Methods and apparatuses are described for wireless communications. A first method includes transmitting a first Orthogonal Frequency-Division Multiple Access (OFDMA) communications signal to a wireless node in a licensed spectrum, and transmitting, concurrently with the transmission of the first OFDMA communications signal, a second OFDMA communications signal to the wireless node in an unlicensed spectrum. A second method includes receiving a first Orthogonal Frequency-Division Multiple Access (OFDMA) communications signal from a wireless node in a licensed spectrum, and receiving, concurrently with the reception of the first OFDMA communications signal, a second OFDMA communication signal from the wireless node in an unlicensed spectrum. A third method includes generating a periodic gating interval for a cellular downlink in an unlicensed spectrum, and synchronizing at least one boundary of the periodic gating interval with at least one boundary of a periodic frame structure associated with a primary component carrier of the cellular downlink.

A method and device for estimating a carrier frequency offset, and a computer-readable storage medium are provided. The method includes: determining a target area where a phase discrimination signal is located, wherein the target area is one of N numbers of candidate areas, the N numbers of candidate areas correspond to different value ranges, an union range of the N numbers of candidate areas is [π, −π], and N≥2; determining a first estimation value of a direct current component corresponding to the phase discrimination signal based on the target area; and performing a carrier frequency offset compensation on the phase discrimination signal based on the first estimation value of the direct current component.

Techniques described herein can facilitate Channel-State Information (CSI) measurement and feedback for communication in unlicensed spectrum or Sounding Reference Signal (SRS) transmission and/or channel-state estimation for communication in unlicensed spectrum. In an example, an apparatus is configured to be employed in a User Equipment (UE), and the apparatus comprises a Radio Frequency (RF) circuitry interface and processing circuitry configured to perform CSI measurement for communication in unlicensed spectrum. The apparatus further generates data for feedback according to the CSI measurement, and sends the data for feedback to RF circuitry via the RF circuitry interface. In an example, a frame structure of a data channel begins with a downlink (DL) transmission or soon after an initial signal. In an example, the CSI measurement includes measuring Channel Quality Information (CQI) for one or more sub-bands.

Aspects of the present disclosure include methods, apparatuses, and computer readable media for identifying an initial rank, modulating information into a first plurality of layers associated with the initial rank, scrambling the first plurality of layers by a first common scrambler to generate a first plurality of scrambled layers, transmitting, to the receiver, the first plurality of scrambled layers, receiving an indication of failed demodulation of a portion of the first plurality of scrambled layers, modulating at least a portion of the information into a second plurality of layers, wherein the second plurality of layers includes a same number of layers as the first plurality of layers, scrambling the second plurality of layers by a second common scrambler to generate a second plurality of scrambled layers, and transmitting, to the receiver, the second plurality of scrambled layers.

Joint estimation of the framer index and the frequency offset in an optical communication system are described among various other features. A transmitter can transmit data frames using pilot and framer symbols. A receiver can estimate the framer index and frequency offset using the pilot and framer symbols, and identify the beginning of a header portion of a data frame. By identifying the beginning of the header portion of a data frame, the receiver can synchronize, with less error, the data transmitted by the transmitter and the data it received. To further improve the framer index estimation, a lock indicator signal can be generated to signal to other receiver components that the estimated framer indices are reliable. The receiver can determine frequency offset and additional framer index estimations with increased reliability when performed after the lock indicator signal is generated.

A wireless communications and imaging system is described. The system includes a receiver and a transmitter. The receiver includes a synchronized array of clocks, wherein a speed of time measured by each one of the clocks in the synchronized array of clocks relative to the other clocks is tracked. The transmitter includes a constellation of masses. A relative position of individual ones of the masses of the constellation of masses (with respect to one another) encodes digital data that is sensed by the receiver in the form of a gravity field change that causes a difference in the speed of clocks measured and utilized by the quantifiable receiver which clock speed differential corresponds to and enables the replication of the original digital data set that was input into the transmitter.

Provided are a configuration method and a transmission method of a new reference signal for frequency offset estimation in a novel wireless communication system. The method may include configuring a synchronization signal to be transmitted through a first bandwidth part of one or more bandwidth parts configured by dividing an entire bandwidth into one or more parts, allocating the one or more reference signals for estimating the frequency offset on one or more resources other than a resource for configuring the synchronization signal, and transmitting the one or more reference signals for estimating the frequency offset.

Embodiments of the present application provide a signal transmission method, a terminal, a network device, and a storage medium. The method comprises: receiving multiple first downlink signals; determining downlink receiving frequency corresponding to the first downlink signal, and respectively determining, on the basis of the downlink receiving frequency corresponding to the first downlink signal, transmitting frequency of uplink signals in association with the first downlink signal; and transmitting the uplink signals on the basis of the transmitting frequency of the uplink signals, wherein a frequency shift determined on the basis of the uplink signals in association with the first downlink signal is used for determining transmitting frequency of second downlink signals. In the embodiments of the present application, a pre-compensation of a downlink Doppler shift is performed by means of each transmission receiving point, and therefore, an error of channel estimation is reduced, and the performance of downlink transmission is improved.

Systems, methods, and apparatus are provided for automated identification of open space in a wireless communications spectrum, by identifying sources of signal emission in the spectrum by automatically detecting signals, analyzing signals, comparing signal data to historical and reference data, creating corresponding signal profiles, and determining information about the open space based upon the measured and analyzed data in near real-time.

Systems, methods, apparatuses, and computer program products for transmitter residual carrier frequency offset compensation. The method may include receiving, at a reference user equipment, configuration for a positioning reference measurement from a network element. The method may also include estimating a transmission carrier frequency offset of the network element based on the positioning reference measurements. The method may further include transmitting the estimated transmission carrier frequency offset in a report to the network element.