3137 results about "Constellation" patented technology

A low attenuation surface wave transmission line system for launching surface waves on a bare and unconditioned conductor, such as are found in abundance in the power transmission lines of the existing power grids. The conductors within the power grid typically lack dielectric and special conditioning. Accordingly, the present invention includes a first launcher, preferably including a mode converter and an adapter, for receiving an incident wave of electromagnetic energy and propagating a surface wave longitudinally on the power lines. The system includes at least one other launcher, and more likely a number of other launchers, spaced apart from one another along the constellation of transmission lines. The system and associated electric fields along any given conductor are radially and longitudinally symmetrical.

A method for a combined adaptive digital pre-distorter and pre-equalizer apparatus in single- and/or multiple-link hopping radio systems including hopping among a plurality of radio links to transmit variable-length bursts of radio signals on the plurality of radio links. Further, pre-distorting amplitude and phase of transmitted signal constellations based on the inverse AM-to-AM and AM-to-PM characteristics and the operating conditions of the high-power amplifier, respectively. Further, pre-equalizing amplitude and group-delay variations of the transmit RF radio using the pre-stored estimated complex tap coefficient of the pre-equalizer under different frequency bands.

A reduction in a peak-to-mean envelope power ratio of a multicarrier signal, represented as a time domain signal, is achieved by applying (76) an offset, indicative of a difference (74) between a mean signal level and a midpoint level of the time domain signal, to the time domain signal. Alternatively, constellation values of positive and negative frequency components are modified by differing functions to produce a modified data set. Preferably, the negative frequency components are set to a predetermined value (namely zero (124)) to provide an alternate coding scheme Once the multicarrier signal has been converted into a time domain representation, real and imaginary parts (126-128) of the modified data set that consequently only contain positive frequency components and zeros are compared with one another to identify (130) which of the real and imaginary parts has a lower peak-to-average signal ratio (134) for the time domain representation. Then, based upon which of the peak-to-average signal ratios is lowest (136), either the real and imaginary part of the time domain signal is selected for subsequent transmission (138).

An interleaving method performed by a transmitter for a communication system with quasi-cyclic low-density parity-check codes, spatial multiplexing, and T transmit antennas is used for applying permutation to N cyclic blocks of a codeword in order to map bits of the permutated cyclic blocks onto T constellation words constituting multiple spatial-multiplexing blocks from the codeword. Each cyclic block consists of Q bits.

A sensor connecting sheet material for inclusion in appropriately structured multiple-axes controllers comprised of a single input member operable in 6 DOF relative to a reference member of the controller. The input member having return-to-center resiliency relative to the reference member on at least the three perpendicular linear axes. The input member can be of a continuously rotatable trackball-type or a limited rotation joystick-type, and the reference member can be a shaft, a base or a housing. The controllers include carriage structuring for influencing sheet connected sensors by hand-applied operation of the input member. The preferred structures provide cooperative interaction with movement or force influenced sensors in primarily a single area. Some, most, or all of the sensors are preferably supported on a generally single plane, such as on a printed flexible membrane sensor sheet or circuit board sheet. In an alternative embodiment, sensors and conductive traces are applied on a generally flat, flexible membrane sensor sheet, which is then bent into a three dimensional configuration which may in some cases reach a widely-spread 3-D constellation of 6 DOF and/or other sensor mountings. The use of sensors connected by a sheet member, whether finally applied in a flat or 3-D configuration, enables efficient circuit and sensor connection and placement during manufacture, resulting in low product costs and high reliability.

A method for automatically creating a database of parameters (e.g., fingerprints/landmarks) used in a media sample recognition system. The user places a media sample in his media player, e.g., a CD or DVD player in his personal computer. A software process installed on the user's personal computer, to which is connected the CD/DVD player, extracts the constellation or “raw parameters” from the CD tracks as the CD plays, or under control of the software process. This extraction process may operate in the background. These raw parameters are then transmitted via the Internet (or other computer network) to a server coupled to a recognition database. The raw parameters are stored in the database. At some point in time, the raw parameters are processed into fingerprint/landmarks (e.g., using linkage) using another software process and then stored either back in the database or in random access memory (RAM) for use during a subsequent recognition process. The media sample can also be simultaneously identified during playback, which identity information is then sent to the server coupled to the recognition database.

A broadcasting base station device transmits broadcast signals modulated by a hierarchical modulation scheme to a mobile terminal device. A hierarchical modulation setup section compares the reception quality of the broadcast signals at the location of the mobile terminal device to predetermined reference quality. Based on the result of the comparison, the hierarchical modulation setup section specifies a hierarchical modulation scheme. For example, the constellation in each quadrant is reduced or enlarged. Accordingly, the broadcasting base station device can transmit optimal broadcast signals that match with actual reception quality to each mobile terminal device.

A method and apparatus are described for a User Equipment (UE) to transmit in a control channel ACKnowledgement signals associated with a Hybrid Automatic Repeat reQuest process (HARQ-ACK signals) in response to receiving Transport Blocks (TBs) transmitted from a base station. The UE conveys the HARQ-ACK information by selecting one resource from multiple resources in the control channel and by selecting a constellation point of the modulation scheme for the HARQ-ACK signal. Transmission diversity is supported using different control channel resources that are already available to the UE without configuring additional resources. Design principles are described to optimally map the HARQ-ACK information to control channel resources and modulation constellation points for a Time Division Duplex (TDD) system and for a Frequency Division Duplex (FDD) system.

In transmitter apparatus for a digital television (DTV) broadcasting system, internet-protocol (IP) packets of digital television information are subjected to multilevel concatenated Bose-Chaudhuri-Hocquenghem (BCH) coding and low-density parity-check convolutional coding (LDPCCC) before being bit-interleaved and mapped to quadrature-amplitude-modulation (QAM) constellations. The QAM constellations are used in coded orthogonal frequency-division modulation (COFDM) of plural carrier waves up-converted to a radio-frequency broadcast television channel. In receiver apparatus for the DTV broadcasting system the results of de-mapping QAM constellations recovered from demodulating the COFDM carrier waves are de-interleaved, and the constituent LDPCCC codewords are decoded to recover constituent BCH codewords of the multilevel BCH coding. The constituent BCH codewords are decoded to correct remnant bit errors in them. Then, IP packets of digital television information are reconstituted from the systematic data bits in those BCH codewords.

According to embodiments of the invention, a communications system includes an error correction encoder that error correction encodes a bitstream according to an error correction code. The system also includes a variable symbol generator that generates a symbol according to a selected one of a plurality of selectable signal constellations from a group of bits of the error correction encoded bitstream. The system further includes a spreader that spreads the symbol according to a spreading code, and a transmitter that transmits the spread symbol in a communications medium. Preferably, the plurality of selectable signal constellations includes at least two signal constellations of different order. In other embodiments, the error correction encoder includes a variable error-correction encoder that encodes the bitstream according to a selected error correction code of a plurality of selectable error correction codes. In still other embodiments, the spreader includes a variable spreader that spreads the symbol according to a selected spreading code of a plurality of selectable orthogonal spreading codes including at least two spreading codes of different lengths. A controller may select the error correction code used by the variable error correction encoder, the signal constellation used by the variable symbol generator, and the spreading code used by the variable spreader to provide a desired information transmission rate for the bitstream. Related methods are also described.

A waterpouring system and method for use with a multiple-input, multiple-output (MIMO) transmitter. In one embodiment, the waterpouring system includes an encoding decision subsystem that selects a constellation combination based on gains in channels of the MIMO transmitter, and a vector modulator subsystem, coupled to the encoding decision system, that modulates a fixed number of bits in a bitstream with the constellation combination to generate a symbol vector. The waterpouring system also includes a normalization and precoding subsystem, coupled to the vector modulator subsystem, that weights the symbol vector based on the gains to yield a weighted symbol vector and distributes the weighted symbol vector among the channels.

In one embodiment, a method for generating an adaptive air interface waveform includes generating a waveform that includes a variable carrier frequency and variable bandwidth signal. The variable bandwidth signal includes one or more subcarriers that are dynamically placeable over a range of frequencies, and each subcarrier is separately modulated according to a direct sequence (DS) spread spectrum (SS) technique. The waveform has an embedded pilot usable to optimize one or more spectrum efficiencies of the waveform. A modulation constellation, a code rate, and a code length of the generated waveform are adapted according to an available spectrum and one or more sub-carrier conditions.

An RF device including a control loop for maximizing output power for each of several data rates or constellation types. The RF device includes a power detector, a power amplifier and a MAC that includes input and output adjust circuits. A power level value is generated from measured output power. The MAC compares an adjusted power level value with a set point value and generates an error value. The MAC adjusts a power control value based on the error value for controlling the gain of the power amplifier. The MAC uses a data rate signal indicative of a selected constellation type or data rate. The input adjust circuit stores one or more input adjustment values selected by the data select signal for adjusting the power level value. The output adjust circuit stores one or more output adjustment values selected by the data select signal for adjusting the power control value.

A wireless system (e.g., Bluetooth, WCDMA, etc.) with multiple antenna communication channel eigenvector weighted transmissions including possibly differing order symbol constellations for differing eigenvectors. Comparison of maximizations of minimum received symbol distances provides for selection of eigenvector combinations and symbol constellations.

An apparatus and method for wireless transmission of uncompressed HDTV video overcomes the challenges of sending vast amounts of information over a wireless link. This is achieved by direct mapping of transformation coefficients of the video components to communication symbols, such as OFDM symbols. A main portion of the important transform coefficients, for example the MSBs of the coefficients representing lower frequencies of each of the video components, and in particular the quantized values of the lower frequencies components, are sent in a coarse representation using, for example, QPSK or QAM. The coefficients representing higher frequencies of the video components, and the quantization error values of the lower frequencies components, or some, non-linear transformation thereof, are sent as pairs of real and imaginary portions of a complex number that comprises a point in a fine constellation. The invention further provides a delay-less and buffer-less implementation of transmitter and receiver pairs.

Methods and apparatuses for decoding codewords received over a MIMO channel are provided. According to one aspect of the disclosure, a cost function is computed for each constellation point of an Mth rank or spatial layer, and N_cand of those constellation points having minimum cost are preserved as candidate points, where N_cand is a parameter specified to the decoding algorithm. In addition, a cost function may be computed for all possible transitions from the N_cand candidate points of the Mth rank to all possible constellation points of the (M-1)th spatial layer, and N_cand of those transitions having minimum cost are preserved as candidate points. The process is repeated for all spatial layers, resulting in the identification of N_cand candidate codewords and their associated cost functions.

The invention relates generally to the field of wireless communications and more particularly to a method of and device for detecting the presence of a received data packet in a digital receiver. The present invention proposes a simplified method of correlation by removing dependency on the amplitude fluctuations while at the same time maintaining phase relevancy. The key advancement involves mapping the complex quadrature amplitude modulation (QAM) preamble to a quantized phase shift keying (PSK) constellation before application to a matched complex correlator. The proposed process essentially “amplitude normalizes” the input signal without the use or complexity associated with a divider. This simplified normalization scheme makes the packet detection algorithm robust against amplitude variations in the input signal, while still allowing for good correlation output. In applications where interference is superimposed on the I/Q input signals, the invention improves the detection capability over automatic gain control (AGC) normalization methods.

Provided is a detector system for detecting a plurality of items each having at least one RFID tag attached thereto. The detector system may include a presence detector and/or a message detector. The presence detector may include a signal reader which receives modulated carrier frequencies from the RFID tags during a predetermined response time period for comparison to a reference level. The signal reader may be configured as a power integrator or a constellation discriminator. The power integrator sums the power contained in signals transmitted by the RFID tags by integration for comparison to an environmental noise level measurement taken during a quiet period. For the constellation discriminator, bits contained in the modulating message are compared to the bit pattern of a predetermined reference constellation. The detector system may be configured as a 3-state detector which combines the presence detector with a message detector that indicates the identification code of the RFID tags.

Soft symbol decoder algorithms for multiple input, multiple output (MIMO) receivers reduce the search complexity by searching over fewer than all possible combinations of transmitted symbols to compute log metrics for each transmitted bit from each transmit antenna. In one algorithm, a sub-optimal set of transmitted symbols is computed and the transmitted symbols are restricted to neighboring constellation points of the sub-optimal set. In another algorithm, all constellation points are searched for every antenna except one. In yet another algorithm, constellation points are searched excluding more than one antenna. The non-searched antenna(s) can be handled by either a bit stuffing or a soft slicing technique.