Having Correlation-type Receiver Patents (Class 375/142)
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Publication number: 20110206090Abstract: A method for optimizing the acquisition phase of a spread-spectrum signal by a mobile receiver includes searching for the path having the maximum energy for different frequency assumptions and among all the positive trend paths of said frequencies between two initial and final instants marking the beginning and the end of a coherent signal integration.Type: ApplicationFiled: September 25, 2009Publication date: August 25, 2011Applicants: THALES, CENTRE NATIONAL D'ETUDES SPATIALES - CNESInventors: Damien Kubrak, Michel Monnerat, Lionel Ries, GĂ©raldine Artaud
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Patent number: 8005129Abstract: A User Equipment (UE) receives and samples communication signals, where the communication signals have a time frame format, a transmission chip rate and a synchronization code associated with a time slot that includes a midamble that indicates a modulation of the synchronization code where a specified modulation of received synchronization codes identifies the timing for a timeslot in which data is to be received. The UE preferably includes a synchronization code determination circuit, a midamble determination circuit, and a phase modulation sequence detection circuit operatively associated with the midamble determination circuit. The UE can be configured for use with the low chip rate option of the Third Generation Partnership Project (3GPP) Universal Mobile Telecommunication System (UMTS) standards that employ a predefined set of downlink SYNC codes that point to midambles which indicate SYNC code modulation sequence to enables reading of data in a subsequent Broadcast Channel (BCH) message.Type: GrantFiled: October 26, 2009Date of Patent: August 23, 2011Assignee: InterDigital Technology CorporationInventors: Alpasian Demir, Fatih M. Ozluturk
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Patent number: 8005159Abstract: The present invention relates to a method for estimating a propagation channel in the presence of transmit beam-forming within a receiver, accounting for the structure of two logical channels referred as to a common channel and a dedicated physical channel (CPICH, DPCH) and based on a common structure of corresponding propagation channels, said DPCH channel comprising two sub-channels (DPDCH, DPCCH), said propagation channels being modeled as a linear superposition of a finite number of discrete multipath components following an uncorrelated-scattering wide-sense stationary model, a multipath component being characterized by a time-varying multipath complex coefficient and a delay. Use: RAKE Receiver.Type: GrantFiled: October 10, 2003Date of Patent: August 23, 2011Assignee: ST-Ericsson SAInventor: Giuseppe Montalbano
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Patent number: 8000381Abstract: A feedback control law steers a reference phase that tracks the phase of a received code sequence. The reference phase clocks a track-reference signal consisting of a series of correlation kernels, over which data is extracted and then summed in various combinations. The correlation kernels are designed in such a manner that errors caused by multipath are eliminated or substantially reduced. Furthermore, the areas of the correlation kernels are balanced across level-transitions of a code and non-transitions to eliminate phase biases when tracking specific satellites. Extra care must be taken to balance the correlation kernels in this manner due to a little known aspect of GPS C/A codes. Specifically, not all C/A codes have the same ratio of level-transitions to non-transitions as has been assumed in prior art.Type: GrantFiled: February 26, 2008Date of Patent: August 16, 2011Assignee: Hemisphere GPS LLCInventors: Michael L. Whitehead, Steve R. Miller
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Patent number: 8000413Abstract: Signal quality estimation and demodulation are tailored to the received signal quality. According to one embodiment, a received signal is processed by determining a first set of combining weights based on a first impairment covariance estimate derived assuming a low signal quality environment. A second set of combining weights is determined based on a second impairment covariance estimate derived assuming a high signal quality environment. A metric is determined corresponding to the difference between symbol estimates derived from the second set of combining weights and hard symbol decisions. The received signal is demodulated based on the second set of combining weights if the metric satisfies a threshold indicating high signal quality and otherwise based on the first set of combining weights.Type: GrantFiled: August 20, 2007Date of Patent: August 16, 2011Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventor: Douglas A. Cairns
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Patent number: 8000380Abstract: A detection unit is disclosed for the detection of data symbols contained in a demodulated signal, whereby band spreading occurs transmit-side with the use of first sequences, whose first chips each assume one of two different first values.Type: GrantFiled: November 9, 2006Date of Patent: August 16, 2011Assignee: Atmel CorporationInventor: Frank Poegel
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Publication number: 20110194588Abstract: A wireless communication system includes: a frequency down-converting circuit for receiving a wireless signal and for performing frequency down-conversion on the wireless signal to output a frequency down-converted signal; a first training circuit for performing frequency comparison between the frequency down-converted signal and a plurality of candidate carrier signals having different frequencies so as to determine a plurality of selected carrier signals from the candidate carrier signals; a second training circuit for performing phase comparison between the frequency down-converted signal and phases of a pseudo-noise sequence at each of the selected carrier signals so as to determine a matching phase and a matching carrier; and a demodulator for demodulating the frequency down-converted signal according to the matching carrier and the matching phase so as to generate a demodulated signal.Type: ApplicationFiled: February 1, 2011Publication date: August 11, 2011Applicant: REALTEK SEMICONDUCTOR CORP.Inventor: Kun-Sui HOU
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Patent number: 7995641Abstract: As taught herein channelization code power estimates are generated for a number of data channels in a received CDMA signal based on a joint determination process. Joint processing in this context yields improved estimation of data channel code powers and corresponding estimations of noise variance. These improvements arise from exploitation of joint processing of measured data value correlations across two or more data channel codes represented in the received signal. In one or more embodiments, joint determination of data channel code powers comprises forming a correlation matrix as a weighted average of correlations determined for a plurality of data channels. In one or more other embodiments, joint determination of data channel code powers comprises jointly fitting the correlation matrices for a plurality of data channels in a least squares error estimation process.Type: GrantFiled: November 6, 2007Date of Patent: August 9, 2011Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Gregory E. Bottomley, Douglas A. Cairns, Yi-Pin Eric Wang
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Patent number: 7991040Abstract: Methods and apparatus for reduction of a peak to average ratio for an OFDM transmit signal. In an aspect, a method is provided for reducing a peak to average ratio of a transmit waveform. The method includes obtaining a primary scrambler sequence, generating a secondary scrambler sequence having a length characteristic based on data to be scrambled, and combining the primary and secondary scrambler sequences to produce a PAR reduction sequence. In another aspect, an apparatus is provided for reducing a peak to average ratio of a transmit waveform. The apparatus includes a secondary generator configured to generate a secondary scrambler sequence having a length characteristic based on data to be scrambled, and combining logic configured to combine a primary scrambler sequence and the secondary scrambler sequences to produce a PAR reduction sequence.Type: GrantFiled: September 11, 2006Date of Patent: August 2, 2011Assignee: QUALCOMM IncorporatedInventors: Durk L. van Veen, Fuyun Ling, Raghuraman Krishnamoorthi
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Patent number: 7991083Abstract: A method and system is provided for detecting preambles in a multi-cell communication system. The method detects preambles reliably even in the presence of interference caused by multiple cells reusing the same frequency in the multi-cell communication system. After receiving a signal in the receiving period, the time domain signal is sampled and transformed into the frequency domain vector. The correlation vector is calculated with the frequency domain vector and pseudonoise code of the wireless station. The presence of a preamble is verified if the value in the correlation vector exceeds a predetermined threshold.Type: GrantFiled: November 28, 2006Date of Patent: August 2, 2011Assignee: Cisco Technology, Inc.Inventors: Yanxin Na, Hang Jin
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Patent number: 7986729Abstract: The present invention provides for a methods, system, and apparatus relating to data transmission. One method of the present invention includes representing data using at least one ultra wideband pulse, sending the at least one ultra wideband pulse over an electrically conductive guided media, and recovering the data from the at least one ultra wideband pulse. The present invention can be used in conjunction with telephony applications, cable TV applications, power line applications, fiber optic applications, and data bus applications.Type: GrantFiled: October 18, 2004Date of Patent: July 26, 2011Assignee: Lightwaves Systems, Inc.Inventors: Philip T. Kennedy, Bruce D. Melick, David M. Snyder, Leslie D. Baych, Gregory P. Probst, Joseph A. Gerke
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Patent number: 7986724Abstract: A method for providing information to a plurality of wireless mobile communication devices. The method includes dedicating at least one channel of a plurality of spread spectrum data channels as a broadcast channel. The frequency and phase of a carrier signal and of a chip rate clock of the at least one channel are synchronized for each of a plurality of cell transmitters of a respective plurality of base stations. The Information is then broadcast over the at least one dedicated channel from each base station.Type: GrantFiled: July 12, 2002Date of Patent: July 26, 2011Assignee: Rhomson LicensingInventors: Jeffrey Allen Cooper, Kumar Ramaswamy
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Patent number: 7986739Abstract: A method and system for detecting the presence of narrowband transmitters utilizing frequencies also utilized by wider band communication systems. In some embodiments an ultrawideband transceiver detects signals at specific frequencies within a spectrum of frequencies, and analyzes the signals to determine if the signals indicate transmissions by a narrowband transmitter in a narrowband communication system. In further embodiments transmission circuitry reduces signal components at frequencies occupied by the narrowband transmitters.Type: GrantFiled: February 25, 2008Date of Patent: July 26, 2011Assignee: Realtek Semiconductor Corp.Inventors: Turgut Aytur, Stephan ten Brink, Ravishankar H. Mahadevappa, Venkatesh Rajendran
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Apparatus and method of acquiring initial synchronization of terminal in mobile communication system
Patent number: 7986757Abstract: The present invention relates to an apparatus and method of acquiring initial synchronization of a terminal in a mobile communication system. According to an exemplary embodiment of the present invention, one or more auto-correlation values of a preamble constituting a signal that is received from a base station are calculated. Averages of the calculated auto-correlation values according to samples are calculated, and then a peak value is detected among the calculated values. Then, a cell search is performed on the basis of the detected peak value, and a peak value from the result of the cell search is regularized. Then, the regularized peak value is compared with a predetermined reference value such that it is checked whether synchronization of a signal that has been searched is accurate or not.Type: GrantFiled: October 24, 2007Date of Patent: July 26, 2011Assignees: Samsung Electronics Co., LLP, Electronics and Telecommunications Research InstituteInventors: Hyeong-Sook Park, Jun-Woo Kim, Kyung-Yeol Sohn, Youn-Ok Park -
Patent number: 7983324Abstract: The present invention relates to a symbol acquisition apparatus and a method thereof. The method includes: determining a first boundary according to a first preamble symbol and generating a first confidence value according to signal quality of the first preamble symbol; determining a second boundary according to a second preamble symbol and generating a second confidence value according to signal quality of the second preamble symbol; and determining a symbol boundary from the first and the second boundaries according to the first and the second confidence values.Type: GrantFiled: August 18, 2006Date of Patent: July 19, 2011Assignee: Realtek Semiconductor Corp.Inventors: Kuo-Ming Wu, Der-Zheng Liu, Kuang-Yu Yen
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Patent number: 7974331Abstract: Rake receivers in code division multiple access (CDMA) telecommunication comprise fingers (1,2,3) with each finger processing signal components for a particular transmission path to be able to better synchronize with a RF signal received via different paths, and a combiner (4) for combining the results originating from said fingers, and a compensator in the form of a controlled oscillator in a feedback loop. By locating a finger compensator (20-25) in a finger, said finger can handle complex situations, like Doppler shifts under high-speed conditions. Preferably, most or all fingers each comprise such a finger compensator, in which case said feedback loop can be avoided. Such a finger compensator can be hardware, software or a mixture of both when comprising a filter (21) plus an amplitude normalizer (22) between two arithmetical modules (20,25) for multiplying an input symbol signal with a conjugated previous input symbol signal and an output symbol signal with a previous output symbol signal.Type: GrantFiled: December 9, 2002Date of Patent: July 5, 2011Assignee: ST-Ericsson SAInventors: Luzhou Xu, Dong Wang
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Patent number: 7961776Abstract: A device for decoding a direct sequence spread spectrum-encoded binary message includes a sampler that captures at least one sequence of binary samples corresponding to one bit of the transmitted message. The captured sequence of samples are applied to a filter matched to the spreading code used, thus making it possible to delete the spreading applied to the original message. The device further includes, at the output of the sampler, an error correction block including a memory storing a plurality of binary sequences corresponding to all of the possible values for a captured sequence of samples. A replacement circuit replaces the captured sequence of samples with the stored sequence, thereby minimizing the number of samples different from the captured sequence of samples, and allowing the stored sequence to be applied to the matched filter.Type: GrantFiled: November 28, 2006Date of Patent: June 14, 2011Assignees: STMicroelectronics (Rousset) SAS, Universite de Provence d'Aix-Marseille IInventors: Benoît Durand, Christophe Fraschini, Philippe Courmontagne, Stéphane Meilleire
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Publication number: 20110134965Abstract: This disclosure relates to method, device and system for controlling power in a communication system. A plurality of power levels is measured from a received signal that includes a pulsed noise source. The received signal is correlated with a known sequence creating a correlation metric. A signal power is determined based on the correlation metric and the plurality of power levels. An uplink signal is transmitted at a transmit power that is based on the signal power.Type: ApplicationFiled: February 25, 2011Publication date: June 9, 2011Inventors: Theodore J. Myers, Robert W. Boesel
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Patent number: 7957494Abstract: A system for determining the burst start timing of a signal includes logic configured to receive the signal, generate correlation moduli and generate a first timing output based on the correlation moduli. The logic may also be configured to receive operating mode information and timing information and generate search controls. The logic may further be configured to identify a maximum of the correlation moduli using the search controls and determine a second timing output associated with the maximum correlation modulus. The second timing output represents a more accurate approximation of a burst start time than the first timing output.Type: GrantFiled: September 30, 2009Date of Patent: June 7, 2011Assignee: Juniper Networks, Inc.Inventors: Joseph Boutros, Emmanuel Lemois
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Patent number: 7953059Abstract: An apparatus and method for determining feedback information detection in a broadband wireless communication system are provided. In the detection determining apparatus, a demodulator correlates each of tiles carrying received feedback information with an orthogonal vector including a pilot symbol in each possible codeword, each tile being a predetermined number of subcarriers, and calculates the squares of the absolute values of the correlations. A codeword correlation calculator sums the squares of the absolute value of the correlations of the tiles for each possible codeword. A detection decider determines whether to perform detection on the feedback information based on the maximum of the sums.Type: GrantFiled: September 20, 2006Date of Patent: May 31, 2011Assignee: Samsung Electronics Co., LtdInventors: Ha-Young Yang, Joon-Young Bae, Jae-Ho Jeon, Seung-Joo Maeng, Chang-Soo Park
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Patent number: 7953199Abstract: Provided is a synchronization error tracking device and method. The method and system estimates and corrects the synchronization error generated by time and frequency offsets during the data transmission interval and uses a module designed for initial synchronization or channel estimation without adding a new correlation operator. Further, a combining mark value and a synchronization position value acquired during the synchronization process are used.Type: GrantFiled: November 2, 2009Date of Patent: May 31, 2011Assignee: Electronics and Telecommunications Research InstituteInventors: Kyu-Min Kang, Sang In Cho, Sung Woo Choi, Sangsung Choi
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Patent number: 7953142Abstract: A variable code-tracking loop filter in a receiver having the ability to change its parameters multiple times in response to received signals. Parameters for the code-tracking loop filter may be varied based on phase and frequency errors from an error detector. In one implementation, the code-tracking loop filter is able to repeatedly vary a single parameter, such as its received bandwidth, based on the phase and frequency errors, while in another, the code-tracking loop filter may vary two or more parameters, such as the loop bandwidth and the natural frequency.Type: GrantFiled: October 17, 2002Date of Patent: May 31, 2011Assignee: Sirf TechnologyInventor: Mangesh Chansarkar
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Patent number: 7949038Abstract: A method and a system for the acquisition and tracking of BOC(m,n) modulated codes, m/n equal to an integer, in which a correlation function is calculated of the BOC(m,n) modulated code received from a remote transmitter with a code wa locally generated at a receiver terminal according to one from the following the relationships: wa(?)=c(?n)?a·[prn(?n+Tc/2)?prn(?n?Tc/2)] wa(?)=c(?n)?a·[prn(?n+nTc/2m)?prn(?n?nTc/2m)] wa(?)=c(?n)?a·[prn(?n+nTc/4m)+prn(?n?nTc/4m)] wa(?)=c(?n)?a·[prn(?n+3nTc/4m)+prn(?n?3nTc/4m)] w(?)=[prn(?n+nTc/4m)+prn(?n?nTc/4m)] w(?)=[prn(?n+nTc/2m)?prn(?n?nTc/2m)] wherein c(?) is a local replica of the BOC modulated pseudo-random noise code with delay ?n, PRN(?) is a replica of the unmodulated pseudo-random noise code, and a is a predetermined weight coefficient, and the correlation function being at the base of an acquisition test function whereby a code acquisition is recognized for a value of the test function being higher than a predetermined threshold.Type: GrantFiled: December 12, 2007Date of Patent: May 24, 2011Assignee: STMicroelectronics, S.r.l.Inventors: Giuseppe Avellone, Maristella Frazzetto, Ettore Messina
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Patent number: 7944961Abstract: Systems and methods for avoiding non-linear behavior of conventional early-minus-late correlator-based code loop discriminators. The present invention provides a model of correlator behavior that takes into account whether both correlators are on the same side of the correlation peak or they straddle the peak. The result is a piecewise solution that can be stitched together quite readily to produce an extended range of linear response, thereby improving the pull-in capability of GPS code loops when closely spaced correlators are being used.Type: GrantFiled: August 27, 2007Date of Patent: May 17, 2011Assignee: Honeywell International Inc.Inventor: Robert G. Simpson
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Patent number: 7940834Abstract: A GNSS receiver and method using alternating “A” and “B” time segments for a reception time length of two or more data bits. The GNSS signal in an “A” time period comprising the “A” time segments is integrated for determining “A” magnitudes corresponding to code phase increments and the GNSS signal in a “B” time period comprising the “B” time segments is integrated for determining “B” magnitudes corresponding to code phase increments. A trial-and-error data bit search is performed for depolarizing data bit senses. The code phase increment showing the largest correlation level is used for acquisition of the GNSS signal and/or determination of the location where the GNSS is being received.Type: GrantFiled: May 15, 2008Date of Patent: May 10, 2011Assignee: Trimble Navigation LimitedInventors: David R. Gildea, Peter Van Wyck Loomis
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Publication number: 20110103430Abstract: A receiver device for detecting a multi-band signal, the receiver device comprising a bank of autocorrelation units adapted for separating the multi-band signal into a set of autocorrelation signals, and a sampling stage arranged downstream the bank of autocorrelation units and adapted for sampling the set of autocorrelation signals to thereby select individual signal components for detection.Type: ApplicationFiled: May 4, 2009Publication date: May 5, 2011Applicants: Technische Universitat Graz, Forschungsholding Tu Graz GmbHInventor: Klaus Witrisal
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Patent number: 7933366Abstract: A channel estimation method and system using linear correlation based interference cancellation combined with decision-feedback-equalization (LCIC-DFE) are provided. The channel estimation method includes generating a first correlation sequence by calculating a linear correlation between a baseband sampled complex signal and a locally stored pseudo-noise signal and obtaining a second correlation sequence by iteratively removing inter-path interference from the first correlation sequence and generating a first channel impulse response (CIR) sequence based on the second correlation sequence. And, obtaining a third correlation sequence by removing random-data interference from the second correlation sequence based on the first CIR sequence and a feedback signal and generating a second CIR sequence based on the third correlation sequence.Type: GrantFiled: May 4, 2007Date of Patent: April 26, 2011Assignee: Samsung Electronics Co., Ltd.Inventor: Guanghui Liu
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Patent number: 7933313Abstract: Disclosed herein are a signal quality measuring apparatus for the WiBro system and a method thereof. The signal quality measuring apparatus for a WiBro system includes a WiBro signal reception unit, a preamble code correlation unit, a channel compensation/demodulation unit, and a control unit. The WiBro signal reception unit receives a WiBro signal from each base station. The preamble code correlation unit searches the WiBro signal for a number of preamble codes equal to the number of base stations for which measurement of signal quality measurement is required. The channel compensation/demodulation unit acquires the information of a Frame Control Header (FCH) section and a DownLink-MAP (DL-MAP) section with reference to the preamble codes found by the preamble code correlation unit, and demodulates the information of a unique number of the base station.Type: GrantFiled: May 8, 2007Date of Patent: April 26, 2011Assignee: Innowireless Co., Ltd.Inventors: Jinsoup Joung, Jaesung Lee, Seunghwan Ji
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Patent number: 7929647Abstract: Systems and methods are provided for dynamically analyzing radar pulses at a receiver. A digital signal is provided to an amplitude detector. At least one digital waveform representing an emitter pulse is identified at the amplitude detector. A matched filter associated with the emitter is generated, comprising at least one characteristic of the identified digital waveform.Type: GrantFiled: March 13, 2006Date of Patent: April 19, 2011Assignee: Lockheed Martin CorporationInventor: J. Andrew Johnson
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Patent number: 7924906Abstract: An assembly of simultaneously transmitted electrically generated signals, which contains a subset of binary spreading-code sequences that are members of a large set of binary spreading-code sequences available to a particular node of a multi-node communication network. All sequences in the set of spreading-code sequences available to the particular node of the network can be generated by the same configurations of two linear feedback binary shift registers, where feedback taps of the two linear-feedback binary shift registers correspond to primitive polynomials of the same degree over GF(2), the field of two elements.Type: GrantFiled: September 7, 2006Date of Patent: April 12, 2011Assignee: Kipling Sahibs LLCInventor: Bart F. Rice
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Patent number: 7917163Abstract: Techniques for intra-frequency searching in the presence of frequency gaps are disclosed. In one embodiment, a search is scheduled and frequency switches are suppressed during the scheduled search. In another embodiment, a search is scheduled in between anticipated frequency gaps. In yet another embodiment, a timer is deployed, the expiration of which indicates a search is to be scheduled. In yet another embodiment, a timer is deployed, the expiration of which indicates a search is to be scheduled and frequency switches are suppressed during the scheduled search. Various other embodiments are also presented. Benefits include allowing prescribed levels of intra-frequency and inter-frequency search to be performed which allows for improved base station selection and therefore improved performance and system capacity.Type: GrantFiled: August 27, 2003Date of Patent: March 29, 2011Assignee: QUALCOMM, IncorporatedInventor: Messay Amerga
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Patent number: 7912113Abstract: A technique for determining a received signal strength indicator of a target base station at a subscriber station includes performing a discrete Fourier transform on a received signal to provide a transformed signal. In this case, the transformed signal occupies one or more segments of a channel and the one or more segments each include multiple subcarriers. A shift-n cross-correlation is calculated based on the transformed signal and a preamble sequence of the target base station to provide a coarse received signal strength indicator for the target base station.Type: GrantFiled: October 5, 2007Date of Patent: March 22, 2011Assignee: Motorola Mobility, Inc.Inventors: Krishna Kamal Sayana, Xiangyang Zhuang, Kenneth A. Stewart, Pallav Sudarshan
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Patent number: 7912165Abstract: A method is disclosed, including identifying a preamble in a frame, where the preamble has a preamble length 1. M data items received in succession are stored. The m data items once divided into n portions, where the data items in each portion have respectively been received at successive times and where m and n are natural numbers and the following applies to m and n: m>n, m>1, n>1. The n portions are respectively correlated to the expected values to form component correlation results. Delaying the component correlation results, with at least two component correlation results being delayed by different lengths. The method also includes combining the delayed component correlation results to form a total correlation value. The total correlation value is used to determine whether the m received data items contain the preamble of a frame.Type: GrantFiled: May 25, 2007Date of Patent: March 22, 2011Assignee: Infineon Technologies AGInventors: Stefan Herzinger, Andreas Menkhoff, Stefan Meier, Norbert Neurohr
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Publication number: 20110058592Abstract: In multicarrier transmission for multiplying transmit data individually by each code constituting orthogonal codes and transmitting each result of multiplication by a prescribed subcarrier, a plurality of different subcarriers are assigned exclusively to each user and each user performs multicarrier transmission of the transmit data by the subcarriers assigned. Further, a base station assigns a plurality of different subcarriers to each user exclusively, applies beam-forming processing on a per-user basis and performs multicarrier transmission of transmit data to each user by the subcarriers assigned.Type: ApplicationFiled: April 17, 2008Publication date: March 10, 2011Applicant: FUJITSU LIMITEDInventors: Hiroyuki Seki, Daisuke Jitsukawa, Yoshinori Tanaka
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Patent number: 7903723Abstract: Multipath components of transmitted data symbols are received with individual delays and processed by a RAKE unit having a number of fingers. A delay profile is calculated, and delay values for peaks detected therein are determined. A number of peak delay values representing the largest peaks for the profile are pre-selected, and for each of them a signal-to-interference ratio for delay values in an interval around the pre-selected peak delay value is calculated. In each interval the delay value having the highest signal-to-interference ratio is selected and provided to the RAKE unit with each selected delay being assigned to a RAKE finger. Hereby the ability to select correct and accurate path delays can be improved also in time critical processes, where filtering of the delay profiles over several frames is not possible, because quite accurate delay values can be provided shortly after wake-up of the receiver.Type: GrantFiled: April 5, 2006Date of Patent: March 8, 2011Assignee: Telefonaktiebolaget L M Ericsson (Publ)Inventor: Xiaohui Wang
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Patent number: 7890075Abstract: A radio receiver such as a frequency modulation (FM) receiver, for example, includes a radio frequency (RF) amplifier having an adjustable gain output. The RF amplifier may be configured to receive and amplify an incoming RF signal. The receiver also includes an intermediate frequency (IF) amplifier having an adjustable gain output. The IF amplifier may be configured to receive and amplify an IF signal that corresponds to the RF signal. The receiver also includes a gain control unit that is coupled to the RF amplifier and the IF amplifier. The gain control unit may be configured to independently adjust the gain of each of the RF amplifier and the IF amplifier, dependent upon a peak output level of both the RF amplifier and the IF amplifier.Type: GrantFiled: December 29, 2006Date of Patent: February 15, 2011Assignee: Silicon Laboratories, Inc.Inventors: Chunyu Xin, G. Tyson Tuttle, Scott D. Willingham, Peter J. Vancorenland
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Patent number: 7889780Abstract: A method for estimating a Doppler spread and a signal-to-noise ratio of a received signal includes: (a) calculating one or more functions of a carrier component of the received signal at a first time point relative to a pilot signal embedded in the received signal; (b) Calculating the one or more functions of the carrier component of the received signal at a second time point relative to the pilot signal; (c) repeating steps (a) and (b) over multiple time periods, each time period being substantially longer than the second time, and accumulating the one or more functions for the first time points and the second time points; and (d) Deriving the Doppler spread and the signal-to-noise ration based on the accumulated one or more functions calculated at the first and second time points. In one embodiment, the first time point is substantially closer to the pilot signal than the second time point. The first time point is one symbol interval from the pilot signal.Type: GrantFiled: January 2, 2007Date of Patent: February 15, 2011Assignee: Sirf Technology, Inc.Inventor: Donald Leimer
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Patent number: 7889782Abstract: A correlator (140) for de-spreading a spread-spectrum signal includes a state machine (205), a frequency correction look-up table (207), a pseudorandom code generator (209), and a correlator structure (301 and 801). The spread-spectrum signal includes symbols, and each symbol includes a plurality of chips. The correlator structure includes a plurality of taps (309 and 809) at which a coordinate rotation digital computer (CORDIC) operation is performed to determine an offset from a nominal carrier frequency of the spread-spectrum signal and to change a phase of each chip of a received symbol, in order to correct a carrier frequency of the spread-spectrum signal while de-spreading the spread-spectrum signal.Type: GrantFiled: February 23, 2007Date of Patent: February 15, 2011Assignee: Freescale Semiconductor, Inc.Inventors: Robert Mark Gorday, Jorge Ivonnet
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Publication number: 20110032974Abstract: A correlation calculator and carrier frequency synchronization detection circuit are provided that enable a code phase, carrier frequency, and carrier frequency phase match to be detected even if a carrier frequency is greatly displaced. A correlation value calculation section (130) has n storage elements (501 through 507) that store a spread code, n-integral-multiple first delay elements (401 through 414) that perform sequential shifting by delaying an I component baseband signal by a fixed time interval, and n-integral-multiple first multipliers (701 through 714) that respectively perform multiplication between sequentially shifted I component baseband signals and the storage elements (501 through 507). The same kind of configuration as in the case of an above I component baseband signal is also provided for a Q component baseband signal.Type: ApplicationFiled: October 13, 2010Publication date: February 10, 2011Applicant: PANASONIC CORPORATIONInventor: Shingo Karino
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Patent number: 7881401Abstract: A transmitter arrangement includes a first and a second phase-locked loop, each having a power amplifier. The first phase-locked loop generates a first amplified oscillator signal depending on a first input signal representing a first phase information, wherein a first feedback signal for the first phase-locked loop is derived from the first amplified oscillator signal. Accordingly, the second phase-locked loop generates a second amplified oscillator signal depending on a second input signal representing a second phase information. A second feedback signal for the second phase-locked loop is derived from the second amplified oscillator signal. The transmitter arrangement further includes a summation element to combine the amplified first oscillator signal and the amplified second oscillator signal to an output signal.Type: GrantFiled: November 17, 2006Date of Patent: February 1, 2011Assignee: Infineon Technologies AGInventors: Gunther Kraut, Junqi Liu, Qi Yu
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Patent number: 7881410Abstract: Disclosed is a method for detecting a user in a communication system. The method includes selecting i ranging sub-carrier signals among k sub-carrier signals upon which a k-point fast Fourier transform (FFT), has been performed multiplying the i ranging sub-carrier signals by a ranging code, performing k-point inverse fast Fourier transform (IFFT) on the i ranging sub-carrier signals multiplied by the ranging code, and (k-i) 0s, detecting a power of each of the IFFT-processed k point signals, estimating a power of a desired received signal and a power of an interference signal by using powers of the k point signals according to a predetermined scheme, and detecting a user depending on the power of the desired received signal and the power of the interference signal.Type: GrantFiled: June 28, 2006Date of Patent: February 1, 2011Assignee: Samsung Electronics Co., Ltd.Inventors: Jae-Hyok Lee, Evgeny Gontcharov, Jae-Ho Jeon, Seung-Joo Maeng
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Publication number: 20110019719Abstract: Systems (100) and methods (700) for providing a communications link with a power-limited communication transmitter (102) positioned remotely from an intended receiver system (104). The methods involve channel encoding a carrier signal with data provided at the power-limited communication transmitter to form an information signal. The methods also involve generating a chaotic spreading sequence based on a chaotic number sequence. The chaotic spreading sequence has a magnitude that is constant and a variable arbitrary phase angle comprising phase values which are uniformly distributed over a predetermined range of angles. A spread spectrum signal is formed by multiplying the information signal by the chaotic spreading sequence. The spread spectrum signal has an adjustable amplitude characteristic and a zero autocorrelation. The spread spectrum signal is transmitted from the power-limited communication transmitter to the intended receiver system.Type: ApplicationFiled: July 22, 2009Publication date: January 27, 2011Applicant: Harris CorporationInventors: Alan J. Michaels, Chester B. David
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Patent number: 7876784Abstract: Methods and apparatus provide low-complexity receivers for use in superposition coded multi-user systems. In a downlink scenario, a superposition coded signal that includes data unique to first and second users is compared with every permutation of the bit positions of the transmitted signal. The values of the received signal that are nearest to the transmitted signal are located to extract the data unique to the first user. In an uplink scenario, a superposition coded signal that includes data unique to the first and second users is compared with every permutation of the bit positions of transmitted signals corresponding to the first and the second users. The values of the received signal that are nearest to the transmitted signal corresponding to the first user are located to extract the data unique to the first user simultaneously with the extraction of the data unique to the second user.Type: GrantFiled: August 18, 2008Date of Patent: January 25, 2011Assignee: Marvell International Ltd.Inventor: Jungwon Lee
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Patent number: 7876839Abstract: Embodiments of system and method for generating channel estimates in a wireless network are generally described herein. Other embodiments may be described and claimed. In some embodiments, a linear interpolator uses refined cross-correlation and autocorrelation estimates and pilot subcarrier estimates to generate channel estimates for the current OFDM data symbol.Type: GrantFiled: December 30, 2005Date of Patent: January 25, 2011Assignee: Intel CorporationInventors: Xiaofei Dong, Qinghua Li, Minnie Ho, Hongming Zheng, Hongmei Sun, Shilpa Talwar
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Patent number: 7876807Abstract: This invention is directed to a method for estimating and compensating for multipath errors in a pseudorandom noise ranging receiver. The method exploits the asymmetry of the correlation function and proportionately relates it to the magnitude of multipath error. In a pseudorandom noise ranging receiver, the correlation function is obtained by generating the local pseudorandom noise sequences at different programmed non-uniform phases resulting in non-uniformly spaced correlators. Numerically controlled oscillators, code generators and shift registers are programmed to determine the correlation values at non-uniformly distributed points on a correlation function. Curve fitting is undertaken to determine the code phase at which the correlation function peaks. A proportionality constant is applied to the measure of asymmetry of the correlation function to determine the multipath error in the pseudorandom noise signal. A filter is used to detect and eliminate outliers.Type: GrantFiled: July 5, 2004Date of Patent: January 25, 2011Assignee: Accord Software & Systems Pvt. Ltd.Inventors: Jayanta Kumar Ray, Rakesh Nayak
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Patent number: 7873100Abstract: In a reception apparatus, a matched filter that has conventionally been arranged in a searcher unit is mounted on an acquisition unit together with a large scale memory. The large scale memory once stores reception chip signals, and thereafter outputs them to the matched filter and to the delay profile calculation unit. A setting register receives an acquisition signal and outputs it to the matched filter. The matched filter performs acquisition of the reception chip signals outputted from the large scale memory, and outputs a despread timing signal to a despread circuit, a code generation circuit and the delay profile calculation unit.Type: GrantFiled: December 14, 2004Date of Patent: January 18, 2011Assignee: Renesas Electronics CorporationInventor: Masayuki Koyama
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Patent number: 7864832Abstract: A reconfigurable multi-code correlation unit for correlating a sequence of chip samples comprising 1) a memory for storing the chip samples; 2) a plurality of add-subtract cells, each add-subtract cell receiving a plurality of real bits, a, and a plurality of imaginary bits, b, from a first chip sample and storing each real bit, a, and each imaginary bit, b, in a data store; and 3) a plurality of sign select units. Each sign select units receives from one add-subtract cell a plurality of first inputs equal to a sum (a+b) of the real bits, a, and the imaginary bits, b, and a plurality of second inputs equal to a difference (a?b) of the real bits, a, and the imaginary bits, b. Each sign select unit generates a plurality of real outputs and a plurality of imaginary outputs, wherein each of the real and imaginary outputs is equal to one of 1) the sum (a+b) multiplied by one of +1 and ?1 and 2) the difference (a?b) multiplied by one of +1 and ?1.Type: GrantFiled: August 9, 2006Date of Patent: January 4, 2011Assignee: Samsung Electronics Co., Ltd.Inventors: Eran Pisek, Yan Wang
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Patent number: 7860152Abstract: A wireless communication system. The system comprises transmitter circuitry (BST1), the transmitter circuitry comprising encoder circuitry (50) for transmitting a plurality of frames (FR). Each of the plurality of frames comprises a primary synchronization code (PCS) and a secondary synchronization code (SSC). The encoder circuitry comprises of circuitry (501) for providing the primary synchronization code in response to a first sequence (32). The encoder circuitry further comprises circuitry (502) for providing the secondary synchronization code in response to a second sequence (54) and a third sequence (56). The second sequence is selected from a plurality of sequences. Each of the plurality of sequences is orthogonal with respect to all other sequences in the plurality of sequences. The third sequence comprises a subset of bits from the first sequence.Type: GrantFiled: December 15, 2009Date of Patent: December 28, 2010Assignee: Texas Instruments IncorporatedInventors: Anand G. Dabak, Sundararajan Sriram, Srinath Hosur
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Publication number: 20100316092Abstract: An apparatus for detecting a spread spectrum signal in a wireless signal environment includes at least one antenna for receiving spread spectrum signals, such as UMTS signals, from a signal source in the wireless signal environment. In one embodiment, a detection circuit is configured for correlating a code in signal received by the apparatus with a set of possible codes for spread spectrum signals in order to detect the existence of a spread spectrum signal. In another embodiment, a detection circuit is configured for obtaining at least one reference frame of data from a received signal. The detection circuit is further operable for correlating a segment of the reference frame with a repeated segment of at least one subsequent frame of data in order to detect the existence of a spread spectrum signal. A repeater might incorporate such an apparatus wherein the variable gain of the repeater is adjusted based upon the correlation and the detection of a spread spectrum signal.Type: ApplicationFiled: June 11, 2009Publication date: December 16, 2010Inventors: Ariful Hannan, John Carlson
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Patent number: 7852905Abstract: Implementation of an improved matched filter system for despreading a PN code from a spread spectrum signal utilizes a matched filter system that may be broadly conceptualized as a system that optimizes the number of multipliers and adders utilized by the system in despreading a PN code from a spread spectrum signal. This lowers the power consumption of the improved matched filter system and increases the speed at which the system despreads the PN code from the spread spectrum signal.Type: GrantFiled: June 16, 2004Date of Patent: December 14, 2010Assignee: SiRF Technology, Inc.Inventors: Paul A. Underbrink, Steven A. Gronemyer