A user device communicates in a wireless network by encoding a set of data symbols with a set of complex-valued codes to produce a set of subcarrier values. The subcarrier values are modulated onto a set of Orthogonal Frequency Division Multiplexing (OFDM) subcarriers assigned to the user device to produce a time-domain waveform that comprises a superposition of modulated subcarriers, and the time-domain waveform is transmitted in the wireless network. The set of subcarrier values comprises a first polyphase code that encodes a first of the set of data symbols and at least a second polyphase code that encodes at least a second of the set of data symbols. The first polyphase code causes constructive and destructive interference between the modulated subcarriers to produce a first periodic pulse waveform having a peak value centered at a first time in an OFDM symbol interval, and the second polyphase code causes constructive and destructive interference between the modulated subcarriers to produce a second periodic pulse waveform having a peak value centered at a second time in the OFDM symbol interval, wherein the second time is different from the first time.

A method comprises: digitizing a signal to produce a reference frame of amplitude samples in a time-domain; generating a spectrogram that includes energy content of the reference frame, represented by amplitude and phase, across frequency and time of the spectrogram; detecting regions of the spectrogram that have energy levels greater than a threshold level to produce detected regions; copying energy content from the detected regions into an energy vector; and performing an Inverse Fourier transform (IFT) based on the energy vector to transform the energy vector into in-phase (I) and quadrature (Q) (IQ) samples in the time-domain.

A transmitter in a wireless communication network includes a bits-to-symbol mapper that produces a plurality of data symbols; and a waveform modulator that receives a first discrete-time waveform and at least a second discrete-time waveform that comprises a cyclic shift of the first discrete-time waveform; modulates a first one of the plurality of data symbols onto the first discrete-time waveform and modulates a second one of the plurality of second data symbol onto the second discrete-time waveform, to produce a plurality of modulated discrete-time waveforms; and sums the plurality of modulated discrete-time waveforms to produce a modulated discrete-time signal to be transmitted in the network. The first discrete-time waveform and at least the second discrete-time waveform are multicarrier signals.

The present disclosure discloses a method and a system for transmitting DFT-s-OFDM symbols. A data sequence for transmitting as an OFDM symbol is received as input from a data source. A reference sequence for transmitting along with the data sequence as the OFDM symbol is generated and time-multiplexed with the data sequence, to generate a multiplied sequence. Thereafter, a Discrete Fourier Transform (DFT) operation is performed on the multiplexed sequence to generate a DFT-spread-Orthogonal Frequency Division Multiplexing (DFT-s-OFDM) symbol that is further processed for transmitting over a channel. The transmission of the reference sequence and the data sequence in a single OFDM symbol provides better bandwidth utilization and flexibility in modulation of the reference sequence and the data sequence.

When a frequency deviation compensation amount is compensated for by use of frequency shift, a phase offset occurs between adjacent input blocks included in a plurality of input blocks as divided, with the result that an error occurs in a reconstructed bit sequence. A frequency deviation compensation system of the invention is characterized by comprising: a frequency deviation compensation means for compensating for a frequency deviation occurring in a signal by use of frequency shift; and a phase offset compensation means for compensating for a phase offset occurring, in the signal, due to the frequency shift.

A transmitting apparatus includes a first signal generating unit that generates, on the basis of data a first signal transmitted by single carrier block transmission; a second signal generating unit that generates, on the basis of an RS, a second signal transmitted by orthogonal frequency division multiplex transmission; a switching operator that selects and outputs the second signal in a first transmission period and selects and outputs the first signal in a second transmission period; an antenna that transmits the signal output from the switching operator; and a control-signal generating unit that controls the second signal generating unit such that, in the first transmission period, the RS is arranged in a frequency band allocated for transmission of the RS from the transmitting apparatus among frequency bands usable in OFDM.

A transmitting apparatus includes a first signal generating unit that generates, on the basis of data a first signal transmitted by single carrier block transmission; a second signal generating unit that generates, on the basis of an RS, a second signal transmitted by orthogonal frequency division multiplex transmission; a switching operator that selects and outputs the second signal in a first transmission period and selects and outputs the first signal in a second transmission period; an antenna that transmits the signal output from the switching operator; and a control-signal generating unit that controls the second signal generating unit such that, in the first transmission period, the RS is arranged in a frequency band allocated for transmission of the RS from the transmitting apparatus among frequency bands usable in OFDM.

Device, methods and systems for implementing aspects of orthogonal time frequency space (OTFS) modulation in wireless systems are described. In an aspect, the device may include a surface of an object for receiving an electromagnetic signal. The surface may be structured to perform a non-electrical function for the object. The surface may generate an electrical signal from an electromagnetic signal. The electromagnetic signal may be received from a transmitter. The transmitter may map digital data to a digital amplitude modulation constellation in a time-frequency space. The digital amplitude modulation constellation may be mapped to a delay-Doppler domain and the transmitter may transmit to the surface according to an orthogonal time frequency space modulation signal scheme. The apparatus may further include a demodulator to demodulate the electrical signal to determine digital data.

In a wireless communication system according to an embodiment, a method of receiving, by a user equipment (UE), physical downlink control channels (PDCCHs) based on discrete Fourier transform spreading orthogonal frequency division multiplexing (DFT-S-OFDM) includes receiving, from a base station (BS), a first PDCCH including first downlink control information (DCI) in which information about a size of OFT precoding applied to a second PDCCH is included; performing blind decoding on the first PDCCH to obtain the first DCI; receiving the second PDCCH including second DCI from the BS; and performing blind decoding on the second PDCCH to obtain the second DCI, based on the information about the size of DFT precoding applied to the second PDCCH included in the first DCI.

A wireless communication device is described. The wireless communication device includes a receiver. The receiver is configured to determine a time-domain sample of a single carrier based on a received signal. The receiver is also configured to determine an estimated value based on the time-domain sample. The receiver is further configured to perform slicing based on the estimated value to produce a sliced value. The receiver is additionally configured to adapt a frequency-domain coefficient based on the estimated value and the sliced value. The receiver is also configured to perform channel equalization based on the frequency-domain coefficient.