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公开(公告)号：CA2629787C
公开(公告)日：2012-01-03
申请号：CA2629787
申请日：2006-11-15
Applicant: QUALCOMM INC
Inventor： GLAZKO SERGUEI A , LAI KUEI-CHIANG , PATEL SHIMMAN
IPC: H04L27/26
Abstract: Techniques for performing time tracking at a receiver are described. A first arriving path (FAP) and a last arriving path (LAP) are detected based on a channel impulse response estimate for a communication channel. The detected FAP and LAP may be correct or swapped. To resolve ambiguity in the detected FAP and LAP, a first hypothesis corresponding to the FAP and LAP being correctly detected and a second hypothesis corresponding to the FAP and LAP being incorrectly detected are evaluated. For each hypothesis, hypothesized FAP and LAP are determined based on the detected FAP and LAP, a correlation window is determined based on the hypothesized FAP and LAP, and correlation is performed using the correlation window. The correct hypothesis is determined based on correlation results for the two hypotheses. The receiver timing is updated based on the hypothesized FAP and LAP for the correct hypothesis and used for demodulation.
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公开(公告)号：HK1114725A1
公开(公告)日：2008-11-07
申请号：HK08103461
申请日：2008-03-27
Applicant: QUALCOMM INC
Inventor： CHEN QINGXIN , PATEL SHIMMAN
IPC: H04W24/02 , H04L1/00 , H04L1/20 , H04W20100101
Abstract: Techniques to detect for DTX frames in a "primary" transmission that may be sent in a non-continuous manner using a "secondary" transmission that is sent during periods of no transmission for the primary transmission. The primary and secondary transmissions may be the ones sent on the F-DCCH and Forward Power Control Subchannel, respectively, in an IS-2000 system. In one method, a determination is first made whether or not a frame received for the primary transmission in a particular frame interval is a good frame (e.g., based on CRC). If the received frame is not a good frame, then a determination is next made whether the received frame is a DTX frame or an erased frame based on a number of metrics determined for the primary and secondary transmissions. The metrics may include symbol error rate of the received frame, secondary transmission (e.g., PC bit) energy, and received frame energy.
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公开(公告)号：DE60315883D1
公开(公告)日：2007-10-04
申请号：DE60315883
申请日：2003-12-10
Applicant: QUALCOMM INC
Inventor： CHEN QINGXIN , PATEL SHIMMAN
Abstract: Techniques to detect for DTX frames in a "primary" transmission that may be sent in a non-continuous manner using a "secondary" transmission that is sent during periods of no transmission for the primary transmission. The primary and secondary transmissions may be the ones sent on the F-DCCH and Forward Power Control Subchannel, respectively, in an IS-2000 system. In one method, a determination is first made whether or not a frame received for the primary transmission in a particular frame interval is a good frame (e.g., based on CRC). If the received frame is not a good frame, then a determination is next made whether the received frame is a DTX frame or an erased frame based on a number of metrics determined for the primary and secondary transmissions. The metrics may include symbol error rate of the received frame, secondary transmission (e.g., PC bit) energy, and received frame energy.
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公开(公告)号：CA2629787A1
公开(公告)日：2007-05-24
申请号：CA2629787
申请日：2006-11-15
Applicant: QUALCOMM INC
Inventor： GLAZKO SERGUEI A , LAI KUEI-CHIANG , PATEL SHIMMAN
IPC: H04L27/26
Abstract: Techniques for performing time tracking at a receiver are described. A first arriving path (FAP) and a last arriving path (LAP) are detected based on a channel impulse response estimate for a communication channel. The detected FAP and LAP may be correct or swapped. To resolve ambiguity in the detected FAP and LAP, a first hypothesis corresponding to the FAP and LAP being correctly detected and a second hypothesis corresponding to the FAP and LAP being incorrectly detected are evaluated. For each hypothesis, hypothesized FAP and LAP are determined based on the detected FAP and LAP, a correlation window is determined based on the hypothesized FAP and LAP, and correlation is performed using the correlation window. The correct hypothesis is determined based on correlation results for the two hypotheses. The receiver timing is updated based on the hypothesized FAP and LAP for the correct hypothesis and used for demodulation.
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公开(公告)号：BR0206878A
公开(公告)日：2005-01-18
申请号：BR0206878
申请日：2002-01-31
Applicant: QUALCOMM INC
Inventor： WILBORN THOMAS BRIAN , PATEL SHIMMAN , SIH GILBERT C , ABRISHAMKAR FARROKH
Abstract: A velocity estimate is determined from a received signal by counting the number of times a signal in one multipath crosses a predetermined threshold in a given amount of time. A signal is received and a single multipath is extracted from the received signal. Instantaneous envelope values of the extracted multipath are calculated. A plurality of the instantaneous envelope values are used to calculate a running RMS value. A level crossing threshold is determined using the running RMS value. The number of times the instantaneous envelope value crosses the level crossing threshold is counted. The number of level crossings is mapped to a velocity estimate.
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Patent Agency Ranking
公开(公告)号：AU2003297901A8
公开(公告)日：2004-06-30
申请号：AU2003297901
申请日：2003-12-10
Applicant: QUALCOMM INC
Inventor： PATEL SHIMMAN , CHEN QINGXIN
Abstract: Techniques to detect for DTX frames in a "primary" transmission that may be sent in a non-continuous manner using a "secondary" transmission that is sent during periods of no transmission for the primary transmission. The primary and secondary transmissions may be the ones sent on the F-DCCH and Forward Power Control Subchannel, respectively, in an IS-2000 system. In one method, a determination is first made whether or not a frame received for the primary transmission in a particular frame interval is a good frame (e.g., based on CRC). If the received frame is not a good frame, then a determination is next made whether the received frame is a DTX frame or an erased frame based on a number of metrics determined for the primary and secondary transmissions. The metrics may include symbol error rate of the received frame, secondary transmission (e.g., PC bit) energy, and received frame energy.
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公开(公告)号：CA2508869A1
公开(公告)日：2004-06-24
申请号：CA2508869
申请日：2003-12-10
Applicant: QUALCOMM INC
Inventor： PATEL SHIMMAN , CHEN QINGXIN
Abstract: Techniques to detect for DTX frames in a "primary" transmission that may be sent in a non-continuous manner using a "secondary" transmission that is sen t during periods of no transmission for the primary transmission. The primary and secondary transmissions may be the ones sent on the F-DCCH and Forward Power Control Subchannel, respectively, in an IS-2000 system. In one method, a determination is first made whether or not a frame received for the primary transmission in a particular frame interval is a good frame (e.g., based on CRC). If the received frame is not a good frame, then a determination is nex t made whether the received frame is a DTX frame or an erased frame based on a number of metrics determined for the primary and secondary transmissions. Th e metrics may include symbol error rate of the received frame, secondary transmission (e.g., PC bit) energy, and received frame energy.
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公开(公告)号：HK1048572A1
公开(公告)日：2003-04-04
申请号：HK03100676
申请日：2003-01-27
Applicant: QUALCOMM INC
Inventor： CHEN TAO , PATEL SHIMMAN
Abstract: Techniques for detecting zero rate frames in a received data transmission. A modulated signal is received and demodulated in accordance with a particular demodulation format to generate demodulated symbols. The demodulated symbols are partitioned into a number of received frames. For each received frame, a quality metric is computed and compared against a threshold value. The threshold value is selected based, in part, on the quality metrics of received frames. Based on the comparison result, the received frame is indicated as being either transmitted and received in error (i.e., erased or bad) or not transmitted at all (i.e., zero rate or empty). The quality metric can relate to an energy of a received frame, a distance between a received frame and a codeword corresponding to the received frame, or other metrics. The threshold value can be selected based on the quality metrics computed for decoded frames or received frames identified as good, and can be dynamically adjusted based on current information available at the receiver. The method is advantageously used in a CDMA communications system.
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公开(公告)号：BR0013669A
公开(公告)日：2002-07-02
申请号：BR0013669
申请日：2000-08-31
Applicant: QUALCOMM INC
Inventor： CHEN TAO , PATEL SHIMMAN
Abstract: Techniques for detecting zero rate frames in a received data transmission. A modulated signal is received and demodulated in accordance with a particular demodulation format to generate demodulated symbols. The demodulated symbols are partitioned into a number of received frames. For each received frame, a quality metric is computed and compared against a threshold value. The threshold value is selected based, in part, on the quality metrics of received frames. Based on the comparison result, the received frame is indicated as being either transmitted and received in error (i.e., erased or bad) or not transmitted at all (i.e., zero rate or empty). The quality metric can relate to an energy of a received frame, a distance between a received frame and a codeword corresponding to the received frame, or other metrics. The threshold value can be selected based on the quality metrics computed for decoded frames or received frames identified as good, and can be dynamically adjusted based on current information available at the receiver. The method is advantageously used in a CDMA communications system.
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公开(公告)号：AU1840500A
公开(公告)日：2000-06-19
申请号：AU1840500
申请日：1999-12-02
Applicant: QUALCOMM INC
Inventor： CHEN TAO , HOLTZMAN JACK M , RAZOUMOV LEONID , PATEL SHIMMAN , SAINTS KEITH , TIEDEMANN EDWARD G JR
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