator, or otherwise minimize the power expended in the enhancement layer demodulator.

Power savings in hierarchically coded modulation

A frequency tracking method and apparatus is provided. A receiver receives OFDM symbols and determines associated frequency offset. A frequency error estimator selects a cross correlation window for determining frequency offset based on timing offset. A symbol timing estimator is used to determine the timing offset.

Frequency tracking which adapts to timing synchronization

Techniques for performing frequency control using dual-loop automatic frequency control (AFC) are described. The dual-loop AFC includes an inner loop that corrects short-term frequency variations (e.g., due to Doppler effect) and an outer loop that corrects long-term frequency variations (e.g., due to component tolerances and temperature variations). In one design, a first inner loop is implemented for frequency control of a first system (e.g., a broadcast system), a second inner loop is implemented for frequency control of a second system (e.g., a cellular system), and at least one outer loop is implemented for adjusting a reference frequency used to receive signals from the first and second systems. Each inner loop estimates and corrects the frequency error in an input signal for the associated system and may be enabled when receiving the input signal from the system. The reference frequency may be used for frequency downconversion, sampling and/or other purposes.

Dual-loop automatic frequency control for wireless communication

A method of detecting that a condition exists that adversely impacts a digital subscriber line service (DSL) over a telephone line shared by the DSL service and a telephone service. The method includes obtaining information regarding operation of the DSL service over a plurality of different time periods, comparing the information for a first of the plurality of time periods with the information for a second of the plurality of time periods, and determining the condition exists based on the comparison.

DSL ring signal compatibility

A decoder for a layered modulation system can be configured to independently and concurrently decode each of a base and enhancement layer. The base layer decoder and enhancement layer decoder can be configured substantially in parallel and can each operate concurrently on the same received layered modulation symbol. Each of the base and enhancement layer decoders can be configured with a bit metric module that is configured to determine a signal quality metric based on the received symbol. In systems having turbo encoded data, the bit metric module can be configured to determine a log likelihood ratio. The ratio is based in part on a channel estimate and an energy ratio used in the layered modulation constellation.

Method and apparatus for decoding data in a layered modulation system

A media access control (MAC) layer controller can manage base layer data and enhancement layer data in a layered modulation system. The MAC layer controller can process both base layer data and enhancement layer data and map the encoded symbols to a layered modulation constellation when both are present. If data for one of the layers terminates, then the MAC layer controller can generate and supply predetermined stuffing data to the layer lacking additional data. The MAC layer controller can send a control signal to the physical layer hardware to cause the hardware to map the layered signals having the stuffing data to a modified signal constellation. The MAC controller can also generate an overhead message that indicates the occurrence of the stuffing data. The receiver can receive the overhead message and can use the information to configure the receiver for the layered modulation constellation or the modified signal constellation.

Methods and apparatus for transmitting layered and non-layered data via layered modulation

A system and method are provided for generating bit log likelihood ratio (LLR) values for two-layered Quadrature Phase-Shift Keying (QPSK) turbo decoding in a wireless communications user terminal (UT). The method includes receiving a two-layered QPSK signal with an energy ratio that is unknown, but typically defined as either kor k. The method selects a mismatched energy ratio (k) between kand k, and generating bit LLR values for two-layered QPSK turbo decoding, using the mismatched kenergy ratio. For example, if the received two-layered QPSK signal is known to have an energy ratio of about 4 or about 6.25. Then, kis selected to be about 5.0625. Alternately stated, the mismatched kenergy ratio in selected by determining the approximate midpoint between kand k.

Bit log likelihood ratio evaluation

Configuration or otherwise controlling parameters of a Digital Subscriber Line (DSL) system related to power, band usage and margin is based on collected operational data. Operational data are collected from at least one DSL system operating under a known configuration and/or a profile. A target profile is selected based on binder-level information. The collected operational data is analyzed and conditions for changing the DSL system configuration to the target profile are evaluated, including any applicable transition rules pertaining to changing profiles. If the conditions hold, then the DSL system is instructed to operate with the target profile. Binder-level information can include deployment point information, topology information, and/or crosstalk coupling information. The controlled parameters may have values that are chosen using one or more spectrum balancing methods. Such spectrum balancing methods may be executed infrequently, and may make use of all binder-level information that is available.

Adaptive margin and band control

Techniques for performing frequency control in an OFDM system are described. In one aspect, frequency acquisition is performed based on a received pilot, and frequency tracking is performed based on received OFDM symbols. For frequency acquisition, an initial frequency error estimate may be derived based on the received pilot, and an automatic frequency control (AFC) loop may be initialized with the initial frequency error estimate. For frequency tracking, a frequency error estimate may be derived for each received OFDM symbol, and the AFC loop may be updated with the frequency error estimate. Frequency error in input samples is corrected by the AFC loop with the initial frequency error estimate as well as the frequency error estimate for each received OFDM symbol. In another aspect, a variable number of samples of a received OFDM symbol are selected, e.g., based on the received OFDM symbol timing, for use for frequency error estimation.

Automatic frequency control for a wireless communication system with multiple subcarriers

Methods and apparatus for frequency tracking of a received signal. In an aspect, a method is provided wherein the received signal comprises one or more symbols having a periodic structure. The method comprises receiving a plurality of samples of a selected symbol that comprises pilot signals scrambled with data and determining a window size and a periodicity factor. The method also comprises accumulating a correlation between samples in a first window and samples in a second window to produce an accumulated correlation value, wherein the first and second windows have a size and a separation based on the window size and the periodicity factor, respectively, and deriving a frequency error estimate based on the accumulated correlation value.

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Redwood City, CA, United States of America

Seong Taek Chung