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.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may communicate with a base station by initiating a random access procedure with a two-root preamble. The UE may receive, from the base station, control signaling that indicates a set of root preamble sequences. The UE may transmit, to the base station, a preamble signal that is generated based on a first root preamble sequence and a second root preamble sequence of the set of root preamble sequences. The UE may then monitor for a preamble response based on the preamble signal. In some cases, the base station may be a base station in a terrestrial network. In other cases, the base station may be a satellite in a non-terrestrial network (NTN).

Example synchronization signal sending and receiving methods and apparatus are described. In one example method, a terminal device determines a target frequency resource. A frequency domain position of the target frequency resource is determined based on a frequency domain position offset and a frequency interval of synchronization channels. The terminal device receives a synchronization signal by using the target frequency resource.

A non-data-aided method of calculating an estimate of the sampling frequency offset (SFO) in a digital receiver involves performing a plurality of correlations between two identical sized groups of samples within a received signal where the spacing of the groups is varied for each correlation. In various examples the number of samples in the groups is also varied. For larger symbols, the group of samples may comprise approximately the same number of samples as the guard interval in a symbol and for smaller symbols, the group of samples may comprise approximately the same number of samples as an entire symbol. An estimate of the SFO is determined by identifying the largest correlation result obtained from all the correlations performed. The largest correlation result indicates the largest correlation.

Aspects present herein relate to methods and devices for wireless communication including an apparatus, e.g., a UE. The apparatus may measure a frequency error from a first pair of pilot symbols and a second pair of pilot symbols received via a channel associated with communication between the UE and a base station, the measured frequency error from the first pair of pilot symbols and the second pair of pilot symbols corresponding to a first frequency error measurement and a second frequency error measurement. The apparatus may detect a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement. The apparatus may adjust the first frequency error measurement based on the first frequency wraparound or the second frequency error measurement based on the second frequency wraparound if the first frequency wraparound or the second frequency wraparound is the non-zero value.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first user equipment (UE) may receive, from a second UE and using a first fast Fourier transform (FFT) window configuration, a physical sidelink control channel (PSCCH) signal associated with a physical sidelink shared channel (PSSCH) signal. The UE may identify, based at least in part on the reception of the PSCCH signal, one or more values of one or more parameters estimated from the PSCCH signal. The UE may select, based at least in part on the one or more values of the one or more parameters, a second FFT window configuration to be used to receive the PSSCH signal. The UE may receive, from the second UE, the PSSCH signal using the second FFT window configuration, Numerous other aspects are described.

This application provides a random access method and an apparatus. The method includes: receiving, by a terminal device, a broadcast signal; and sending, by the terminal device, a random access signal, where a preamble sequence in the random access signal includes K first symbols and Q second symbols, the first symbol and the second symbol are different from each other, K and Q are integers greater than or equal to 1, K+Q=N.sub.SEQ, and N.sub.SEQ is a quantity of symbols included in the preamble sequence.

A method of frequency-offset determination includes: receiving a resource block containing one or more auxiliary frequency-offset estimation signals and pilot signals from a second device; and calculating the one or more auxiliary frequency-offset estimation signals and the pilot signals to determine a frequency offset for demodulating the resource block. At least one of the first device or the second device is a vehicle.

Example synchronization signal sending and receiving methods and apparatus are described. In one example method, a terminal device determines a target frequency resource. A frequency domain position of the target frequency resource is determined based on a frequency domain position offset and a frequency interval of synchronization channels. The terminal device receives a synchronization signal by using the target frequency resource.

Systems and methods are described, and one method includes acquiring a frequency offset for a demodulator receiving one symbol rate in combination with acquiring another frequency offset for another demodulator, based on sweeping the other frequency offset until detecting a qualifying symbol pattern or acquiring the frequency offset for the demodulator receiving one symbol rate, whichever occurs first. Associated with acquiring the other frequency offset based on acquiring the frequency offset for the demodulator receiving one symbol rate, setting the other frequency offset includes adjusting the frequency offset for the demodulator receiving one symbol rate.