Carlos Alberto Aldana

US Patent:

6990196, Jan 24, 2006

Filed:

Feb 16, 2001

Appl. No.:

09/788267

Inventors:

Chaohuang Zeng - Palo Alto CA, US
Carlos Aldana - Stanford CA, US
Atul Salvekar - Stanford CA, US
John M. Cioffi - Atherton CA, US

Assignee:

The Board of Trustees of the Leland Stanford Junior University - Palo Alto CA

International Classification:

H04J 3/10

US Classification:

379417, 370201

Abstract:

Methods, apparatus and systems for identifying crosstalk interference in xDSL systems are disclosed and are useful in a variety of xDSL systems to assist in the provisioning, maintenance and diagnosis of the xDSL system and in spectral management and assignments. Signal data are collected from a receiver, a primary transmitter and any crosstalk transmitters. The signal data are resampled, if necessary. A first estimate of the timing offset between the received signal and each crosstalk signal is then obtained by cross-correlating the received data with the transmitted crosstalk data. The first timing offset estimate is then used in connection with a least-squares estimation of the crosstalk response for the considered crosstalk data and a second estimate of the timing offset. The invention may be used at a third party site remote from the system transmitters and receivers. The crosstalk identification of the present invention can be used in dynamic spectrum management for DSL services and signals.

US Patent:

7394752, Jul 1, 2008

Filed:

Oct 31, 2002

Appl. No.:

10/286185

Inventors:

Kazutomo Hasegawa - Kawasaki, JP
Georgios Ginis - Mountain View CA, US
Carlos Aldana - Irvine CA, US
John M. Cioffi - Atherton CA, US

Assignee:

The Board of Trusttees of the Leland Stanford Junior University - Palo Alto CA
Fujitsu Limited - Kanagawa

International Classification:

H04J 1/12

US Classification:

370201, 370286

Abstract:

Methods, apparatus, techniques and computer program products for joint reduction of crosstalk in a synchronized, time division duplexed DSL systems use sequential removal of NEXT interference followed by removal of FEXT interference from a received DSL signal. Crosstalk is removed from a primary signal in a synchronized TDD DSL system having a primary channel that carries the primary signal, at least one NEXT generating channel that generates NEXT interference in the primary signal and at least one FEXT generating channel that generates FEXT interference in the primary signal. Signal data is acquired, where the signal data includes received signal data for the primary channel and at least one FEXT generating channel, transmitted signal data for at least one NEXT generating channel, and channel data comprising channel transfer function data and crosstalk coupling coefficient data for the primary channel, each NEXT generating channel and each FEXT generating channel. After the signal data is acquired, NEXT interference in the primary signal is then removed using the transmitted signal data and the channel data, followed by removal of FEXT interference in the primary signal using vectored DMT FEXT removal, the received signal data and the channel data. In another system in which FEXT generating received signals are not necessarily available, FEXT removal can be achieved using expectation cancellation, the primary signal and the channel data in connection with possible transmitted signal values.

US Patent:

7564914, Jul 21, 2009

Filed:

Feb 7, 2005

Appl. No.:

11/052353

Inventors:

Christopher J. Hansen - Sunnyvale CA, US
Carlos H. Aldana - Mountain View CA, US
Joonsuk Kim - San Jose CA, US

Assignee:

Broadcom Corporation - Irvine CA

International Classification:

H04B 7/02
H04B 7/216

US Classification:

375267, 370342

Abstract:

A method and system for frame formats for MIMO channel measurement exchange is provided. Aspects of a method for communicating information in a communication system may comprise transmitting data via a plurality of radio frequency (RF) channels utilizing a plurality of transmitting antenna, receiving feedback information via at least one of a plurality of RF channels, and modifying a transmission mode based on the feedback information. Aspects of a method for communicating information in a communication system may also comprise receiving data via a plurality of receiving antenna, transmitting feedback information via at least one of the plurality of RF channels, and requesting modification of a transmission mode for the received data in transmitted response messages comprising the feedback information.

US Patent:

7693228, Apr 6, 2010

Filed:

Dec 9, 2005

Appl. No.:

11/298157

Inventors:

Carlos Aldana - San Francisco CA, US
Jason A. Trachewsky - Menlo Park CA, US

Assignee:

Broadcom Corporation - Irvine CA

International Classification:

H04B 7/02

US Classification:

375267, 375259, 375219, 375295, 375316, 370208, 370210

Abstract:

A general architecture scheme to perform channel estimation on orthogonal transmissions for any number of transmitting antennas present. Generally, the channel estimation is applicable for wireless communications in a MIMO system.

US Patent:

7693234, Apr 6, 2010

Filed:

Feb 23, 2006

Appl. No.:

11/359460

Inventors:

Carlos Aldana - Sunnyvale CA, US

Assignee:

Broadcom Corporation - Irvine CA

International Classification:

H04B 7/02
H04L 27/00

US Classification:

375299, 375267

Abstract:

The method and apparatus in accordance with the present invention receives bits, writes the bits row-by-row in a matrix, reads the bits column-by-column from the matrix, groups and rotates the bits read column-by-column from the matrix so as to evenly separate the bits in position, frequency, space over one symbol period.

US Patent:

7916807, Mar 29, 2011

Filed:

Oct 17, 2007

Appl. No.:

11/873626

Inventors:

Carlos Aldana - San Francisco CA, US

Assignee:

Broadcom Corporation - Irvine CA

International Classification:

H04L 27/04

US Classification:

375299

Abstract:

Aspects of a method and system for choice of a steering matrix (Q) for sounding in antenna selection are presented. Aspects of the system may include a transmitting station that enables determination of values for a plurality of matrix elements, which are represented in a steering matrix (Q). The contents of the steering matrix may be determined based on the contents of a plurality of protocol data units (PDU). Each of the PDUs may comprise a sounding frame. One or more space-time signals may be generated based on the plurality of PDUs. One or more transmit chain signals may be generated by multiplying a vector representation, which comprises the one or more space-time signals, by the steering matrix. One or more transmit chain signals may be transmitted via transmitting antennas selected from a plurality of transmitting antennas.

US Patent:

7924943, Apr 12, 2011

Filed:

Apr 20, 2005

Appl. No.:

11/110241

Inventors:

Joonsuk Kim - San Jose CA, US
Carlos H. Aldana - Mountain View CA, US
Christopher J. Hansen - Sunnyvale CA, US

Assignee:

Broadcom Corporation - Irvine CA

International Classification:

H04L 27/00

US Classification:

375299, 375219, 375316, 375377, 455 25

Abstract:

Aspects of a method and system for an optional closed loop mechanism with adaptive modulations for a multiple input multiple output (MIMO) WLAN system are provided. One aspect of the system may comprise a receiver that may select, for a plurality of spatial streams, a modulation type and/or coding rate. The receiver may communicate a message, via an RF channel, that comprises a plurality of modulation types and/or coding rates. The receiver may configure for receiving subsequent data based on at least one selected modulation type and/or coding rate. Another aspect of the system may comprise a transmitter that may receive a message, via an RF channel, that comprises a specification of, for a plurality of spatial streams, a plurality of modulation types and/or coding rates. The system may configure for transmitting subsequent data based on at least one of the received modulation types and/or coding rates.

US Patent:

7957450, Jun 7, 2011

Filed:

Jul 20, 2009

Appl. No.:

12/506053

Inventors:

Christopher J. Hansen - Sunnyvale CA, US
Carlos H. Aldana - Mountain View CA, US
Joonsuk Kim - San Jose CA, US

International Classification:

H04B 1/00

US Classification:

375130

Abstract:

A method and system for frame formats for MIMO channel measurement exchange is provided. Aspects of a method for communicating information in a communication system may comprise transmitting data via a plurality of radio frequency (RF) channels utilizing a plurality of transmitting antenna, receiving feedback information via at least one of a plurality of RF channels, and modifying a transmission mode based on the feedback information. Aspects of a method for communicating information in a communication system may also comprise receiving data via a plurality of receiving antenna, transmitting feedback information via at least one of the plurality of RF channels, and requesting modification of a transmission mode for the received data in transmitted response messages comprising the feedback information.