Having Multi-receiver Or Interference Cancellation Patents (Class 375/144)
  • Patent number: 7068705
    Abstract: A system and method for transmitting a plurality of spread-spectrum signals over a communications channel having fading. The plurality of spread-spectrum signals are radiated by a plurality of antennas, with each antenna preferably spaced by one-quarter wavelength. A plurality of receiver antennas receive the plurality of spread-spectrum signals and a plurality of fading spread-spectrum signals. Each receiver antenna is coupled to a plurality of matched filters having a respective plurality of impulse responses matched to the chip-sequence signals of the plurality of spread-spectrum signals. A RAKE and space-diversity combiner combines, for each respective chip-sequence signal, a respective plurality of detected spread-spectrum signals and a respective multiplicity of detected-multipath-spread-spectrum signals, to generate a plurality of combined signals. The symbol amplitudes can be measured and erasure decoding employed to improve performance.
    Type: Grant
    Filed: June 7, 2004
    Date of Patent: June 27, 2006
    Assignee: Linex Technologies, Inc.
    Inventor: Donald L. Schilling
  • Patent number: 7068637
    Abstract: In a mobile communication system employing code division multiple accesses and having radio logical channels such as control channels and traffic channels, for the purpose of interference cancellation processing which is implemented without a large processing delay even under a call control application, the baseband receiving part of the mobile communication system includes a common control channel demodulator 302 which executes the demodulation processing of a common control channel as to a received baseband reception signal 301, an interference canceller 309 which executes interference cancellation processing for a received multiplexed signal on the basis of the notification information of the control channels, and a synthesis/error correction processor 315 which executes error correction processing, etc. as to user information having undergone the interference cancellation processing and thereafter executes frame formation processing.
    Type: Grant
    Filed: February 28, 2001
    Date of Patent: June 27, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Joichi Saito, Yuuji Ishida, Toshiro Suzuki
  • Patent number: 7068743
    Abstract: A DS-CDMA (Direct Sequence-Code Division Multiple Access) multi-user interference canceller cancels interference waves of a plurality of users. The DS-CDMA includes a variable gain controller for comparing reception characteristics of reception signals received from the plurality of users prior to interference cancellation processing with reception characteristics upon the interference cancellation processing and evaluating a comparison result, and controlling gains prior to baseband decoding of the reception signals so as to maximize improvements of the reception characteristics of the reception signals on the basis of an evaluation result. A CDMA multi-user system using the above canceller is also disclosed.
    Type: Grant
    Filed: December 16, 1999
    Date of Patent: June 27, 2006
    Assignee: NEC Corporation
    Inventor: Hideto Suzuki
  • Patent number: 7068708
    Abstract: A method (400) and a receiving unit (220) for demodulating a multi-path signal are described herein. The receiving unit (220) may be configured to receive the multi-path signal. The receiving unit (220) may include an input buffer controller (305), an input buffer (310), a rake finger (330), and a sum generator (340). The input buffer (310) may be configured to store data samples associated with a plurality of paths of the multi-path signal. The input buffer controller (305) may be configured to time-align the data samples relative to each other, and to delay the data samples. The rake finger (330) may be configured to de-spread and to accumulate the delayed data samples for a sub-correlation length. The sum generator (340) may be configured to combine a plurality of outputs from the rake finger (330). Each of the plurality of outputs corresponds to one of the plurality of paths of the multi-path signal.
    Type: Grant
    Filed: December 13, 2002
    Date of Patent: June 27, 2006
    Assignee: Motorola, Inc.
    Inventors: Christopher LaRosa, Tracie Schitzinger, David Steckl
  • Patent number: 7061971
    Abstract: A method and apparatus for diversity searching and demodulator finger assignment in receivers with multiple receive chains enhances reception using optimal search and demodulator finger assignment operations. Optimal search and demodulator finger assignment for diversity environments provides improved interference cancellation and exploitation of independent fading by ensuring cell and receive chain diversity. After performing standard single antenna searching operations for each diversity receive chain, demodulator finger assignments are made according to signal strength and cell diversity. Signal paths are then re-assigned to achieve receive chain diversity if necessary. The availability of power control combiners may be considered when making demodulator finger assignments depending on the architecture of diversity receiver.
    Type: Grant
    Filed: July 11, 2002
    Date of Patent: June 13, 2006
    Assignee: Qualcomm Incorporated
    Inventors: Fatih Ulupinar, Senthilkumar K. Sundaram
  • Patent number: 7062001
    Abstract: An adaptive receiver for determining parameters of an incoming signal is provided.
    Type: Grant
    Filed: September 3, 2002
    Date of Patent: June 13, 2006
    Assignee: Her Majesty the Queen in right of Canada, as represented by the Minister of National Defence of Her Majesty's Canadian Government
    Inventor: Jim P. Y. Lee
  • Patent number: 7054351
    Abstract: In order to control memory accesses in RAKE receivers having early-late tracking in telecommunications systems with wire-free telecommunication between mobile and/or stationary transmitters/receivers, in particular in third-generation mobile radio systems, such that the number of memory accesses is less than with previous known methods, data which is received in the RAKE receiver and is read by an early finger in the early-late tracking is buffer-stored and is passed on one read cycle later to a late finger for reading by the same in the early-late tracking.
    Type: Grant
    Filed: October 27, 1999
    Date of Patent: May 30, 2006
    Assignee: Siemens Aktiengesellschaft
    Inventors: Reinhold Braam, Ulf Niemeyer, Oskar Skuk, Andreas Falkenberg, Christoph Rohe
  • Patent number: 7050481
    Abstract: In a method for improving signal extraction in a code division multiple access (CDMA) telecommunications system, a first iteration of interference cancellation is performed on the basis of bit rates for every signal which are the same as those in a previous frame of the same signal. Filtered and down-converted signals are demodulated in Rake receivers to provide output signals corresponding to decision variables and channel estimates. The decision variables are limited and remodulated and respread prior to the signals being reconstructed using the channel estimates. The reconstructed signals are summed, and each signal is subtracted from the sum to provide an ‘interference’ signal which is then used to obtain the individual signals. Each signal is then demodulated a second time in another Rake receiver to provide a tentative DPDCH signal, a TFI signal, a TPC signal and a SNI signal.
    Type: Grant
    Filed: October 26, 1999
    Date of Patent: May 23, 2006
    Assignee: Roke Manor Research Limited
    Inventor: Anthony Peter Hulbert
  • Patent number: 7042862
    Abstract: A path searching apparatus which is used in a base station apparatus according to the CDMA (Code Division Multiple Access) systems for increasing the accuracy for path detection depending on the number of communication channels to be processed.
    Type: Grant
    Filed: July 21, 2000
    Date of Patent: May 9, 2006
    Assignee: NEC Corporation
    Inventor: Sei Hirade
  • Patent number: 7035317
    Abstract: Improved branch metrics for Viterbi decoders in CDMA systems take into account the time dependency of the variance of the multiple access interference in any user's signal after the single-user detector, and the time dependency of the residual multiple access interference in any user's signal after subtractive interference cancellation is applied in two-stage detectors. The (residual) multiple access interference can be modeled as a Gaussian random variable with time dependent variance. Modeling the RMAI in such a way reduces the bit error rate in CDMA systems.
    Type: Grant
    Filed: September 20, 2001
    Date of Patent: April 25, 2006
    Assignee: North Carolina State University
    Inventors: Ayman Elezabi, Alexandra Duel-Hallen
  • Patent number: 7031374
    Abstract: A RAKE receiver with demodulating fingers is presented having the capability to assign a specific sample stream, from among a plurality of received sample streams, to any of the demodulating fingers. The demodulating finger includes a MUX to receive the plurality of sample streams. Commands from a controller to the MUX of a demodulating finger select a specific sample stream to be demodulated by that demodulating finger. Since each demodulating finger receives all the sample streams, and any sample stream can be selected, the receiver has the flexibility of optimally varying the assignment of demodulating fingers to sample streams. A method for selecting a sample stream for demodulation, from among a plurality of sample streams, is also provided.
    Type: Grant
    Filed: October 6, 2000
    Date of Patent: April 18, 2006
    Assignee: Texas Instruments Incorporated
    Inventor: John G. McDonough
  • Patent number: 7020073
    Abstract: Techniques to determine the rate for a data transmission in an OFDM system. The maximum data rate that may be reliably transmitted over a given multipath (non-flat) channel by the OFDM system is determined based on a metric for an equivalent (flat) channel. For the given multipath channel and a particular rate (which may be indicative of a particular data rate, modulation scheme, and coding rate), the metric is initially derived from an equivalent data rate and the particular modulation scheme. A threshold SNR needed to reliably transmit the particular data rate using the particular modulation scheme and coding rate is then determined. The particular rate is deemed as being supported by the multipath channel if the metric is greater than or equal to the threshold SNR. Incremental transmission is used to account for errors in the determined data rate.
    Type: Grant
    Filed: February 28, 2002
    Date of Patent: March 28, 2006
    Assignee: Qualcomm Incorporated
    Inventors: Tamer Kadous, Ahmad Jalali, Ivan Jesus Fernandez Corbaton
  • Patent number: 7012952
    Abstract: A weighted mean arrival time determines a delay offset of a fractionally spaced equalizer. The weighted mean arrival time is determined using path arrival times and energies from a Rake receiver. 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. 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 and the equalizer filter coefficients are shifted by a number of tap spacings. Otherwise, the current delay offset is not updated and the filter coefficients of the fractionally spaced equalizer are not shifted. 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.
    Type: Grant
    Filed: August 1, 2001
    Date of Patent: March 14, 2006
    Assignee: QUALCOMM Incorporated
    Inventors: Srikant Jayaraman, Ivan Jesus Fernandez Corbaton, John E. Smee
  • Patent number: 7012883
    Abstract: Techniques to determine the rate for a data transmission in an OFDM system. The maximum data rate that may be reliably transmitted over a given multipath (non-flat) channel by the OFDM system is determined based on a metric for an equivalent (flat) channel. For the given multipath channel and a particular rate (which may be indicative of a particular data rate, modulation scheme, and coding rate), the metric is initially derived from an equivalent data rate and the particular modulation scheme. A threshold SNR needed to reliably transmit the particular data rate using the particular modulation scheme and coding rate is then determined. The particular rate is deemed as being supported by the multipath channel if the metric is greater than or equal to the threshold SNR. Incremental transmission is used to account for errors in the determined data rate.
    Type: Grant
    Filed: November 21, 2001
    Date of Patent: March 14, 2006
    Assignee: Qualcomm Incorporated
    Inventors: Ahmad Jalali, Ivan Jesus Fernandez Corbaton
  • Patent number: 7012977
    Abstract: The present invention provides a system, method and apparatus for estimating channel parameters in spread spectrum communication systems. A first method is accomplished by receiving a base station signal and then demodulating the base station signal. After demodulating the base station signal, a maximum signal is selected from the base station signal. If the maximum signal is the common pilot channel, then the channel parameters are estimated directly from the common pilot channel. If the maximum signal is not the common pilot channel, then the demodulated base station signal is iteratively fed back for further demodulation and re-selection of the maximum signal until the maximum signal is the common pilot channel. A second method is accomplished by incorporating channel estimates made from the interfering signals in a constructive manner to the first method.
    Type: Grant
    Filed: June 20, 2001
    Date of Patent: March 14, 2006
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Mohamed F. Madkour, Yi Pin Eric Wang
  • Patent number: 7013165
    Abstract: There is provided an antenna array apparatus using a GPS signal in a base station and a beamforming method thereof. In the antenna array apparatus, a GPS signal processor receives GPS position information from a mobile station and calculates the position information of the mobile station. A signal processor calculates a weight vector using the position information to form a transmission/reception beam. A transmission/reception beamformer forms the transmission/reception beam according to the weight vector.
    Type: Grant
    Filed: August 16, 2001
    Date of Patent: March 14, 2006
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jae-Seung Yoon, Kyong-Joon Chun, Byung-Jin Chun
  • Patent number: 7009947
    Abstract: A high integrity process is provided to apply pilot phase rates to call processing decisions. An estimate or measurement of the rate of change of a pilot's PN phase offset is used to assist in making CDMA call processing decisions. The phase rate is a measure of the rate of change of a pilot's PN phase offset relative to a mobile time reference and is directly related to the multipath environment and movement of the mobile. Both an integrity algorithm to compute an integrity indicator and a technique to apply the integrity indicator to predict future pilot strengths are included.
    Type: Grant
    Filed: October 26, 2001
    Date of Patent: March 7, 2006
    Assignee: DENSO Corporation
    Inventor: Jason F. Hunzinger
  • Patent number: 7010019
    Abstract: Method and system are disclosed for detecting a situation where it is likely that additional multipath components are available in the channel, but are not included in the RAKE processing. In some embodiments, the invention uses the interference estimates for all RAKE fingers associated with tracked multipath components to detect the fraction of the available signal energy that is captured by the path searcher. The invention provides an activation signal to the path searcher if the fraction of the available power that is captured by the tracked paths falls below a predefined threshold.
    Type: Grant
    Filed: September 18, 2002
    Date of Patent: March 7, 2006
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventor: Andres Reial
  • Patent number: 6999499
    Abstract: A demodulation apparatus for a base station of a CDMA mobile communication system is provided, having an analog-to-digital converter device to convert an intermediate frequency signal into a digital signal and provide a quadrature component and an in-phase component of the digital signal, a plurality of filters to filter the components of the digital signal in the low pass band respectively, and a CDMA modem to demodulate the outputs of the plurality of filters. Since direct control by the digital signal of the base-band I channel and Q channel at the intermediate frequency can be performed and the analog-to-digital converter simultaneously performs the QPSK demodulation and the analog-to-digital conversion, the circuit design can be simplified and the characteristics reducing the noise can be obtained.
    Type: Grant
    Filed: May 26, 2000
    Date of Patent: February 14, 2006
    Assignee: LG Electronics Inc.
    Inventor: Won Hyoung Park
  • Patent number: 6999719
    Abstract: A symbol combining device for multi-path diversity includes a plurality of demodulation circuits for demodulating received signals, a common memory for storing outputs of the demodulation circuits, a symbol combiner for receiving the outputs of the common memory corresponding to the demodulation circuits and for combining the outputs, and a memory controller for controlling the common memory to timely separate the write and read operations. To timely separate the write and read operations, the memory controller controls the common memory in order that the demodulation circuits sequentially access the common memory and the resultant outputs of the demodulation circuits are written in the common memory, and the symbol combiner reads the outputs of the demodulation circuits written in the common memory sequentially.
    Type: Grant
    Filed: February 1, 2002
    Date of Patent: February 14, 2006
    Assignee: Samsung Electronics Co., LTD
    Inventor: Sung-Chul Han
  • Patent number: 6999501
    Abstract: The method and device attenuate an interferer of substantially known spectrum in a communication signal which has been transmitted through a transmission channel and processed through a signal-processing receiver chain. In these method and device, the substantially known spectrum is used to generate, independently of the communication signal, at least one image representative of a replica of the interferer after processing through the signal-processing receiver chain. The generated image is subtracted from the processed communication signal to produce a subtraction signal, and quality-indicative parameters of the processed communication signal and the subtraction signal(s) are calculated. Finally, the quality-indicative parameters are used to select one of the processed communication signal and subtraction signal(s) for further processing through the receiver. When a plurality of images are generated, these images have different features, for instance different amplitudes or phases.
    Type: Grant
    Filed: September 15, 2000
    Date of Patent: February 14, 2006
    Assignee: Telefonaktiebolaget LM Ericsson (Publ)
    Inventor: Francois Sawyer
  • Patent number: 6996160
    Abstract: A channel estimation method which reduces the strain on resources of a Rake receiver using a complex weight gain (CWG) algorithm. In one embodiment, a non-adaptive algorithm is used to average blocks of pilot symbols from several slots. In another embodiment, an adaptive algorithm implements sliding window averaging or a recursive filter. Using a CWG algorithm reduces the memory and processor requirements of the Rake receiver.
    Type: Grant
    Filed: November 20, 2003
    Date of Patent: February 7, 2006
    Assignee: InterDigital Technology Corporation
    Inventors: Bin Li, Alexander Reznik
  • Patent number: 6993064
    Abstract: A receiver is provided, in which the receiver includes K signal extraction parts, a signal estimation part, K joint probability calculation parts and a multiplying part, wherein: an ith (1?i?K) signal extraction part extracts ith to Kth user signals; an ith joint probability calculation part calculates a joint probability density function that any signal set in the ith to Kth user signals will be obtained if ith to Kth user signals estimated by the signal estimation part are assumed to be received; the multiplying part multiplies probability density functions calculated by the joint probability calculation parts; and the signal estimation part estimates first to Kth user signals which maximize the multiplied value, and outputs the first to Kth user signals.
    Type: Grant
    Filed: December 28, 2001
    Date of Patent: January 31, 2006
    Assignee: NTT DoCoMo, Inc.
    Inventor: Satoshi Denno
  • Patent number: 6985515
    Abstract: A code division multiple access communication system transmits a pilot and traffic signal over a shared spectrum. The pilot and traffic signal have an associated code and are received over the shared spectrum. The received signals are sampled and the samples are delayed to produce a window. A weighted value for each despread pilot code window sample is determined using an adaptive algorithm. Each window sample is despread with a traffic code. Each despread traffic code window sample is weighted according to a weight corresponding to its respective pilot code sample.
    Type: Grant
    Filed: August 23, 2004
    Date of Patent: January 10, 2006
    Assignee: InterDigital Technology Corporation
    Inventors: David K. Mesecher, Alexander Reznik, Donald Grieco, Gary Cheung
  • Patent number: 6985544
    Abstract: It is an object of the present invention to improve the diversity gain by conducting linear prediction of fading fluctuations and switching antennas.
    Type: Grant
    Filed: December 8, 2003
    Date of Patent: January 10, 2006
    Assignee: Uniden Corporation
    Inventors: Masaki Matsui, Muneki Ito, Akio Horibe, Shigeo Sato
  • Patent number: 6985545
    Abstract: An RF radio receiver utilizing wideband RF technology, a wideband digital IF (channelizer) tuner, a common digitizing rate, and multi-user detection (MUD) processes a superposed RF signal to allow simultaneous reception of two or more RF signals sharing overlapping frequency spectrum (RF bandwidth). The RF radio receiver is particularly effective for two or more RF signals of differing RF channel bandwidth and can also receive signals which accord to different air interface standards. The use of a common digitizing rate provides for oversampling of at least one of the RF signals for more accurate decoding and allows for a synchronized signal (i.e. at a common rate) to be used in decoding, and in particular multi-user decoding of other RF signals.
    Type: Grant
    Filed: December 26, 2000
    Date of Patent: January 10, 2006
    Assignee: Nortel Networks Limited
    Inventors: Koon H. Teo, Shiquan Wu, David G. Steer
  • Patent number: 6980771
    Abstract: A digital CDMA wireless communication system. The system includes one or more of said transmitters with a base station baseband processor, a finite impulse response (FIR) filter, a pre-distortion phase equalizer and a digital-to-analog (DAC) converter. Receivers have an analog-to-digital (ADC) converter, a FIR filter, a phase equalizer and a receiver baseband processor. The receiver FIR filter is matched to the transmitter FIR filter and the receiver phase equalizer is matched to the pre-distortion phase equalizer.
    Type: Grant
    Filed: January 3, 2002
    Date of Patent: December 27, 2005
    Assignee: VIA Technologies, Inc. of R.O.C.
    Inventor: Hong Kui Yang
  • Patent number: 6977915
    Abstract: A method and system for closed loop power control in a wireless communication network. A received signal is despread. The signal power of the despread received signal is estimated. The noise power of the despread received signal is estimated. Estimating the noise power includes multiplying the despread received signal with an orthogonal noise code to cancel the received signal, accumulating the multiplied despread received signal over one frame and determining a signal-to-noise ratio of the received signal at least in part by dividing the estimated signal power by the estimated noise power. A reverse power control bit is determined based on the determined signal-to-noise ratio.
    Type: Grant
    Filed: January 30, 2001
    Date of Patent: December 20, 2005
    Assignee: Nortel Networks Limited
    Inventors: Xixian Chen, Neil N. McGowan, Weigang Li, Jeffrey D. Stanier, M. Khaled Islam, Qiang Shen, Xin Jin
  • Patent number: 6977955
    Abstract: A demodulation circuit for CDMA mobile communications systems includes a path comparison portion that detects whether one and the same path has been successively detected or not, and a calculation portion that calculates the timing variation between currently detected path and previously detected path when one and the same path is detected successively. A path timing determination portion assigns a new path to the finger portion in place of a path with a maximum variation if the variation of the path with a maximum variation within the paths already assigned to the finger portion has the variation larger than/equal to a variation threshold when a new path which is not assigned to the finger portion and of which level is higher than/equal to a predetermined assignment threshold is detected.
    Type: Grant
    Filed: January 28, 2002
    Date of Patent: December 20, 2005
    Assignee: NEC Corporation
    Inventor: Koichi Tamura
  • Patent number: 6975671
    Abstract: A system for providing an accurate interference value signal received over a channel and transmitted by an external transceiver. The system includes a first receiver section for receiving the signal, which has a desired signal component and an interference component. A signal extracting circuit extracts an estimate of the desired signal component from the received signal. A noise estimation circuit provides the accurate interference value based on the estimate of the desired signal component and the received signal. A look-up table transforms the accurate noise and/or interference value to a normalization factor. A carrier signal-to interference ratio circuit employs the normalization factor and the received signal to compute an accurate carrier signal-to-interference ratio estimate. Path-combining circuitry generates optimal path-combining weights based on the received signal and the normalization factor.
    Type: Grant
    Filed: October 8, 2003
    Date of Patent: December 13, 2005
    Assignee: Qualcomm Incorporated
    Inventors: Nagabhushana T. Sindhushayana, Eduardo A. S. Esteves
  • Patent number: 6975670
    Abstract: Managing assigned fingers in wireless telecommunication, such as Code Division Multiple Access (CDMA), using a finger lock mechanism. The method includes a series of steps, including a first step of receiving a finger assignment from a searcher portion of a communication device. Next, the signal-strength of the finger assignment is determined, and a time period over which the signal-strength exists is determined. The finger assignment is then compared to multiple signal-strength thresholds and to a time threshold. In the next step, the finger assignment is evaluated for a combing operation based upon which of the aforementioned thresholds it satiates. In particular, the finger assignment is enabled for a combining operation if it is a new finger assignment or if it continues to satiate a combine signal-strength threshold. Alternatively, the finger assignment is not enabled for combining but neither is it deassigned (e.g.
    Type: Grant
    Filed: October 2, 2000
    Date of Patent: December 13, 2005
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Luis Aldaz, Daniel Jeng Hsia
  • Patent number: 6970497
    Abstract: A base station receives a signal resulting from multiplexing a communication signal spread using a signal-specific spreading code and sent by mobile station apparatus and a calibration (CAL) signal spread using a signal-specific spreading code and sent for each unit frame for a predetermined time by a CAL radio signal generator in a same frequency band. An A/D conversion/despreading section and an A/D conversion/despreading section extract the communication signal and CAL signal from the received signal. A calibration processing section carries out calibration processing using the CAL signal in parallel with a communication using the communication signal. An array combining/signal processing section carries out demodulation processing on the communication signal using the calibration processing result.
    Type: Grant
    Filed: January 12, 2001
    Date of Patent: November 29, 2005
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masayuki Hoshino, Kazuyuki Miya, Katsuhiko Hiramatsu
  • Patent number: 6967990
    Abstract: When transmission rate information and required quality information for each user are known, each of the K units of multipliers (where K is a natural number and represents the number of users) multiplies the transmission rate information and the required quality information for each user. A sorting circuit estimates the power of the incoming signal based on the value output by the multipliers, determines the rank of the users based on the estimated power between users, and sends the information on the rank of the users to the first stage. Interference cancellation is then sequentially executed from the first stage to the final stage based on the rank information.
    Type: Grant
    Filed: August 29, 2000
    Date of Patent: November 22, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takeo Suzuki, Hideshi Murai
  • Patent number: 6965589
    Abstract: The invention is a method for limiting the peak transmit power in a CDMA communication system including the steps transmitting a first communication signal having a first high transmit power region and transmitting a second communication signal having a second high transmit power region. One of the first and second communication signals is time offset to prevent the first and second high transmit power regions from occurring simultaneously. Time shifting only a portion of one of the first and second communications signals is also taught. The first and second communication signals can also include respective first and second low transmit power regions. The time offset can be selected to align one of the first and second high transmit power regions with one of the first and second low transmit power regions.
    Type: Grant
    Filed: February 25, 2002
    Date of Patent: November 15, 2005
    Assignee: QUALCOMM, Incorporated
    Inventors: Stein A. Lundby, Edward G. Tiedemann, Jr., Jack M. Holtzman, Daisuke Terasawa
  • Patent number: 6959065
    Abstract: A system, method and apparatus for demodulating a received signal using a configurable receiver. The receiver performs the demodulation of a signal according to a selected interference cancellation demodulation scheme. The same receiver can be configured, by setting certain parameters, to behave as a successive interference cancellation (SIC) scheme receiver, a parallel interference cancellation (PIC) scheme receiver, or a hybrid interference cancellation (HIC) scheme receiver. In another aspect of the present invention, the receiver performs its demodulation operation using a single interference cancellation unit (ICU). In addition, the ICU's despreading and respreading functions may be performed by the same processing element.
    Type: Grant
    Filed: April 20, 2001
    Date of Patent: October 25, 2005
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Erik Sparrman, Stefan Parkvall, Alex Murillo Barrera
  • 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: 6952589
    Abstract: An apparatus, system and method for improving the SNR of a desired signal received at a receiver in a multiple access communication system is disclosed. The apparatus, system and method subtracts known or knowable signals from the total signal received at the receiver and the desired signal is then determined from the result of the subtraction. The known, or knowable, signals can be synchronization signals or other interfering channel signals transmitted by the transmitter, such as a wireless network base station, serving the receiver, such as a subscriber station in such a wireless network, and/or can be such signals transmitted by another transmitter, such as an adjacent base station, or an adjacent sector in multi-sector systems.
    Type: Grant
    Filed: November 28, 2000
    Date of Patent: October 4, 2005
    Inventor: Ramesh Mantha
  • Patent number: 6950411
    Abstract: A mobile user receiver having a cancellation system for removing selected signals from a traffic signal prior to decoding includes a receiver having a system input for receiving communication signals from a transmitter over an air interface. The system input is supplied to a traffic signal cancellation system for canceling unwanted traffic signals. The system input is also supplied to a pilot signal cancellation system for removing a global pilot signal. The output of the pilot signal cancellation system is subtracted from the output of the traffic signal cancellation system to provide a cancellation system output free from unwanted traffic signals and the global pilot signal.
    Type: Grant
    Filed: June 16, 2003
    Date of Patent: September 27, 2005
    Assignee: InterDigital Technology Corp.
    Inventors: Fatih M. Ozluturk, Nadir Sezgin
  • Patent number: 6950457
    Abstract: A signal processing method is for use in an array antenna system included in a Code Division Access (CDMA) mobile telecommunications network base station. The signal processing method includes initializing a weight vector and a snapshot index; obtaining a gradient of output power of an array antenna to a phase of each of the antennas in the array antenna system at every snapshot and determining whether an adaptive gain is added or subtracted depending on the signature of the gradient to update the phase of each antenna; and determining a weight value for each of the antennas to apply the weight value to a signal received at the corresponding one of the antennas.
    Type: Grant
    Filed: December 13, 2000
    Date of Patent: September 27, 2005
    Assignees: Hantel Co., Ltd., SAS Technologies Co., Ltd.
    Inventor: Seung-Won Choi
  • Patent number: 6947470
    Abstract: A rake receiver uses a delayed version of the received sequence and a delayed version of a scrambling code. The flexible hardware structure of the time-aligning and descrambling unit includes at least two delay chains and one multiplier. By controlling two multiplexers, the delayed versions of the received sequence can be multiplied with an arbitrary scrambling code having an arbitrary phase. During one chip period, one multiplication is performed for each path to be processed.
    Type: Grant
    Filed: July 17, 2001
    Date of Patent: September 20, 2005
    Assignee: STMicroelectronics N.V.
    Inventor: Friedbert Berens
  • Patent number: 6944207
    Abstract: In a CDMA receiver comprising a searcher for preparing a delay profile to produce path information identifying main propagation paths, a path monitor monitors the path information from the searcher to produce a detection signal when the main propagation paths are stable for a predetermined time interval. Responsive to the detection signal, a searcher operation controller controls the searcher to make the searcher intermittently operate at a predetermined intermittent period. The path monitor includes a path information memory for storing current path information from the searcher as stored path information and a path comparator for comparing the stored path information with the current path information. The path comparator produces a path coincidence signal when the stored path information coincides with the current path information. The path comparator produces a path inconsistency signal when the stored path information coincides with the current path information.
    Type: Grant
    Filed: January 26, 2001
    Date of Patent: September 13, 2005
    Assignee: NEC Corporation
    Inventor: Katsumaru Ohno
  • Patent number: 6944206
    Abstract: Methods and systems are provided for communicating encoded data. L received encoded signal values including soft information are received and transformed to L data symbols. In various embodiments, the L received encoded signal values are demodulated and the demodulated L received encoded signal values are convolutional decoded using a rate one convolutional decoder having only one output symbol per input symbol to provide the L data symbols, wherein the L received encoded signal values are convolutional encoded using a rate one convolutional encoder having only one output symbol per input symbol. In other embodiments of the present invention the L received encoded signal values are transformed using associated spectral energy at a plurality of frequency ranges within a bandwidth of a channel over which the L received encoded signal values are received for at least one of the L received encoded signal values.
    Type: Grant
    Filed: November 20, 2000
    Date of Patent: September 13, 2005
    Assignee: Ericsson Inc.
    Inventor: Paul W. Dent
  • Patent number: 6937642
    Abstract: A common pilot channel-use reverse diffusion unit generates common pilot data using a received digital signal and a common pilot channel-use reverse diffusion code, while an individual channel-use reverse diffusion unit generates individual channel data using the received digital signal and an individual channel-use reverse diffusion code. Power calculating unit converts respective output data items of the common pilot channel-use reverse diffusion unit and the individual channel-use reverse diffusion unit into power values, a larger one of which is then determined by a comparator. A selector unit selects the data item having thus determined larger power value of those output data items of those reverse diffusion units. A channel estimating unit estimates the channel using data symbols of the data item thus selected by the selector unit.
    Type: Grant
    Filed: May 16, 2001
    Date of Patent: August 30, 2005
    Assignee: NEC Corporation
    Inventor: Masaru Hirata
  • Patent number: 6934319
    Abstract: A configurable multimode despreader for spread spectrum applications is disclosed herein. The despreader includes a plurality of data lines, at least one selective coupler coupled to the plurality of data lines, at least one multiplier coupled to the selective coupler, and a code input line coupled to the multiplier. The selective coupler selectively couples one of the plurality of data lines with the multiplier per any one of a plurality of despreading protocols. The multiplier then multiplies a desired input data type received from the selective coupler with a despreading code chip received from the code input line to produce an observation. The programmable multimode despreader supports variable code and data modulation schemes and variable spreading factors.
    Type: Grant
    Filed: December 29, 2000
    Date of Patent: August 23, 2005
    Assignee: Infineon Technologies AG
    Inventor: Ravi Subramanian
  • Patent number: 6931052
    Abstract: The present invention provides for improved parallel interference cancellation. An input signal composed of multiple user signals is processed over a select time duration. The input signal is separated into individual signals corresponding to each of the multiple users and demodulated to recover symbols for each of the individual signals. The recovered symbols are processed based on the consistency of previous estimates of the given symbol to provide weighted symbol estimates. The respective weighted symbol estimates for each of the users are modulated with the appropriate coding and processed using channel estimates to create individual, regenerated signals. For each user, the regenerated signals for the other users are subtracted from the original input signal to form new individual signals. The new individual signals are each demodulated and reprocessed for multiple iterations. The output of the last iteration is used to form the final symbol decisions for each user signal.
    Type: Grant
    Filed: November 16, 2001
    Date of Patent: August 16, 2005
    Assignee: Nortel Networks Limited
    Inventors: Arthur T. G. Fuller, Bradley J. Morris
  • Patent number: 6922433
    Abstract: To provide a CDMA demodulation circuit and a CDMA demodulation method capable of maintaining good receiving characteristics even in a mobile communication environment. A fading pitch estimation portion estimates a time at which a level of a received input signal drops due to fading by monitoring fluctuation in the level provided by a rake combining portion. Before the level drops, a finger path assignment control portion controls assignment of path timing to a fingers portion performed by a finger path assignment portion.
    Type: Grant
    Filed: March 28, 2001
    Date of Patent: July 26, 2005
    Assignee: NEC Corporation
    Inventor: Koichi Tamura
  • Patent number: 6907094
    Abstract: The present invention provides a diversity receiving device with superior interference resistance in a simple construction, comprising a plurality of antennas (11, 12); an antenna switching device (13) that selects any one of a plurality of antennas (11, 12) and carries out connection switching thereof; a demodulator (14) that demodulates a wireless signal and obtains a baseband spread spectrum signal; an A/D converter (15) that A/D converts the baseband spread spectrum signal and generates chip data; a digital matched filter (16) that finds the correlation value of the chip data and the spreading code; a maximum correlation value detection portion (18) that detects the maximum correlation value; an average value calculation portion (21) that finds the average value per frame of the maximum correlation value; and a level comparison device (22) that compares the above-mentioned average value and a predetermined threshold value, and outputs a control signal to the antenna switching device (13) to control antenn
    Type: Grant
    Filed: March 12, 2002
    Date of Patent: June 14, 2005
    Assignee: Uniden Corporation
    Inventors: Masaki Matsui, Shigeo Sato, Toshiaki Fujikura, Akio Horibe, Muneki Ito
  • 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: 6907049
    Abstract: A radio communication apparatus which is used in a CDMA communication system, has a plurality of fingers, and performs rake reception, includes a delay profile calculating section and a finger path allocating section. The delay profile calculating section calculates a delay profile using a reception signal. The finger path allocating section allocates path positions to the plurality of fingers on the basis of the delay profile calculated by the delay profile calculating section. A delay profile calculation cycle in the delay profile calculating section is variable. A power consumption control method is also disclosed.
    Type: Grant
    Filed: July 5, 2000
    Date of Patent: June 14, 2005
    Assignee: NEC Corporation
    Inventor: Koichi Tamura
  • Patent number: 6901104
    Abstract: A wireless network is disclosed including at least one base station and a plurality of assigned terminals for exchanging user data and control data. The base station is arranged for transmitting the start time of at least one signaling sequence of at least terminal. For evaluating the signaling sequences transmitted by the terminals, the base station includes a device for correlating a received signaling sequence and for detecting the pulse evolving from a received and correlated signaling sequence. A terminal generates a signaling sequence by folding two code sequences.
    Type: Grant
    Filed: November 30, 1999
    Date of Patent: May 31, 2005
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Yonggang Du, Christoph Herrmann