Intel Corporation

Sigang Qiu

Bo A Zhang

Vedavalli Gomatam Krishnan

Wesley Hamilton Smith

Mandayam Krishnan

Atul A Salvekar

Prashant Pratap Tawade

Kennan Herbert Laudel

Yongfang Guo

Xiaoshu Qian

Baohong Liu

Chih-Kang Chen

Xuefeng Jiang

Minh-Anh Vuong

Sathish K Kumar

Kerry Cai

Sowmiya Narasimhan

Vedavalli G Krishna

Methods and systems to synchronize to a remote node counting rate, symbol rate, and carrier frequency as functions of an estimated frequency offset and relationships between the remote node carrier frequency and counting rate, and between the remote node carrier frequency and symbol rate. The carrier frequency offset may be scaled in accordance with a ratio between the carrier frequency and the remote counting rate to synchronize the local counting rate with the remote counting rate, and/or scaled in accordance with a relationship between the carrier frequency and the remote symbol rate to synchronize the local receive path and/or transmit path sample rate with the remote symbol rate. The carrier frequency offset may be applied as compensation in the receive path and/or the transmit path. The remote and local nodes may correspond to a network coordinator and an existing node, respectively, in a Multimedia Over Coax (MoCA) environment.

Methods and systems to synchronize network nodes

A technique for modifying communication operational parameters using fast, low complexity, accurately calculated SNR values. Techniques may improve upon prior art by calculating SNR values in a more color noise insensitive manner in the frequency domain. An agent may be implemented to calculate SNR values and either store or use the SNR values to modify operational parameters in communicative system.

Signal-to-noise ratio (SNR) determination in the frequency domain

A method for switched diversity, including: determining, on a pair-wise basis, a plurality of comparative quality factors corresponding to at least two antennas based on signals received by the at least two antennas; filtering, over a period of time, multiple instances of at least one of the plurality of comparative quality factors; and selecting at least one of the signals to couple to at least one receiver chain based on the comparative quality factors.

Diversity switching

A technique for modifying communication operational parameters using fast, low complexity, accurately calculated SNR values. Techniques may improve upon prior art by calculating SNR values in a more time efficient and accurate manner in time domain. An agent may be implemented to calculate SNR values and either store or use the SNR values to modify operational parameters in communicative system.

Signal-to-noise ratio (SNR) determination in the time domain

A multicarrier receiver sequentially correlates two training symbols to determine a length of a cyclic prefix associated with each of the training symbols.

Multicarrier receivers and methods for detecting cyclic prefixes having unknown lengths

Embodiments of the invention provide methods for determining the characteristics of a local loop using the multi-carrier tones of a DSL activation process. For one embodiment, one or more sets of downstream multi-carrier tones of a digital subscriber line activation process are received at an extended voice-band modem and are capable of transmitting upstream multi-carrier tones of the digital subscriber line activation process over a local loop. The downstream carrier tones and the upstream carrier tones are folded into a first multi-tone signal and a second multi-tone signal, respectively, each having a plurality of component signals within the spectrum band of the extended voice-based modem. The total signal power of the first multi-tone signal is divided by the power of one of the plurality of component signals of the second multi-tone signal to determine a ratio value. The ratio value is used to determine a characteristic of the local loop.

Methods and apparatuses for determining loop characteristics using an extended voice-band modem

A technique is proposed to accurately estimate the Network CODEC levels for each PCM code a server modem generates. These levels are affected by the digital impairments such as Digital attenuation PAD in the trunk, the Robbed Bit Signaling, the type of CODEC (&#x3bc;-law or a-law&#x2014;or non standard), and by analog impairments such as loop distortion, noise, inter-modulation distortion, echo. At client modem equalizer output good estimates for these levels are derived. By detecting RBS pattern of the trunk, and using averages of decode levels of similar RBS slots, more accurate data points are obtained. By further replacing these levels with the closest CODEC receive levels, good accuracy is obtained. Non-monotonic points are detected and eliminated. An upper limit is set for constellation points to avoid saturation of the receiver. IMD correction is applied to the decode levels. Ideal points that are not signaled, are added if possible. When PAD-detection or Codec detection fails, PAD is set to 0 dB and the constellation is based on originally received and averaged data points. Techniques are presented for V.90 type modem constellation generation.

Receiver codec super set constellation generator

A method, apparatus, and system for adaptively synchronizing a sampling clock.

Adaptive synchronization

Embodiments of the invention provide methods and apparatuses to determine the characteristics of a local loop using the multi-tone line-probing signals of a standard voice-based modem. For one embodiment, the multi-tone, line-probing signals of a voice-band modem are transmitted over a local loop and received at a standard voice band modem. Discrete Fourier transform values are determined for each of two or more frequencies of the plurality of frequencies of the multi-tone signals. A set of discrete Fourier transform values corresponding to a set of high frequencies is summed to obtain a first value and a set of discrete Fourier transform values corresponding to a set of low frequencies is summed to obtain a second value. A power ratio is determined by dividing the first value by the second value. The power ratio is then used to determine a characteristic of the local loop.

Methods and apparatuses for determining loop characteristics using standard voice-band modem

In some embodiments, a method includes performing at least part of a digital subscriber line (DSL) handshaking process by transmitting at least one handshaking signal via a telephone subscriber loop, and analyzing the at least one handshaking signal to detect a characteristic of the telephone subscriber loop.

Methods and apparatus for characterizing subscriber loop based on analysis of DSL handshaking signals and for optimization of DSL operation

A method, apparatus, and system for detecting a tone. In some embodiments, a signal is communicated by applying a first quantity of samples per period and a second quantity of samples per period. The samples may then be translated into information. For example, the first and second quantity of samples may be translated into information and identified. According to some embodiments, a signal communicates information at at least two different frequencies simultaneously to determine a common carrier for transmitting and receiving nodes.

Signal detector

A method of generating a data constellation at a client modem is provided whereby an optimum distance between data constellation data points may be calculated for a predetermined, acceptable error probability. An iterative process may be carried out using proposed data constellations which may be used to provide factors for calculating corrected constellations. Once a constellation is generated to satisfy the required probability of error, the constellation may be re-evaluated using CRC errors and detected noise variance at the client modem. Based upon predetermined levels of noise variance and CRC error, the constellation may be regenerated to operate at either a higher bit rate or a lower bit rate.

Constellation generation and re-evaluation

A technique is proposed to accurately estimate the Network CODEC levels for each PCM code a server modem generates. These levels are affected by the digital impairments such as Digital attenuation PAD in the trunk, the Robbed Bit Signaling, the type of CODEC (&mgr;-law or a-law&mdash;or non standard), and by analog impairments such as loop distortion, noise, inter-modulation distortion, echo. At client modem equalizer output good estimates for these levels are derived. By detecting RBS pattern of the trunk, and using averages of decode levels of similar RBS slots, more accurate data points are obtained. By further replacing these levels with the closest CODEC receive levels, good accuracy is obtained. Non-monotonic points are detected and eliminated. An upper limit is set for constellation points to avoid saturation of the receiver. IMD correction is applied to the decode levels Ideal points that are not signaled, are added if possible . When PAD-detection or Codec detection fails, PAD is set to 0 dB and the constellation is based on originally received and averaged data points. Techniques are presented for V.90 type modem constellation generation.

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Raleigh, NC, United States of America

Sigang Qiu