Provided is a transmission device for transmitting data in a wireless communication based on DFT-spread OFDM. Specifically, provided is a transmission device which outputs a first sub-band and a second sub-band by performing DFT on an input symbol with a tail part and a head part in which at least one 0 has been inserted by a DFT block controlled by a processor, outputs a signal by performing IDFT on the first sub-band which has been mapped by a first IDFT block, allows the signal to be filtered by a first band pass filter, outputs a signal by performing IDFT on the second sub-band which has been mapped by a second IDFT block, and allows the signal to be filtered by a second band pass filter.

Embodiments of the present disclosure include an OFDM receiver circuit, which includes an FFT circuit configured to calculate an FFT of a plurality of sample values received by the receiver circuit, and a smoothing circuit configured to identify equalizer coefficients for the sample values by truncating portions of an impulse response of the FFT.

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.

Systems and methods for adjusting timing in a communication system, such as an OFDM system are described. In one implementation an error signal is generated to adjust the timing of a variable rate interpolator so as to adjust FFT timing. The error signal may be based on detection of significant peaks in an estimate of the impulse response of the channel, with the peak locations being tracked over subsequent symbols and the system timing adjusted in response to changes in the peaks.

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.

It is proposed a method for delay spread classification of an orthogonal frequency-division multiplexing signal (multiplexing signal), and a receiving device and a telecommunication device connected thereto, the multiplexing signal comprising at least a first multiplexing symbol comprising at least two first reference symbols in the frequency domain, the method comprising: receiving at least the first multiplexing symbol; demodulating at least the first reference symbols of the first multiplexing symbol; determining at least a first autocorrelation value by autocorrelating the demodulated first reference symbols in the frequency domain; computing the filtered output energy of the autocorrelation and classifying the delay spread by mapping the ratio of the output energy for the filters.

Data can be received characterizing a first signal transmitted in an orthogonal frequency-division multiplexing (OFDM) system by a transmitter with one or more transmit antennas through a wireless channel and received by a receiver with a plurality of receive antennas, the first signal including a plurality of pilot pulses. A final estimated channel impulse response of the wireless channel can be determined for each pair of transmitter and receiver antennas by iteratively finding one or more significant delay taps of an intermediate channel impulse response estimate and adding the one or more significant delay taps to an error of the intermediate channel impulse response estimate. Data characterizing the final estimated channel impulse response can be provided. Related apparatus, systems, techniques, and articles are also described.

Systems and methods for adjusting timing in a communication system, such as an OFDM system are described. In one implementation an error signal is generated to adjust the timing of a variable rate interpolator so as to adjust FFT timing. The error signal may be based on detection of significant peaks in an estimate of the impulse response of the channel, with the peak locations being tracked over subsequent symbols and the system timing adjusted in response to changes in the peaks.

Disclosed is an apparatus, computer implemented method and method for preforming channel estimation in a millimeter wave wireless communication system which includes receiving complementary sequences at a receiver of the millimeter wave wireless communication system; estimating a channel estimation of a channel among the received complementary sequences; estimating a signal-to-noise ratio (SNR) estimation of the channel; detecting a maximum channel response value of the channel estimation; computing a de-noised threshold value from the maximum channel response value and the SNR estimation of the channel; comparing the de-noised threshold value to the channel estimation to detect a last valid tap of a channel impulse response; and zeroing out all the taps after the detected last valid tap of the channel impulse response.

A wireless transmit/receive unit (WTRU) may receive configuration information that indicates one or more of a first transmission configuration indicator (TCI) state, a second TCI state, a first cyclic prefix (CP) size, a first channel state information-reference signal (CSI-RS) resource set, and a second CSI-RS resource set. The WTRU may determine a first delay spread and a first measurement value associated with a first CSI-RS. The WTRU may determine a second delay spread and a second measurement value associated with a second CSI-RS. The WTRU may send a first indication indicating whether the first delay spread is greater than or less than the first CP size.