US-12627531-B2 - Selecting a signal phase in a communication system

US12627531B2US 12627531 B2US12627531 B2US 12627531B2US-12627531-B2

Abstract

In some aspects, there is provided a method. The method may include estimating, based on a first signal-phase in a plurality of signal-phases associated with an input signal, a first channel impulse response; estimating, based on a second signal-phase in the plurality of signal-phases, a second channel impulse response; selecting, based on at least one characteristic of the estimated first channel impulse response and the estimated second channel impulse response, a signal-phase from the plurality of signal-phases; equalizing, based on the selected signal phase, the input signal to produce an equalized signal; and outputting, to a symbol detector, the equalized signal. Related systems, methods, and articles of manufacture are also disclosed.

Inventors

Thomas Guerena

Assignees

Nantworks, LLC

Dates

Publication Date: 20260512
Application Date: 20230818

Claims (20)

1 . A signal processing system comprising: an analog-to-digital (ADC) converter configured to sample an analog input signal and provide a data stream including one or more data packets; a channel impulse response (CIR) estimator-generator configured to receive channel-estimation data for each of the one or more data packets, and generate a CIR estimate including a plurality of sequences each associated with a different signal phase of the sampled analog input signal, wherein each different signal phase is based on a product of an oversampling factor and an up-sampling factor, and the product is an integer value greater than two; a phase selection logic configured to determine, based on CIR characteristics received from the CIR estimator-generator, a signal phase for equalization; and a symbol-spaced equalizer configured to, generate equalization coefficients based on one of the plurality of sequences of the CIR estimate which corresponds to the determined signal phase for equalization, and output an equalized signal, based on the equalization coefficients, to one or more downstream processing stages.
2 . The signal processing system of claim 1 , wherein the ADC converter is configured to operate at a sampling rate, based on a frequency of a sampling clock signal, to generate a signal including digital samples representative of the analog input signal.
3 . The signal processing system of claim 1 , further comprising a filter configured to execute at least one of up-sampling of the sampled analog input signal, interpolation of the sampled analog input signal, or down-sampling of the sampled analog input signal.
4 . The signal processing system of claim 3 , further comprising a time-frequency offset compensator configured to apply a correction to a filtered signal received from the filter, to compensate for a frequency offset between a sampling clock signal and a transmitter of a wireless signal associated with the sampled analog input signal.
5 . The signal processing system of claim 3 , wherein the phase selection logic is configured to provide a control signal to the filter to request the filter to output at least one of a signal which is shifted in time or one or more specific signal phases.
6 . The signal processing system of claim 1 , wherein the CIR estimator-generator is configured to, based on a control signal received from the phase selection logic, generate an intermediate phase CIR interpolating two estimated sequences having two signal phases.
7 . The signal processing system of claim 6 , wherein the interpolation includes at least one of linear interpolation, polynomial interpolation, and spline interpolation.
8 . The signal processing system of claim 1 , wherein each of the one or more data packets includes a synchronization field, a channel estimation field, a header field, and a payload field.
9 . The signal processing system of claim 1 , wherein the symbol-spaced equalizer is configured to generate the equalization coefficients according to at least one of zero-forcing (ZF) coefficient generation criteria and minimum mean-squared error (MMSE) coefficient generation criteria.
10 . The signal processing system of claim 1 , wherein the symbol-spaced equalizer is configured to perform a shift of the equalized signal in a frequency domain.
11 . A non-transitory computer readable medium configured to store instructions which, when executed by at least one processor, cause the at least one processor to perform a method including: estimating, by a communication device based on a first signal phase in a plurality of signal phases associated with an input signal, a first channel impulse response, wherein the plurality of signal phases is based on a product of an oversampling factor and an up sampling factor, and the product is an integer value greater than two; estimating, based on a second signal phase in the plurality of signal phases, a second channel impulse response; selecting, based on at least one characteristic of the estimated first channel impulse response and the estimated second channel impulse response, a signal phase from the plurality of signal phases; equalizing, based on the selected signal phase, the input signal to produce an equalized signal; and outputting, to a symbol detector, the equalized signal.
12 . The non-transitory computer readable medium of claim 11 , wherein the first channel impulse response estimate includes a first sequence of values, wherein the at least one characteristic of the first channel impulse response estimate includes a first maximum value of the first sequence of values, wherein the second channel impulse response estimate includes a second sequence of values, and wherein the at least one characteristic of the second channel impulse response estimate includes a second maximum value of the second sequence of values.
13 . The non-transitory computer readable medium of claim 12 , wherein each value in the first sequence of values is associated with a first sequence time index, and wherein each value in the second sequence of values is associated with a second sequence time index.
14 . The non-transitory computer readable medium of claim 13 , wherein the instructions cause the at least one processor to further perform: determining, by the communication device, a first set of threshold values based on the first maximum value being equal to or greater than the second maximum value; and determining, by the communication device, a second set of threshold values based on the first maximum value being less than the second maximum value.
15 . The non-transitory computer readable medium of claim 14 , wherein the instructions cause the at least one processor to further perform: selecting, by the communication device, at least one of the first signal phase, the second signal phase, and an intermediate signal phase from the plurality of signal phases, wherein the selection is based on the first maximum value, the second maximum value, the first sequence time index, the second sequence time index, and at least one of the first set of threshold values and the second set of threshold values.
16 . The non-transitory computer readable medium of claim 12 , wherein the instructions cause the at least one processor to further perform: selecting the second signal phase as the signal phase based on the second maximum value being greater than the first maximum value.
17 . The non-transitory computer readable medium of claim 12 , wherein the instructions cause the at least one processor to further perform: selecting the first signal phase as the signal phase based on the first maximum value being equal to or greater than the second maximum value.
18 . The non-transitory computer readable medium of claim 12 , wherein the first channel impulse response estimate includes a first sequence of values, wherein the second channel impulse response estimate includes a second sequence of values, wherein each value in the first sequence of values is associated with a first sequence time index, and wherein each value in the second sequence of values is associated with a second sequence time index.
19 . A non-transitory computer readable medium configured to store instructions which, when executed by at least one processor, cause the at least one processor to perform a method including: estimating, by a communication device based on a first signal phase in a plurality of signal phases associated with an input signal, a first channel impulse response; estimating, based on a second signal phase in the plurality of signal phases, a second channel impulse response; selecting, based on at least one characteristic of the estimated first channel impulse response and the estimated second channel impulse response, a signal phase from the plurality of signal phases, wherein the first channel impulse response estimate includes a first sequence of values, the at least one characteristic of the first channel impulse response estimate includes a first maximum value of the first sequence of values, the second channel impulse response estimate includes a second sequence of values, the at least one characteristic of the second channel impulse response estimate includes a second maximum value of the second sequence of values, each value in the first sequence of values is associated with a first sequence time index, and each value in the second sequence of values is associated with a second sequence time index; generating, by the communication device, an interpolated sequence of values based on a first portion of the first channel impulse response estimate and a second portion of the second channel impulse response estimate, wherein the first portion and the second portion are based on at least one of the first maximum value, the second maximum value, the first sequence time index, and the second sequence time index; selecting, by the communication device, the signal phase based on a third maximum value of the interpolated sequence of values; generating, by the communication device, a third channel impulse response estimate by down sampling, based on the third maximum value, the interpolated sequence of values; equalizing, based on the selected signal phase, the input signal to produce an equalized signal; and outputting, to a symbol detector, the equalized signal.
20 . The non-transitory computer readable medium of claim 19 , wherein the plurality of signal phases is based on a product of an oversampling factor and an up sampling factor, and wherein the product is an integer value greater than two.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 17/204,738, filed Mar. 17, 2021, which claims the benefit of U.S. Provisional Patent Application No. 62/992,670, filed Mar. 20, 2020. The disclosures of each of the above applications are incorporated by reference herein in their entireties. FIELD The subject matter described herein relates generally to communication systems and, more specifically, to selecting a signal phase. BACKGROUND A communication device may include one or more systems, including circuitries and software, for receiving and processing an analog signal (e.g., a baseband signal.) A signal processing system may apply one or more analog-to-digital conversion techniques to convert the analog signal to digital samples. Moreover, the signal processing system may determine and select a signal phase and estimate a channel impulse response for equalization. SUMMARY In certain aspects of the current subject matter, challenges associated with the performance of a symbol-spaced equalizer may be addressed by the inclusion of one or more features described herein or comparable/equivalent approaches as would be understood by one of ordinary skill in the art. Aspects of the current subject matter relate to apparatuses, methods, and systems for generating and selecting a signal phase. In some aspects, there is provided a method. The method may include estimating, based on a first signal-phase in a plurality of signal-phases associated with an input signal, a first channel impulse response; estimating, based on a second signal-phase in the plurality of signal-phases, a second channel impulse response; selecting, based on at least one characteristic of the estimated first channel impulse response and the estimated second channel impulse response, a signal-phase from the plurality of signal-phases; equalizing, based on the selected signal phase, the input signal to produce an equalized signal; and outputting, to a symbol detector, the equalized symbol. In some variations, one or more of the features disclosed herein including the following features may optionally be included in any feasible combination. The first channel impulse response estimate and the second channel impulse response estimate may each be a time-domain estimate. The first channel impulse response estimate may include a first sequence of values, and the second channel impulse response estimate may include a second sequence of values. The at least one characteristic of the first channel impulse response estimate may include a first maximum value of the first sequence of values, and the at least one characteristic of the second channel impulse response estimate may include a second maximum value of the second sequence of values. The method may include selecting the second signal-phase as the signal-phase based on the second maximum value being greater than the first maximum value. The method may include selecting the first signal-phase as the signal-phase based on the first maximum value being equal to or greater than the second maximum value. The plurality of signal-phases may be based on a product of an oversampling factor and an up-sampling factor, and wherein the product is an integer value greater than 2. Each value in the first sequence of values may be associated with a first sequence time index, and each value in the second sequence of values may be associated with a second sequence time index. The method may include determining a first set of threshold values based on the first maximum value being equal to or greater than the second maximum value. The method may include determining a second set of threshold values based on the first maximum value being less than the second maximum value. The method may include selecting at least one of the first signal-phase, the second signal-phase, and an intermediate signal-phase from the plurality of signal-phases, wherein the selection is based on the first maximum value, the second maximum value, the first sequence time index, the second sequence time index, and at least of the first set of threshold values and the second set of threshold values. The first set of threshold values and/or the second set of threshold values may include at least one of a set of fixed values, a set of programmable values, and a set of threshold values based on at least one of the first maximum value and the second maximum value. The selected signal-phase may correspond to one of the plurality of signal-phases having the oversampling factor being at least 3 and the up-sampling factor being 1. The selected signal-phase may correspond to one of a plurality of interpolated signal-phases. The method may include estimating a third channel impulse response based on an intermediate signal-phase selected as the signal-phase. The third channel impulse response may be estimated based on the first channel impulse response estimate and the second channel impulse respon