Anti-multipath Patents (Class 455/65)
  • Patent number: 7383022
    Abstract: A method for operating a mobile equipment (ME 10) in a wireless network (12) includes determining a parameter that is indicative of a signal quality experienced by the ME, such as by determining a speed of the ME; calculating in the ME an indication of link quality, the calculation employing a filtering operation having a filter length that is a function of the determined parameter, such as speed or derivative of the speed of the ME; and reporting the calculated indication of link quality to the wireless network. The step of determining includes steps of (a) deriving an indication of ME speed in the wireless network; and (b) transmitting the speed indication to the ME using a point-to-point message.
    Type: Grant
    Filed: February 16, 2007
    Date of Patent: June 3, 2008
    Assignee: Nokia Corporation
    Inventors: Guillaume Sebire, Yuping Zhao, Eero Nikula
  • Patent number: 7379745
    Abstract: A path searcher used in a receiver includes a power delay profile generating unit configured to generate a power delay profile based on a signal received by the receiver, a sidelobe generating unit configured to identify a sidelobe component of a path contained in the power delay profile based on a response characteristic of a band-limiting filter of the receiver, a sidelobe removing unit configured to remove the sidelobe component from the power delay profile to produce a corrected power delay profile, and a path timing detection unit configured to detect a path timing based on the corrected power delay profile.
    Type: Grant
    Filed: May 5, 2005
    Date of Patent: May 27, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Junichiro Kawamoto, Noriyuki Maeda, Kenichi Higuchi, Mamoru Sawahashi
  • Publication number: 20080045154
    Abstract: There is provided a system and method of transmitting wireless data. The data signal has a multipath effected upon it and the effected multipath is used to decode the received signal. This is achieved by either passing the signal through a multipath filter prior to transmission or by producing a plurality of reflections of the transmitted signal. In the receiving end, the multipath selector will choose a preferred multipath profile and then form the data vectors for further processing. Systems for multiple input multiple output (MIMO) are thereby possible with fewer receiving antennas than transmitting antennas. Also orthogonal frequency division multiples (OFDM) systems are possible in multipath environments. Combining of beam-forming and MIMO and OFDM systems is also enabled.
    Type: Application
    Filed: August 18, 2006
    Publication date: February 21, 2008
    Inventor: Shiquan WU
  • Patent number: 7308052
    Abstract: A wireless transmission apparatus that can accurately select an optimal modulation scheme on a per block basis in a multi-carrier communication system in which block division of subcarriers and adaptive modulation are performed. In this wireless transmission apparatus, a propagation path characteristics acquisition section (107) acquires the average SNR and SNR dispersion for each block, which are estimated by a wireless reception apparatus (200), using received signals inputted from a reception RF section (106) and outputs these to an assignment section (108), the assignment section (108) selects a modulation scheme for each block based on the average SNR and SNR dispersion of each block inputted from the propagation path characteristics acquisition section (107), and modulation sections (101-1, 101-2, . . . , 101-L) modulate multi-carrier signals included in each block, with the modulation scheme for each block selected by the assignment section (108).
    Type: Grant
    Filed: July 30, 2004
    Date of Patent: December 11, 2007
    Assignee: Matsushita Electrical Industrial Co., Ltd.
    Inventors: Jun Cheng, Kenichi Miyoshi
  • Patent number: 7308287
    Abstract: In a wireless communication device, transmit weights are iteratively processed to compensate for any group delay caused by receive synchronization in the receive device. A transmit matrix of weights is computed from signals transmitted by a second communication device and received at a plurality of antennas of the first communication device. The transmit matrix processing includes normalizing a transmit weight vector with respect to a mode of the transmit weight associated with one of the plurality of antennas. The processed transmit matrix is then applied to a transmit signal to produce a plurality of transmit signals to be simultaneously transmitted from corresponding ones of the plurality of antennas of the first communication device. A plurality of eigenmodes is transmitted accordingly between the two devices in a converging iteration.
    Type: Grant
    Filed: July 14, 2006
    Date of Patent: December 11, 2007
    Assignee: IPR Licensing Inc.
    Inventor: Chandra Vaidyanathan
  • Patent number: 7305216
    Abstract: A transmitting and receiving arrangement is disclosed having a transmission path, a reception path, and a control device for suppression of interference signals which are produced by crosstalk from the transmission path to the reception path. The control device inputs correction signals that are derived from the transmission signals into the reception path at a point therein such that the interference signals are suppressed downstream from the point. The control device has a detector that detects the interference signals on the basis of characteristics of the transmission signals.
    Type: Grant
    Filed: May 16, 2005
    Date of Patent: December 4, 2007
    Assignee: Infineon Technologies AG
    Inventor: Zdravko Boos
  • Patent number: 7292609
    Abstract: The N peaks are selected from a delay profile in order starting from the highest peak involved in the delay profile, the path level and path timing are determined for each of the selected peaks, and the identical paths individually responsible for different delay profiles are detected by comparing the path timings calculated for the preceding time and the path timings calculated for the present time. Based of the path levels calculated for the preceding time and the path levels calculated for the present time, averaged path levels are computed on a path-by-path basis for the present time, a predetermined threshold is applied to the computed average path levels, and the paths to be allocated to the fingers are selected. Of the path timings that have been obtained for respective selected paths, the latest path timings are allocated to the fingers as synchronization timings.
    Type: Grant
    Filed: October 8, 2004
    Date of Patent: November 6, 2007
    Assignee: NEC Corporation
    Inventor: Satoshi Oura
  • Patent number: 7257377
    Abstract: A method for improving channel estimation in a wireless communication system is disclosed. A wireless signal that includes a plurality of multipath components is received. N channel estimates are then obtained, where N is any positive integer greater than one. Each channel estimate of the N channel estimates corresponds to a different multipath component of the plurality of multipath components. The effects of interference between the plurality of multipath components on the N channel estimates is then reduced.
    Type: Grant
    Filed: February 18, 2003
    Date of Patent: August 14, 2007
    Assignee: Qualcomm, Incorporated
    Inventors: Durga Prasad Malladi, Josef Blanz, Yongbin Wei
  • Patent number: 7251457
    Abstract: Methods, apparatuses and systems directed to securing a wireless network environment from eavesdropping and other unauthorized activities. One implementation prevents or disrupts meaningful access to information contained in WLAN RF signals that escape from a given physical space during operation of the wireless network. One implementation utilizes overlay RF signals transmitted on one or more operating channels of the WLAN to overpower or mask the internal RF signals escaping from a defined security line or perimeter. One implementation monitors the RF energy escaping to dynamically adjust the power of the overlay signal as required. Implementations of the invention can secure the outer perimeter of an office within a building, or even the outer perimeter of an entire building.
    Type: Grant
    Filed: December 4, 2003
    Date of Patent: July 31, 2007
    Assignee: Airespace, Inc.
    Inventor: Gregg Scott Davi
  • Patent number: 7236744
    Abstract: A base station having at least one reception antenna generates a reception beam using a previous reception beam weight and a despread signal of a current reception signal, calculates an error value indicating a difference between the current reception signal and a desired reception signal, and calculates a current reception beam weight using the previous reception beam weight, the despread signal and the error value. The base station generates a reception beam weight step value using the error value and an output signal, calculates a difference between the previous reception beam weight and a product of the reception beam weight step value, the despread signal, and a conjugate value of the error value, as the current reception beam weight, and selects the reception beam weight step value such that the current reception beam weight becomes the optimal reception beam.
    Type: Grant
    Filed: August 9, 2004
    Date of Patent: June 26, 2007
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Chan-Byoung Chae, Pan-Yuh Joo, Seok-Hyun Yoon
  • Patent number: 7221913
    Abstract: An algorithm identifies a line-of-sight (LOS) signal that may be used to provide an effective time-of-arrival (TOA) estimation.
    Type: Grant
    Filed: June 23, 2004
    Date of Patent: May 22, 2007
    Assignee: Intel Corporation
    Inventors: Stuart A. Golden, Jong-Kae Fwu
  • Patent number: 7190929
    Abstract: The present invention is an assigning system and method for assigning a plurality of rake finger tracking units of a rake receiver in a Code Division Multiple Access (CDMA) communication system. The plurality of rake finger tracking units is used for tracking a plurality of path signal of each multipath signal by a plurality of corresponding predetermined tracking time positions. The assigning system and method estimate a plurality of corresponding tracking ranges of the plurality of path signals and compare the plurality of predetermined tracking time positions with the plurality of tracking ranges. If there is more than one predetermined tracking time positions in one tracking range, the assigning system assigns a rake finger tracking unit corresponding to one of the tracking time positions to track the path signal corresponding to the tracking range.
    Type: Grant
    Filed: March 13, 2003
    Date of Patent: March 13, 2007
    Assignee: BENQ Corporation
    Inventor: Tai-Cheng Liu
  • Patent number: 7187940
    Abstract: A decorrelating rake receiver (401) using a signal processor (213) and corresponding method (1000) to determine filter coefficients (1005). The decorrelating rake receiver includes a plurality of filters (219) arranged to be coupled to an input signal (403) and the filter coefficients (409), the plurality of filters operable to provide a plurality of output signals and a coefficient generator (407), coupled to the input signal, to explicitly and definitely determine the filter coefficients for the plurality of filters such that the plurality of filters perform a decorrelating rake process. The decorrelating rake receiver further includes a combiner (221) to combine the plurality of output signals and provide a received signal (405). The decorrelating rake receiver (401) is suitable for use in a wireless communication device (101) or base transceiver (103).
    Type: Grant
    Filed: July 31, 2003
    Date of Patent: March 6, 2007
    Assignee: Motorola, Inc.
    Inventor: Brian Todd Kelley
  • Patent number: 7184734
    Abstract: A radio communication apparatus using an array antenna has a plurality of reception branches for conveying reception signals received at the antenna element of the array antenna, and a calibration branch for selecting one of the plurality of reception branches and conveying the reception signal. Channel estimations are made respectively on the reception-branch signals and a calibration-branch signal. RAKE composition is made on the channel estimation values, a result of which is used to detect amplitude and phase deviations on the reception branch thereby carrying out a correction.
    Type: Grant
    Filed: November 14, 2003
    Date of Patent: February 27, 2007
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasuaki Yuda, Takaaki Kishigami, Takashi Fukagawa, Keiji Takakusaki, Shoji Miyamoto
  • Patent number: 7181246
    Abstract: An arrangement where a transmitter has multiple transmitting antennas that simultaneously transmit, and where the signals delivered to each transmitting antenna is processed by a space-time transmitter based on the side information that is related to the channel coefficients found between the transmitting antennas and multiple receiving antennas. The receiver's receiving antennas simultaneously receive the transmitted signals, and the signal from each receiving antenna is processed by the space-time receiver to extract the information symbols that have been transmitted. Alternative systems are possible, such as those employing frequency or code diversity, as well as those employing only one transmit antenna and multiple receive antennas (or visa versa).
    Type: Grant
    Filed: June 5, 2003
    Date of Patent: February 20, 2007
    Assignee: Neocific, Inc.
    Inventor: Titus Lo
  • Patent number: 7155245
    Abstract: An adaptive filter for an FM receiver comprises a digital filter, an error detection section for detecting an error between the amplitude of the output signal of the digital filter and a reference value, and a coefficient updating section for updating tap coefficients so as to minimize the error detected. The reference value for determining the error is variably set according to the amplitude of an input signal. This eliminates the effect of Doppler fading included in the reception wave and stabilize the adaptive processing. Thus, the adaptive filter can remove multipath distortion with reliability.
    Type: Grant
    Filed: August 13, 2004
    Date of Patent: December 26, 2006
    Assignee: Pioneer Corporation
    Inventors: Yuji Yamamoto, Toshiaki Kubuki
  • Patent number: 7155165
    Abstract: A method and radio stations for transmitting signals between a first radio station (1) and a second radio station (2) are proposed, in which the influence of amplitude fluctuations or fading can be reduced. In a modulator (4) of the first radio station (1) a pre-equalization of the signals to be transmitted is performed. The pre-equalized signals are transmitted from the first radio station (1) to the second radio station (2) via a plurality of radio channels (20, 25).
    Type: Grant
    Filed: October 16, 1999
    Date of Patent: December 26, 2006
    Assignee: Robert Bosch GmbH
    Inventor: Frank Kowalewki
  • Patent number: 7151944
    Abstract: The present invention relates to a method and apparatus for reducing interference arising from signal propagation delay in multipath signal environments in wireless communication systems. The present invention provides a method of operating a mobile communications base station which receives multipath components of signals from a number of high mobility subscriber terminals, the method comprising: for each subscriber terminal signal received, determining a best signal component; determining the difference in time between reception of said best signal component and a reference time; transmitting to said terminal a transmission timing offset in order to receive said best component at substantially said reference time.
    Type: Grant
    Filed: September 27, 2001
    Date of Patent: December 19, 2006
    Assignee: Nortel Networks Limited
    Inventors: Bassam M Hashem, David G Steer, Robert Matyas
  • Patent number: 7127252
    Abstract: The object of a radio terminal equipment is to achieve a highly accurate channel control and a favorable transmission quality. In order to achieve the object, in the radio terminal equipment, a channel controlling means is given in advance a period which accordingly makes both the processing and processing to be done to a transmission wave(s) by a radio station connected through a radio transmission line have lengths of time needed for the processes suitable for channel controlling and which is also suitable for a transmission system in a radio transmission line, and makes a radio wave received by a receiving means during the period the object of the processing. Therefore, a radio transmission system having the present invention applied adapts flexibly to various multiple access systems and modulation systems, and stably maintains the transmission quality of channels high, without having drastic restrictions on the configuration.
    Type: Grant
    Filed: February 22, 2000
    Date of Patent: October 24, 2006
    Assignee: Fujitsu Limited
    Inventors: Nobuhisa Aoki, Makoto Uchishima, Hiroaki Iwamoto
  • Patent number: 7103384
    Abstract: A method and apparatus for a base station including an antenna array calculates a direction of a weight vector of a transmission beam to maximize in-phase component power for a common channel signal in a transmission channel signal for transmission to a mobile station and to minimize a sum of quadrature-phase power component and interference power for other mobile stations inside and outside a cell due to a transmission channel signal for the mobile station.
    Type: Grant
    Filed: May 19, 2003
    Date of Patent: September 5, 2006
    Assignee: Samsung Electronics, Co., Ltd.
    Inventor: Byung-Jin Chun
  • Patent number: 7095993
    Abstract: An automatic frequency correction (AFC) apparatus used for CDMA multipath fading channels comprises a frequency-offset evaluator, an automatic frequency correction loop filter and a carrier frequency adjuster. The present invention provides a “multipath energy window” designing method for the non-determinacy of multipath signals in mobile communication environment. Frequency-offset information can be extracted from the multipath energy window by a simple calculation and evaluated by a maximal SNR weight process. This invention also provides a step-variable accumulation adjusting method and greatly improves the response speed of the AFC apparatus as compared with a conventional loop filter, whereby supplies better AFC required for CDMA mobile terminals.
    Type: Grant
    Filed: December 12, 2001
    Date of Patent: August 22, 2006
    Assignee: The MITT Research Institute of Telecommunication Transmission
    Inventors: Xiaohu You, Yan Zhang, Ling Wang, Liangcheng Jiang, Shixin Cheng
  • Patent number: 7092431
    Abstract: A receiver, comprising a plurality of antennas configured to receive signals that are obtained by multiplying a plurality of data symbols transmitted over a plurality of data channels using spreading codes for each of the data channels, the data symbol being transmitted over a plurality of sub-carriers having different frequencies; a spreading code multiplier configured to multiply reception signals received by the plurality of antennas using spreading codes for the data channels corresponding to the reception signals; a weight controller configured to adjust antenna weights by which a reception signal received by each antenna is to be multiplied, and sub-carrier weights by which a reception signal received over each sub-carrier is to be multiplied; a weight multiplier configured to multiply the reception signals by the antenna weights and the sub-carrier weights adjusted by the weight controller; and a combining unit configured to combine the reception signals multiplied by the antenna weights and the sub-ca
    Type: Grant
    Filed: December 27, 2002
    Date of Patent: August 15, 2006
    Assignee: NTT DoCoMo, Inc.
    Inventors: Noriyuki Maeda, Hiroyuki Atarashi, Sadayuki Abeta, Mamoru Sawahashi
  • Patent number: 7088956
    Abstract: A path search circuit according to the present invention has an orthogonal multi-beam forming section 4 for directional reception with a plurality of orthogonal multi-beams orthogonal one to another, correlation-operating sections 61–6M for correlation-operating outputs of the orthogonal multi-beam forming section 4 with a known signal, weight multiplying sections 81–8Nb for multiplying the output of the correlation-operating section 61–6M by a weight converted into a beam space, delay profile generating sections 91–9Nb for generating delay profiles from the output signals of the weight multiplying sections 81–8Nb, and a path detecting section 10 for detecting a reception timing and arrival direction of arrival path from the delay profile. This path search circuit can enhance the accuracy of path direction detection by the use of a directional reception signal, and further reduce the direction dependence of path timing detection accuracy.
    Type: Grant
    Filed: April 10, 2003
    Date of Patent: August 8, 2006
    Inventors: Takaaki Kishigami, Takashi Fukagawa, Yasuaki Yuda, Keiji Takakusaki, Shoji Miyamoto
  • Patent number: 7088977
    Abstract: A wireless communication apparatus is provided in which a wireless part receives multipath detection information sent from a wireless communication apparatus at the other end (a mobile station, for example) and provides the multipath detection information to a multipath component canceling signal generation part. The multipath component canceling signal generation part generates a multipath component canceling signal based on the multipath detection information, and provides the multipath component canceling signal to the wireless part. The wireless part sends the multipath component canceling signal with a send wave to the wireless communication apparatus at the other end.
    Type: Grant
    Filed: May 23, 2001
    Date of Patent: August 8, 2006
    Assignee: NTT DoCoMo, Inc.
    Inventors: Ryuusuke Kaneda, Seiji Hagiwara, Tadao Takami
  • Patent number: 7085537
    Abstract: A system and method are disclosed by which the effects of time of arrival errors may be reduced. In a mobile unit, such as a CDMA device, a correlation pulse is generated when a transmitted code matches a stored reference code. In the absence of multipath effects, correlation pulses are generated in response to the detection of multiple transmissions of the reference code from multiple transmitters. However, multipath effects distort the generated correlation pulses leading to errors in the time of arrival measurements. The present invention calculates the width of the correlation pulses and determines a delay correction factor based on the pulse width. The delay correction factor is added to the measured delay time to provide a more accurate delay time, thus permitting more accurate location measurements based on time of arrival. In alternative embodiments, other signal factors may also be used to apply delay correction factors.
    Type: Grant
    Filed: September 1, 2004
    Date of Patent: August 1, 2006
    Assignee: Qualcomm Incorporated
    Inventors: Ivan J. Fernandez-Corbaton, Roland Rick, Messay Amerga
  • Patent number: 7082286
    Abstract: A Node-B/base station has a path searcher and at least one antenna for receiving signals from users. The path searcher comprises a set of correlators. Each correlator correlates an inputted user code with an inputted antenna output of the at least one antenna. An antenna controller selectively couples any output of the at least one antenna to an input of each correlator of the set of correlators. A code phase controller selects a user code for input into the set of correlators. Each delay of a series of delays delays the selected user code by a predetermined amount and each correlator of the set of correlators receives a different code phase delay of the selected user code. A sorter and path selector sorts the output energy levels of each correlator of the sets of correlators and produces a path profile for a user based on the sorted output energy levels.
    Type: Grant
    Filed: April 11, 2003
    Date of Patent: July 25, 2006
    Assignee: InterDigital Technology Corporation
    Inventors: John David Kaewell, Jr., Timothy Berghuis, Jan Meyer, Peter Bohnhoff, Alexander Reznik, Edward L. Hepler, Michael Koch, William C. Hackett, David S. Bass, Steven Ferrante
  • Patent number: 7079870
    Abstract: In a beamforming communication device, transmit weight vectors are iteratively processed to compensate for any group delay caused by receive synchronization in the receive device. The initial transmit weights are computed from signals transmitted by a second communication device and received at a plurality of antennas of the first communication device. The transmit weight processing includes normalizing a transmit weight vector with respect to an element of the transmit weight vector associated with one of the plurality of antennas. The processed transmit weight vectors are then applied to a transmit signal to produce a plurality of transmit signals to be simultaneously transmitted from corresponding ones of the plurality of antennas of the first communication device. These group delay compensation techniques may be extended to a vector beamforming system in which a plurality of eigenmodes is transmitted between the two devices.
    Type: Grant
    Filed: February 13, 2004
    Date of Patent: July 18, 2006
    Assignee: IPR Licensing, Inc.
    Inventor: Chandra Vaidyanathan
  • Patent number: 7072669
    Abstract: Systems and methods for localizing the position of a wireless device using a plurality of coordinated highly directional or adaptive antennas to detect signals from the wireless device. Because of the directional nature and/or adaptive processing of the antennas, off-angle multipath signals resulting from reflection and scattering as the wireless signal propagates through a cluttered environment are rejected by the antennas and processing. As a result, the antennas pass primarily direct path signals from the wireless device to the location estimator. The time of arrival of the signal and the angle of arrival at each antenna are used to in the location estimator to calculate the position of the wireless device. Various robust inversion techniques may also be applied to the data to minimize the effect of residual multipath-corrupted detections. Furthermore, the systems and methods include specialized wireless devices that provide locating signals and signals related to the biological condition of their owner.
    Type: Grant
    Filed: May 23, 2003
    Date of Patent: July 4, 2006
    Assignee: Verizon Corporate Services Group Inc.
    Inventor: Gregory L. Duckworth
  • Patent number: 7043257
    Abstract: A positioning apparatus for determining a present position of a mobile station by using radio waves coming from a plurality of base stations arranged within a communication area is provided. The positioning apparatus receives the radio waves coming from the plurality of base stations to generate reception signals corresponding to the respective radio waves, and determines propagation ranges of the radio waves coming from the respective base stations. The apparatus further derives propagation ranges of direct waves coming from the respective base stations from the determined propagation ranges. Then, the present position of the mobile station is determined by performing positioning operation using the derived propagation ranges of the direct waves.
    Type: Grant
    Filed: February 27, 2002
    Date of Patent: May 9, 2006
    Assignee: Pioneer Corporation
    Inventor: Manabu Nohara
  • Patent number: 7043252
    Abstract: Method for data transmission in a wireless local area network refers to wireless local area networks (WLAN) consisting of a multitude of transceivers capable of establishing communication with one another (i.e. operating in a peer-to-peer mode). Implies the determination of the quality of communication between all transceivers and storage of communication quality data by each of the transceivers. Based on stored data on communication quality, a transceiver operating in the transmission mode transmits information to an addressee by a transmission route that provides for the quality of communication, which is equal to or better than a specified threshold value of communication quality. Stored data are updated periodically. The method improves the quality and reliability of communication for WLAN users (including mobile users) thus increasing the data transmission rate.
    Type: Grant
    Filed: October 31, 2002
    Date of Patent: May 9, 2006
    Assignee: Airgain, Inc.
    Inventors: Semen Aleksandrovich Khitrik, Aleksandr Nikolaevich Kirdin, Yury Pavlovich Sukharnikov
  • Patent number: 7035652
    Abstract: Wireless communication structures and methods are provided that enhance range and performance via managed access to a wireless communication medium between system clients. The access is configured to maintain the low equipment costs and widespread equipment availability of standards-based communication systems. In particular, the structures include at least one antenna, a processor that spatially processes receive signals from the antenna, a media access controller that compares the age of receive location information with a predetermined time coherence, a location-information transformer that transforms the receive location information into transmit location information, and a transmit spatial processor configured to provide a transmit signal to the antenna that is spatially processed in accordance with the transmit location information if the age is less than the time coherence and spatially processed in accordance with predetermined location information if the age exceeds the time coherence.
    Type: Grant
    Filed: January 23, 2004
    Date of Patent: April 25, 2006
    Assignee: Calamp Corp.
    Inventor: Kris Kelkar
  • Patent number: 7027782
    Abstract: A method for retransmitting coded bits by a transmitter in response to a retransmission request from a receiver in a mobile communication system which separates coded bits output from an encoder into coded bits with higher priority and coded bits with lower priority, and transmits from the transmitter to the receiver a stream of symbols obtained by symbol mapping the coded bits by a specific modulation technique. The method comprises determining orthogonal codes available for retransmission; separating the coded bits with higher priority and the coded bits with lower priority into a plurality of sub-packets with a given size, and selecting a part of the sub-packets or sub-packets to be repeatedly transmitted, depending on the determined number of available orthogonal codes; and transmitting a stream of symbols obtained by symbol-mapping coded bits of the selected sub-packets by the specific modulation technique, with the determined available orthogonal codes.
    Type: Grant
    Filed: October 18, 2002
    Date of Patent: April 11, 2006
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Yong-Suk Moon, Hun-Kee Kim, Jae-Seung Yoon
  • Patent number: 7016650
    Abstract: A system and method for reducing multi-path distortion of an M-ary communication signal is implemented with M×N parallel processors, a multi-path estimator, a metric selector and a decision processor. Parallel processors process each combination of possible signal symbols M and hypothesized guard times N, the output of the processors are supplied to the multi-path estimator which estimates the actual multi-path distortion of the transmitted symbol. The metric selector selects the processors with a guard time Gn most closely approximating the estimate from the multi-path estimator. The selected outputs are used in a decision processor to determine the transmitted symbols. The selected outputs are low passed filtered.
    Type: Grant
    Filed: February 13, 2003
    Date of Patent: March 21, 2006
    Assignee: Harris Corporation
    Inventors: William Nelson Furman, John Wesley Nieto
  • Patent number: 6999778
    Abstract: A method for enhancing the accuracy of Advanced Forward Link Trilateration (AFLT) position location calculations is disclosed. A position determination entity (PDE) constructs a statistical database of pilot phase measurements reported by mobile stations (MSs) located in a geographic region about a reference base station (BS). When a MS's location is to be calculated, the MS reports a set of PN phase offsets to the PDE. Using only that set of PN phase offsets, the PDE determines a rough estimate of the MS's location using conventional AFLT and also determines the region within which the MS is located. If the PDE determines that the MS did not report one or more earlier arriving PN phase offsets but reported a delayed multipath component, the PDE sends a message to the MS to look for an earlier arriving PN phase offset at a certain time prior to the reported PN phase offset.
    Type: Grant
    Filed: July 3, 2002
    Date of Patent: February 14, 2006
    Assignee: Denso Corporation
    Inventor: Marcus DiBuduo
  • Patent number: 6999726
    Abstract: A radio system (10) and radio system (1, 2) in which the value of parameters for a model of a received multipath signal transmitted by a remote station (20) are estimated. A sounding signal transmitted and received by the radio station is used to derive data about the reflecting environment and this data is incorporated into the model after scaling it to represent the multipath signal received from a remote station. Optionally or alternatively the remote station may transmit a sounding signal and derive data about its reflecting environment and transmit this data to the radio station, The model may incorporate both sets of derived data, particularly if they are uncorrelated. The values of the resulting parameters are exploited in applications such as ranging, location or equalization.
    Type: Grant
    Filed: August 15, 2002
    Date of Patent: February 14, 2006
    Assignee: Koninklijke Philips Electronics N.V.
    Inventor: Josi Rosenfeld
  • Patent number: 6999724
    Abstract: A method and apparatus for reducing the observed rate of change of the channel characteristics in a system with multiple antennas at a mobile terminal. The slowing down of the observed channel fluctuations is effectuated on the downlink by either calculating or receiving signals that have a similar Doppler shift, referred to herein as Doppler-compensatable signals, and processing one or more of the Doppler-compensatable signals to compensate for Doppler shift. The slowing down of the observed channel fluctuations is effectuated on the uplink by pre-compensating symbol streams with the Doppler shift associated with the direction in which they are transmitted, so that the observed Doppler shift of these signals when they are received is reduced or even eliminated.
    Type: Grant
    Filed: June 20, 2002
    Date of Patent: February 14, 2006
    Assignee: Lucent Technologies Inc.
    Inventors: Dmitry Chizhik, Hao Xu
  • Patent number: 6990318
    Abstract: A multi-carrier communications apparatus which communicates between a first station and a second station as a destination station using a reference signal used for estimating a state of a channel, the multi-carrier communications apparatus comprising a multi-carrier modulator which modulates data on a plurality of subcarriers, a transmission unit configured to transmit the reference signal together with the data modulated to the destination station every subcarrier, and a control unit configured to control a reference signal transmission pattern according to a given communication condition, the reference signal transmission pattern including a transmission interval of the reference signal transmitted by the transmission unit.
    Type: Grant
    Filed: September 6, 2002
    Date of Patent: January 24, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Koji Horisaki
  • Patent number: 6990345
    Abstract: In a method for locating a position of a terminal with use of weak signals, a combined weight to be used to separate a path from others through correlation calculation is obtained from a plurality of delay profiles measured in course of time. The obtained weight is used to combine the delay profiles and a path detection is carried out on the combined delay profiles.
    Type: Grant
    Filed: January 16, 2003
    Date of Patent: January 24, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Mikio Kuwahara, Kenzaburo Fujishima
  • Patent number: 6985749
    Abstract: Methods and devices for sending, transmitting and/or receiving information by means of waves, in which an information signal of a carrier wave is impressed, whose frequency is continuously changed to form at least one carrier sweep in a predetermined time interval and in which the information signal is filtered to separate multipath components after being received in the frequency range or is cleaned of noise portions and then evaluated with respect to the information-bearing signal parameters.
    Type: Grant
    Filed: December 20, 2000
    Date of Patent: January 10, 2006
    Inventors: Rudolf Bannasch, Konstantin Kebkal
  • Patent number: 6983172
    Abstract: A method (100) is provided for transmitting a traffic signal with an adaptive antenna array of a base transceiver such that a subscriber unit utilizes a non-dedicated pilot transmitted from a reference antenna element for demodulation of the traffic signal. The method (100) comprises determining a channel impulse response from a plurality of antenna elements in operative communication with the base transceiver to a receive antenna of the subscriber unit (102).
    Type: Grant
    Filed: January 3, 2002
    Date of Patent: January 3, 2006
    Assignee: Motorola, Inc.
    Inventor: R. Mark Harrison
  • Patent number: 6961543
    Abstract: A wireless communication system computes the pilot phase measurement RMSE directly by determining the path width as measured by the searcher component of the modem, the path drift over time, and the measurement resolution. The path width may be based on a measurement error that is half the path width or the larger of the distances from the local maxima to the earliest or latest side. Optionally, the distance from the peak to the 3 dB-down point can be used if the search resolution permits such measurement. The path drift is multiplied with the uncertainty in the measurement time stamp to get an error. This error is added to the measurement error due to path width. The measurement resolution is also added to the error.
    Type: Grant
    Filed: February 12, 2002
    Date of Patent: November 1, 2005
    Assignee: DENSO Corporation
    Inventor: Jason F. Hunzinger
  • Patent number: 6956892
    Abstract: A receiver receives signals which are at least partially known and which have followed a plurality of different paths to said receiver. The receiver has an arrangement for dividing the area of coverage of said receiver into a plurality of sections. A plurality of receiving units are provided to process a different one of said signals to identify the at least partially known part of said signal. A controller is coupled to the output of said dividing arrangement for selecting the signals which are to be allocated to the respective receiving units and an interference removing arrangement is coupled to the output of the receiver units to remove interference.
    Type: Grant
    Filed: June 11, 2001
    Date of Patent: October 18, 2005
    Assignee: Nokia Network Oy
    Inventor: Juha Ylitalo
  • Patent number: 6957046
    Abstract: A system for reducing multipath interference in a wireless data transmission generally includes a processor and memory device for capturing one or more data packets of the wireless data transmission. The transmitting device associates a time value and/or a spatial value to each of the data packets. Upon capture, the processor determines whether the captured data packet is reflective or non-reflective by comparing the time value or spatial value, as applicable, of the captured data packet to the time value or spatial value of each stored non-reflective packet. The system identifies the captured data packet as non-reflective, if the time value (or spatial value) of the captured packet is different from the time value (or spatial value) of each stored non-reflective packet.
    Type: Grant
    Filed: February 19, 2002
    Date of Patent: October 18, 2005
    Assignee: Lucent Technologies Inc.
    Inventor: Narayan L. Gehlot
  • Patent number: 6954618
    Abstract: First estimations of the fading coefficients of a multi-path transmission channel are carried out in the sense of maximum likelihood. Sets of Wiener filter coefficients are stored according to predetermined speeds of movement of the mobile terminal and predetermined power levels of the signal. The real speed of the mobile terminal is estimated and the power of the signal for each path is measured. From this, a set of Wiener filter coefficients is derived with which the first estimations are filtered to obtain the final estimation of the fading coefficients.
    Type: Grant
    Filed: September 24, 2002
    Date of Patent: October 11, 2005
    Assignee: STMicroelectronics N.V.
    Inventor: Corinne Bonhomme
  • Patent number: 6950890
    Abstract: A wireless receiving apparatus and method utilizes a single MCU (microprocessor control unit) in the wireless receiver to receive and process signals having different frequencies transmitted from a plurality of peripheral devices simultaneously, and then performs the steps of reading a predetermined processing procedure from a memory with respect to each of the signals respectively, performing a predetermined process with respect to each of the signals, storing an index of the last finished step for each signal in the memory respectively after at least a set of steps of the predetermined process has been performed, and continuing to perform the steps following the indices of the previous set of steps stored in the memory for carrying out a next set of steps for each signal, and repeating a plurality of sets of steps until all received signals have been processed.
    Type: Grant
    Filed: December 27, 2001
    Date of Patent: September 27, 2005
    Assignee: Globlink Technology Inc.
    Inventors: Ching-Chiang Liu, Chun-Feng Weng
  • Patent number: 6941123
    Abstract: A signal processing method and apparatus for obtaining a diversity gain in the communication system equipping the antenna array when a background noise is a space white noise or a non white noise is disclosed. The signal processing method and apparatus includes steps and functions of calculating a covariance matrix, estimating at least two time invariance vectors by performing an eigen-disintegration operation, estimating a channel vector and outputting a beam-forming vector. The present invention can improve the performance of the antenna array by using at least two time invariance vectors and it also increase a communication quality and quantity of the communication system, if the present invention is implemented to the wireless communication system.
    Type: Grant
    Filed: December 6, 2002
    Date of Patent: September 6, 2005
    Assignees: SAS Technologies Co., Ltd.
    Inventors: Jin-Ho Choi, Sung-Soo Ahn
  • Patent number: 6940914
    Abstract: A system and method for estimating a channel in a wireless receiver is disclosed. The method preferably applies to a communication system using the OFDM standard. The method comprises receiving a block of “n” transmitted symbols, the symbols including pilot symbols and “d” data symbols, estimating a channel using the pilot symbols to create a channel estimate, choosing a group of “m” strongest symbols from the “d” received symbols, compensating the “m” strongest symbols using the channel estimate to create a group of “m” compensated symbols, re-estimating the channel using the group of “m” compensated symbols and pilot symbols; and either (1) repeating the steps of choosing a group of “m” strongest symbols, compensating the group of “m” strongest symbols and re-estimating the channel, or (2) using a latest channel estimate to compensate all symbols within the block.
    Type: Grant
    Filed: June 11, 2001
    Date of Patent: September 6, 2005
    Assignee: Cingular Wireless II, LLC
    Inventors: Titus Lo, Ruifeng Wang
  • Patent number: 6922549
    Abstract: Describe herein is an apparatus for inclusion in a station of a wireless network, and a method implemented in a station of a wireless network. The method includes wirelessly receiving data via each of a plurality of antennas, the data corresponding to a packet of information transmitted from a remote station, sampling the received data corresponding to the received packet to form data samples for each of the antennas, and determining a measure of signal quality from samples of the received data for each of the antennas. The method further includes selecting one of the plurality of receive antennas as the antenna for receiving from the remote station according to the determined measure of signal quality.
    Type: Grant
    Filed: October 31, 2003
    Date of Patent: July 26, 2005
    Assignee: Cisco Technology, Inc.
    Inventors: Daniel Joseph Lyons, Brian Hart
  • Patent number: 6907061
    Abstract: The present invention relates to a method for use in controlling the emission power of a transceiver which is in communication with another transceiver via a communication system, said method including the steps of measuring the amplitude or the power of the signal received by said transceiver and of evaluating a power control command which is then used to command the emission power of said transceiver according to said control command signal. According to the invention, the method includes the steps of evaluating the fast fading duration of the received signal on basis of said amplitude or power measurement and of deducing the power control command from said fast fading duration.
    Type: Grant
    Filed: May 26, 2000
    Date of Patent: June 14, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Bruno Jechoux
  • Patent number: 6898420
    Abstract: An apparatus and method for eliminating interference caused by spurious signals in communication signals communicated via a communication device on any one of a plurality of different channels, the communication device operating at a rate set by a system clock signal. The system clock frequency is generated at a first frequency, the first frequency generating spurious signals on at least one of the different channels. The system clock frequency is toggled by a first predetermined amount to a second frequency when the communication device is to be tuned to one of the different channels so as to remove the spurious signals from the tuned channel. The communication device is tuned to the at least one of the different channels. A return of the timing error to a predetermined value is synchronized at a start of a receive data capture event.
    Type: Grant
    Filed: August 23, 2002
    Date of Patent: May 24, 2005
    Assignee: Motorola Inc.
    Inventors: Gregory R. Black, Charles Philipp Binzel