公开(公告)号：AT527792T

公开(公告)日：2011-10-15

申请号：AT10175826

申请日：2003-07-18

Applicant: QUALCOMM INC

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

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

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：AT525839T

公开(公告)日：2011-10-15

申请号：AT04700634

申请日：2004-01-07

Applicant: QUALCOMM INC

Inventor： SMEE JOHN E ,  WALTON JAY ,  MALLADI DURGA

IPC: H04L27/26 ,  H04B7/06 ,  H04B7/08 ,  H04L1/00 ,  H04L1/06 ,  H04L25/02 ,  H04L25/03

Abstract: Pilot transmission schemes suitable for use in wireless multi-carrier (e.g., OFDM) communication systems. These pilot transmission schemes may utilize frequency, time, or both frequency and time orthogonality to achieve orthogonality among the pilots transmitted by multiple base stations on the downlink. Frequency orthogonality is achieved by transmitting pilots on disjoint sets of subbands. Time orthogonality is achieved by transmitting pilots using different orthogonal codes (e.g., Walsh codes). The pilots may also be scrambled with different scrambling codes, which are used to randomize pilot interference and to enable identification of the transmitters of these pilots. Pilot interference cancellation may be performed to improve performance since subbands used for data transmission by one transmitter may also be used for pilot transmission by another transmitter. Pilot interference is estimated and then subtracted from received symbols to obtain pilot-canceled symbols having improved quality.

公开(公告)号：UA90244C2

公开(公告)日：2010-04-26

申请号：UA2005007804

申请日：2004-01-07

Applicant: QUALCOMM INC

Inventor： SMEE JOHN E ,  WALTON JAY RODNEY ,  MALLADI DURGA PRASAD

IPC: H04L27/26

公开(公告)号：CA2731510A1

公开(公告)日：2010-02-11

申请号：CA2731510

申请日：2009-08-07

Applicant: QUALCOMM INC

Inventor： HOU JILEI ,  SMEE JOHN E ,  MALLADI DURGA PRASAD ,  HASSANPOUR GHADY NAVID ,  MALLIK SIDDHARTHA

IPC: H04B7/02 ,  H04B7/04

Abstract: Techniques for supporting distributed multiple-input multiple-output (MIMO) transmissions are described. In one design, a user equipment (UE) determines channel estimates for multiple cells and reports the channel estimates. The UE thereafter receives a data transmission sent by the multiple cells to the UE based on the channel estimates. The data transmission may include at least one data stream, and each data stream may be sent by one cell or the multiple cells to the UE. In another design, a UE determines first and second channel estimates for first and second cells, respectively, and reports the channel estimates. The UE then receives a first data transmission sent by the first cell to the UE based on the first channel estimate. The UE also receives a second data transmission sent by the second cell to another UE and steered away from the UE based on the second channel estimate.

公开(公告)号：CA2731098A1

公开(公告)日：2010-02-11

申请号：CA2731098

申请日：2009-08-06

Applicant: QUALCOMM INC

Inventor： HOU JILEI ,  FARAJIDANA AMIR ,  YANG LIN ,  SMEE JOHN E ,  HASSANPOUR GHADY NAVID ,  MALLIK SIDDHARTHA ,  MALLADI DURGA PRASAD

IPC: H04B7/02 ,  H04B7/04

Abstract: Systems and methods for providing coverage to a first cell (104i) through a first antenna system (106i) and coverage to a second cell (104 j) through a second antenna system (106g). Data is also processed for transmission to a mobile device (108i) in the first cell using the first and second antenna systems.

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：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.