公开(公告)号：DE60325336D1

公开(公告)日：2009-01-29

申请号：DE60325336

申请日：2003-01-07

Applicant: QUALCOMM INC

Inventor： JAYARAMAN SRIKANT ,  CORBATON IVAN JESUS ,  SMEE JOHN E

IPC: H03M13/01 ,  H04L1/00 ,  H04B1/7105 ,  H04B1/712 ,  H04L1/02

Abstract: Methods and apparatus are presented herein for determining log likelihood ratios (LLRs) for code symbols. Pilot and code symbols are transmitted over diversity channels, which can be modeled as a slowly time varying system. A formulation for a multipath gain vector is derived herein based on the slowly time varying model. The multipath gain vector is then solved using iterative procedures. Using the solved multipath gain vector, the LLRs for code symbols are computed.

公开(公告)号：AU2003256623B2

公开(公告)日：2008-12-04

申请号：AU2003256623

申请日：2003-07-18

Applicant: QUALCOMM INC

Inventor： CORBATON IVAN JESUS FERNANDEZ ,  JAYARAMAN SRIKANT ,  SMEE JOHN E

IPC: H04L27/01 ,  H04B7/005 ,  H04L25/00 ,  H04L25/03

Abstract: A method and apparatus for a decision feedback equalizer wherein a correction term is used to compensate for slicer errors, thus avoiding error propagation. Filter coefficients for the equalizer are selected so as to minimize a cost function for the equalizer, including a correction term as a function of the energy of the filter coefficients. The equalizer includes a coefficient generator responsive to the correction term. One embodiment estimates a transmitted symbol from a received sample as a function of Signal-to-Interference and Noise Ratio (SINR) of the received sample. The received sample is quantized and mapped to a region of a grid overlaid on the transmitted symbol constellation. The region may correspond to a symbol estimate value or may be processed further to obtain a symbol estimate value.

公开(公告)号：DE60229138D1

公开(公告)日：2008-11-13

申请号：DE60229138

申请日：2002-07-25

Applicant: QUALCOMM INC

Inventor： FERNANDEZ-CORBATON IVAN ,  SMEE JOHN E ,  JAYARAMAN SRIKANT

IPC: H04B1/69 ,  H04B7/08 ,  H04B7/005 ,  H04L1/06 ,  H04L25/03

Abstract: A communication receiver (400) minimizes a combined local and global mean square error for signal equalization. A base station (101) or a mobile station (102-104) may include a plurality of antennas (292) for receiving a plurality of signals transmitted from a common source. The plurality of signals carry a common stream of data symbols. A pre-processing block (299) processes the received signals to produce a plurality of processed received signals (298). A signal equalizer (401) minimizes a combined local and global MSE over the processed received signals (298) to produce a combined signal (499). A decoder decodes the combined signal (499) to retrieve the stream of data symbols. A processor is configured for combining a local MSE and a global MSE in accordance with an adjustable weighting factor a to produce the combined local and global MSE.

公开(公告)号：AT409988T

公开(公告)日：2008-10-15

申请号：AT02756726

申请日：2002-07-25

Applicant: QUALCOMM INC

Inventor： FERNANDEZ-CORBATON IVAN ,  SMEE JOHN E ,  JAYARAMAN SRIKANT

IPC: H04B1/69 ,  H04B7/08 ,  H04B7/005 ,  H04L1/06 ,  H04L25/03

Abstract: A communication receiver (400) minimizes a combined local and global mean square error for signal equalization. A base station (101) or a mobile station (102-104) may include a plurality of antennas (292) for receiving a plurality of signals transmitted from a common source. The plurality of signals carry a common stream of data symbols. A pre-processing block (299) processes the received signals to produce a plurality of processed received signals (298). A signal equalizer (401) minimizes a combined local and global MSE over the processed received signals (298) to produce a combined signal (499). A decoder decodes the combined signal (499) to retrieve the stream of data symbols. A processor is configured for combining a local MSE and a global MSE in accordance with an adjustable weighting factor a to produce the combined local and global MSE.

公开(公告)号：DE602005008082D1

公开(公告)日：2008-08-21

申请号：DE602005008082

申请日：2005-09-16

Applicant: QUALCOMM INC

Inventor： NAMGOONG JUNE ,  XU HAO ,  BLACK PETER J ,  JAYARAMAN SRIKANT

IPC: H04L27/26 ,  H04B1/10 ,  H04L1/20

Abstract: The present patent application comprises a method and means for demodulating symbols, comprising converting an OFDM symbol from a time domain to a frequency domain, selecting pilot tones, making a soft decision based on received data, and estimating a channel frequency response. In another example, the method and means further comprises selecting guard tones. In another example, the method and means further comprises generating channel estimates for in-band and band-edge pilot tones.

公开(公告)号：DE602004014807D1

公开(公告)日：2008-08-14

申请号：DE602004014807

申请日：2004-12-03

Applicant: QUALCOMM INC

Inventor： FERNANDEZ-CORBATON IVAN JESUS ,  JAYARAMAN SRIKANT ,  SWEET CHARLES WHEELER III

IPC: H04W72/08

Abstract: Systems and methods for adaptively allocating resources between a dedicated reference signal and a traffic signal are disclosed. In an exemplary embodiment, a wireless communication system 100 includes a base station 404. The base station 404 includes a receiver 428 that receives a quality metric 432 from a remote station 106. The quality metric 432 indicates the quality of a signal transmitted from the base station 404 and received by the remote station 106. The base station 404 also includes a resource allocation component 434 that uses the quality metric 432 to allocate a resource between the traffic signal 422 and the dedicated reference signal 418. The base station 404 also includes a transmitter 426 that transmits the traffic signal 422 and the dedicated reference signal 418 to the remote station 106.

公开(公告)号：AT400957T

公开(公告)日：2008-07-15

申请号：AT05797433

申请日：2005-09-16

Applicant: QUALCOMM INC

Inventor： NAMGOONG JUNE ,  XU HAO ,  BLACK PETER J ,  JAYARAMAN SRIKANT

IPC: H04L27/26 ,  H04B1/10 ,  H04L1/20

Abstract: The present patent application comprises a method and means for demodulating symbols, comprising converting an OFDM symbol from a time domain to a frequency domain, selecting pilot tones, making a soft decision based on received data, and estimating a channel frequency response. In another example, the method and means further comprises selecting guard tones. In another example, the method and means further comprises generating channel estimates for in-band and band-edge pilot tones.

公开(公告)号：AT374486T

公开(公告)日：2007-10-15

申请号：AT02748283

申请日：2002-07-31

Applicant: QUALCOMM INC

Inventor： JAYARAMAN SRIKANT ,  CORBATON IVAN JESUS FERNANDEZ ,  SMEE JOHN E

IPC: H04L25/03 ,  H04B1/707 ,  H04B1/7115 ,  H04B1/7117 ,  H04B1/712 ,  H04B7/005 ,  H04L7/02

Abstract: A weighted mean arrival time determines a delay offset of a fractionally spaced equalizer (350). The weighted mean arrival time is determined using path arrival times and energies from a Rake receiver (604). The difference between a weighted mean arrival time and a current delay offset is set to a difference X, in units of the equalizer tap spacing (608). If the difference X is greater than or equal to 1 or less than or equal to -1, then the current delay offset is updated by an incremental delay offset (610), (612), (614), (616) and the equalizer filter coefficients are shifted by a number of tap spacings (618), (620). Otherwise, the current delay offset is not updated and the filter coefficients of the fractionally spaced equalizer are not shifted (350). Adaptation of the filter coefficients and updates of the delay offset of the equalizer occur only during pilot bursts so as to minimize adaptation transients.

公开(公告)号：BR0312747A

公开(公告)日：2007-06-26

申请号：BR0312747

申请日：2003-07-18

Applicant: QUALCOMM INC

Inventor： JAYARAMAN SRIKANT ,  FERNANDEZ-CORBATON IVAN JESUS ,  SMEE JOHN E

IPC: H04L25/00 ,  H04L27/01 ,  H04B7/005 ,  H04L25/03

Abstract: A method and apparatus for a decision feedback equalizer wherein a correction term is used to compensate for slicer errors, thus avoiding error propagation. Filter coefficients for the equalizer are selected so as to minimize a cost function for the equalizer, including a correction term as a function of the energy of the filter coefficients. The equalizer includes a coefficient generator responsive to the correction term. One embodiment estimates a transmitted symbol from a received sample as a function of Signal-to-Interference and Noise Ratio (SINR) of the received sample. The received sample is quantized and mapped to a region of a grid overlaid on the transmitted symbol constellation. The region may correspond to a symbol estimate value or may be processed further to obtain a symbol estimate value.

公开(公告)号：NO20071739L

公开(公告)日：2007-06-15

申请号：NO20071739

申请日：2007-04-02

Applicant: QUALCOMM INC

Inventor： BLACK PETER J ,  JAYARAMAN SRIKANT ,  NAMGOONG JUNE ,  XU HAO

IPC: H04J11/00 ,  H04B1/10 ,  H04L27/26

Abstract: The present patent application comprises a method and means for demodulating symbols, comprising converting an OFDM symbol from a time domain to a frequency domain, selecting pilot tones, making a soft decision based on received data, and estimating a channel frequency response. In another example, the method and means further comprises selecting guard tones. In another example, the method and means further comprises generating channel estimates for in-band and band-edge pilot tones.