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公开(公告)号：NO20070422A
公开(公告)日：2007-03-30
申请号：NO20070422
申请日：2007-01-23
Applicant: QUALCOMM INC
Inventor： BENDER PAUL E , LEVIN JEFFREY A , SMEE JOHN E , HOU JILEI , CORALLI ALESSANDRO VANELLI , PFISTER HENRY DAVID , PADOVANI ROBERTO , BUTLER BRIAN K , WILBORN THOMAS B
IPC: H04B1/707
CPC classification number: H04B1/7107 , H04B2201/70701
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102.发明专利
公开(公告)号：ECSP077211A
公开(公告)日：2007-02-28
申请号：ECSP077211
申请日：2007-01-29
Applicant: QUALCOMM INC
Inventor： HOU JILEI , BENDER PAUL E , CORALLI ALESSANDRO VANELLI , PFISTER HENRY DAVID , SMEE JOHN E , PADOVANI ROBERTO , BUTLER BRIAN K , LEVIN JEFFREY A , WILBORN THOMAS B
IPC: H04B1/707
Abstract: Métodos y sistemas para estimar y cancelar la interferencia piloto en un sistema de comunicación inalámbrica (por ejemplo CDMA). En un método, una señal recibida comprendida de un número de instancias de señal, cada una incluyendo un piloto, es inicuamente procesada para proporcionar muestras de datos. Cada interferencia piloto de la instancia de señal puede ser estimada mediante la diseminación de las muestras de datos con una secuencia diseminadora para la instancia de señal, canalizando los datos de-diseminados para proporcionar símbolos pilotos, filtrar los símbolos pilotos para estimar la respuesta del canal a la instancia de señal, y multiplicar la respuesta del canal estimada con la secuencia de diseminación. Los estimados de la interferencia piloto debido a una pluralidad de multi-direccionales interferentes se acumulan para derivar la interferencia piloto total, la cual se resta de las muestras de datos para proporcionar muestras de datos piloto-canceladas. Estas muestras son entonces procesadas para derivar datos de-modulados para cada una de al menos una instancia de señal (deseado) en la señal recibida
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公开(公告)号：BR0312959A
公开(公告)日：2005-06-14
申请号：BR0312959
申请日：2003-07-18
Applicant: QUALCOMM INC
Inventor： FERNANDEZ-CORBATON IVAN JESUS , SMEE JOHN E , JAYARAMAN SRIKANT
Abstract: A non-parametric matched filter receiver that includes a digital (e.g., FIR) filter and a channel estimator. The channel estimator (1) determines the timing to center the digital filter, (2) obtains the characteristics of the noise in received samples, (3) estimates the system response for the samples using a best linear unbiased (BLU) estimator, a correlating estimator, or some other type of estimator, and (4) derives a set of coefficients for the digital filter based on the estimated system response and the determined noise characteristics. The correlating estimator correlates the samples with their known values to obtain the estimated system response. The BLU estimator pre-processes the samples to whiten the noise, correlates the whitened samples with their known values, and applies a correction factor to obtain the estimated system response. The digital filter then filters the samples with the set of coefficients to provide demodulated symbols.
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公开(公告)号：CA2787842A1
公开(公告)日：2005-06-09
申请号：CA2787842
申请日：2004-11-12
Applicant: QUALCOMM INC
Inventor： WALTON J RODNEY , KETCHUM JOHN W , SMEE JOHN E , WALLACE MARK S , HOWARD STEVEN J
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公开(公告)号：BR0213984A
公开(公告)日：2005-05-10
申请号：BR0213984
申请日：2002-10-29
Applicant: QUALCOMM INC
Inventor： JAYARAMAN SRIKANT , SMEE JOHN E , CORBATON IVAN JESUS FERNANDEZ
Abstract: Techniques for detecting and mitigating adjacent channel interference (ACI) in a wireless (e.g., CDMA) communication system. In one aspect, ACI may be determined by signaling or detected by filtering a pre-processed signal in each frequency range where ACI may be present (e.g., with a respective bandpass filter), estimating the energy of the filtered signal for each frequency range, comparing the estimated energy against an ACI threshold, and indicating the presence or absence of ACI at each frequency range based on the result of the comparison. In another aspect, a selectable filter (e.g., a FIR filter) having a number of possible filter responses (e.g., provided by a number of sets of filter coefficients) may be used to provide filtering for the pre-processed signal and to reject any detected ACI. One of the possible filter responses is selected for use depending on whether and where ACI has been detected.
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Patent Agency Ranking
公开(公告)号：CA2512551A1
公开(公告)日：2004-07-29
申请号：CA2512551
申请日：2004-01-07
Applicant: QUALCOMM INC
Inventor： MALLADI DURGA PRASAD , WALTON JAY RODNEY , SMEE JOHN E
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 randomi ze 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 interferen ce is estimated and then subtracted from received symbols to obtain pilot- canceled symbols having improved quality.
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公开(公告)号：AU2004204911A1
公开(公告)日：2004-07-29
申请号：AU2004204911
申请日：2004-01-07
Applicant: QUALCOMM INC
Inventor： SMEE JOHN E , WALTON JAY RODNEY , MALLADI DURGA PRASAD
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.
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公开(公告)号：AU2003256623A1
公开(公告)日：2004-02-09
申请号：AU2003256623
申请日：2003-07-18
Applicant: QUALCOMM INC
Inventor： CORBATON IVAN JESUS FERNANDEZ , SMEE JOHN E , JAYARAMAN SRIKANT
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.
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公开(公告)号：BR0113095A
公开(公告)日：2003-09-16
申请号：BR0113095
申请日：2001-08-01
Applicant: QUALCOMM INC
Inventor： SMEE JOHN E , JALALI AHMAD , LING FUYUN , WALLACE MARK
Abstract: A receive filter receives signals from a communication channel. The received signals correspond to original Walsh covered chip sequences transmitted by a transmit filter through the communication channel to the receive filter. The received signals are processed by an equalizer to generate a soft estimate of chip sequences corresponding to the original Walsh covered chip sequences. An N chip Walsh decover is then utilized to generate a soft estimate of code symbols corresponding to the soft estimate of the chip sequences. A number of symbol slicers are then used in parallel to produce a hard estimate of the code symbols corresponding to the soft estimate of code symbols generated by the N chip Walsh decover. Thereafter an N chip Walsh cover is used as part of a scheme to generate a hard estimate of chip sequences corresponding to the hard estimate of the code symbols generated by the symbol slicers. The hard estimate of the chip sequences generated with the aid of the N chip Walsh cover, and the soft estimate of the chip sequences generated by the equalizer, are used to generate a tracking mode error signal to adapt the response of the equalizer to the received signals.
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公开(公告)号：CA2473233A1
公开(公告)日：2003-07-24
申请号：CA2473233
申请日：2003-01-07
Applicant: QUALCOMM INC
Inventor： JAYARAMAN SRIKANT , SMEE JOHN E , CORBATON IVAN JESUS FERNANDEZ
IPC: H03M13/01 , H04B1/7105 , H04B1/712 , H04L1/00 , 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 (550). Using the solved multipath gain vector, the LLRs for code symbols are computed.
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