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公开(公告)号：EP1323242A2
公开(公告)日：2003-07-02
申请号：EP01986378.6
申请日：2001-09-25
发明人： CARLSSON, Torsten , GUSTAFSSON, Kjell , ATARIUS, Roozbeh , ERIKSSON, Haakan , ÖSTBERG, Christer , PALENIUS, Torgny
IPC分类号： H04B1/707
CPC分类号： H04B1/70758 , H04B1/70757 , H04B1/712
摘要： A method and system enable matched filters of a CDMA system to be simplified using a two stage search. A course stage and a fine stage jointly produce the locations(s) of received signal path-rays. In a first stage, an oversampled digital signal (240) is decimated, and the decimated signal (415) is applied to a matched filter (420) to eventually produce an approximate location (460). In a second stage, the oversampled signal (240) is shifted based on the determined approximate location (460) and then correlated to a generated code (440), and a more-exact location is selected from the outputs of the correlations (450). Alternatively, a shifted version of the generated code (440) is correlated to the oversampled signal (240), and the more-exact location is selected from the outputs of those correlations (450).
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公开(公告)号：EP1125372B1
公开(公告)日：2003-03-26
申请号：EP99971979.2
申请日：1999-11-03
发明人： ATARIUS, Roozbeh , ERIKSSON, Hakan , PALENIUS, Torgny , CARLSSON, Torsten , ÖSTBERG, Christer , GUSTAFSSON, Kjell
CPC分类号： H04B1/7115 , H04B2201/70707
摘要： The present invention provides a system and method for reducing the power consumed by a RAKE receiver. In exemplary embodiments of the present invention, an environment variation estimator is implemented in a CDMA mobile station. The environment variation estimator is connected to the searcher of the RAKE receiver and provides an estimate of the rate at which the mobile station's environment is changing. By providing an estimate of the rate of change of the mobile station's environment, the duty cycle of the searcher can be optimized, thereby reducing the overall power consumed by the receiver. By also providing the estimate to the RAKE fingers, channel tracking can be improved.
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公开(公告)号：EP1032975A1
公开(公告)日：2000-09-06
申请号：EP98956071.9
申请日：1998-11-13
发明人： ATARIUS, Roozbeh , FRANK, Georg
IPC分类号： H03J7/02
CPC分类号： H03J7/02 , H04L2027/0065
摘要： In a communication system including at least one transmitter and at least one receiver, a frequency offset between a carrier frequency of the transmitter and a local frequency reference of the receiver is estimated. A phase difference is computed between successively collected samples of a frequency synchronization signal transmitted by the transmitter and detected by the receiver. The phase difference is added to accumulated phase differences. Phase differences of successively collected samples are computed and added to accumulated phase differences until M accumulated phase differences have been added. The sum of the M phase differences is dumped, resulting in zero accumulated phase differences. Phase differences of successively collected samples are computed, the phase differences are added to accumulated phase differences, and the sum of M phase differences is dumped until N sums of M phase differences have been dumped. The N sums of the M phase differences are added to produce the estimated frequency offset.
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公开(公告)号：EP1138126B1
公开(公告)日：2004-03-03
申请号：EP99963768.9
申请日：1999-11-26
发明人： ATARIUS, Roozbeh , ERIKSSON, H kan , PALENIUS, Torgny , CARLSSON, Torsten , GUSTAFSSON, Kjell , ÖSTBERG, Christer
IPC分类号： H04B1/707
CPC分类号： H04B1/7115 , H04B1/7093
摘要： A searcher uses an input signal, and for example, a matched filter to generate a first set of candidate paths. A selector uses the input signal and the first set of candidate paths to generate a second set of paths. The second set of paths is used to configure the fingers of a RAKE receiver. According to one aspect of the invention, the first set of candidate paths contains M paths, and the second stage uses M correlators to generate a set of M correlation values. The second stage uses the M correlation values to select N paths that are used to configure the N fingers of the RAKE receiver. According to another aspect of the invention, the first set of candidate paths contains M paths, and the second stage uses a multiple of M correlators to track the M paths and generate a set of M estimates. The second stage uses the M estimates to select N paths that are used to configure the N fingers of the RAKE receiver. According to another aspect of the invention, the selector can generate new sets of N paths while the searcher is either active or inactive. The receiver can use a quality signal or a counter to notify the searcher and/or the selector to generate new sets of paths. The selector decreases the need to continuously run the matched filter. The receiver car re-configure the fingers without having to search for new paths. The receiver can also find paths that are uncorrelated and less susceptible to fading.
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公开(公告)号：EP1232589A1
公开(公告)日：2002-08-21
申请号：EP00974524.1
申请日：2000-11-13
发明人： ATARIUS, Roozbeh , NILSSON, Johan
CPC分类号： H04W52/282 , G01S11/02 , H04B17/336 , H04W52/04
摘要： In a system having a transmitter and a receiver that communicate over a radio channel and in which signal transmission power of the transmitter is adjusted to compensate for fading dips in the channel, the Rayleigh fading rate of the radio channel, and thus the relative velocity between the transmitter and the receiver, are estimated by effectively observing the adjustments or fluctuations in signal transmission power or amplitude of the transmitter. In accordance with an exemplary embodiment of the invention, this is done by observing TPC (Transmission Power Control) commands that cause the transmitter to adjust its signal transmission power to combat Rayleigh fading, i.e., fading dips, in the radio channel. Since the TPC commands cause the transmitter to vary its signal transmission power to compensate for the fading dips, the fading dips and thus the fading rate and the relative velocity between the transmitter and the receiver can be determined by observing the signal transmission power fluctuations represented by the TPC commands.
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6.发明公开
公开(公告)号：EP1323236A2
公开(公告)日：2003-07-02
申请号：EP01974324.4
申请日：2001-10-04
发明人： DENT, Paul , BOTTOMLEY, Gregory , ATARIUS, Roozbeh
IPC分类号： H04B1/00
CPC分类号： H04B1/7087 , H04B1/712 , H04L2027/0055 , H04L2027/0093
摘要： A frequency offset is estimated between at least one frequency of at least one transmitter and a local reference frequency of a receiver. Received signals are processed using the local frequency reference oscillator to obtain representative complex numerical samples which are correlated with shifts of a locally generated despreading code to produce a number of complex channel estimates, each corresponding to a different delayed ray of the multipath propagation channel. A frequency error estimate is computed for each ray based on successive values of a respective one of the channel estimates. A weighted summation is formed of the frequency error estimate to provide a relative frequency error estimate to control the local frequency reference.
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7.发明公开METHOD AND APPARATUS FOR FAST DETECTION OF LOCATIONS OF PATH RAYS IN A RAKE RECEIVER 有权快速检测位置的方法和装置RAYS团伙RAKE接收机
公开(公告)号：EP1260032A1
公开(公告)日：2002-11-27
申请号：EP01909801.1
申请日：2001-02-28
发明人： ATARIUS, Roozbeh , DAHLBÄCK, Erik
IPC分类号： H04B1/707
CPC分类号： H04B1/7085 , H04B1/7113 , H04B1/7115
摘要： Locations of path rays in a multi-path channel receiver having multiple time references are detected, e.g., when the receiver switches time references. Locations of received path rays are searched for and determined. The locations are tracked for a predetermined amount of time. If the locations are lost after a predetermined amount of time, a new search for the locations of the received path rays is initiated. The searching may include determining a probable location of a most significant path ray, shifting the location within a predetermined interval, analyzing each shifted location to determine whether the shifted location corresponds to the actual location of the received path ray, and depending on the analysis results, completing the search or determining a probable location of a next most significant ray. The analysis may be performed by correlating each shifted location with a pilot sequence and determining if the location results exceed a predetermined threshold. If the correlation results do not exceed the threshold, a determination is made whether all the most significant path rays have been analyzed, and if so, a complete search for the path ray location is initiated. When switching from a time reference of low accuracy to a time reference of high accuracy, the low accuracy time reference may be calibrated to the high accuracy time reference based on averaged measurements of the ration of clock cycles of the time reference of high accuracy to the clock cycles of the time reference of low accuracy.
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公开(公告)号：EP1125372A1
公开(公告)日：2001-08-22
申请号：EP99971979.2
申请日：1999-11-03
发明人： ATARIUS, Roozbeh , ERIKSSON, H kan , PALENIUS, Torgny , CARLSSON, Torsten , ÖSTBERG, Christer , GUSTAFSSON, Kjell
CPC分类号： H04B1/7115 , H04B2201/70707
摘要： The present invention provides a system and method for reducing the power consumed by a RAKE receiver. In exemplary embodiments of the present invention, an environment variation estimator is implemented in a CDMA mobile station. The environment variation estimator is connected to the searcher of the RAKE receiver and provides an estimate of the rate at which the mobile station's environment is changing. By providing an estimate of the rate of change of the mobile station's environment, the duty cycle of the searcher can be optimized, thereby reducing the overall power consumed by the receiver. By also providing the estimate to the RAKE fingers, channel tracking can be improved.
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公开(公告)号：EP1057260A1
公开(公告)日：2000-12-06
申请号：EP99934375.9
申请日：1999-02-05
IPC分类号： H03J7/04
CPC分类号： H03J7/04
摘要： In a communication system including at least one transmitter and at least one receiver, a frequency synchronization signal transmitted from the transmitter to the receiver is detected. An in-phase component of a signal received by the receiver is delayed, and the delayed in-phase component is multiplied by a quadrature component of the received signal. The steps of delaying and multiplying are repeated for a predetermined number of samples of the received signal to produce an estimated cross-correlation value. A determination is made whether the estimated cross-correlation value is at least as great as a predetermined threshold, indicating that the transmitted signal is a frequency synchronization signal.
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公开(公告)号：EP1279266A1
公开(公告)日：2003-01-29
申请号：EP01940374.0
申请日：2001-04-27
发明人： ATARIUS, Roozbeh
IPC分类号： H04L27/233 , H04L27/227
CPC分类号： H04L27/233 , H04L2027/0065
摘要： A method and apparatus for estimate a frequency offset between a carrier frequency of a transmitter and a local frequency reference of a receiver in a communication system. Successive samples of a frequency synchronization signal transmitted by the transmitter and detected by the receiver are collected, and a phase difference is computed between the successively collected samples. The frequency synchronization signal can be a non-sinusoidal signal, e.g., a pilot symbol and/or data employed as a pilot symbol. Phase differences of successively collected samples are computed until N-1 phase differences have been computed. The N-1 phase differences are added to produce the estimated frequency offset. Adding may be performed using linear regression or by computing a weighted average.
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