Embodiments of the present disclosure provide a method performed by a communication device. The method includes obtaining, in frequency domain, channel estimation for a transmission unit for a channel between the communication device and another communication device, and calculating correlation coefficients for the transmission unit based on the channel estimation. The method also includes obtaining a delay spread for the channel from the calculated correlation coefficients.

A method and device for increasing an accuracy of a phase measurement, wherein the method includes: receiving a measurement signal; performing a frequency-domain transformation to the measurement signal to obtain a frequency-domain measurement sequence; determining phases that correspond to frequency-domain measurement signals, and determining a phase difference between the frequency-domain measurement signals that correspond to two neighboring specified frequency points; according to the phases, the phase difference and a window function, performing a sliding-window-type phase fitting to the frequency-domain measurement sequence, to obtain phase-fitting data that correspond to sliding windows; and according to the phase-fitting data of the sliding windows, determining phase-calibration data that correspond to the sliding windows, and, by using the phase-calibration data of the sliding windows, forming phase-calibration data within a specified frequency band. The method reduces an error of fitting, and increases an accuracy of a phase calibration.

Techniques are provide for neural network based positioning of a mobile device. An example method for determining a line of sight delay, an angle of arrival, or an angle of departure value, according to the disclosure includes receiving reference signal information, determining a channel frequency response or a channel impulse response based on the reference signal information, processing the channel frequency response or the channel impulse response with a neural network, and determining the line of sight delay, the angle of arrival, or the angle of departure value based on an output of the neural network.

A system and method of DFT-S-OFDM modulation is provided that uses a set of frequency domain patterns. For a given transmitter, for a set of DFT-S-OFDM symbols, the frequency domain pattern changes according to a time domain hopping pattern. Advantageously, the time domain hopping patterns are defined to allow only a certain amount of overlap, for example for only one DFT-S-OFDM symbol, between any two time domain hopping patterns. This functions to reduce the effect of a collision, when two transmitters use the same frequency pattern, they will do so only for part of the overall transmission. Optionally, frequency domain spectral spreading is used in the transmitter. This can further reduce the PAPR. In the receiver, successive interference cancellation may be employed to reduce the effect of colliding transmissions.

An HE-LTF transmission method is provided, including: determining, based on a total number N.sub.STS of space-time streams, a number N.sub.HELTF of OFDM symbols included in an HE-LTF field; determining a HE-LTF sequence in frequency domain according to a transmission bandwidth and a mode of the HE-LTF field, where the HE-LTF sequence in frequency domain includes but is not limited to a mode of the HE-LTF field sequence that is in a 1x mode and that is mentioned in implementations; and sending a time-domain signal according to the number N.sub.HELTF of OFDM symbols and the determined HE-LTF sequence in frequency domain. In the foregoing solution, a PAPR value is relatively low.

Disclosed are a wireless transmitter and a reference signal transmission method that improve channel estimation accuracy. In a terminal, which transmits a reference signal using n (n is a non-negative integer 2 or greater) band blocks (which correspond to clusters here), which are disposed with spaces therebetween in a frequency direction, a reference signal controller switches the reference signal formation method of a reference signal generator between a first formation method and a second formation method based on the number (n) of band blocks. In addition, a threshold value setting unit adjusts a switching threshold value based on the frequency spacing between band blocks. Thus, the reference signal formation method can be selected with good accuracy and, as a result, channel estimation accuracy is further improved.

Certain aspects of the present disclosure provide techniques for channel estimation for two-stage sidelink control using sidelink data channel demodulation reference signals (DMRS). A user equipment (UE) can transmit DMRS for the sidelink data channel. The UE may transmit the second stage of the sidelink control using antenna ports or a precoder used for the sidelink data channel. The receiving device may receive the DMRS, estimate the channel, and demodulate the second stage of the sidelink control based on the estimated channel. The receiving device may flexibly determine the DMRS to use for the estimation and demodulation.

A method and system to determine an adjusted guard interval duration associated with a wireless signal transmitted via a wireless communication link between a first network device and a second network device in a wireless network. The second network device receives a first wireless signal including a first duration of a guard interval from the first network device at a first time. The second network device determines, in view of the set of pilot symbols, a channel impulse response. A channel parameter value is determined based on the channel impulse response. An adjusted guard interval duration corresponding to the channel parameter value is established and used to estimate a second physical rate of the link. The second network device provides a communication identifying the adjusted guard interval duration to the first network device in response to determining the second physical rate is greater than the first physical rate.

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Embodiments herein disclose methods for managing CSI feedback compression in wireless network by base station. The method includes transmitting at least one pilot symbol over first window. The method includes receiving at least one of a first and second type feedback from a UE at an end of the first window or after the first window. The method includes receiving the compressed CSI feedback based on predefined precoder weights in the first window. The method includes computing and predicting at least one precoder weight for the UE in at least one time instant in a second window for at least one sub-band of the UE based on the at least one of the first and second type feedback. The method includes managing the received CSI feedback compression based on the predicted precoder weight.

Wireless communication transmission and reception techniques are described. At transmitter, source data bits are modulated into a number Nd of constellation symbols. An invertible transform is applied to the constellation symbols, thereby resulting in mapping the transformed symbols into Nd elements in the time-frequency grid. A signal resulting from the invertible transform is transmitted over a communication channel.