Methods and apparatus for processing multichannel signals in a multichannel receiver are described. In one implementation, a plurality of demodulators may provide a plurality of outputs to a processor, with the processor then simultaneously estimating noise characteristics based on the plurality of outputs and generating a common noise estimate based on the plurality of outputs. This common noise estimate may then be provided back to the demodulators and used to adjust the demodulation of signals in the plurality of demodulators to improve phase noise performance.

A group of data symbols for a current block of data symbols in multiple blocks received over a communication channel is equalized, based on a pilot block, to generate a group of equalized symbols. The group of equalized symbols is de-rotated as a function of a current phase estimate to determine initial de-rotated equalized symbols. The phase estimate is an estimate of phase caused by noise for blocks previous to the current block. Additionally, a phase metric is calculated from real and imaginary parts of the initial de-rotated equalized symbols, wherein the phase metric estimates phase caused by noise for the current block. The current phase estimate is updated with the phase metric. The initial de-rotated equalized symbols are de-rotated by the phase metric to determine final equalized and de-rotated symbol estimates. The final equalized and de-rotated symbol estimates are output. Apparatus, methods, and computer program products are disclosed.

The proposed solution relates to a method and an apparatus in a communication system. The solution includes receiving as an input a frame including of a set of data symbols and reference symbols, each data symbol forming a rectangular symbol constellation of samples, derotating the first symbol of the set on the basis of the reference symbols, and setting phase rotating angle of the first symbol as zero. The solution further includes for each following successive symbol in the set of symbols: performing equalization; reducing the number of samples in the constellation by selecting samples in two or more corners of the constellation by utilising two or more threshold values; estimating the phase rotating angle of the symbol from the reduced number of samples and derotating the symbol on the basis of the determined phase rotating angle.

Methods, systems, and devices for wireless communications are described. The described techniques may provide for an adaptive digital post-distortion (DPoD) procedure and reporting of modulation and coding scheme (MCS) indices for communications between a user equipment (UE) and a network entity. The UE may select a kernel from a set of kernels indicated by the network entity for a DPoD procedure based on a target error vector magnitude (EVM). Additionally, or alternatively, the UE may determine a limitation for an MCS index for the network entity to use in communications with the UE based on a power limitation of the UE and an EVM associated with the MCS. The network entity and the UE may accordingly communicate using the MCS limitation requested by the UE and the determined DPoD kernel.

Methods and apparatus for processing multichannel signals in a multichannel receiver are described. In one implementation, a plurality of demodulators may provide a plurality of outputs to a processor, with the processor then simultaneously estimating noise characteristics based on the plurality of outputs and generating a common noise estimate based on the plurality of outputs. This common noise estimate may then be provided back to the demodulators and used to adjust the demodulation of signals in the plurality of demodulators to improve phase noise performance.

A receiver circuit includes a conversion circuit configured to down-convert a received radio-frequency signal to a baseband signal, an analog-to-digital converter configured to sample the baseband signal into a sampled signal, a Fast Fourier transform (FFT) circuit configured to perform an FFT on the sampled signal, and a digital compensation circuit configured to compensate for IQ distortion in a frequency domain.

Methods, systems, and devices for wireless communications are described. The described techniques may provide for an adaptive digital post-distortion (DPoD) procedure and reporting of modulation and coding scheme (MCS) indices for communications between a user equipment (UE) and a network entity. The UE may select a kernel from a set of kernels indicated by the network entity for a DPoD procedure based on a target error vector magnitude (EVM). Additionally, or alternatively, the UE may determine a limitation for an MCS index for the network entity to use in communications with the UE based on a power limitation of the UE and an EVM associated with the MCS. The network entity and the UE may accordingly communicate using the MCS limitation requested by the UE and the determined DPoD kernel.

Techniques for detecting and demodulating a signal/transmission are described. Signal detection is performed in multiple stages using different types of signal processing, e.g., using time-domain correlation for a first stage, frequency-domain processing for a second stage, and time-domain processing for a third stage. For the first stage, products of symbols are generated for at least two different delays, correlation between the products for each delay and known values is performed, and correlation results for all delays are combined and used to declare the presence of a signal. For demodulation, the timing of input samples is adjusted to obtain timing-adjusted samples. A frequency offset is estimated and removed from the timing-adjusted samples to obtain frequency-corrected samples, which are processed with a channel estimate to obtain detected symbols. The phases of the detected symbols are corrected to obtain phase-corrected symbols, which are demodulated, deinterleaved, and decoded.

Methods and systems for equalizing signals are disclosed. In an example, a method for equalizing a digital signal at an equalizer, comprises: receiving, at the equalizer, a plurality of samples of the signal in a plurality of unit intervals (UIs) of a channel response of the digital signal, the plurality of samples comprising a first plurality of samples of a primary response and a second plurality of samples of one or more reflection responses; equalizing, by the equalizer, the first plurality of samples using a first set bitwidth; equalizing the second plurality of samples using one or more further set bitwidths, wherein the first set bitwidth is greater than each of the one or more further set bitwidths; and generating, by the equalizer, an equalized digital signal.

An estimating apparatus for bias drift of a transmitting end modulator, a compensating apparatus, a receiver and a method are disclosed. Estimation and compensation of the bias drift are performed directly at the receiving end according to phase recovered received signals, with no need of providing an extra bias control circuit at the transmitting end. Estimating and compensating for the bias drift includes recovering received signals by removing a frequency difference and a phase difference between a transmitting end laser and a receiving end laser producing phase recovered received signals, estimating the bias drift of the transmitting end modulator according to the phase recovered received signals and compensating the bias drift of the transmitting end modulator in a receiver.