A wireless communications system configured to perform wireless communication by using a first band dedicated to the system and a second band shared by the system and another wireless communications system, the system including: a base station configured to transmit in the first band to the terminal, a control signal permitting data transmission in the second band from a terminal to the base station; and the terminal configured to detect an available carrier wave of the second band after a predetermined time from the transmission of the control signal by the base station, the terminal performing the data transmission after waiting until detection of the available carrier wave.

Provided are a preamble symbol generation method and receiving method, and a relevant frequency-domain symbol generation method and a relevant device, characterized in that the method comprises: generating a cyclic prefix according to a partial time-domain main body signal truncated from a time-domain main body signal; generating a modulation signal based on a portion or the entirety of the partial time-domain main body signal; and generating time-domain symbols based on at least one of the cyclic prefix, the time-domain main body signal and the modulation signal, wherein the preamble symbol contains at least one of the time-domain symbols. Therefore, using the entirety or a portion of a certain length of a time-domain main body signal as a prefix, it is possible to implement coherent detection, which solves the issues of performance degradation with non-coherent detection and differential decoding failure under complex frequency selective fading channels; and generating a modulation signal as a postfix based on the entirety or a portion of the above truncated time-domain main body signal enables the generated preamble symbol to have sound fractional frequency offset estimation performance and timing synchronization performance.

The present disclosure includes a method of performing synchronization and frequency offset estimation The method includes an input signal corresponding to a single received training sequence. Phase information and a phase index are generated by performing an auto-correlation function (ACF) on the input signal. A templet signal associated with a sample index of the input signal is generated based on at least one pre-stored look-up table (LUT), the phase index, a frequency bandwidth of the input signal, and the sample index. Power associated with the sample index is calculated by performing a matched filtering on the input signal based on the templet signal. A synchronization timing and a frequency offset for the input signal are simultaneously determined based on a result of the matched filtering.

Disclosed are a method for multi-user transmission and reception in a wireless communication system and a device for same. More particularly, a method for performing multi-user (MU) transmission by a station (STA) device in a wireless communication system comprises the steps of: generating a high efficiency-long training field (HE-LTF) sequence in a frequency domain in accordance with an MU transmission bandwidth; and transmitting a physical protocol data unit (PPDU) which comprises one or more symbols to which the HE-LTF sequence is mapped, wherein the HE-LTF sequence can be generated by multiplying one row of a P matrix to a length unit of a row of the P matrix in a predetermined sequence.

A radio-transmitting device comprises a radio interface operating in a predetermined frequency band, operatively arranged for modulating a carrier having a frequency in the frequency band, while switching the frequency of the carrier among several hopping frequencies in the frequency band, according to a hopping sequence, to obtain a spread-spectrum modulated signal, wherein the spread-spectrum modulated signal includes, in a preamble portion, a plurality of sync words, each combined with at least one instance of a sequential index, the sync words being transmitted at different frequencies, and a data portion following the preamble portion and including a plurality of frequency hops.

This disclosure relates to techniques for performing presence discovery in a wireless communication. A wireless device may monitor a wireless medium for discovery signals. A candidate discovery signal may be detected. A frequency offset estimation consistency check may be performed on the candidate discovery signal. A peak to sidelobe ratio check may be performed on the candidate discovery signal. The wireless device may determine whether the candidate discovery signal is a false positive based at least in part on the frequency offset estimation consistency check and the peak to sidelobe ratio check.

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.

According to certain embodiments, a user equipment (810) is provided for use in a cellular network. The user equipment (810) may include a transceiver (910), a processor (920), and a memory (930). The user equipment (810) may be configured to acquire a Demodulation Reference Signal (DMRS) configuration. A mapping is determined from the DMRS configuration to a phase noise tracking reference signal (PNT-RS). A channel estimate is performed using the DMRS configuration. Phase noise estimation and compensation is performed based on the PNT-RS by using the mapping and the channel estimate.

Disclosed are a robust method and device for estimating frequency offset in orthogonal frequency division multiplexing communication. The method includes: performing frequency-domain cyclic shift cross-correlation on preprocessed signal sequences with a short training field sequence in multiple symbol periods respectively in an initial signal receiving stage to obtain a cross-correlation result set; detecting a short training field signal according to the cross-correlation result set; when the short training field signal is detected, performing rough frequency offset estimation to obtain a rough frequency offset estimation value; performing rough frequency offset compensation according to the rough frequency offset estimation value; fixing the rough frequency offset estimation value, performing fine frequency offset estimation, and compensating residual frequency estimation; detecting a long training field signal to obtain a frame boundary; and performing channel estimation to obtain a final signal.

Methods and devices for configuring an initial active downlink bandwidth part as part of an initial access procedure are provided. In one provided method, a base station broadcasts a synchronization signal block (SSB) that includes a control resource set CORESET) configuration index. The CORESET configuration index is one of a plurality of CORESET configuration indexes, each CORESET configuration index being associated with a respective configuration of a CORESET. Each configuration includes a CORESET frequency size, a CORESET time duration, and a frequency offset of the CORESET with respect to the SSB selected from a set of predefined frequency offsets. The initial active downlink bandwidth part is defined as having the same frequency location and bandwidth as the CORESET. The base station transmits, as part of a physical downlink control channel (PDCCH) within the CORESET, information indicating scheduling of remaining minimum system information (RMSI) in a physical downlink shared channel (POSCH).