Li J Liu

US Patent:

7539458, May 26, 2009

Filed:

Oct 23, 2006

Appl. No.:

11/584831

Inventors:

Hamid Jafarkhani - Irvine CA, US
Li Liu - Aliso Viejo CA, US

Assignee:

The Regents of the University of California - Oakland CA

International Classification:

H04B 1/00
H04B 15/00

US Classification:

455 631, 455 6711, 455 6716, 455 69, 455 91, 343368, 343754, 343753

Abstract:

A multiple antenna wireless system including a transmitter and a receiver comprises a reconfigurable large antenna array having a plurality of antennas. A plurality of RF chains in the transmitter is coupled to the reconfigurable large antenna array. A pilot assisted round robin channel estimation means tracks the fading channel; and an adaptive round robin transmit beamforming means beam forms the reconfigurable large antenna array. A method for multiple antenna wireless communication comprising the steps of tracking a plurality of fading channels in a reconfigurable large antenna array having a plurality of antennas using pilot assisted round robin channel estimation to selectively couple a plurality of RF chains in the transmitter to the reconfigurable large antenna array, and adaptively, round-robin transmit beamforming the reconfigurable large antenna array.

US Patent:

7599419, Oct 6, 2009

Filed:

Jan 12, 2006

Appl. No.:

11/332019

Inventors:

Hamid Jafarkhani - Irvine CA, US
Li Liu - Aliso Viejo CA, US

Assignee:

The Regents of the University of California - Oakland CA

International Classification:

H04B 1/00

US Classification:

375137, 375135, 375229, 375261, 375265, 375267

Abstract:

A method for multiple-input-multiple-output (MIMO) wireless communication comprises the steps of generating inner and outer codes based on channel state information available at a transmitter and concatenating different inner codes with different outer codes; and using the generated concatenated inner and outer codes for wireless communication. The inner and outer codes are based on channel phase information at the transmitter or channel feedback. High-performance trellis codes or block codes for use in cellular networks are illustratively described. The space-time trellis codes are generated by set partitioning on a plurality of classes of signal designs to generate a series of inner codes, each of the series of inner codes being optimized by channel phase feedback, and concatenating each inner code with a multiple trellis coded modulated outer code to provide a complete space-time trellis code as a cophase space-time trellis code.

US Patent:

7912142, Mar 22, 2011

Filed:

Apr 4, 2008

Appl. No.:

12/062650

Inventors:

Jun Ma - Irvine CA, US
Nabil Yousef - Foothill Ranch CA, US
Li Liu - Aliso Viejo CA, US

Assignee:

Newport Media, Inc. - Lake Forest CA

International Classification:

H04B 15/00

US Classification:

375285, 375267, 375346, 375347

Abstract:

An apparatus, method, and system for reducing a C/N in an OFDM receiver using diversity combining techniques in the presence of ICI, wherein the apparatus comprises an encoded data estimator adapted to estimate data received in the OFDM receiver; a pair of ICI estimators operatively connected to the encoded data estimator and adapted to calculate an inter-carrier-interference term of the data; and a pair of diversity combining equalizers adapted to compensate multi-path interference of the data, wherein a first one of the diversity combining equalizers is operatively connected to the encoded data estimator, and a second one of the diversity combining equalizers is operatively connected to the pair of ICI estimators. The diversity combining equalizer may comprise a MRC diversity combining equalizer. Preferably, the encoded data estimator, the pair of ICI estimators, and the pair of diversity combining equalizers are implemented on a DVB-T/H diversity SoC.

US Patent:

8150433, Apr 3, 2012

Filed:

Aug 15, 2006

Appl. No.:

12/063851

Inventors:

Li Liu - Aliso Viejo CA, US
Hamid Jafarkhani - Irvine CA, US

Assignee:

The Regents of the University of California - Oakland CA

International Classification:

H04B 15/00

US Classification:

455504, 455506

Abstract:

An improvement in a method of transmit beamforming between a transmitter () and a receiver () for a time varying lading channel comprises the step of performing transmit beamforming using less than complete knowledge of the previous fading blocks to design a codebook () of a current fading block with each time frame. One embodiment comprises a successive beamforming algorithm and a second embodiment comprises a vector quantization beamforming algorithm. A fading parameter α is determined at least in the transmitter or receiver by monitoring a mobile Doppler frequency.

US Patent:

8315323, Nov 20, 2012

Filed:

Aug 23, 2006

Appl. No.:

12/064616

Inventors:

Li Liu - Aliso Viejo CA, US
Hamid Jafarkhani - Irvine CA, US

Assignee:

The Regents of the University of California - Oakland CA

International Classification:

H04B 7/02

US Classification:

375267, 375260, 375296, 375299, 375347, 375349

Abstract:

An improvement in a method of transmit beamforming between a transmitter and a receiver in an OFDM wireless system having a plurality of subcarriers for a time varying fading channel comprises performing successive beamforming for each of the plurality of subcarriers using less than complete knowledge of the previous fading blocks for the subcarriers by beamforming an adaptive codebook, C=(C;. . . ; c}, of a current fading block for the subcarriers by correlating inter-frame and/or inter-subcarrier signals among the plurality of subcarriers.

US Patent:

20090252263, Oct 8, 2009

Filed:

Apr 4, 2008

Appl. No.:

12/062678

Inventors:

Li Liu - Aliso Viejo CA, US
Yongru Gu - Lake Forest CA, US
Jun Ma - Shaanxi, CN

Assignee:

Newport Media, Inc. - Lake Forest CA

International Classification:

H04L 27/06

US Classification:

375344

Abstract:

A technique for estimating maximum Doppler frequency of a wireless signal in a wireless communication system, wherein the method comprises receiving a wireless signal; determining an impulse response of the received wireless signal; determining an auto-correlation function (ACF) value of the impulse response of the received wireless signal; determining a power spectrum density of said received wireless signal based on the ACF value; and selecting an algorithm for performing demodulation of the received wireless signal by utilizing the determined power spectrum density.