Techniques are described for wireless communication. One method includes identifying a plurality of channel responses corresponding to a plurality of channels. Each channel of the plurality of channels corresponds to a pairing of a transmit antenna with a receive antenna. Each channel response of the plurality of channel responses corresponds to a plurality of tone subsets. The method also includes selecting, for each channel of the plurality of channels, a subset of non-frequency domain components of the channel response for the channel, and transmitting, for at least one channel of the plurality of channels, at least one subset of channel state information (CSI). The at least one subset of CSI is based at least in part on at least one of the selected subsets of non-frequency domain components.

A system that incorporates the subject disclosure may include, for example, determining an interference based on a channel gain for each signal of a group of signals received at a receiver from a group of transmitters. A determination is made as to whether the interference satisfies a threshold range of an analog-to-digital converter of the receiver for each of the group of transmitters. An analog time domain cancellation is performed responsive to a determination that the interference does not satisfy the threshold range, and a digital time domain cancellation is performed responsive to a determination that the interference satisfies the threshold range. Other embodiments are disclosed.

In a digital communication system there is provided a method for OFDM channel estimation that jointly considers the effects of coarse timing error and multipath propagation. The method uses an iterative channel estimation technique, which considers the practical scenario of fractional timing error and non-sample space echo delays. The method does not require channel state information such as second-order statistic of the channel impulse responses or the noise power. Moreover, timing error can be conveniently obtained with the proposed technique. Simulation shows that, when comparing OFDM channel estimation techniques under DOCSIS 3.1 realistic channel conditions, the proposed algorithm significantly outperforms conventional methods.

A channel estimator, comprises: a receiver receives a first time-domain training sequence; a first convolution circuit generates an estimated value for the first time-domain training sequence by convoluting a second time-domain training sequence with a current channel estimation value; a first subtractor generates an error by subtracting the estimated value for the first time-domain training sequence from the value of the first time-domain training sequence; an updating circuit generates an updated channel estimation value by updating the current channel estimation value with the error; the receiver iteratively receives a next symbol of the first time-domain training sequence, the first convolution circuit, the subtractor and the updating circuit repeat their operation until completion of receipt of a last symbol of the first time-domain training sequence. The updating circuit outputs the current updated channel estimation value upon completion of receipt of a last first time-domain training sequence.

A control method for a decision feedback equalizer (DFE) includes: generating a channel impulse response (CIR) estimation vector according to an input signal at a CIR estimation frequency; generating an FFE coefficient according to the CIR estimation vector at a first frequency; generating an FBE coefficient according to the CIR estimation vector, and the FFE coefficient at a second frequency; generating a feed-forward equalization filtered result according to the input signal and the FFE coefficient; generating a feed-backward equalization filtered result according to a decision signal and the FBE coefficient; and generating an updated decision signal according to the feed-forward equalization filtered result and the feed-backward equalization filtered result. At least one of the first frequency and the second frequency is smaller than the CIR estimation frequency.

The present invention relates to a method and apparatus for adaptive channel estimation for signal-amplitude-based communications systems. In one arrangement, the method comprises: receiving an observation (r) of a transmitted coded symbol (d); generating, with a weight generator, a first coefficient (v) for weighting the received observation based on an estimate of the transmitted coded symbol (d_est), the first coefficient having a magnitude that is invariable with the amplitude of the transmitted coded symbol; and forming a new channel estimate (h_est) based on a weighted observation using the first coefficient (v).

The present invention relates to a method and apparatus for demodulation in a wireless communications system transmitted across a wireless communications channel. The described wireless receiver includes a first antenna for receiving a wireless signal including a symbol transmitted across a wireless communications channel perceived by the first antenna, an observation modifier for generating a modified observation (y) of the symbol based on a product of the received observation (r) and the complex conjugate of a channel estimate (h*), a log-likelihood ratio (LLR) module generating log-likelihood ratios (LLRs) based on the modified observation and the channel estimate, and a maximum-likelihood-based decoder for decoding the symbol based on the LLRs.

A calibration apparatus for calibrating a transceiver includes a loop back circuit, an estimation circuit, and a calibration circuit. The loop back circuit is coupled between a mixer output port of a transmitter (Tx) of the transceiver and a mixer input port of a receiver (Rx) of the transceiver, and applies a sequence of different loop gains. The estimation circuit receives a loop back receiving signal that is output from the Rx under the sequence of different loop gains, and generates at least one estimated value of impairment of the transceiver by performing channel estimation according to at least the loop back receiving signal. The calibration circuit performs calibration upon the transceiver according to the at least one estimated value.

Methods, systems, and devices for wireless communications are described. A device may receive a set of demodulation reference signals (DMRSs) over a multi-path channel on a set of resources in accordance with a reference signal pattern. The reference signal pattern may be associated with a non-uniform frequency spacing that results in a row-sampled Discrete Fourier Transform (DFT) matrix associated with the reference signal pattern having a lower coherence than other row-sampled DFT matrices. Additionally or alternatively, the device may receive a set of tracking reference signals (TRSs) over the multi-path channel. The set of TRSs may be specific to wide-area terrestrial broadcast services, single frequency network (SFN)-based broadcast services, multimedia broadcast multicast services (MBMSs), or the reference signal pattern. The device may perform channel estimation based on receiving one or both of the set of DMRSs or the set of TRSs over the multi-path channel.

Various solutions for an artificial intelligence/machine learning (AI/ML) positioning model using relative time input with respect to an apparatus in mobile communications are described. The apparatus may measure a first channel delay profile with a first path timing according to a first reference signal associated with a first network node. The apparatus may adjust the first path timing by a timing difference associated with a reference network node. The apparatus may: (1) generate a model output by a positioning model based on the first channel delay profile with the adjusted first path timing used as model inputs; or (2) report the first channel delay profile with the adjusted first path timing to a network.