A method is provided for estimating at least one characteristic of a signal received by a receiver, the signal having been transmitted in succession by a plurality of antennas in successive time segments, each segment being dedicated to one separate antenna, the signal being modulated into the form of pulses according to ultra-wideband modulation. The method includes steps of: receiving and digitizing the signal, computing the product of multiplication of each symbol of the received signal by the complex conjugate of the corresponding transmitted symbol, for each segment and for each symbol of the signal received for this segment, estimating a phase error by means of a phase-locked loop applied to the product, for each segment, determining a reference phase by means of a linear regression applied to the phase errors estimated for all of the segments, determining, for at least one pair of antennas, a phase difference between the signals transmitted by the antennas of the pair, on the basis of the difference between the reference phases computed for the segments associated with the antennas.

An over-the-air computation (AirComp) scheme is proposed for federated edge learning (FEEL) without channel state information (CSI) at the edge devices (EDs) or edge server (ES). The proposed scheme adopts the majority vote (MV) principle and uses pulse-position modulation (PPM) symbols constructed with discrete Fourier transform (DFT)-spread orthogonal frequency division multiplexing (OFDM) (DFT-s-OFDM) as votes from EDs. By taking the delay spread and synchronization errors into account, we show how to eliminate the need for truncated-channel inversion (TCI) at the EDs and detect MV at the ED with a non-coherent detector. The proposed method naturally reduces the peak-to-mean envelope power ratio (PMEPR) of the signal as it inherits the properties of the single-carrier (SC) waveform. An alternative proposed scheme also adopts the majority vote (MV) principle but further defines multiple subcarriers and orthogonal frequency division multiplexing (OFDM) symbols for voting options, which reduces to frequency-shift keying (FSK) over OFDM subcarriers as a special case. Since the votes from EDs are separated on orthogonal resources, the proposed scheme eliminates the need for truncated-channel inversion (TCI) at the EDs and allows the ES to detect MV with a non-coherent detector. We also mitigate the peak-to-mean envelope power ratio (PMEPR) of the synthesized signals by using randomization symbols. Through simulations, we show that the proposed schemes provide high test accuracy in fading channels for both independent and identically distributed (IID) and non-IID data while resulting in lower PMEPR symbols as compared to one-bit broadband digital aggregation (OBDA) with quadrature amplitude modulation (QAM).

A communication device receives a physical layer (PHY) protocol data unit (PPDU). The PPDU includes i) a PHY preamble and ii) PHY data portion that includes one or more PHY midambles, and the PHY preamble includes i) an indication of a length of the PPDU, and ii) an indication of a periodicity of PHY midambles in the PHY data portion. The communication device calculates a number of PHY midambles in the PPDU using i) the indication of the length of the PPDU, and ii) the indication of the periodicity of PHY midambles. The communication device calculates a reception time for the PPDU using the calculated number of PHY midambles, and processes the PPDU using the calculated reception time.

The disclosure relates to a wireless communication system, and relates to a method and apparatus for scheduling a plurality of user equipments (UEs) by considering a frequency selectivity. A method, performed by a base station, for transmitting or receiving data in a wireless communication system according to an embodiment includes determining a UE candidate group set based on channel state information for channels of a plurality of carriers, determining an offset used to adjust the number of UEs of the UE candidate group set, based on frequency selectivity information between a representative channel selected from among the channels of the plurality of carriers and other channels, based on the offset, determining a plurality of UEs to which data is to be transmitted, and transmitting the data to the determined plurality of UEs.

In one embodiment, an apparatus includes a baseband circuit to generate a plurality of subcarriers of a complex sample of a message to be transmitted, and a compensation circuit coupled to the baseband circuit, the compensation circuit to compensate for IQ mismatch. The compensation circuit may include: a calibration circuit to determine, using a tone signal, gain correction values and phase correction values for a subset of the plurality of subcarriers; and a correction circuit to apply the gain correction values and the phase correction values to the plurality of subcarriers to compensate for the IQ mismatch.

One embodiment according to the present specification relates to a method for constructing a preamble in a wireless LAN (WLAN) system. According to various embodiments, a PPDU may comprise a first signal field and a second signal field. The first signal field may include first information about PHY version. The first information may be determined on the basis of whether the PPDU is an EHT PPDU. The second signal field may include second information about the transmission of the PPDU, which is set on the basis of the first information.

The present disclosure relates to a method and apparatus for receiving signal, which belong to the field of a communication technology. The method comprises the following steps: determining a first frequency domain position and a second frequency domain position; determining a first frequency resource allocated for the first subcarrier spacing and a second frequency resource allocated for the second subcarrier spacing in the frequency band; receiving the signal on the first frequency resource according to the first frequency domain position, and receiving the signal on the second frequency resource according to the second frequency domain position. According to the method and apparatus, expanded service demands of a terminal can be met.

Presented herein are systems and methods for beam information feedback. A first communication node may receive, from a second communication node, a group of reference signals that are carried either on respective beams or on a same beam. The group of reference signals may be determined based on one or more time-frequency-code resources. The first communication node may determine, based on the group of reference signals, one or more beam indexes and channel state information. The first communication node may transmit, to the second communication node, a set including the one or more beam indexes and the channel state information.

The apparatus may be a UE. The UE may be configured to measure, over a time interval, a plurality of instances of a signal received from a serving device (e.g., a base station or serving UE). The UE may further be configured to adjust, based on at least two previously measured instances of the signal, a sampling rate associated with the signal received from the serving device. The UE may further be configured to maintain a particular number (e.g., 2-10) of previously measured instances of the signal, where adjusting the sampling rate is based on the maintained particular number of previously measured instances. The particular number of previously measured instances of the signal may be used to calculate a gradient of the measurements to identify a sampling rate associated with the calculated gradient.

A method for detecting OTFS pilot interference including receiving delay-Doppler-domain samples of a received OTFS delay-Doppler frame, wherein the delay-Doppler domain samples are derived by a two-dimensional symplectic Fourier transformation of time-frequency domain samples resulting from sampling a time-varying received OFTS coded signal; summing the squares of the amplitudes of the delay-Doppler domain samples of the delay-Doppler grid positions evaluated for the channel estimation to establish the received non-interfering pilot power; summing the squares of the amplitudes of all the delay-Doppler domain samples of the complete delay-Doppler grid to establish the total received frame power; comparing a pilot power ratio derived by dividing the non-interfering pilot power by the total received frame power with a guard space ratio derived by dividing the sum of the number of guard and pilot grid spaces in the transmitted OTFS frame by the total number of grid spaces of the transmitted OTFS frame.