Patents Examined by Lawrence B. Williams
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Patent number: 8005165Abstract: A MIMO-OFDM transmission and reception apparatus is provided which allows high accuracy estimation of frequency offset; high accuracy estimation of a transmission path fluctuation and high accuracy synchronization/signal detection. A mapping section generates a plurality of OFDM signals. In these OFDM signals, some pilot carriers are assigned to the same carrier position and orthogonal sequences are assigned to the same time slot in the same carrier position.Type: GrantFiled: July 20, 2010Date of Patent: August 23, 2011Assignee: Panasonic CorporationInventors: Yutaka Murakami, Kiyotaka Kobayashi, Masayuki Orihashi
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Patent number: 7995662Abstract: Various embodiments of the invention may use bitmaps to communicate channel quality index (CQI) information for multiple sub-channels in an orthogonal frequency division multiple access (OFDMA) wireless communications network. A base station may use bitmaps to report on whether the CQI information for each sub-channel has been under-reported or over-reported. A mobile station may use bitmaps to consolidate CQI information for multiple sub-channels into a single CQI set of parameters.Type: GrantFiled: September 14, 2007Date of Patent: August 9, 2011Assignee: Intel CorporationInventor: Rath Vannithamby
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Patent number: 7991043Abstract: A demodulator in a receiver includes a correlator (240) for de-spreading a spread-spectrum signal, and a decision module (250) for detecting a preamble and for synchronizing to data frames of the spread spectrum signal. The demodulator includes symbol timers (231 and 233) that allow the demodulator to correlate to two preamble symbols simultaneously, where the two preamble symbols occur one-half a symbol period apart. The correlator includes a correlator structure having taps that correct for any frequency offset of a carrier signal. The correlator correlates to each of the two preamble symbols a plurality of times through oversampling, where each correlation compensates for a different amount of frequency offset. By analyzing occurrence of peaks in magnitude of the correlations, the decision module detects the preamble and selects weights for the taps to de-spread data frames received after the preamble.Type: GrantFiled: June 17, 2008Date of Patent: August 2, 2011Assignee: Freescale Semiconductor, Inc.Inventor: Robert Mark Gorday
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Patent number: 7991041Abstract: Techniques for recovering a desired transmission in the presence of interfering transmissions are described. For iterative detection and cancellation, multiple groups of code channels are formed for a plurality of code channels for at least one sector. Processing is performed for the multiple groups of code channels in multiple iterations. For each iteration, data detection and signal cancellation are performed for the multiple groups of code channels in multiple stages, e.g., in a sequential order starting with the strongest group to the weakest group. Each stage of each iteration may perform data detection, signal reconstruction, and signal cancellation. Each stage of each iteration may also perform equalization, data detection, signal reconstruction, and signal cancellation.Type: GrantFiled: November 15, 2006Date of Patent: August 2, 2011Assignee: QUALCOMM, IncorporatedInventors: Byonghyo Shim, Farrokh Abrishamkar, Inyup Kang
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Patent number: 7986752Abstract: A method and system for detecting and decoding multiple signals. A low-complexity MIMO detector that combines sphere decoding and m-algorithm approaches, while accounting for the effect of channel condition on the decoding operation, is provided. Taking into account the channel condition effectively controls the size of the search tree, and consequently the search complexity, in an adaptive manner. The channel condition is exploited in the construction of the tree to manage the number of branches in the tree and to avoid undesirable growth.Type: GrantFiled: March 30, 2007Date of Patent: July 26, 2011Assignees: BCE Inc., University of WaterlooInventors: Hosein Nikopour-Deilami, Amir Keyvan Khandani, Aladdin Saleh
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Patent number: 7986725Abstract: A code phase signalling module arranged to provide code phase signalling to assist in signal acquisition of direct sequence spread spectrum signalling received by a receiver module from a transmitter module. The code phase signalling is arranged to be used by the receiver module to synchronise the phase of a synchronisation code provided from within the receiver module with the phase of a modulation code of the direct spread spectrum sequence signalling received by the receiver module. The synchronisation code sequence corresponds to the modulation code sequence. The code phase signalling module is arranged to provide code phase time signalling representing the offset time of the synchronisation code from a reference time. The reference time is associated with the time of transmission of a particular reference portion of the modulation code of the direct spread spectrum signaling.Type: GrantFiled: March 4, 2005Date of Patent: July 26, 2011Assignee: Nokia CorporationInventor: Kimmo Alanen
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Patent number: 7978751Abstract: The present invention provides a method and apparatus for adapting a current path delay estimate for path delay tracking. In order to determine the path delay an operating mode is selected and a set of hypothesized path delays are determined based on said operating mode. A metric for each hypothesized path delay is determined, and a current path delay estimate is adapted based on the computed metrics for the hypothesized path delays.Type: GrantFiled: March 20, 2008Date of Patent: July 12, 2011Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Karsten Brueninghaus, Oliver Klein, Jaroslaw Niewczas
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Patent number: 7978786Abstract: Disclosed is an apparatus and a method for actively adjusting the quantization interval of signals inputted to a decoder in a digital communication system. The apparatus includes a quantization level generator for measuring a dynamic range of received packet data and calculating a corresponding scale factor, and an input signal converter for scaling a received data signal according to the scale factor so as to output a quantized signal.Type: GrantFiled: March 29, 2007Date of Patent: July 12, 2011Assignee: Samsung Electronics Co., LtdInventor: Tae-Ik Song
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Patent number: 7965761Abstract: Carrier Interferometry (CI) provides wideband transmission protocols with frequency-band selectivity to improve interference rejection, reduce multipath fading, and enable operation across non-continuous frequency bands. Direct-sequence protocols, such as DS-CDMA, are provided with CI to greatly improve performance and reduce transceiver complexity. CI introduces families of orthogonal polyphase codes that can be used for channel coding, spreading, and/or multiple access. Unlike conventional DS-CDMA, CI coding is not necessary for energy spreading because a set of CI carriers has an inherently wide aggregate bandwidth. Instead, CI codes are used for channelization, energy smoothing in the frequency domain, and interference suppression. CI-based ultra-wideband protocols are implemented via frequency-domain processing to reduce synchronization problems, transceiver complexity, and poor multipath performance of conventional ultra-wideband systems.Type: GrantFiled: December 5, 2008Date of Patent: June 21, 2011Assignee: Lot 41 Acquisition Foundation, LLCInventor: Steve Shattil
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Patent number: 7961777Abstract: A signal processing apparatus configured to process a signal transmitted via a transmission path where a waveform represented by a signal value of a particular symbol is stationarily distorted in accordance with values of symbols transmitted prior to the particular symbol, including the following elements: a receiving unit configured to receive a test signal which is the signal including symbols set to predetermined values via the transmission path; an obtaining unit configured to obtain the signal value of the particular symbol from the test signal received by the receiving unit; and a characteristic computing unit configured to compute a characteristic of distortion of the waveform represented by the signal value of the particular symbol in accordance with the values of the symbols transmitted prior to the particular symbol on the basis of waveforms represented by signal values obtained by the obtaining unit from a plurality of test signals.Type: GrantFiled: November 29, 2007Date of Patent: June 14, 2011Assignee: Sony CorporationInventors: Takashi Nakanishi, Shunsuke Mochizuki, Masahiro Yoshioka, Ryosuke Araki, Hiroto Kimura, Seiji Wada, Hiroshi Ichiki, Tetsujiro Kondo
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Patent number: 7957458Abstract: A jitter measuring apparatus measures timing jitter of a signal-under-test. The jitter measuring apparatus includes a pulse generator for outputting a pulse signal of a predetermined pulse width for an edge of the signal-under-test, and a jitter measuring sub-unit for extracting the timing jitter on the basis of a duty ratio of each cycle of the signal output by the pulse generator.Type: GrantFiled: March 17, 2006Date of Patent: June 7, 2011Assignee: Advantest CorporationInventors: Kiyotaka Ichiyama, Masahiro Ishida, Takahiro Yamaguchi, Mani Soma
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Patent number: 7953177Abstract: A radio communication apparatus that is capable of switching modulation schemes. The radio communication apparatus includes a QPSK modulation signal generator, a QAM modulation signal generator, a transmission radio, and a common transmission power amplifier. The QPSK modulation signal generator modulates transmission data by a QPSK modulation scheme and outputs a QPSK modulation signal. The QAM modulation signal generator modulates transmission data by a QAM scheme and outputs a QAM modulation signal. The transmission radio receives the QPSK modulation signal or the QAM modulation signal and outputs a transmission signal, which is amplified by the common transmission power amplifier.Type: GrantFiled: April 9, 2010Date of Patent: May 31, 2011Assignee: Panasonic CorporationInventors: Yutaka Murakami, Shinichiro Takabayashi, Katsuaki Abe, Masayuki Orihashi, Akihiko Matsuoka
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Patent number: 7944969Abstract: A method and system for sampling video data uses re-sampling filters having lengths optimized relative to a quantization parameter of video processing. The method uses modeling of an optimal length of the re-sampling filter as a function of the quantization parameter to derive empirical formulas and a look up table for optimal lengths of re-sampling filters. The resulting re-sampling filters are selectively adapted for sampling video data having different bit rates.Type: GrantFiled: January 5, 2007Date of Patent: May 17, 2011Assignee: Freescale Semiconductor, Inc.Inventor: Yong Yan
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Patent number: 7940855Abstract: A digital broadcast transmitter and a method of processing a DTV signal in the digital broadcast transmitter are disclosed. The digital broadcast transmitter includes a pre-processor, a first multiplexer, a post-processor, and a second multiplexer. The pre-processor includes a first interleaver, a group formatter, and a packer formatter. The first interleaver interleaves symbols corresponding to mobile service data. The group formatter maps data corresponding to the interleaved symbols into at least one region of a data group and adds place holders for main service data and non-systematic RS parity data to the data group. The packet formatter removes the place holders for the main service data and the non-systematic RS parity data, and generates mobile service data packets having data in the data group in which the place holders for the main service data and the non-systematic RS parity data are removed.Type: GrantFiled: July 6, 2007Date of Patent: May 10, 2011Assignee: LG Electronics Inc.Inventors: Jong Moon Kim, In Hwan Choi, Kook Yeon Kwak, Byoung Gill Kim, Won Gyu Song, Jin Woo Kim, Hyoung Gon Lee
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Patent number: 7936812Abstract: Decision feedback equalization (DFE) circuits are disclosed for use with fractional-rate clocks of lesser frequency than the data signal. For example, a one-half-rate clocked DFE circuit utilizes two input data paths, which are respectively activated on rising and falling edges of an associated half-rate clock. Each of the input data paths has a pair of comparators with differing reference voltage levels. The comparators in each input data path output to a multiplexer, which picks between the two comparator outputs depending on the logic level of the previously received bit. The output of each input data path is sent as a control input to the multiplexer of the other data path. Thus, the results from previously-detected bits affect which comparator's output is passed to the output of the circuit, even though the synchronizing clock is half the frequency of the data. A quarter-rate DFE circuit is also disclosed which operates similarly.Type: GrantFiled: July 2, 2007Date of Patent: May 3, 2011Assignee: Micron Technology, Inc.Inventor: Timothy M. Hollis
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Patent number: 7936844Abstract: A channel estimation apparatus and the method thereof are disclosed. The channel estimation apparatus includes a time-domain-axis channel estimation unit, a peak-detection module, a first-shift unit, a frequency-domain-axis channel estimation unit and an optimal shift searching module. The time-domain-axis channel estimation unit is used for performing the channel estimation in the time domain so as to obtain initial channel frequency responses by estimating. The peak-detection module is used for outputting a peak information. The shift-optimal-searching module decides the optimal shift information according to the peak information, a feedback signal and entire channel frequency responses. The first-shift unit is used for adjusting the positions of the initial channel frequency responses in the time domain according to the optimal shift information.Type: GrantFiled: September 13, 2007Date of Patent: May 3, 2011Assignee: Sunplus Technology Co., Ltd.Inventors: Kuo-Li Lai, Ching-Piao Hung
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Patent number: 7936856Abstract: A synchronization circuit includes a correlator, an energy calculator, a post-processing unit, and a decision device. The correlator correlates a received sequence r(t) with a local sequence c(i) to obtain a correlation result h(t). The energy calculator calculates an energy function of the correlation result h(t), and filters the energy function of the correlation result by a channel impulse response wc(l) to obtain a filtered energy function e(t), where l is the index of the channel impulse response. The post-processing unit applies weighting function wa(t) to the filtered energy e(t) to obtain a weighted energy function e?(t), wherein the weighting function wa(t) weights a central portion of the filtered energy function e(t). The decision device selects a maximum energy value from the weighted energy function e?(t), and the time index t with maximum energy value is the time shift of the received sequence and the local sequence.Type: GrantFiled: September 13, 2007Date of Patent: May 3, 2011Assignee: Mediatek Inc.Inventors: Chun-Ming Kuo, I-Ping Chang, Chi-Yeh Yu, Shih-Kung Chang, Ho-Chi Huang
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Patent number: 7933370Abstract: A Multiple Input Multiple Output (MIMO) receiver and a signal detection method thereof are provided. Since no square root calculation needs to be performed when a calculation for detecting a transmission signal is performed using a Zero Forcing-Sorted QR Decomposition (ZF-SQRD) algorithm and a Minimum Mean Square Error-Sorted QR Decomposition (MMSE-SQRD) algorithm, the complexity of a calculation for detecting a transmission signal under a MIMO channel environment can be reduced.Type: GrantFiled: March 18, 2008Date of Patent: April 26, 2011Assignee: Samsung Electronics Co., Ltd.Inventors: Jeong-Taek Lee, Eoi-Young Choi
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Patent number: 7929594Abstract: A total power consumption of a radio communication apparatus is reduced, the radio communication apparatus including a semiconductor integrated circuit (high-frequency IC) which has a clock generation circuit which generates a reference clock signal for use in modulating a transmit signal and demodulating a received signal. The clock generation circuit is provided with a voltage-controlled oscillator circuit (VCXO) which oscillates, when a quartz oscillator is connected thereto, at a frequency dependent on a natural frequency of the quartz oscillator and a control voltage applied thereto. The voltage-controlled oscillator circuit is configured such that a result obtained by converting, in an internal D/A converter circuit, digital frequency control information supplied from the baseband circuit is applied as the control voltage to the voltage-controlled oscillator circuit and such that the voltage-controlled oscillator circuit oscillates at a frequency corresponding to the control voltage.Type: GrantFiled: May 9, 2006Date of Patent: April 19, 2011Assignee: Renesas Electronics CorporationInventors: Takao Okazaki, Satoru Fukuchi
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Patent number: 7924946Abstract: By shifting an RF signal to IQ components of a modulated baseband signal directly, the zero-IF technology and IQ interface are applied in ATSC, NTSC, and PAL systems, and VSB and SSB modulations. The mathematic calculations are based on Fourier transform for shifting the RF signal and for recovering a baseband signal from the modulated baseband signal.Type: GrantFiled: September 12, 2007Date of Patent: April 12, 2011Assignee: Fitipower Integrated Technology, Inc.Inventor: Yum-Cheng Chang