Quadrature Amplitude Modulation Patents (Class 375/261)
  • Patent number: 8879667
    Abstract: Embodiments of the present disclosure describe methods, apparatuses, and systems related to use of interphase/quadrature component layer shifting in open loop multiple-input, multiple-output communications. Other embodiments may be described and/or claimed.
    Type: Grant
    Filed: November 30, 2011
    Date of Patent: November 4, 2014
    Assignee: Intel Corporation
    Inventors: Xiaogang Chen, Yuan Zhu, Jong-Kae Fwu, Qinghua Li
  • Patent number: 8879653
    Abstract: This invention concerns soft-decision demapping of Quadrature Amplitude Modulation (QAM) signals to enable soft-decision channel decoding in a communications system. In a first aspect the invention is a method for performing the soft-decision demapping of Quadrature Amplitude Modulation (QAM) signals to enable soft-decision channel decoding in a communications system. The method comprises the steps of Extracting baseband signals from both I-and-Q channels. Sampling the baseband signals to extract a stream of complex numbers. Converting the stream of complex numbers to frequency domain vectors with components for each subcarrier frequency. Approximating bit log-likelihood ratios for each symbol directly from the real and imaginary parts of the corresponding frequency vector, without equalization by the estimated channel. And, soft-decoding of the channel codes using the approximated log-likelihood ratios.
    Type: Grant
    Filed: August 6, 2010
    Date of Patent: November 4, 2014
    Assignee: Nitero Pty Limited
    Inventor: Yunxin Li
  • Patent number: 8873658
    Abstract: An apparatus for receiving signals includes a receiver for receiving a time domain signal from a transmitter, wherein at least one first information bit is mapped, resulting in at least one first mapped symbol; at least one second information bit is mapped, resulting in at least one second mapped symbol; the at least one second mapped symbol is multiplied by at least one third information bit; and the time domain signal is generated from the at least one first mapped symbol and the at least one second mapped symbol.
    Type: Grant
    Filed: December 21, 2012
    Date of Patent: October 28, 2014
    Assignee: LG Electronics Inc.
    Inventors: Yeong Hyeon Kwon, Seung Hee Han, Min Seok Noh, Young Woo Yun
  • Patent number: 8867662
    Abstract: Techniques for rotating and transmitting multidimensional constellations are disclosed. A method for rotating a multidimensional constellation may include constructing a first rotation matrix, constructing a second rotation matrix, applying orthogonality constraints to the first and second rotation matrices; selecting an optimizing rotation matrix from the first and second rotation matrices; and rotating the multidimensional constellation using the optimizing rotation matrix. Constructing the first rotation matrix and second rotation matrices may include constructing a first column that includes first matrix elements based on the number of axes in the multidimensional constellation, and additional columns that include permutations of the first matrix elements.
    Type: Grant
    Filed: March 27, 2009
    Date of Patent: October 21, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Rabih Chrabieh, Ozgur Dural
  • Patent number: 8867656
    Abstract: When a determination is made that communication by an SM scheme is suitable, a setting unit performs switching from a communication level by an STC scheme to the communication level by the SM scheme, between the communication level at a first level of MCS by the space-time coding scheme and the communication level at a second level of MCS by the SM scheme. When a determination is made that communication by the SM scheme is unsuitable, the setting unit performs switching from the communication level by the STC scheme to the communication level by the spatial multiplexing scheme, between the communication level at a third level of MCS, which is higher than the first level, by the space-time coding scheme and a fourth level of the modulation scheme and the coding rate, which is higher than the second level, by the SM scheme.
    Type: Grant
    Filed: December 14, 2011
    Date of Patent: October 21, 2014
    Assignee: KYOCERA Corporation
    Inventor: Takeo Miyata
  • Patent number: 8867659
    Abstract: A communications device includes a transmitter, a transmission processing device, a receiver, and a reception processing device. The transmission processing device assigns signal-space points within an I/Q signal space to digital signals, which include data values. The reception processing device assigns data values to signal-space points. The transmitter generates a transmission signal from signal-space points to be transmitted. The receiver determines received signal-space points from a received signal. The individual transmitted and received signal-space points provide in each case a smaller spacing distance from adjacent signal-space points than from the origin of the signal space.
    Type: Grant
    Filed: June 28, 2010
    Date of Patent: October 21, 2014
    Assignee: Rohde & Schwarz GmbH & Co. KG
    Inventor: Detlev Liebl
  • Patent number: 8867644
    Abstract: A receiver, in particular a VAMOS receiver, is provided. The receiver is adapted to split the complex-valued baseband signal into its real and imaginary parts. The two branch system thus created is modeled as a real-valued Multiple Input Multiple Output, MIMO, system. The receiver is further adapted to use correlations of the noise, both in time and between branches of a channel to suppress the noise for multi-users in the same channel. In accordance with one embodiment the receiver is adapted to take into account the known symmetries present in a symbol constellation when more than one user exists in the same channel. This is for example the case in adaptive symbol constellation such as an adaptive alpha-QPSK constellation. Using the receiver in accordance with the above can provide the same performance as a joint detection receiver in the presence of Gaussian white noise, while giving better interference suppression than either SAIC or joint detection in the presence of GMSK modulated interference.
    Type: Grant
    Filed: June 24, 2009
    Date of Patent: October 21, 2014
    Assignee: Telefonaktiebolaget L M Ericsson (Publ)
    Inventor: Miguel Lopez
  • Patent number: 8866660
    Abstract: A system and method for mitigating Analog to Digital (A/D) clipping is disclosed. The mean and variance of analog input data are tracked and the bits of A/D are dynamically reassigned to keep the input signal within their range. The quantization levels of A/D are dynamically re-mapped to avoid changes in sensitivity of sensor system. The method is based on random walk statistic and keeps the sensitivity of the sensor system constant. Also the system and method provides a way to mitigate A/D clipping that avoids changing the sensitivity by dynamically re-mapping the quantization levels of the A/D, keeping the sensitivity of the system constant.
    Type: Grant
    Filed: April 23, 2013
    Date of Patent: October 21, 2014
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventors: Edward C. Real, Joanne K. Como
  • Patent number: 8867645
    Abstract: The proposed invention teaches basic principles of “orthonormal transform” to be used to convert a set of discrete samples into a set of coefficient real samples that is contained in a finite field. The number of real values in each coefficient samples is finite and coded for transmission using digital modulation. It also teaches that handling of multi-path fading of Doppler effects implies that the Bit Error Rate (BER) performance as a function of Bit Energy/Noise (Eb/N0) is close to the performance of Additive White Gaussian Noise (AWGN) channel. The effect of impairments is minimized and only the effect of thermal noise (AWGN) is maintained. The inventive apparatus is simple and maintains constant end-to-end response time, sustainable effective data rate and bounded error performance which is conducive to specify a Quality of Service (QoS) which is useful for service provisioning.
    Type: Grant
    Filed: December 5, 2012
    Date of Patent: October 21, 2014
    Assignee: Digital Compression Technology, LLC
    Inventors: Dhadesugoor Vaman, Siew T. Koav
  • Patent number: 8861627
    Abstract: In one embodiment, a circuit comprises a first pair of elements, a second pair of elements, a combiner, and a signal output. Each element in the first and second pair of elements comprises an amplitude-control input for receiving an amplitude-control bit, a phase-control input for receiving a phase-control bit, a signal input for receiving an input signal, a modulator for producing an output signal based on the amplitude-control bit, the phase-control bit, and the input signal, and an signal output for transmitting the output signal to the combiner. The combiner combines the two output signals from the first and second pair of elements to produce an output signal for the circuit to be transmitted by the signal output of the circuit.
    Type: Grant
    Filed: July 15, 2009
    Date of Patent: October 14, 2014
    Assignee: Fujitsu Limited
    Inventors: Sorin P. Voinigescu, Alexander Tomkins, Magnus O. Wiklund, William Warren Walker
  • Patent number: 8861642
    Abstract: A method and an apparatus for mapping a quadrature amplitude modulation (QAM) symbol. The QAM symbol mapping apparatus includes a frequency checker, which checks frequencies of sub-carriers in an orthogonal frequency division multiplexing (OFDM) symbol; and a data categorizer, which maps data coded for error correction and uncoded data to the sub-carriers based on the checked frequencies, wherein the data categorizer maps a combination of the coded data and the uncoded data with respect to sub-carriers having frequencies lower than a reference frequency.
    Type: Grant
    Filed: September 14, 2012
    Date of Patent: October 14, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Chang-hyun Baik, Hyun-jung Ko, Jun-yeub Lee, Jun-seok Kang
  • Patent number: 8848764
    Abstract: The present invention proposes an LTE eNodeB receiver channel estimation technique that is referred to as reduced complexity minimum mean squared error (MMSE) technique for channel estimation. From the invention's assumptions, estimations and modified calculations, the present invention generates precise channel estimates of RS using the reduced complexity MMSE matrix and previously computed LS channel estimates HLS is as follows: (Formula I) which generates precise channel estimates of RS using the reduced complexity MMSE matrix and previously computed LS channel estimates. As a second aspect of the present invention, it is desired that the SNR be estimated within ?3 dB of the actual channel SNR. As a third aspect of the invention, an adaptive method of data channel interpolation from RS channel is being proposed in this invention.
    Type: Grant
    Filed: November 13, 2009
    Date of Patent: September 30, 2014
    Assignee: BlackBerry Limited
    Inventors: John P. Panicker, Gary Boudreau, Michael Petras, Ed Illidge
  • Patent number: 8848683
    Abstract: In a method, modulator, transmitter and receiver, the modulator of data signals to be transmitted simultaneously to at least two receiving mobile stations in the same transmission time slot is adapted to select rotational angle of a QPSK transmission modulation, such as a hybrid ?-QPSK modulation used to modulate the data signals to the at least two mobile stations in response to the capabilities of the mobile stations that share the same transmission slot.
    Type: Grant
    Filed: November 11, 2008
    Date of Patent: September 30, 2014
    Assignee: Telefonaktiebolaget LM Ericsson (Publ)
    Inventors: Miguel Lopez, Stefan Eriksson
  • Patent number: 8842753
    Abstract: Techniques are provided for generating an estimate of the phase and magnitude imbalance of a receiver in a communication device. For each of a plurality of symbols in a signal received by the communication device, a plurality of tones that make up the symbol are obtained. For each of the plurality of symbols, each tone is multiplied by its respective mirror tone to produce a plurality of mirror tone multiplication results, and the plurality of the mirror tone multiplication results are summed over tones to produce a sum of multiplication results for each symbol. The total power of all tones for each symbol is obtained to produce a tone power quantity for each symbol. The estimate of the phase and magnitude imbalance in the received signal is generated based on the sum of the multiplication results for each of the plurality of symbols and the tone power quantity for each of the plurality of symbols.
    Type: Grant
    Filed: June 27, 2011
    Date of Patent: September 23, 2014
    Assignee: Cisco Technology, Inc.
    Inventors: Mohammad Janani, Ahmadreza Hedayat
  • Patent number: 8842761
    Abstract: Communication systems are described that use geometrically shaped constellations that have increased capacity compared to conventional constellations operating within a similar SNR band. In several embodiments, the geometrically shaped is optimized based upon a capacity measure such as parallel decoding capacity or joint capacity. In many embodiments, a capacity optimized geometrically shaped constellation can be used to replace a conventional constellation as part of a firmware upgrade to transmitters and receivers within a communication system. In a number of embodiments, the geometrically shaped constellation is optimized for an Additive White Gaussian Noise channel or a fading channel. In numerous embodiments, the communication uses adaptive rate encoding and the location of points within the geometrically shaped constellation changes as the code rate changes.
    Type: Grant
    Filed: September 14, 2012
    Date of Patent: September 23, 2014
    Assignee: Constellation Designs, Inc.
    Inventors: Maged F. Barsoum, Christopher R. Jones
  • Patent number: 8842747
    Abstract: The present invention provides, inter alia, a method for digital communication between at least one first node and a plurality of second nodes which are connected with the first node by a field bus. According to one aspect a highly effective presence detection scheme for checking the operational status of the second nodes by the first node is integratively combined with a message query for providing an effective first mode of digital communication between said nodes, which may be used very effectively to provide a communication channel which is independent of message priorities. According to another aspect the first mode of digital communication is combined with a second mode of digital communication which is based on message priorities of digital messages to be send by a respective second node to the first node. To advantage, a bitwise bus access arbitration mechanism may be used for implementing those modes of communication.
    Type: Grant
    Filed: October 7, 2011
    Date of Patent: September 23, 2014
    Assignee: Honeywell International Inc.
    Inventor: Hubert Willms
  • Publication number: 20140269959
    Abstract: A method of operating a base station in a wireless communication system supporting Frequency-Quadrature Amplitude Modulation (FQAM) and Multi-Tone FQAM (MT-FQAM) is provided. The method includes determining a modulation scheme of data to be transmitted, and modulating the data according to the determined modulation scheme, wherein if at least one resource block is included in the data and if the at least one resource block is mapped to at least one tone in a distributed manner, the MT-FQAM scheme is selected, or if one resource block is included in the data and if the one resource block is mapped to at least one tone in a continuous manner, the FQAM scheme is selected, or if multiple resource blocks are included in the data and if the multiple resource blocks are mapped to at least one tone in a continuous manner, the MT-FQAM scheme is selected.
    Type: Application
    Filed: March 13, 2014
    Publication date: September 18, 2014
    Applicant: Samsung Electronics Co., Ltd.
    Inventors: Chi-Woo LIM, Min SAGONG, Sung-Nam HONG, Hyun-Kyu YU, Kyung-Whoon CHEUN
  • Publication number: 20140269960
    Abstract: D-dimensional vectors that each have D real-valued symbols as elements are converted into D-dimensional rotated vectors that each have D real symbols as elements. The conversion is performed by multiplying each of the D-dimensional vectors by a D×D orthogonal matrix. A complex symbol sequence including NC=NS/2 complex symbols is generated from NS real symbols. The complex symbol sequence is generated such that the distance between any two of the D real symbols of each of the D-dimensional rotated vectors is NC/D complex symbols or NC/D?1 complex symbols, or such that the distance between any two of the D real symbols of each of the D-dimensional rotated vectors, except for part of the D-dimensional rotated vectors, is NC/D complex symbols or NC/D?1 complex symbols.
    Type: Application
    Filed: November 7, 2012
    Publication date: September 18, 2014
    Inventor: Mihail Petrov
  • Patent number: 8837618
    Abstract: Information bits are encoded according to a low density parity check code with code rate 7/15 and a codeword length of 16200. The resulting codeword bits are bit-interleaved and the interleaved bits are demultiplexed into 8 sequences of bits. The 8 sequences of bits are permuted according to a predetermined permutation rule: v0=b2, v1=b6, v2=b0, v3=b1, v4=b4, v5=b5, v6=b3, v7=b7.
    Type: Grant
    Filed: June 14, 2012
    Date of Patent: September 16, 2014
    Assignee: Panasonic Corporation
    Inventor: Mihail Petrov
  • Publication number: 20140254441
    Abstract: The present invention helps eliminate ingress noise addition (i.e., the “noise funneling effect” for an HFC coaxial plant). A system according to various aspects of the present invention comprises a switch that includes: (i) a first state for allowing passage of a signal therethrough; and (ii) a second state for preventing passage of the signal therethrough. The system further includes a detection circuit in communication with the switch. The detection circuit is configured to: (i) detect whether the signal includes an amplitude of at least a predetermined level; (ii) operate the switch to the first state if the amplitude of the signal is at least the predetermined level; and (iii) operate the switch to the second state if the amplitude of the signal is less than the predetermined level, wherein operation of the switch to the second state is delayed by a predetermined period of time.
    Type: Application
    Filed: May 20, 2014
    Publication date: September 11, 2014
    Applicant: PCT INTERNATIONAL, INC.
    Inventor: Jon-En Wang
  • Publication number: 20140254698
    Abstract: A software defined radio is disclosed. The software defined radio may utilize a method for encoding a bit stream into non-periodic spiral-based symbol waveforms for transmission and reception. The method includes transmitting a signal constructed from one or more non-periodic modulation sets residing on a memory system of the software defined radio, where each modulation set corresponds to a symbol alphabet and provides non-periodic symbol waveforms corresponding to symbol bit sequences segmented by a microprocessor according to alphabet size. The method also includes receiving the signal constructed from one or more spiral modulation sets, wherein the signal from one or more spiral modulation sets are filtered and then fed to an analog to digital converter, where the signal constructed from the one or more spiral modulation sets is digitized and are fed to the microprocessor. A non-transitory computer storage media may also execute the method.
    Type: Application
    Filed: March 7, 2014
    Publication date: September 11, 2014
    Applicant: Astrapi Corporation
    Inventors: Nigel JONES, Jerrold Prothero
  • Patent number: 8831123
    Abstract: Provided is a soft demapping apparatus that may detect a log likelihood ratio (LLR) value of a quadrature amplitude modulation (QAM) signal, using a shifted table scheme, may designate a sub-region of the QAM signal corresponding to bit information that is obtained by decoding the LLR value, and may calculate an LLR value of other bit information included in the designated sub-region.
    Type: Grant
    Filed: May 30, 2012
    Date of Patent: September 9, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Ki Taek Bae, Kyeong Yeon Kim, Ho Yang
  • Patent number: 8827159
    Abstract: The present invention relates to a two-dimensional array code. The two-dimensional array code comprises a plurality of equal-height code characters arranged into a two-dimensional array, wherein each of the code characters corresponds to a bit group representing information, and the adjacent code characters in the row direction of the two-dimensional array have equal center distances; and a locating mechanism, for defining size and/or direction of the two-dimensional array arranged by the code characters. The present invention greatly reduces the cost for issuing a two-dimensional code, and significantly increases the user convenience. This two-dimensional array code has high compatibility for user mobile terminals. In addition, the entire system apparently improves its safety and stability, and is suitable for the present network application environment.
    Type: Grant
    Filed: April 12, 2010
    Date of Patent: September 9, 2014
    Assignees: Gmedia Technology (Beijing) Co., Ltd., Beijing Sigone Venture Limited
    Inventors: Wei Shen, Jia Bing Liu, Xiao Wei Guo, Li Duo Zhong
  • Patent number: 8830107
    Abstract: A frequency translating analog-to-digital converter for receiving an analog band-pass signal is described. The analog-to-digital converter comprises an adder/input block for receiving the analog band-pass signal and an analog band-pass feedback signal, thereby forming an analog band-pass error signal. The analog-to-digital converter has at least one analog mixer for mixing and down converting the analog band-pass error signal and thus generating a down-converted analog error signal and at least one quantization path for generating at least one digital signal.
    Type: Grant
    Filed: April 16, 2013
    Date of Patent: September 9, 2014
    Inventor: Udo Karthaus
  • Patent number: 8831124
    Abstract: A transmitter may comprise a symbol mapper circuit and operate in at least two modes. In a first mode, the number of symbols output by the mapper circuit per orthogonal frequency division multiplexing (OFDM) symbol transmitted by said transmitter may be greater than the number of data-carrying subcarriers used to transmit the OFDM symbol. In a second mode, the number of symbols output by said mapper circuit per orthogonal frequency division multiplexing (OFDM) symbol transmitted by said transmitter is less than or equal to the number of data-carrying subcarriers used to transmit said OFDM symbol. The symbols output by the symbol mapper circuit may be N-QAM symbols. While the circuitry operates in the first mode, the symbols output by the mapper may be converted to physical subcarrier values via filtering and decimation prior to being input to an IFFT circuit.
    Type: Grant
    Filed: June 19, 2013
    Date of Patent: September 9, 2014
    Assignee: MagnaCom Ltd.
    Inventors: Amir Eliaz, Ilan Reuven
  • Patent number: 8831117
    Abstract: Method and apparatus for signal processing to minimize the peak to average power ratio of an Orthogonal Frequency Division Multiplexing (“OFDM”) or Orthogonal Frequency Division Multiple Access (“OFDMA”) signal with bounded error vector magnitude for an integrated circuit are described. An Active Constellation Extension (“ACE”) iteration, using a constellation points adjustment module, is performed. Symbols outside of a bounded region after the ACE iteration are identified. The bounded region is determined responsive to an error vector magnitude target. The symbols identified are translated to the bounded region.
    Type: Grant
    Filed: April 27, 2009
    Date of Patent: September 9, 2014
    Assignee: Xilinx, Inc.
    Inventors: Raghavendar M. Rao, Christopher H. Dick
  • Patent number: 8831129
    Abstract: A method, an apparatus, and a system for transmitting information bits, where the method for transmitting information bits includes: dividing the information bits to be transmitted into at least two groups; encoding the information bits to be transmitted in each group; modulating the coded bits obtained by the encoding to obtain modulation symbols, in which each modulation symbol is obtained by using the modulation of the coded bits in the same group; and mapping and transmitting the modulation symbols. In this way, the receiving end easily reduces the algorithm complexity, thereby ensuring the performance of the receiving end.
    Type: Grant
    Filed: May 10, 2011
    Date of Patent: September 9, 2014
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Xiaofeng Chen, Yongxia Lv, Yan Cheng
  • Publication number: 20140233664
    Abstract: A method for performing orthogonal frequency division multiplexing (OFDM)/offset quantization amplitude modulation (OQAM) includes obtaining a data burst. The method includes performing weighted circularly convolved filtering modulation on the data burst to produce an output signal. The method further includes a first wireless device transmitting the output signal to a second wireless device. The second wireless device receives an input signal from the first wireless device, and the second wireless devices performs weighted circularly convolved demodulation filtering on the input signal to produce the data burst.
    Type: Application
    Filed: September 24, 2013
    Publication date: August 21, 2014
    Applicant: FutureWei Technologies, Inc.
    Inventors: Mohammad-Javad Abdoli, Jia Ming, Jianglei Ma
  • Patent number: 8811509
    Abstract: Forward error correction (FEC) m-bit symbol modulation. Any desired FEC, error correction code (ECC), and/or combination thereof generates coded bits for combination with either uncoded bits, separately generated coded bits, and/or combination thereof to generate a number of symbols that undergo mapping to a constellation whose respective constellation points have a mapping characterized by a maximum minimum intra-Euclidean distance between the respective constellation points thereby generating a sequence of discrete-valued modulation symbols. The sequence of discrete-valued modulation symbols may then undergo modulation of any of a number of different operations (e.g., digital to analog conversion [e.g., digital to analog converter (DAC)], scaling, frequency shifting, filtering, etc.) to generate a continuous time signal for transmission via a communication channel. Such a device operative to perform including such functionality, circuitry, capability, etc.
    Type: Grant
    Filed: September 22, 2011
    Date of Patent: August 19, 2014
    Assignee: Broadcom Corporation
    Inventors: Ba-Zhong Shen, Avi Kliger
  • Patent number: 8811460
    Abstract: A burst processing modem. Implementations may include a receive side including a channelizer adapted to process a plurality of channels and write a plurality of frames to a receive RAM array. A receive frame state machine may be adapted to generate a timing signal using a burst time plan for the plurality of frames. A demodulator may be coupled with the receive RAM array and adapted to read from the receive RAM array only the one or more bursts from the plurality of frames indicated by the timing signal. A transmit side may include a modulator coupled with a transmit frame state machine, with a transmit RAM array, and a combiner bank. The combiner bank may read the modulated plurality of channels from the transmit RAM array and assemble a plurality of frames using a timing signal generated from a burst time plan by the transmit frame state machine.
    Type: Grant
    Filed: January 31, 2012
    Date of Patent: August 19, 2014
    Assignee: Comtech EF Data Corp.
    Inventors: Richard Hollingsworth Cannon, John Scott Crockett, Cris M. Mamaril, Mark Dale
  • Patent number: 8811973
    Abstract: Techniques for managing peak-to-average power ratio (PAPR) for multi-carrier modulation in wireless communication systems. Different terminals in a multiple-access system may have different required transmit powers. The number of carriers to allocate to each terminal is made dependent on its required transmit power. Terminals with higher required transmit powers may be allocated fewer carriers (associated with smaller PAPR) to allow the power amplifier to operate at higher power levels. Terminals with lower required transmit powers may be allocated more carriers (associated with higher PAPR) since the power amplifier is operated at lower power levels. The specific carriers to assign to the terminals may also be determined by their transmit power levels to reduce out-of-band emissions. Terminals with higher required transmit powers may be assigned with carriers near the middle of the operating band, and terminals with lower required transmit powers may be assigned with carriers near the band edges.
    Type: Grant
    Filed: July 10, 2008
    Date of Patent: August 19, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Rajiv Vijayan, Avneesh Agrawal, Sanjay Jha
  • Publication number: 20140226738
    Abstract: According to some embodiments, a receiving device: receives a radio frequency (RF) signal from a transmitting device over a wireless channel; performs a channel estimation of the wireless channel based on the RF signal; obtains a direct current (DC) bin measurement based on the channel estimation; determines a direct current (DC) offset correction based on the DC bin measurement; and sending the DC offset correction to the transmitting device via a local transmitter. The transmitting device: receives the DC offset correction information from the receiving device over a first wireless channel; receives data to be transmitted to the receiving device, where the DC offset correction information describing the DC offset correction; applies the DC offset correction to a transient signal that is based on the data; converts the transient signal to an RF signal; and transmits the RF signal to the receiving device over a second wireless channel.
    Type: Application
    Filed: February 12, 2014
    Publication date: August 14, 2014
    Applicant: Aviat U.S., Inc.
    Inventors: Sreco Plevel, Samo Vehovc
  • Patent number: 8804605
    Abstract: Systems and methods are disclosed for feeder link configurations to layered modulation. One feeder link system employs feeder link spot beam to antennas in distinct coverage areas to enable frequency reuse. Another system employs narrow beam width feeder link antenna to illuminate individual satellites also enabling frequency reuse. Yet another system uses layered modulation in the feeder link. Another feeder link system employs a higher order synchronous modulation for the satellite feeder link than is used in the layered modulation downlink signals.
    Type: Grant
    Filed: August 31, 2012
    Date of Patent: August 12, 2014
    Assignee: The DIRECTV Group, Inc.
    Inventors: Paul R. Anderson, Joseph Santoru, Ernest C. Chen
  • Patent number: 8804861
    Abstract: A method and apparatus for multicarrier transmission of a signal representing a source signal. The source signal includes symbols including a set of subcarriers, transmitted simultaneously and having pilot subcarriers intended for at least one processing operation for assisting and/or improving decoding in at least one receiver, and data subcarriers, the location in time-frequency space and a reference value of the pilot subcarriers being known to the at least one receiver. The method of transmission includes: a phase of modifying, for a given symbol, the reference value of at least one subset of the pilot subcarriers, by correction data configured to correct phase and/or amplitude for each of the pilot subcarriers of the subset, so as to minimize peak-to-average power ratio, the correction data taking at least three distinct values, a transition between the values of two successive pilot subcarriers of the subset on a frequency axis being constant.
    Type: Grant
    Filed: May 4, 2010
    Date of Patent: August 12, 2014
    Assignees: Institut National des Sciences Appliquees de Rennes, Centre National de la Recherche Scientifique
    Inventors: Jean-Francois Helard, Yves Louet, Irene Masinjara Mahafeno
  • Patent number: 8798200
    Abstract: The present invention provides a constellation mapping method, and the method includes: flipping a plurality of bits in each modulation symbol unit to be mapped in part of or all of modulation symbol units to be mapped of a bit sequence to be mapped; and mapping each flipped modulation symbol unit to be mapped as a modulation symbol in a constellation. By means of the present invention, the phenomenon that consecutive bits have the same reliability can be effectively avoided by changing unevenness of reliability distribution of the consecutive bits, and at the same time, the link performance can be improved.
    Type: Grant
    Filed: July 3, 2009
    Date of Patent: August 5, 2014
    Assignee: ZTE Corporation
    Inventors: Jin Xu, Jun Xu, Zhifeng Yuan, Qianzi Xu, Xianwei Gong, Bo Sun, Huiying Fang
  • Patent number: 8798177
    Abstract: Digital IQ imbalance estimation and compensation is facilitated by shaping the frequency response of receiver branches. In particular, in a multi-carrier receiver, the frequency response of signal processing elements in at least one receiver branch is set to not fully attenuate received signals in a frequency band of interest. The frequency band of interest is greater than the carrier bandwidth of the received signal processed by that receiver branch. In some embodiments, the received signal is not attenuated, and adjacent interfering signals are partially attenuated. This allows information regarding the interfering signals to appear in an IQ imbalance-induced, inter-carrier image of the signals in anther receiver branch, facilitating digital estimation and compensation of IQ imbalance.
    Type: Grant
    Filed: May 2, 2011
    Date of Patent: August 5, 2014
    Assignee: Telefonaktiebolaget L M Ericsson (Publ)
    Inventors: Chester Park, Lars Sundström, Jim Svensson
  • Patent number: 8798198
    Abstract: A calibration system may be provided for calibrating wireless communications circuitry in an electronic device during manufacturing. The calibration system may include data acquisition equipment for receiving an amplitude-modulated calibration signal from the electronic device. The calibration system may include calibration computing equipment for extracting pre-distortion coefficients from the amplitude-modulated calibration signal. The calibration computing equipment may be configured to detect a bulk phase drift in the amplitude-modulated calibration signal. The calibration computing equipment may be configured to remove the bulk phase drift from the amplitude-modulated calibration signal. The wireless communications circuitry may include a power amplifier that distorts a signal generated by the wireless communications circuitry. The wireless communications circuitry may include a pre-distortion compensator for countering the distortion.
    Type: Grant
    Filed: August 31, 2011
    Date of Patent: August 5, 2014
    Assignee: Apple Inc.
    Inventor: Gary Lang Do
  • Patent number: 8792574
    Abstract: In a receiver transparent Q-mode, i.e., a Q-mode that is only implemented by a transmitter, the receiver is unaware of the Q-mode state of the transmitter. In this type of Q-mode configuration, the transmitter could enter and exit Q-mode as desired while the receiver, could, for example, continue to function as if operating normally, such as in “showtime.” Through this approach, it is not necessary for the receiver to detect the transmitter's entry and exit of Q-mode.
    Type: Grant
    Filed: December 4, 2012
    Date of Patent: July 29, 2014
    Assignee: TQ Detla, LLC
    Inventors: Marcos C. Tzannes, Arnon Friedmann
  • Patent number: 8792573
    Abstract: Disclosed are a method and apparatus capable of enhancing a closed loop multi-input multi-output (MIMO) capacity through distributed discrete power control in the case of cooperatively transmitting information to multiple users through a downlink.
    Type: Grant
    Filed: November 17, 2009
    Date of Patent: July 29, 2014
    Assignees: LG Electronics Inc., Industry University Cooperation Foundation, Sogang University
    Inventors: Byoung-Hoon Kim, Wonjin Sung, Jaewon Chang, Jun-Ho Jo, Dong-Uk Lee, Jaewon Kim, Ki Jun Kim
  • Publication number: 20140198867
    Abstract: An all outdoor unit communication system, for performing cross polarization interference cancellation, is provided. The system includes a first outdoor unit (ODU) configured to receive a horizontally polarized signal, a first RF module configured to convert the horizontally polarized signal into a first in-phase (I) component and a first quadrature (Q) component, and a first modem configured to up-convert the first I and Q components from baseband into a horizontally polarized intermediate frequency (IF) signal. The system also includes a second ODU configured to receive a vertically polarized signal, a second RF module configured to convert the vertically polarized signal into a second I component and a second Q component, and a second modem configured to up-convert the second I and Q components from baseband into a vertically polarized IF signal. The system is configured to share, via an interconnect, the polarized IF signals between the first and second ODUs.
    Type: Application
    Filed: March 29, 2013
    Publication date: July 17, 2014
    Applicant: Broadcom Corporation
    Inventors: Yaacov Sturkovich, Eitan Tsur
  • Patent number: 8781035
    Abstract: Certain aspects of the present disclosure provide a system and method for improving performance of HARQ operation in a wireless communication system. The proposed method enables a receiver to update a receive buffer only if newly received values corresponding to a data packet are more reliable than previous values corresponding to the same data packet (that are stored in the receive buffer). The receiver may use the more reliable information (e.g., the newly received values or the previously stored values) for decoding.
    Type: Grant
    Filed: January 4, 2012
    Date of Patent: July 15, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Mingxia Cheng, Yongbin Wei
  • Publication number: 20140192851
    Abstract: A transmitting device may determine a physical layer transmission properties based upon an amount of data to transmit via a communications channel. The physical layer transmission properties may comprise a derated tone map that has a lower physical layer transmission throughput capability than an original tone map. An indication regarding the derated tone map may be included in a first message, a portion of a physical layer framing protocol, a physical layer control transmission (such as a frame control symbol), or other transmissions such that the receiving device can derive the derated tone map without significant added overhead.
    Type: Application
    Filed: January 10, 2013
    Publication date: July 10, 2014
    Applicant: QUALCOMM INCORPORATED
    Inventors: Ehab Tahir, Nikolai Kroupetski, John Fraser Chappel, Brian James Langlais, Joubin Karimi, Richard D. Roze, Son Binh Cam
  • Patent number: 8774325
    Abstract: A circuit may include a phase difference selector, a clock signal generator, a reference clock phase detector, and a data signal phase detector. The phase difference selector may be configured to select one of multiple reference clock phase difference signals generated by the reference clock phase detector based on a difference in phase between multiple clock signals and a reference clock. The clock signal generator may be configured to generate the multiple clock signals based on the selected reference clock phase difference signal. The data signal phase detector may be configured to generate a data phase difference signal based on differences in phase between the clock signals and a data signal. The data phase difference signal may be used by the phase difference selector to select one of the reference clock phase difference signals.
    Type: Grant
    Filed: July 31, 2012
    Date of Patent: July 8, 2014
    Assignee: Fujitsu Limited
    Inventor: Nikola Nedovic
  • Patent number: 8767856
    Abstract: A novel framing method for a variable net bit rate digital communications system that utilizes a set of different QAM constellations and punctured trellis code combinations, each combination designated as a mode. This frame structure has a variable integral number of QAM symbols per frame depending on the selected mode, but the number of bytes and Reed-Solomon packets per frame is constant. This is achieved even though the number of data bits per QAM symbol for some modes is fractional. Also the number of trellis coder puncture pattern cycles per frame is an integer for all modes. This arrangement simplifies the synchronization of receiver processing blocks such as the Viterbi decoder, de-randomizer, byte de-interleaver, and Reed-Solomon decoder.
    Type: Grant
    Filed: June 27, 2013
    Date of Patent: July 1, 2014
    Assignee: Intersil Americas LLC
    Inventors: Mark Fimoff, Jinghua Jin, Jin H. Kim
  • Patent number: 8767858
    Abstract: Provided is a communication system using a space division multi-user multiple input multiple output (SD-MIMO) communication method. A transmission apparatus may transmit, to each of terminals included within a coverage, common control information commonly transmitted to the terminals and individual control information individually transmitted to each of the terminals. The transmission apparatus does not precode the common control information and transmits the non-precoded common control information. The transmission apparatus precodes the individual control information and transmits the precoded individual control information.
    Type: Grant
    Filed: November 30, 2010
    Date of Patent: July 1, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Ui Kun Kwon, Tae Rim Park, Young Soo Kim, Eung Sun Kim
  • Patent number: 8767854
    Abstract: Modulation code set (MCS) and LDPC (Low Density Parity Check) coding within multiple user, multiple access, and/or MIMO wireless communications. Selective operation in accordance with different operational modes is performed. Operation within a first mode may correspond to that which is in full compliance with a given protocol, standard, and/or recommended practice, while operation within a second mode may correspond to that which provides additional/augmented capability and/or functionality with respect to that protocol, standard, and/or recommended practice. Operational modes selectivity may be made between proprietary and non-proprietary modes of operation. All available modulation coding sets (MCSs) may be in employed by providing such multi-mode operation. When operating within one of the operational modes (e.g., proprietary), a signal is generated to include an integer number of data bits per orthogonal frequency division multiplexing (OFDM) symbol using any desired operation (e.g.
    Type: Grant
    Filed: August 30, 2011
    Date of Patent: July 1, 2014
    Assignee: Broadcom Corporation
    Inventors: Jun Zheng, Vinko Erceg, Andrew J. Blanksby
  • Patent number: 8767855
    Abstract: A SCO estimator comprises the following units. A module obtains a first data output by a first unit and copies the first data to obtain copied data. A QAM unit quadrature modulates the copied data into each sub-carrier of each OFDM symbol to regenerate transmitted modulated data. A first phase unit obtains a first phase of each sub-carrier of each OFDM symbol of the modulated data. A second phase unit obtains a second data from a second unit, and obtains a second phase of each sub-carrier of each OFDM symbol of the second data. A comparator generates a comparing result according to the first phase and the second phase of each sub-carrier of each OFDM symbol. A divider divides the comparing result of each sub-carrier by the subcarrier index within each OFDM symbol and the OFDM symbol index of each OFDM symbol. An averaging unit averages the divided comparing result over number of sub-carriers and number of OFDM symbols.
    Type: Grant
    Filed: April 4, 2013
    Date of Patent: July 1, 2014
    Assignee: Greenvity Communications, Inc.
    Inventors: Rui Zhang, Hung C. Nguyen
  • Patent number: 8761285
    Abstract: In one embodiment, a device (e.g., a transmitter) determines a level of error protection of each bit position within symbols of a particular constellation map used for modulation-based communication, and also determines priority levels of application data bits to be placed into a communication frame. Application data bits may then be placed into symbols of the communication frame, where higher priority application data bits are placed into bit positions with greater or equal levels of protection than bit positions into which lower priority application data bits are placed. The communication frame may then be transmitted to one or more receivers with an indication of how to decode the placement of the application data bits within the symbols. In another embodiment, the particular constellation map may be dynamically selected from a plurality of available constellation maps, such as based on communication channel conditions and/or applications generating the data.
    Type: Grant
    Filed: February 22, 2012
    Date of Patent: June 24, 2014
    Assignee: Cisco Technology, Inc.
    Inventors: Sateesh K. Addepalli, Kevin C. Lee, Raghuram S. Sudhaakar, Jean-Philippe Vasseur, Flavio Bonomi
  • Patent number: 8755470
    Abstract: A mechanism for jointly correcting carrier phase and carrier frequency errors in a demodulated signal. A computer system may receive samples of a baseband input signal (resulting from QAM demodulation). The computer system may compute values of a cost function J over a grid in a 2D angle-frequency space. A cost function value J(?,?) is computed for each point (?,?) in the grid by (a) applying a phase adjustment of angle ? and a frequency adjustment of frequency ? to the input signal; (b) performing one or more iterations of the K-means algorithm on the samples of the adjusted signal; (c) generated a sum on each K-means cluster; and (d) adding the sums. The point (?e, ?e) in the 2D angle-frequency space that minimizes the cost function J serves an estimate for the carrier phase error and carrier frequency error. The estimated errors may be used to correct the input signal.
    Type: Grant
    Filed: March 28, 2013
    Date of Patent: June 17, 2014
    Assignee: National Instruments Corporation
    Inventors: I Zakir Ahmed, Krishna Bharadwaj, Vijaya Yajnanarayana
  • Patent number: 8750434
    Abstract: A joint soft output ML receiver that is able to reduce interference based on partial transmission information (i.e., without knowing the existence of other layers or other users and their modulation schemes) is described. In one implementation, the partial information based joint ML receiver can achieve performance that is similar to full information based joint ML receivers even when full information regarding the interfering UE is not available at the desired UE due to transparent Multi-user Multiple Input and Multiple Output (MU-MIMO) transmission (such as with TM 8 and TM 9 transmissions in EUTRA LTE).
    Type: Grant
    Filed: April 26, 2012
    Date of Patent: June 10, 2014
    Assignee: Motorola Mobility LLC
    Inventors: Hyejung Jung, Vijay Nangia