RF signal is received (1006). The received RF signal includes a first RF signal encoding a first orthogonal frequency-division multiplexing (OFDM) symbol of a first long-term evolution (LTE) V2X data packet. A channel estimation in the time domain is determined (1012) using the received signal and an as-transmitted time domain version of an L-LTF symbol is determined (1014). The channel estimation in the time domain is applied to the as-transmitted time domain version of the L-LTF symbol to determine an as-transmitted version of the L-LTF symbol that exhibits channel fading (1018). A first portion of the as-transmitted version of the L-LTF symbol that exhibits channel fading is subtracted from a second portion of the received RF signal (1022) to remove inter-symbol interference from the received signal to generate a second received RF signal.

A method and apparatus comprises acquiring set of input streams associated with a spatial layer configured for a terminal device, and estimating a channel vector h representing a radio channel response associated with the spatial layer. An interference covariance matrix R representing power of interference is computed from at least one other spatial layer in the set of input streams and correlation of the interference within the set of input streams of the spatial layer. A per-layer interference rejection is performed, combining equalization on the set of input streams, comprising: a) estimating x=R1h as a combination of a set of linear equations, wherein the number of linear equations is defined by an input parameter to be equal to or smaller than dimensions of the interference covariance matrix; and b) computing an estimate of a transmitted symbol on the basis of the channel vector and the estimated x.

The present disclosure is directed to timestamp detection using a cable modem and to a control apparatus, control device and control method for detecting time stamps in various signals such as orthogonal frequency division multiplexing (OFDM) signals. The control apparatus comprising processing circuitry being configured to obtain information a channel frequency response of the multi-path channel, the channel frequency response being based on a signal comprising a sequence of symbols. The processing circuitry is configured to transform the channel frequency response into a channel impulse response. The processing circuitry is configured to identify a peak in the channel impulse response. The processing circuitry is configured to determine a timestamp offset time between the peak in the channel impulse response and a trigger time indicative of a beginning of a symbol in the signal. The processing circuitry is configured to synchronize the device clock based on the timestamp offset time.

Methods, systems, and devices for wireless communications are described. According to one or more aspects, a device, such as a user equipment (UE), may receive a signal including one or more channel transmission parts associated with one or more zones. The UE may identify, based on receiving the signal, at least one zone of the one or more zones that is associated with the UE. Additionally or alternatively, the UE may identify multiple zones of the one or more zones that are associated with the UE. The UE may select a channel transmission part of the one or more channel transmission parts based on receiving the signal and the identified zone associated with the UE. The UE may decode the one or more selected channel transmission parts, and may communicate based on the decoded channel transmission part or the decoded channel transmission parts.

The disclosure provides a subspace-based blind identification algorithm of an ocean underwater acoustic channel for multi-channel fir filter, which adopts a technical solution that a channel impulse response coefficient is calculated by quadratic minimization. The disclosure has beneficial effects that estimation precision can be met when using a proper number of samples, and especially when a few noise vectors are used for estimating channel parameters, so that calculation amount is greatly reduced.

A physical layer transceiver for a wireline channel medium includes a host interface to a host device, a line interface to the medium, encoding/decoding circuitry for interfacing between the host device and the medium, and adaptive filter circuitry coupled to the encoding/decoding circuitry. The adaptive filter circuitry includes a plurality of filter taps, each corresponding to a segment of the medium, and capable of being powered ON and OFF separately from each other filter tap. Adaptive control circuitry can power ON a first subset, fewer than all the filter taps, corresponding to segments distributed along the medium, monitor powered-ON filter taps for occurrence of interference events, and upon detection of an interference event at a particular segment to which a particular powered-ON filter tap corresponds, power ON one or more additional filter taps corresponding to one or more segments in a vicinity of the particular segment.

This disclosure describes systems, methods, and devices related to a trigger-based null data packet (NDP) for channel sounding system. A device may send a trigger frame to a group of station devices, the group of station devices including a first station device, the trigger frame indicating a high efficiency (HE) long training field (HE-LTF) mode and a guard interval duration. The device may identify a HE trigger-based (TB) null data packet (NDP) received from the first station device, the HE TB NDP including a first packet extension field, wherein the HE TB NDP is associated with the HE-LTF mode and the guard interval duration indicated in the trigger frame. The device may send a downlink NDP including a second packet extension field, a second HE-LTF mode, and a second guard interval duration. The device may determine channel state information based on HE TB NDP received from the first station device.

An ultra-wideband (UWB) wireless communication system, comprises a first wireless apparatus; a second wireless apparatus that participates in a first ranging sequence with the first wireless apparatus; and a transmission channel between the first and second wireless apparatuses that transmits data of the first ranging sequence. At least one of the first wireless apparatus or second wireless apparatus generating at least one channel impulse response (CIR) and determining from the at least one CIR whether the transmission channel includes a line-of-sight channel. A special purpose processor reduces a current performance level of at least one of the first and second wireless apparatuses during a second ranging sequence in response to a determination that the transmission channel includes the line-of-sight channel.

A baseband system includes: an estimation and compensation circuit estimating frequency-independent non-ideal effects based on an original IQ signal pair, and compensating the original IQ signal pair based on a result of the estimation to obtain a compensated IQ signal pair; a channel estimation and equalization circuit performing channel estimation and equalization based on the compensated IQ signal pair to obtain an equalized IQ signal pair; and a tracking and compensation circuit obtaining a result of tracking of residual quantities of the aforesaid non-ideal effects based on the equalized IQ signal pair, and compensating the equalized IQ signal pair based on the result of the tracking to obtain an output IQ signal pair.

An optical transmission method for processing a signal based on direct detection includes setting, by an equalizer, an adaptive equalization coefficient by performing an equalization process during a training symbol field section in a frame of a received signal, performing, by a channel estimator, channel estimation to perform an equalization process of a soft output maximum likelihood sequence equalizer (MLSE) during the training symbol field section, driving the soft output MLSE, and compensating for, by the soft output MLSE, distortion of the received signal during a data symbol field section in the frame on the basis of the adaptive equalization coefficient and an estimated result value of a channel, and recovering, by an error corrector which allows soft-decision processing to be performed, the received signal by performing error correction on the received signal in which the distortion is compensated for.