Abstract: The present invention provides an advantageous transmitter apparatus and associated method, for generating a Single-Carrier Discrete Cosine Transform (SC-DCT) OFDM signal for transmission. These transmit-side innovations include circuit configuration and signal processing methods for mapping Ku “input subcarriers” to N “output subcarriers,” where the “output subcarriers” are some or all of the subcarriers defined for the SC-DCT OFDM signal. In one or more embodiments, Ku is less than N, and the mapping is based on advantageous DCT/IDCT precoding. The present invention additionally or alternatively includes advantageous frequency-selective mapping, and further provides a corresponding receiver apparatus and associated method, for receiving and de-mapping the SC-DCT OFDM signals contemplated herein.

Abstract: A signal processing system is provided. The signal processing system includes: a peak-to-average ratio (PAPR) reducer that reduces a peak-to-average ratio (PAPR) of an input signal x(n), a clipping noise processing system that generates an equivalent clipping noise signal ?*CL(n) that is defined as a weighted sum of a weighted in-band clipping signal WIN*?CL,IN(n) and a weighted out-of-band clipping signal WOUT*?CL,OUT(n) to be used for determining functions of a predistorter that suppresses out-of-band spectrum caused during peak-to-average power reduction process and for generating an input signal of an amplifier which input signal has reduced clipping noise and be distorted so as to compensate nonlinearity of the amplifier.

Abstract: The remote communications system, intended for low-throughput data transfer between at least two users located substantially on the surface of a celestial body, includes: a plurality of transmitting/receiving surface terminals, each associated to a user, one or more geostationary element installed on board satellites placed in geostationary orbit around the celestial body, these geostationary elements being able to transmit data from and to a predefined coverage area on the surface of the celestial body with a line of sight to the geostationary satellite, and one or more signal repetition element for the signals transmitted and/or received from the geostationary elements to the surface terminals these traveling repetition elements being on board satellites moving in a traveling orbit; the same frequency band is used for communications between the surface terminals and the traveling elements and for communications between the traveling elements and the geostationary elements.

Abstract: The present disclosure provides a means to adjust the relative location of output rising and falling transitions to reduce single-ended duty cycle distortion (DCD) effects in the output data stream originating from the transmitter data path. This serves to improve high-speed single-ended signal characteristics and reduce electromagnetic interference (EMI). Another feature enabled by embodiments of the present disclosure is polarity skew (also referred to as differential skew) reduction between transmitter outputs. In an embodiment, the disclosed method and apparatus for transmitter data path single-ended DCD correction describes a closed-loop calibration system including the actuation apparatus within the transmitter, a sensing block at the output of the transmitter to measure the amount of single-ended DCD, and a calibration block operating on the sensor output to devise correction control inputs to the actuator in the transmitter to correct the data path single-ended DCD present.

Abstract: An equalizer that includes equalizer circuitry, a mean squared error (MSE) system, and adaptive control logic includes features that inhibit undesirable convergence to local minima.

Abstract: Provided is a method in which a Digital Pre-Distorter (DPD) performs digital pre-distortion on a received In-phase (I) signal, a received Quadrature-phase (Q) signal, a feedback I signal, and a feedback Q signal; a mixer mixes a signal output from the DPD with a frequency signal output from an oscillator; each of n phase shifters phase-shifts a signal output from the mixer according to a preset beamforming pattern; each of n Power Amplifiers (PAs) amplifies a signal output from an associated phase shifter according to a gain, the PAs connected to the associated phase shifter on a one-to-one basis; each of n envelope detectors detects an envelope signal from a signal output from an associated PA, the envelope detector connected to the associated PA on a one-to-one basis; and a control unit determines whether the n PAs operate normally, using the envelope signals output from the n envelope detectors.

Abstract: An embodiment of the time-variant channel estimation in an OFDM transmission system envisages the operations of: a) determining the received signal vector Yj,k for one or more of R receiving antennas, j=1, . . .

Abstract: Methods and apparatuses are provided for providing compressed feedback channel state information for beamforming. A beam transmitted by a transmission source is received at a receiving device. The receiving device computes a channel state matrix H of the transmission channel based on the received beam. Using the channel state matrix H, the receiving device performs a singular value decomposition procedure that produces a steering matrix V. The singular value decomposition procedure generates a set of angles (?V, ?) from which the steering matrix V can be computed. The receiving device transmits the set of angles (?V, ?) to the transmitting device. From the set of angles (?V, ?), the transmitting device can compute the steering matrix V.

Abstract: A receiver (100) is provided for signals of different signal strengths and modulated with respective pseudorandom noise (PN) codes. The receiver (100) includes a correlator circuit (120) operable to correlate the signals with a selectable locally-issued PN code having a Doppler and a code lag to produce a peak, the correlator circuit (120) being subject to cross correlation with a distinct PN code carried by least one of the signals that can produce cross correlation; and a cross correlation circuit (370, 400) operable to generate a variable comparison value related to the cross correlation as a function of values representing a Doppler difference and a code lag difference between the locally-issued PN code and the distinct PN code, and to use the variable comparison value to reject the peak as invalid from cross correlation or to pass the peak as a valid received peak.

Abstract: Local oscillator (LO) in-phase/quadrature (IQ) imbalance correction data are generated for one or both of the transmitter and receiver of a radio-frequency (RF) communication device. An RF transmitter output signal is generated by the transmitter from a known test signal and transmitted to the receiver, where a baseband receiver signal is produced. A signal characteristic of the receiver baseband signal is measured in the presence of phase shifts introduced in the transmitter output signal. Joint LO IQ imbalance figures of merit are computed from the signal characteristic measurements, each characterizing signal processing artifacts in the receiver baseband signal caused by joint signal processing in the transmitter and the receiver under influence of transmitter LO IQ imbalance and receiver LO IQ imbalance.

Abstract: Embodiments of the present invention disclose a method and an apparatus for transmitting data in a multiple-antenna system, which are applied in a transmit diversity mode. The method includes: in a data transmission period, determining, according to transmission quality of the system, the number of antennas to be turned off and turning-off time; and in the turning-off time, turning off the determined number of antennas, turning on remaining antennas other than the antennas that are turned off, and transmitting, through the remaining antennas, the data to be transmitted; and during the remaining time of the data transmission period excluding the turning-off time, turning on all antennas and transmitting, through all the antennas, the data to be transmitted. According to the embodiments of the present invention, power consumption may be decreased while at the same time dynamic transmission performance of the system is considered, decreasing implementation complexity.

Abstract: There is a need to reduce secondary intermodulation distortion that may occur in a reception circuit of a high-frequency signal processor and a wireless communication system having the same. In test mode, for example, a test signal generating circuit TSGEN generates a test signal RFtst at f_tx ±0.5 MHz. The test signal RFtst is input to a mixer circuit MIXrx_I (MIXrx_Q). A correction circuit block CALBK detects an IM2 component resulting from the MIXrx_I (MIXrx_Q). The CALBK varies a differential balance for the MIXrx_I (MIXrx_Q) and concurrently monitors a phase for the IM2 component resulting from MIXrx_I (MIXrx_Q). The CALBK searches for the differential balance corresponding to a transition point that allows the phase to transition by approximately 180°. The MIXrx_I (MIXrx_Q) operates in normal mode using the differential balance as a search result.

Abstract: A method and apparatus for a receiver system in a receiver that includes at least two front end branches, each branch having its own intermediate frequency (IF) mixer to shift a received signal to an IF. When receiving multiple independent signals, the signals are digitized and the receiver performs a digital complex transform on each signal to obtain the corresponding quadrature component. When receiving a single signal the signal is routed to two mixers that are 90 degrees out of phase to obtain the quadrature signal components in the analog section of the receiver.

Abstract: The present disclosure describes apparatuses and techniques for low-noise regulation of battery power. In some aspects an indication of a voltage level of a battery supplying power to a linear regulator is received, an output voltage level is determined for the linear regulator that permits the linear regulator to operate in an active condition in which noise of the power supplied by the battery is mitigated, and the linear regulator is configured to output the regulated power at the output voltage level effective to provide low-noise regulated power for components of a device.

Abstract: Systems, methods, and devices enable spectrum management by identifying, classifying, and cataloging signals of interest based on radio frequency measurements. In an embodiment, signals and the parameters of the signals may be identified and indications of available frequencies may be presented to a user. In another embodiment, the protocols of signals may also be identified. In a further embodiment, the modulation of signals, data types carried by the signals, and estimated signal origins may be identified.

Abstract: A system and method is disclosed for reducing inter symbol interference in a high speed data transfer system. One or more decision logic circuits and one or more pull circuits are used to enable the signal level of a bit in a serial bit stream to achieve its nominal value.

Abstract: A receiver containing analog circuitry that generates distortion, a distortion compensation circuit coupled to an output of the analog circuitry, and a slicer, operating as a signal peak detector, coupled to the distortion compensation circuitry. The distortion compensation circuit has a subtractor, a function generator, and a weighting circuit. The subtractor has a first input coupled to the output of the analog circuitry, a second input, and an output. The function generator has an input coupled to the first input of the subtractor. The weighting circuit, responsive to a weighting coefficient, is coupled between an output of the function circuit and the second input of the first subtractor. The function generator has a transfer function with a third-power term and the weighting coefficient is set to a value based on the level of the signal peaks that will least partially reduce distortion in signals on the output of the subtractor.

Abstract: A power line communication modem is provided, including a connection element configured to connect the power line communication modem to at least three wires of a power line network; a transmitter configured to transmit a first signal via a first combination of at least two wires of the at least three wires and to transmit a second signal via a second combination of at least two wires of the at least three wires; a controller adapted to individually control a transmit power of the first signal and the second signal. A corresponding power line communication system and a power line communication method are provided as well.

Abstract: Systems and methods for user specific antenna down tilt in wireless cellular networks are disclosed. A preferred embodiment method comprises synthesizing a plurality of virtual antennas from a single physical antenna, wherein a total number of virtual antennas is less than a total number of antenna elements in the physical antenna, transmitting pilot signals on the plurality of virtual antennas, receiving, from a user equipment, a pre-coding control indicator based on the transmitted pilot signals, determining a multiple-input multiple output pre-coding vector based on the pre-coding control indicator, and transmitting user data modulated by the pre-coding vector to the user equipment via the plurality of virtual antennas.

Abstract: Methods and systems for controlling the supply voltage provided to a power amplifier (PA) in a radio frequency (RF) transmitter based on measured output spectrum emissions are provided. In an embodiment, the PA supply voltage is adjusted such that spectrum emission limits are satisfied with predetermined margins. In another embodiment, the predetermined margins are reduced to lower power consumption of the PA.