A transmitter transmitting payload data using Orthogonal Frequency Division Multiplexed (OFDM) symbols, including: a frame builder configured to receive the payload data and to receive signalling data to use in detecting and recovering the payload data at a receiver, and to form the payload data with the signalling data into frames for transmission: a modulator configured to modulate a first OFDM symbol with the signalling data and to modulate one or more second OFDM symbols with the payload data; a signature sequence processor circuit providing a signature sequence; a combiner circuit combining the signature sequence with the first OFDM symbol; a prefixing circuit prefixing a guard interval to the first OFDM symbol to form a preamble; and a transmission circuit transmitting the preamble and the one or more second OFDM symbols. The guard interval is formed from time domain samples of a part of the signature sequence.

A base station schedules a user equipment (UE) for uplink air link resources, e.g., unlicensed spectrum PUSCH resources, corresponding to one or more slots and, in some embodiments, at least one mini-slot. There may be, and sometimes are gaps between two scheduled slots and/or between a scheduled slot and a scheduled mini-slot. Different uplink air link resources corresponding to a schedule slot or mini-slot may, and sometimes do, use different set of frequencies. The base station generates and sends to the UE a single UL grant which grants uplink air link resources corresponding to the composite of resource allocations corresponding to the one or more slots and, in some embodiments, at least one mini-slot. The single UL grant may, and sometimes does, communicates gap information and frequency information.

A method for initial timing synchronization for a WTRU to communicate with a network includes receiving an in-channel narrowband synchronization sequence from the network to enable initial coarse timing synchronization, determining coarse timing offset and a range between a beam source of a network transmitter and the WTRU, selecting a wideband sequence for fine timing synchronization using the estimated range, transmitting the selected wideband sequence for fine timing synchronization during an uplink timing occasion, receiving from the network a transmission of the selected wideband sequence for fine timing synchronization, and establishing fine timing synchronization between the WTRU and the network using the selected sequence.

Disclosed are techniques to compensate frequency systematic known error (FSKE) in reflector or initiator radios using a hybrid RF-digital approach in multi-carrier phase-based ranging. The hybrid RF-digital approach combines a coarse frequency compensation technique in the RF domain and a fine frequency compensation technique in the digital domain to remove the FSKE across all carrier frequencies from a device. The coarse frequency compensation performed in the RF domain may use a PLL to multiply the crystal frequency to arrive close to a target carrier frequency to compensate for a coarse portion of the known FSKE at the target frequency. The fine frequency compensation may use digital techniques to remove the remaining portion of the known FSKE not compensated by the RF. The hybrid approach reduces the number of fractional bits in the multiplier of the PLL when compared to an approach that uses only the RF-PLL to remove the FSKE.

A radio receiver device determines whether a digital radio signal includes a predetermined cyclic preamble. An input portion samples the digital radio signal and generates a plurality of samples for storage in a buffer. A first autocorrelator correlates first and second subsets of the samples to generate a first correlation metric, the second subset having been stored in the buffer earlier than said first subset by an even integer multiple of half of the preamble period. A second autocorrelator correlates first and third subsets of the plurality of samples to generate a second correlation metric, the third subset having been stored in the buffer earlier than said first subset by an odd integer multiple of half of the preamble period. A processing portion calculates a difference between the correlation metrics and determines that the radio signal includes the predetermined cyclic preamble when the difference is greater than a threshold value.

Various embodiments comprise systems, methods, architectures, mechanisms and apparatus providing a dual-function radar communication (DFRC) system a multiple-input multiple-output (MIMO) radar is configured to have only a small number of its antennas active in each channel use. Probing waveforms are of an orthogonal frequency division multiplexing (OFDM) type. OFDM carriers are divided into two groups, one group that is used by the active antennas in a shared fashion, and another group where each subcarrier is assigned to an active antenna in an exclusive fashion (e.g., private subcarriers). Target estimation is carried out based on the received and transmitted symbols. The system communicates information via the transmitted OFDM data symbols and the pattern of active antennas in a generalized spatial modulation (GSM) fashion. A multi-antenna communication receiver can identify the indices of active antennas via sparse signal recovery methods. The private subcarriers may be used to synthesize a virtual array for high angular resolution, and also for improved estimation on the active antenna indices.

A wireless device includes a radio transceiver, and a digital transmitter configured to transmit, via the radio transceiver, a first data symbol, and to transmit, via the radio transceiver, a repetition of the first data symbol immediately after the first data symbol, where the first data symbol forms a cyclic prefix for the repetition of the first data symbol.

Systems and methods for transmitting data using various Modulation on Zeros schemes are described. In many embodiments, a communication system is utilized that includes a transmitter having a modulator that modulates a plurality of information bits to encode the bits in the zeros of the z-transform of a discrete-time baseband signal. In addition, the communication system includes a receiver having a decoder configured to decode a plurality of bits of information from the samples of a received signal by: determining a plurality of zeros of a z-transform of a received discrete-time baseband signal based upon samples from a received continuous-time signal, identifying zeros that encode the plurality of information bits, and outputting a plurality of decoded information bits based upon the identified zeros.

Methods, systems, and devices for wireless communications are described. Aspects of the present disclosure describe a quick scanning method to reject global synchronization channel numbers (GSCNs) that do not include a synchronization signal block (SSB). The quick scanning method utilizes down-sampling techniques to reduce complexity associated with scanning many GSCNs for an SSB. For example, a user equipment (UE) may down-sample a signal to obtain a coarse signal subset (e.g., by using coarse bin sizes, sampling a portion of symbols). The UE may perform a fast Fourier Transform, along with one or more data processing techniques, to obtain a spectrogram corresponding to the signal. While the spectrogram may represent the signal in the frequency domain with reduced resolution, and may include energy information corresponding to different frequencies. The UE may utilize the spectrogram to examine frequencies corresponding to GSCNs to detect if an SSB is present.

Methods, systems and device for achieving synchronization in an orthogonal time frequency space (OTFS) signal receiver are described. An exemplary signal reception technique includes receiving an OTFS modulated wireless signal comprising pilot signal transmissions interspersed with data transmissions, calculating autocorrelation of the wireless signal using the wireless signal and a delayed version of the wireless signal that is delayed by a pre-determined delay, thereby generating an autocorrelation output, processing the autocorrelation filter through a moving average filter to produce a fine timing signal. Another exemplary signal reception technique includes receiving an OTFS modulated wireless signal comprising pilot signal transmissions interspersed with data transmissions, performing an initial automatic gain correction of the received OTFS wireless signal by peak detection and using clipping information, performing coarse automatic gain correction on results of a received and initial automatic gain control (AGC)-corrected signal.