A circuit arrangement includes a channel estimation circuit configured to acquire a channel estimate including a plurality of channel samples based on a range of time and frequency locations of a received signal, a first calculation circuit configured to calculate a first time and frequency correlation product of the channel estimate and a second calculation circuit configured to calculate a second time and frequency correlation product of the channel estimate, a time offset circuit configured to determine a time offset based on the first time and frequency correlation product and the second time and frequency correlation product, and a frequency offset circuit configured to determine a frequency offset based on the first time and frequency correlation product and the second time and frequency correlation product.

This disclosure presents distributed and decentralized synchronization for wireless transceivers. The disclosed system, device, and method achieve sub-nanosecond synchronization using low-cost commercial off the shelf software defined radios. By providing a decentralized mechanism that does not rely on a hierarchical master-slave structure, networks constructed as disclosed are robust to sensor drop-out in contested or harsh environments. Such networks may be used to create phased array radars and communication systems without requiring wired connections to distribute a common clock or local oscillator reference.

Various solutions for random access channel (RACH) preamble design in non-terrestrial network (NTN) communications with respect to user equipment and network apparatus are described. An apparatus may initiate a RACH procedure. The apparatus may determine a fractional frequency offset pattern or a cover code across groups of preamble sequences. The apparatus may generate a RACH preamble signal according to at least one of the fractional frequency offset pattern and the cover code. The apparatus may transmit the RACH preamble signal to a network node.

Configuring control information comprises determining a frequency offset including an RB and RE level frequency offset, where the frequency offset is determined based on a lowest RE of an SS/PBCH block and a lowest RE of CORESET for RMSI, jointly configuring, using a first field of 4 bits, the RB level frequency offset with a multiplexing pattern of the SS/PBCH block and the CORESET, a BW of the CORESET, and a number of symbols for the CORESET for a combination of a SCS of the SS/PBCH block and a SCS of the CORESET, configuring using a second field of the 4 bits generating an MIB including the RB level frequency offset and the RE level frequency offset; and transmitting, to a UE, the MIB over a PBCH.

In one embodiment, an apparatus comprises: a baseband processor having a preamble generation circuit to generate a preamble for an orthogonal frequency division multiplexing (OFDM) transmission, the preamble generation circuit to generate the preamble having a first portion comprising a first plurality of symbols and a second portion comprising a second plurality of symbols, where the preamble generation circuit is to generate at least some of the second plurality of symbols having at least one frequency disruption between successive symbols of the second portion; a digital-to-analog converter (DAC) coupled to the baseband processor to convert the first plurality of symbols and the second plurality of symbols to analog signals; a mixer coupled to the DAC to upconvert the analog signals to radio frequency (RF) signals; and a power amplifier coupled to the mixer to amplify the RF signals.

Disclosed are techniques related to wireless communication. In an aspect, a sequence generating entity factorizes a comb size N into prime factors of N, and generates one or more offset sequences for a reference signal for positioning based on one or more sequence lists associated with the prime factors of N and a number of symbols M over which the reference signal is scheduled.

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.

A method for operating a user equipment in a wireless communication is provided as an embodiment of the present invention. The method may include: receiving modulation and coding scheme (MCS) information for each of two or more codewords from a base station (BS); determining a demodulation reference signal (DMRS) antenna port to which a phase tracking reference signal (PTRS) antenna port is mapped based on the MCS information; and receiving a PTRS based on the DMRS antenna port, wherein a DMRS antenna port with the lowest index among one or more DMRS antenna ports included in a codeword with the highest MCS among the two or more codewords may be determined as the DMRS antenna port.

Embodiments of the disclosure provide a method and apparatus for performing fractional subframe transmission. The method may comprise: determining first temporal information that indicates when a channel becomes available; and determining, based on the first temporal information and transmission opportunity information, second temporal information that indicates an end of the fractional subframe transmission.

In one embodiment, an apparatus includes: a radio frequency (RF) front end circuit to receive and downconvert a RF signal to a second frequency signal, the RF signal comprising an orthogonal frequency division multiplexing (OFDM) transmission; a digitizer coupled to the RF front end circuit to digitize the second frequency signal to a digital signal; and a baseband processor coupled to the digitizer to process the digital signal. The baseband circuit comprises a first circuit having a first plurality of correlators having an irregular comb structure, each of the first plurality of correlators associated with a carrier frequency offset and to calculate a first correlation on a first portion of a preamble of the OFDM transmission.