| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 370206000 | Quadrature carriers | 30 |
| 20080253279 | Pilot Design for Ofdm Systems with Four Transmit Antennas - Pilot, preamble and midamble patterns are provided that are particularly suited for four transmit antenna OFDM systems. Pilots are inserted in a scattered manner for each of the four antennas, either uncoded, space-time coded in pairs, space-time frequency coded in pairs, or space-time-frequency coded. | 10-16-2008 |
| 20080298225 | Transmitting Apparatus for Transmitting in a Multi-Carrier System Using Multiple Antennas and Receiving Apparatus in the Same System - A transmitting apparatus and receiving apparatus of a multi-carrier system using multiple antennas is proposed. An LCF encoder of the transmitting apparatus performs a liner precoding to input signals to be transmitted to a receiving apparatus using a liner complex matrix considering the number of multiple antennas and the number of subcarriers, and a subcarrier allocator respectively allocates a subcarrier to the signals liner-precoded by the LCF encoder. A transmitter respectively transmits the signals having a subcarrier allocated by the subcarrier allocator through the multiple antennas externally. A subcarrier de-allocator of a receiving apparatus extracts a liner-precoded signal by de-allocating a subcarrier allocated to the received signal. An LCF decoder outputs a bit reliability of the received signal to the liner-precoded signal extracted from the subcarrier de-allocator considering the number m of multiple antennas and the number n of subcarriers. A performance may be improved by using space diversity due to multiple antennas and a frequency diversity due to the OFDMA system, and a complexity may be reduced and a hard decision value of a performance similar to the maximum likelihood detection may be obtained by using a lattice reduction and a 2-branch Chase decoder. | 12-04-2008 |
| 20090016210 | TRANSMITTING/RECEIVING METHOD, METHOD OF GENERATION OF SIGNAL SEQUENCES HAVING NO PERIODIC CORRELATION, AND COMMUNICATION DEVICE - In a transmitting/receiving method, a transmitter device transmits a vertical polarization signal and a horizontal polarization signal, and a receiver device receives the vertical and horizontal polarization signals transmitted by the transmitter device. The vertical polarization signal includes a vertical polarization ID signal which identifies vertical polarization and a vertical polarization data signal which is a data signal. The horizontal polarization signal includes a horizontal polarization ID signal which identifies horizontal polarization and a horizontal polarization data signal which is a data signal. The vertical polarization ID signal and the horizontal polarization ID signal are transmitted simultaneously. The vertical polarization ID signal, the horizontal polarization ID signal, and the vertical polarization data signal are generated from signal sequences having orthogonal correlation. The vertical polarization ID signal, the horizontal polarization ID signal, and the horizontal polarization data signal are generated from signal sequences having orthogonal correlation. | 01-15-2009 |
| 20090059782 | Method and apparatus for extending the transmission capability of twisted pair communication systems - A closed loop feedback system is employed in a receiver to automatically compensate the communication signal from twisted pair cables for AC and DC losses. This is accomplished through the use of a reference pulse signal which is sent along with other digital information. At the receiver, the reference pulse signal is restored to its proper level through a Pulse Width Modulation (PWM)-controlled variable compensation amplifier circuit. The received reference signal is compared to a known reference value and the duty cycle of the PWM circuit is adjusted until the proper level reference signal is achieved. Thereafter, the digital signal is extracted. OFDM (Orthogonal Frequency Division Multiplexing) with pilot tones are used to maximize payload while minimizing crosstalk effects. The pilot tones locate the OFDM symbols in time while supplying compensation information concerning the transmission medium. | 03-05-2009 |
| 20090201794 | MULTIPLEXING DEVICES OVER SHARED RESOURCES - Systems and methodologies are described that facilitate transmitting and receiving signals over I and Q branches of a communication channel to mitigate potential I/Q imbalance. In particular, a device can transmit a signal over the I and Q branches to distribute transmission power substantially evenly for a given channel. The device can demodulate the data with a code or matrix having real and complex modifiers resulting in an I and Q branch signal for transmission. Where the channel has multiple resources, the device can alternate or transmit over the I branch in one resource and the Q branch in another resource for a given signal to distribute power. Also, the device can apply a complex scrambling code to distribute a signal over both the I and Q branches. The device can also use QPSK or higher order modulation to send the signals meant for the same user. | 08-13-2009 |
| 20090279418 | OVERLAY MODULATION OF COFDM USING PHASE AND AMPLITUDE OFFSET CARRIERS - Systems and methods are presented for transmitting additional data over preexisting differential COFDM signals by modulating existing data carriers with a phase and an amplitude offset. In exemplary embodiments of the present invention, additional data capacity can be achieved for an COFDM signal which is completely backwards compatible with existing satellite broadcast communications systems. In exemplary embodiments of the present invention additional information can be overlayed on an existing signal as a combination of amplitude and phase offset from the original QPSK symbols, applied for each information bit of the overlay data. With two additional levels of modulation, a receiver can demodulate the information from each of the previous stages and combine the information into a suitable format for soft decoding. The first stage of demodulation will be recovery of overlay data from the amplitude modulated D8PSK. Because other amplitude variations due to multi-path are also expected, the data gathered from the FFT in the receiver must be equalized to the channel conditions. After channel equalization has been performed, soft overlay data can then be derived from the distance off the unit circle. In order to recover the phase modulated overlay data, the equalized symbols must first be differentially demodulated and corrected for any common phase error offset. After common phase removal, overlay phase information can be obtained. | 11-12-2009 |
| 20090316569 | METHODS FOR TRANSMITTING AND RECEIVING A MULTICARRIER SIGNAL, CARRYING OUT A CHANNEL ESTIMATION, AND CORRESPONDING DEVICES AND COMPUTER PROGRAM PRODUCTS - A method is provided for receiving a received signal corresponding to a multicarrier signal transmitted by at least one transmitter via a transmission channel. The multicarrier signal is formed by a temporal succession of symbols consisting of a set of data elements including informative data elements with real values, and pilots for at least some of the symbols. Due to groups of at least two pilots being respectively located in an adjacent region in the time/frequency space, the reception method includes a step of extracting at least two complex values corresponding the pilots of the group of the adjacent region, once they have passed through the transmission channel, and a step of estimating the transmission channel in the adjacent region on the basis of the complex values. The modulation used is the type of OFDM OQAM. | 12-24-2009 |
| 20100172234 | ADAPTIVE CODING AND MODULATION FLOW CONTROL AND TRAFFIC SHAPING SYSTEMS AND METHODS - A process is described to build physical layer frames with a modcode adapted to the signal quality of a destination terminal. Data packets assigned to the same modcode may be sent in the same frame, although packets associated with higher modcodes may be used to complete a frame before switching to the applicable higher modcode for construction of subsequent frames. After an interval, the order of progression is restarted with an out of order packet above a threshold age. Flow control filtering mechanisms and a variable reliability margin may be used to adapt dynamically to the current data traffic conditions. | 07-08-2010 |
| 20110013504 | METHOD FOR OPTIMIZED REFERENCE SIGNAL DOWNLINK TRANSMISSION IN A WIRELESS COMMUNICATION SYSTEM - A method and system optimizes the transmission of a downlink reference signal (DLRS) in a wireless communication system that uses orthogonal division multiple access (OFDMA) for the downlink. Each Node-B (base station) is capable of transmitting the DLRS reference symbols in different subframes of the OFDM radio frame and changing both the number and location of the subframes in response to changing network conditions. The network conditions include the number of terminals being served by the Node-B and multiple access interference (MAI) from adjacent Node-Bs. | 01-20-2011 |
| 20110019528 | REDUCTION OF OUT-OF-BAND EMITTED POWER - OFDM signal transmission of reduced power emission outside a designated transmission bandwidth is disclosed. At least one subcarrier is allocated for an OFDM symbol for non-data. A weighting signal representation is determined based on an initial error signal representation, which is determined from at least part of a first OFDM symbol and part of a second OFDM symbol, the first and second OFDM symbols being consecutive in time. | 01-27-2011 |
| 20110149717 | INFORMATION MULTIPLEXING METHOD - The present invention discloses an information multiplexing method, comprising: coding multiple feedback information according to number of the feedback information and a linear block code sequence, and truncating corresponding coded information according to a target length of the feedback information coded (S | 06-23-2011 |
| 20110176405 | METHOD AND APPRATUS FOR RATE MATCHING WITHIN A COMMUNICATION SYSTEM - A method and apparatus for rate matching is described. During operation of a transmitter, multiple data streams are received and individually interleaved with a permutation of a same length K | 07-21-2011 |
| 20110249548 | EFFICIENT ZADOFF-CHU SEQUENCE GENERATION - Efficient apparatus and method for Zadoff-Chu (“Chu”) sequence generation avoids additional processing and hardware complexity of conventional quadratic generating formula followed by Discrete Fourier Transform (DFT) with a reference signal generator that produces both a Zadoff-Chu sequence and its DFT. In the wireless communication system (e.g., Long Term Evolution (LTE) system), Chu sequences are extensively used, especially in the uplink (UL). Because of the single carrier operating mode, transmitting a Chu sequence in principle involves a succession of generating that sequence, performing a DFT operation and then an IFFT operation. Assuming that the sequence length is N, the initial sequence generation requires 2N multiplications and the DFT requires more than N log 2(N) multiplications. Given the frequent processing of Chu sequences, this would represent a complexity burden. The invention makes it possible to perform the sequence generation and DFT steps without any multiplication operation, except for possibly calculating certain initial parameters. | 10-13-2011 |
| 20110292785 | DIGITAL DOMAIN CONTENT PROCESSING AND DISTRIBUTION APPARATUS AND METHODS - Methods and apparatus for distributing content using a spectrum generation device. In one embodiment, digital content is received via a time-multiplexed network transport (such as Gigabit Ethernet), and converted to frequency channels suitable for transmission over a content distribution (e.g., Hybrid Fiber Coaxial (HFC)) network. In one variant, the conversion is performed using digital domain processing performed by a full spectrum generation device. Additionally, methods and apparatus for selectively adding, removing, and/or changing digital content from the full spectrum device are also disclosed. Various aspects of the present invention enable physical (infrastructure) consolidation, and software-implemented remote management of content distribution. | 12-01-2011 |
| 20120039159 | SPECTRUM AGGREGATION FOR COMMUNICATION USING ROTATION ORTHOGONAL CODING - A method is disclosed of transmitting a plurality of transmit signals through a plurality of transmit antennas, respectively. The method includes: performing a pre-coding technique in the form of rotation orthogonal coding for a plurality of transmit symbols for a plurality of carriers having respective distinct frequency bands, each of which serves a pre-encoded transmit symbol, to thereby generate a plurality of encoded transmit symbols for the distinct carriers, respectively; and transmitting the generated encoded transmit symbols, through the plurality of transmit antennas, in the transmit signals, respectively, towards a plurality of receive antennas of a receiver through which the transmit signals are received, respectively, to thereby perform spectrum aggregation using the rotation orthogonal coding. | 02-16-2012 |
| 20130258834 | WIRELESS TRANSMISSION SYSTEM, WIRELESS COMMUNICATION DEVICE AND WIRELESS TRANSMISSION METHOD - A wireless transmission system including antenna pairs, a demodulation functional unit, and a transmission characteristic correction unit. The antenna pairs include transmission and reception antennae. A desired wave arrives at a reception antenna in a wireless signal from one transmission antenna. Meanwhile, the reception antenna receives an unnecessary wave in a wireless signal transmitted from a different transmission antenna. The demodulation functional unit corresponding to each antenna pair demodulates a signal received by the reception antenna. The transmission characteristic correction unit carries out correction calculation based on a transmission characteristic of a transmission space between the transmission and reception antennae based on demodulation signals demodulated by the demodulation functional units to acquire an output signal corresponding to a transmission subject signal. | 10-03-2013 |
| 20140160915 | COMMUNICATION DEVICE AND COMMUNICATION SYSTEM - A preamble signal is an OFDM signal, and is a real-part signal obtained by removing an imaginary-part signal from a signal in the time domain that is generated by an IFFT process being performed on a signal in the frequency domain obtained by assigning preamble data to subcarriers in accordance with a predetermined arrangement pattern. The predetermined arrangement pattern indicates that preamble data is assigned to any of subcarriers given numbers equal to or less than N/2−1 and the preamble data is not assigned to subcarriers given numbers more than N/2−1, where a plurality of subcarriers are numbered by integers from 0 to N−1 (N is an integer) in ascending order with respect to the center frequency of each subcarrier. | 06-12-2014 |
| 20140313876 | TRANSMISSION METHOD, APPARATUS AND SYSTEM THAT USE CARRIER MODULATION - Embodiments of the present invention provide a transmission method. The method includes: performing sending of a near-end orthogonal frequency division multiplexing signal and receiving of a far-end orthogonal frequency division multiplexing signal simultaneously on an orthogonal frequency division multiplexing channel; obtaining a carrier phase difference between an echo orthogonal frequency division multiplexing signal and the far-end orthogonal frequency division multiplexing signal, and a channel transfer function of an near-end echo channel; and generating an echo cancellation signal according to the carrier phase difference, the channel transfer function of the near-end echo channel, and a near-end signal to be sent, and overlapping the echo cancellation signal and a received signal to cancel the echo orthogonal frequency division multiplexing signal that is overlapped in the received signal. | 10-23-2014 |
| 20180026825 | METHOD AND APPARATUS FOR SPATIAL MODULATION BASED ON VIRTUAL ANTENNA | 01-25-2018 |
| 20190149392 | SYSTEM AND METHOD FOR AMPLITUDE PRE-DISTORTION OPTIMIZATION FOR GPS SIGNAL CONSTANT ENVELOPE TRANSMISSION | 05-16-2019 |
| 370207000 | Having a signaling constellation | 10 |
| 20080239940 | Method of QAM Soft Demapping - A method of demapping in a receiver including deriving M intermediate soft bit values y | 10-02-2008 |
| 20090092037 | Wireless Interactive System and Method - In a wireless broadband system comprising a base transmitting to a plurality of subscribers, means for achieving an interactive bi-directional system comprising transmitter means in the subscriber system for transmitting signals which are orthogonal to the signals transmitted from other users arriving at the base station. A method for achieving an interactive bi-directional system comprising the steps of: A. using a subscriber transmitter with an upstream physical layer based on the use of a combination of Time Division Multiple Access and Orthogonal Frequency Division Multiple Access; B. dividing the upstream into a number of “time slots” as defined by the MAC layer; C. controlling, in the MAC layer, the assignment of subchannels and time slots by bandwidth on demand and Data Rate on demand. | 04-09-2009 |
| 20090231990 | METHOD AND APPARATUS FOR TRANSMITTING/RECEIVING MULTIPLE CODEWORDS IN SC-FDMA SYSTEM - The present invention relates a method and apparatus for transmitting/receiving data using multiple codewords in a communication system using SC-FDMA (single carrier frequency division multiple access). A transmitter generates the multiple codewords for user data and transmits the generated multiple codewords. A receiver receives the multiple codewords and sequentially performs decoding and SIC (successive interference cancellation) on the received multiple codewords. Therefore, this structure can minimize a PAPR (peak to average power ratio) and considerably reduces interference between symbols in a frequency selective fading environment. | 09-17-2009 |
| 20100097922 | SYSTEMS AND METHODS FOR GENERATING SEQUENCES THAT ARE NEAREST TO A SET OF SEQUENCES WITH MINIMUM AVERAGE CROSS-CORRELATION - A method for generating sequences that are nearest to a set of sequences with minimum average cross-correlation is described. Each element of a set of sequences is projected to a nearest constellation point. The set of sequences is converted into a time domain representation. An inverse discrete Fourier Transform (IDFT) is performed on the set of sequences. A cubic metric of each sequence of the set of sequences is evaluated. A sequence is removed from the set if the cubic metric exceeds a threshold. A minimum maximum cross-correlation is obtained for the set of sequences. | 04-22-2010 |
| 20120140612 | TRANSMISSION APPARATUS, RECEPTION APPARATUS, TRANSMISSION METHOD, RECEPTION METHOD, AND METHOD FOR GENERATING MULTI-DIMENSIONAL CONSTELLATIONS - The present invention relates to digital data communication and provides an efficient method for generating multi-dimensional constellations for digital data modulation with a high degree of modulation diversity, a method for transmitting and receiving data on the basis of such constellations, and a corresponding apparatus. This is achieved by considering only multi-dimensional rotation matrices with all elements on the diagonal having the same first absolute value and all other elements having the same non-zero second absolute value. In this manner, multi-dimensional rotation matrices can be generated having only a single independent parameter and a structure that is as regular as possible. The independent parameter can be configured in order to minimize the error probability for various constellation sizes. | 06-07-2012 |
| 20140307535 | TRANSMISSION APPARATUS, RECEPTION APPARATUS, TRANSMISSION METHOD, RECEPTION METHOD, AND METHOD FOR GENERATING MULTI-DIMENSIONAL CONSTELLATIONS - The present invention relates to digital data communication and provides an efficient method for generating multi-dimensional constellations for digital data modulation with a high degree of modulation diversity, a method for transmitting and receiving data on the basis of such constellations, and a corresponding apparatus. This is achieved by considering only multi-dimensional rotation matrices with all elements on the diagonal having the same first absolute value and all other elements having the same second absolute value. In this manner, multi-dimensional rotation matrices can be generated having only a single independent parameter and a structure that is as regular as possible. The independent parameter can be configured in order to minimize the error probability for various constellation sizes. | 10-16-2014 |
| 20150358195 | DIGITAL MODULATION METHOD AND APPARATUS, AND METHOD AND APPARATUS FOR PROVIDING MULTIPLE SERVICES USING SAID DIGITAL MODULATION - The present invention discloses a digital modulation method for providing multiple services. The method for providing multiple services comprises multiplexing bits by allocating them according to a required SNR (Signal to Noise Ratio) of each service; and modulating multiplexed bits by applying non-uniform distances among constellation symbols. | 12-10-2015 |
| 20160204971 | NON-UNIFORM CONSTELLATIONS | 07-14-2016 |
| 20160380800 | Efficient Constellation - Methods and apparatus for efficient mapping and demapping of constellation are described; the distance calculations are completely removed from the demapping process. | 12-29-2016 |
| 20190149177 | TRANSMITTING APPARATUS AND MAPPING METHOD THEREOF | 05-16-2019 |
