The present disclosure provides a method for estimating timing and/or frequency of a wireless signal; the method including the steps: receiving a digitally modulated signal; extracting a plurality of signal samples associated with a short training field (STF) of a PHY protocol data unit (PPDU) of an 802.11 frame; performing correlation operations on the plurality of signal samples to generate a predetermined number of correlation peaks; comparing the generated correlation peaks with a variable dynamic threshold; and calculating timing and/or frequency of the digitally modulated signal using the outcome of the comparing step.

A MS transmits, to a BS, uplink data (UD) on a PUSCH, PUSCH being assigned by using a PDCCH. The MS receives on PDCCH, an indication instructing the MS to transmit reception quality information (RQI) without UD on PUSCH, and transmits on PUSCH, to the BS, RQI without UD based on the indication which is received on PDCCH. The indication is specified based on values to which a plurality of fields of information transmitted on PDCCH are set. One of the plurality of fields is a field used for instructing the MS to transmit RQI and another is a field used for indicating a redundancy version. For instructing the MS to transmit RQI without UD on PUSCH, the field used for instructing the MS to transmit RQI is set to a first single predetermined value (SPV) and the field used for indicating the redundancy version is set to a second SPV.

A method for accommodating users in an uplink channel is provided. The method comprises a processor for selecting a region of sub carriers in a frequency domain, wherein a channel value of a plurality of users over the selected region varies gradually. The processor is further configured to select the sub carriers within the selected region of sub carriers by skipping the sub carriers by an integer value which is 0 or more than 0. A product of a known sequence and an exponential sequence is transmitting over the selected sub carriers, wherein the exponential sequence is characterized by a cyclic shift value. Further, a base station is configured to perform channel estimation of the users using the received selected sub carriers within the selected region and the processor is also configured to perform data detection for the users over the selected sub carriers using the estimated channel value.

The present disclosure discloses a signal equalization apparatus. A channel length estimation circuit determines a transmission channel length of the input signal such that a processing circuit retrieves predetermined feed-forward equalizer coefficients. A feed-forward equalizer equalizes the input signal according to operation feed-forward equalizer coefficients. An auto gain circuit amplifies the input signal according to an offset signal. A signal adding circuit adds the amplified input signal and a feedback adjusting signal to generate an added input signal. A data slicer generates a data-slicing result and the offset signal according to reference thresholds based on the added input signal. A feedback equalizer equalizes the data-slicing result to generate the feedback adjusting signal according to operation feedback equalizer coefficients. The feed-forward equalizer and the feedback equalizer keeps updating the equalizer coefficients such that a signal interference noise is eliminated rapidly to increase a signal and noise ratio of the system.

In one example aspect, a method of determining a channel estimate of an optical communications channel between at least one optical transmitting component and at least one optical receiving component is provided, the method comprising determining a location of at least one optical transmitting component, determining an orientation of the at least one optical transmitting component, determining a transmission characteristic of the at least one optical transmitting component, determining a location of at least one optical receiving component, determining an orientation of the at least one optical receiving component, determining a reception characteristic of the at least one optical receiving component, and calculating the channel estimate of the optical communications channel based on the location of the at least one optical transmitting component, the orientation of the at least one optical transmitting component, the transmission characteristic of the at least one optical transmitting component, the location of the at least one optical receiving component, the orientation of the at least one optical receiving component and the reception characteristic of at least one optical receiving component.

A reception device includes an equalization processing unit including a linear filter unit and a nonlinear filter unit and performing equalization process on a reception signal; a linear propagation channel estimation unit making propagation channel estimation using a known signal included in a reception signal to calculate a filter coefficient of the linear filter unit; and a synchronization processing unit performing synchronization process of correcting frequency deviation based on a signal output by the equalization processing unit, and when a predetermined condition is satisfied after executing first equalization process of outputting a reception signal filtered by the linear filter unit to the synchronization processing unit, the equalization processing unit starts second equalization process that is an adaptive equalization process of outputting a result of addition of a reception signal filtered by the linear filter unit and a reception signal filtered by the nonlinear filter unit to the synchronization processing unit.

This disclosure describes systems, methods, and devices related to multi-user uplink channel sounding. A device may determine a channel sounding sequence with one or more access points (APs), wherein the channel sounding sequence comprises a null data packet announcement (NDPA) communicated with at least one of the one or more APs. The device may determine a first group of station devices (STAs) associated with a first basic service set (BSS). The device may cause to send a trigger frame to the first group of STAs to solicit an uplink NDP from each STA of the first group of STAs. The device may identify a first uplink NDP received from a first STA of the first group of STAs. The device may identify a second uplink NDP received from a second STA of a second group of STAs.

A wireless communication receiver including a serial to parallel converter receiving an radio frequency signal, a fast Fourier transform device connected to said serial to parallel converter converting N.sub.FFT corresponding serial signals into a frequency domain; an EZC root sequence unit generating a set of root sequence signals; an element-by-element multiply unit forming a set of products including a product of each of said frequency domain signals from said fast Fourier transform device and a corresponding root sequence signal, an N.sub.SRS-length IDFT unit performing a group cyclic-shift de-multiplexing of the products and a discrete Fourier transform unit converting connected cyclic shift de-multiplexing signals back to frequency-domain.

A communication device and method include a reconfigurable receiver that is reconfigurable between communication, ranging and radar modes. The reconfigurable receiver includes a mixer configured to mix digital samples with a carrier phase estimate signal and configured to generate in-phase digital samples based on the carrier phase estimate. The reconfigurable receiver further includes a symbol correlator configured to correlate against the in-phase digital samples and generate correlated data, and a symbol binning unit configured to bin the correlated data and generate a first order channel impulse response estimate. The reconfigurable receiver yet further includes a multiplexer configured to switch the digital samples to the symbol binning unit when the reconfigurable receiver is configured in radar mode and to switch the correlated data to the symbol binning unit when the reconfigurable receiver is configured in a ranging mode.

A phase calibration method includes: segmenting a received measurement sequence according to a preset rule; respectively determining a phase calibration factor of each of segmented measurement sequences, wherein the each of the segmented measurement sequences respectively corresponds to a segmented phase; and when performing a phase calibration on a sequence to be verified, according to a matching relation between a phase of the sequence to be verified and the each of the segmented phases, using the phase calibration factor corresponding to a matched segmented phase to perform the phase calibration on the sequence to be verified. The embodiments of the phase calibration method and the device are equivalent to dividing a non-linear measurement sequence into several approximately linear measurement sequences, and then calibrating each of the several approximately linear measurement sequences using a corresponding phase calibration factor respectively.