Abstract: The present disclosure illustrates a current balance method and a current balance circuit thereof. The current balance method is used in a multiphase digital pulse width modulator. Steps of the current balance method are as follows. A plurality of pulse width values of the pulse width modulated signals within a first period are recorded, and a minimum pulse width value is defined as a standard value. The method determines whether each pulse width value is larger than the sum of the standard value and a pulse width threshold, and if yes, the method adds 1 to a count value of the phase output stage corresponding to the pulse width value. The method determines whether each count value equals to a counting threshold, and if yes, the method adjusts the pulse width modulated signal, and initializing the count value as 0.

Abstract: Methods and apparatuses are provided for canceling interference at a User Equipment (UE) in a wireless communication system. A signal that includes a desired signal and an interference signal is received from at least one Base Station (BS). A random parameter is generated by projecting a vector of the received signal onto a set of projection vectors. A decision metric is determined using the random parameter. A Traffic to Pilot Ratio (TPR) that minimizes the decision metric with respect to both a transmission mode candidate group of the interference signal and a TPR candidate group of the interference signal is determined. The interference signal is canceled from the received signal using the TPR.

Abstract: The present invention is directed to communication systems. According to embodiments of the present invention, a communication system includes at least two communication lanes and a skew management module. The skew management module generates a control current based on output test patterns of the two communication lanes. The control current is integrated and compared to a reference voltage by a comparator, which generates an analog offset signal. A PLL of one of the communication lanes generates a corrected clock signal that is adjusted using the analog offset signal to remove or adjust the skew between the communication lanes. The corrected clock signal is used for output data. There are other embodiments as well.

Abstract: Systems and methods for analyzing the performance of a digital network include capturing a stream of digital data, e.g., internet protocol (IP) packets, that represent streaming video, identifying which of the IP packets include bit errors, determining to which of a plurality of pixels the IP packets including bit errors belong and identifying such pixels as corrupted pixels, and illuminating only the corrupted pixels on a display of a tool. Corrupted pixels in different time blocks can be displayed with different colors to gain a better appreciation of the bit error rate over time.

Abstract: A system includes a first transmitter, a second transmitter, a third transmitter and a controller, where the first transmitter is arranged for transmitting a first signal to a first transmission line, the second transmitter is arranged for transmitting a second signal to a second transmission line, and the third transmitter is arranged for transmitting a third signal to a third transmission line. The controller is coupled to the first transmitter, the second transmitter and the third transmitter, and is arranged for setting impedances of the first transmitter, the second transmitter and the third transmitter according to a coding jitter determination result.

Abstract: A method and apparatus are disclosed for generating a quadrature signal that may be used to modulate and/or demodulate communication signals transmitted between communication devices. A quadrature signal generator may include a control block, a mixer, and a filter. The control block may generate a reference signal and a filter control signal based on an input clock signal. The mixer may generate a mixer output signal based on the input clock signal and the reference signal. The filter, controlled by the filter control signal, may filter the mixer output signal to suppress a band of frequencies within the mixer output signal.

Abstract: Block-encoded transmissions of a multi-antenna terminal unit are effectively detected in the presence of co-channel interfering transmissions when the base station has a plurality of antennas, and interference cancellation is combined with maximum likelihood decoding. More specifically, the signals received at the base station antennas are combined in a linear combination that relates to the channel coefficients between the various transmitting terminal units and the base antennas. By selecting proper coefficients for the linear combination and choosing probable transmitted signals that minimize a minimum mean squared error function, the signals of the various terminal units are canceled when detecting the signal of a particular unit. In another embodiment of the invention, the basic approach is used to obtain an initial estimate of the signals transmitted by one terminal unit, and the contribution of those signals is removed from the received signals prior to detecting the signals of other terminal units.

Abstract: A receiver for radiofrequency signals designed to be installed on board a satellite comprises: a device for frequency controlling the receiver allowing the reception frequency of the receiver to be adjusted based on a frequency command; and a filtering assembly of the bandpass filter type having a passband, referred to as passband of the filtering assembly, having an adjustable passband width able to take a set of values, the filtering assembly allowing the bandwidth of a first signal representative of the input signal of the receiver to be limited to the passband of the filtering assembly; adjustment means allowing the width of the passband of the filtering assembly to be adjusted using a filtering passband control; power acquisition means allowing a measurement of the power of the first signal to be delivered at the output of the filtering assembly.

Abstract: Many communication systems operate based on orthogonal frequency division multiplexing (OFDM) signaling and/or orthogonal frequency division multiple access (OFDMA) signaling. Within such systems, narrowband interference, which may alternatively be referred to as narrowband ingress, narrowband ingress interference, narrowband noise, etc., may adversely affect one or more subcarriers or tones causing a reduction in performance or even link failure. Such narrowband interference may affect only one or a relatively few tones employed within such communications. When the narrowband interference is identified, a transmission may then be made including one or more information-free tones. A device that receives such a transmission then uses those information-free tones to reduce or cancel the narrowband interference. Such processing may be performed in the frequency-domain, the time domain, or both.

Abstract: Methods and apparatus for mitigating baseline wander in an AC coupled transmission line are provided. An apparatus includes an input node, an output node, a sampling circuit and a level-shifting output circuit. The input and output nodes couple the apparatus in parallel with a high-pass filter of the transmission line. The sampling circuit samples an input voltage at the input node. The level-shifting output circuit delivers a level-shifted version of the input voltage to the output node. The apparatus may include a first pair of synchronized switches, a second pair of synchronized switches, and a sampling capacitor therebetween. The switches are driven periodically with concurrent closure of the two pairs of switches inhibited. The sampling capacitor couples between a signal input and a reference node upon closure of the first pair of switches, and between a bias voltage and a signal output upon closure of the second pair of switches.

Abstract: A method for discrete multitone (DMT) transmission is disclosed. In the method, a DMT signal is received from a transmission channel. The DMT signal is passed through a time-domain equalizer (TEQ) to obtain an equalized DMT signal. The DMT signal is passed through a target impulse response (TIR) filter to obtain a TIR signal. A mean square error (MSE) of an error signal is obtained from the equalized DMT signal and the TIR signal. A TEQ coefficient vector of the TEQ is iteratively updated based on the MSE of the error signal, a frequency kernel matrix corresponding to the TEQ and a frequency kernel matrix corresponding to the TIR filter.

Abstract: A double structured codebook is described that has a wideband codebook portion C(W1) and a frequency-selective codebook portion C(W2). Portion C(W2) is characterised in that for at least one rank index RI, each codeword of C(W2) is uniquely distinguished over all other codewords of C(W2) by at least two beam selection vectors per layer. A device (UE, eNB, etc) utilises the at least two different beam selection 10 vectors per layer to uniquely select a codeword W2 from C(W2) (404); and constructs a pre-coder W from the selected codeword W2 and from another codeword W1 selected from the wideband codebook portion C(W1) for signalling channel conditions (406). An additional co-phasing term for ensuring orthogonality can be utilised with the beam selection vectors per layer to uniquely select the codeword from C(W2), and the two different beam selection vectors per layer correspond to different polarizations (410).

Abstract: A control unit of a communication device provides multicast precoding information from at least first beamforming information descriptive for a first transmission channel and second beamforming information descriptive for a second transmission channel. A precoder unit beamforms at least one signal using the multicast precoding information to obtain at least two precoded signals. A transmitter circuit which is electrically coupled to the precoder unit multicasts transmission signals through the at least first and a second transmission channels, wherein the transmission signals are derived from the precoded signals.

Abstract: A broadcast signal transmitter according to one embodiment of the present invention comprises: an input signal generating unit which generates a first input signal and a second input signal; a MIMO encoder which performs MIMO processing of the first input signal and the second input signal to output a first transmission signal and a second transmission signal; and a first OFDM generator and a second OFDM generator which performs OFDM modulation of the first transmission signal and OFDM modulation of the second transmission signal. The MIMO processing applies a MIMO matrix to the first input signal and the second input signal. The MIMO matrix changes phases using a phase rotation matrix, and adjusts power of the first input signal and second input signal using parameter a, wherein the parameter is set to different values in accordance with the modulation types of the first input signal and second input signal.

Abstract: A method for performing loop unrolled decision feedback equalization (DFE) and an associated apparatus are provided.

Abstract: An apparatus and method of constructing a universal polar code is provided. The apparatus includes a first function block configured to polarize and degrade a class of channels Wj to determine a probability of error Pe,j of each bit-channel of Wj, wherein j?{1, 2, . . . , s}, in accordance with a bit-channel index i; a second function block configured to determine a probability of error Pe(i) for the universal polar code for each bit-channel index i; a third function block configured to sort the Pe(i); and a fourth function block configured to determine a largest number k of bit-channels such that a sum of corresponding k bit-channel error probabilities Pe(i) is less than or equal to a target frame error rate Pt for the universal polar code, wherein the indices corresponding to the k smallest Pe(i) are good bit-channels for the universal polar code.

Abstract: A transceiver capable of IQ mismatch compensation on the fly and a method thereof. The transceiver comprises a transmitter circuit and a loop-back circuit. The transmitter circuit is configured to up-convert a modulation signal on the fly to generate a first RF signal. The loop-back circuit is configured to down-convert the first RF signal and then digitize the down-converted first RF signal to determine a first IQ mismatch parameter based on a first statistical measure of the digitized down-converted RF signal. The transmitter circuit is further configured to compensate for first IQ mismatch in the transmitter circuit according to the first IQ mismatch parameter to generate an IQ compensated modulation signal.

Abstract: A digital front end channelization device for one or more carrier signals comprises a per carrier section and a composite section. The composite section may include signal processing units, each of which may include an inverse Fourier transform unit for transforming a composite carrier signal into a time domain signal, a sample detection and selection unit for detecting and selecting a peak of the time domain signal, a clipping unit for clipping the time domain composite carrier signal to produce an error signal, a Fourier transform unit, for transforming the error signal into a frequency domain error signal, a frequency shaping unit for frequency shaping the frequency domain error signal, a summation unit for subtracting the frequency shaped frequency domain error signal from the composite carrier signal, and a phase selection unit for phase adjustment of the resulting signal.

Abstract: A method for acquiring a Gold code, obtained as a sum of a first M-sequence (x) and a second M-sequence (yi), the first M-sequence being generated by a first generator polynomial (gx) and the second M-sequence being generated by a second generator polynomial (gy), the weight of the first generator polynomial being lower than the weight of the second generator polynomial, the acquiring method involving a first step of message passing decoding according to a first bipartite graph the edges of which are determined by the coefficients of the first generator polynomial, a decimation step using a predetermined decimation factor, and a second step of message passing decoding according to a second bipartite graph the edges of which are determined by a third generator polynomial having a minimum weight generating a third M-sequence having the same length as that of the second M-sequence.

Abstract: Embodiments are provided for early termination of an iterative process of determining channel directions and transmissions in multi-user multiple-input and multiple-output (MU-MIMO) communications systems. In an embodiment, a base station or a user equipment (UE) calculates a multi-user channel matrix using a first iteration of a null-space singular value decomposition (SVD) based iterative zero-forcing (I-ZF) algorithm for multi-user MU-MIMO. The base station or UE repeats updating the multi-user channel matrix using a next iteration of the algorithm and the multi-user channel matrix calculated in a previous iteration, until the diagonal elements of the multi-user channel matrix are greater than the off-diagonal elements by a predefined threshold. Upon determining that the diagonal elements are greater than the off-diagonal elements by the predefined threshold, a plurality of transmission signals are calculated using the last updated multi-user channel matrix.