A transmitter device comprises a first predistortion circuit and a second predistortion circuit having at least one correction stage provided with a correction path for determining a correction term. The correction term for each source signal is a function of a corresponding symbol of a predefined constellation for each source signal and of the output of a model having a circuit to emulate modulation means and the second predistortion circuit, a circuit to emulate a non-linear transmission link over which a predistorted version of an aggregate pulse-shaped signal is to be transmitted for amplitude levels before saturation of an AM/AM characteristic of the transmission link occurs and to emulate the non-linear transmission link for amplitude levels beyond saturation of the AM/AM characteristic, and a circuit to emulate demodulation means.

A method for controlling a combined waveform, representing a combination of at least two signals having orthogonal frequency multiplexed signal components, comprising: receiving information defining the at least two signals; transforming the information defining each signal to a representation having orthogonal frequency multiplexed signal components, such that at least one signal has at least two alternate representations of the same information, and combining the transformed information using the at least two alternate representations, in at least two different ways, to define respectively different combinations; analyzing the respectively different combinations with respect to at least one criterion; and outputting a respective combined waveform or information defining the waveform, representing a selected combination of the transformed information from each of the at least two signals selected based on the analysis.

A transmitter device comprises a first predistortion circuit and a second predistortion circuit having at least one correction stage provided with a correction path for determining a correction term. The correction term for each source signal is a function of a corresponding symbol of a predefined constellation for each source signal and of the output of a model having a circuit to emulate modulation means and the second predistortion circuit, a circuit to emulate a non-linear transmission link over which a predistorted version of an aggregate pulse-shaped signal is to be transmitted for amplitude levels before saturation of an AM/AM characteristic of the transmission link occurs and to emulate the non-linear transmission link for amplitude levels beyond saturation of the AM/AM characteristic, and a circuit to emulate demodulation means.

A method and apparatus for receiving a reduced peak to average power ratio signal is disclosed. The method includes receiving a signal, the signal being processed prior to transmission to reduce peak to average power ratio, determining a processing mode used to reduce the peak to average power ratio of the received signal, and reducing the amplitude level for a portion of the received signal using constant modulus clipping if the processing mode includes a two-dimensional constellation extension. The apparatus includes a processing circuit that receives a signal, the signal being processed prior to transmission to reduce peak to average power ratio, and a limiter circuit that determines a processing mode used to reduce the peak to average power ratio of the received signal and reduces the amplitude level for a portion of the received signal using constant modulus clipping if the processing mode includes a two-dimensional constellation extension.

A method and apparatus in a communication system. The method includes: detecting multiple signal peaks of a target exceeding a predetermined threshold magnitude set to constitute one or more peak clusters; generating one or more noise shaping pulse clusters; assigning one or more noise shaping pulse clusters to the detected signal peaks in one or more peak clusters to clip the detected signal peaks in frequency domain; calculating an output signal based on the clipped signal peaks; the noise shaping pulse cluster comprises multiple sub-noise shaping pulses, bandwidths of the multiple sub-noise-shaping pulses are overlapped and a bandwidth of the noise shaping pulse cluster is greater than the bandwidth of the target signal.

This disclosure relates to a peak reduction circuit and method for reducing peaks by identifying peak sample values exceeding a pre-set threshold value in an aggregated baseband carrier signal and determining a maximum peak sample by detecting its maximum peak absolute value and phase. A search is performed a pre-determined search length beyond an identified peak. A stored, predetermined filter impulse response based on the carrier passband configuration is retrieved and its amplitude and phase of the predetermined filter impulse response is adjusted by means of the phase and absolute value of the determined maximum peak sample. Finally, the aggregated baseband carrier signal and the adjusted predetermined filter impulse response are combined by synchronizing their maximum peaks and their opposite phase values for adjusting the aggregated baseband carrier signal to said pre-set threshold value.

Methods, systems, and devices for wireless communication are described. A transmitting device may determine reconstruction information for a time-domain signal and may transmit the reconstruction information with the time-domain signal to a receiving device. The transmitting device may generate the reconstruction information based on estimates of how the receiving device may process the time-domain signal. For example, the transmitting device may apply a channel estimate to samples of the time-domain signal, and further perform clipping and quantization of the samples based on an estimated dynamic analog-to-digital converter (ADC) resolution of the receiving device. The transmitting device may generate the reconstruction information (e.g., using machine learning or other techniques) based on samples having the channel estimate applied and the clipped and quantized samples. The receiving device may process the received time-domain signal and use the reconstruction information to reconstruct the processed time-domain signal.

The disclosure provides a circuit. The circuit includes an IFFT (inverse fast fourier transform) block. The IFFT block generates a modulated signal in response to a data signal. A clip logic block is coupled to the IFFT block, and generates a clipped signal in response to the modulated signal. A first subtractor is coupled to the clip logic block and the IFFT block, and subtracts the modulated signal from the clipped signal to generate an error signal. A cyclic filter is coupled to the first subtractor, and filters the error signal to generate a filtered error signal. A second subtractor is coupled to the cyclic filter and the IFFT block. The second subtractor subtracts the filtered error signal from the modulated signal to generate a processed signal.

The present disclosure describes methods, systems, and computer program products for a reducing crest factors. An input signal is received. The input signal includes a clipping signal that reduces a peak amplitude of a source signal based on a predetermined clipping level. The input signal is transposed to a plurality of transposed signals using a plurality of multipliers. A feedback signal is generated based on the plurality of transposed signals using a first plurality of delay taps. A windowing signal is generated based on the feedback signal. The windowing signal is used to reduce a crest factor of the source signal.

A distributed antenna system includes a plurality of head-end units for each receiving mobile communication signals from at least one corresponding base station, a hub unit communicatively coupled to the plurality of head-end units, and a plurality of remote units communicatively coupled to the hub unit, wherein the hub unit configured to distribute the mobile communication signals received from each of the plurality of head-end units to the plurality of remote units, wherein each of the plurality of remote units is remotely disposed to transmit the distributed mobile communication signals to a terminal in service coverage, and wherein the hub unit includes a mixing processing stage configured to perform digital mixing processing on the mobile communication signals respectively received from the plurality of head-end units, and a crest factor reduction (CFR) module disposed posterior to the mixing processing stage, with respect to a signal transmission direction.