An apparatus comprising a frequency standard circuit and a tracking circuit. The frequency standard circuit may be configured to generate an internal frequency standard and adjust the internal frequency standard in response to a tuning signal. The tracking circuit may be configured to receive a reference signal from an external source and a feedback signal of the internal frequency standard and generate the tuning signal. The tuning signal may be configured to synchronize the internal frequency standard to the reference signal. The internal frequency standard may be implemented local to a frequency converter. The tracking circuit may have a bandwidth that prevents unwanted content on the reference signal from corrupting the internal frequency standard.

A method, an apparatus and a computer program product for enhancing reception of signals in a wireless communication system. A signal containing a frame including a plurality of symbols is received on an uplink communication channel. An angular position of at least one symbol in the plurality of symbols in a constellation of symbols is detected. The plurality of symbols include equalized symbols. An angular difference corresponding a phase error between the detected angular position of the symbol and an expected reference angular position in the constellation of symbols corresponding to an expected reference symbol corresponding to the received frame is determined. Using the determined phase error, a phase of the symbol is compensated.

Aspects of the present disclosure describe a system and method for synchronizing time, frequency, and phase among a plurality of devices.

A cloud radio access network (C-RAN) includes a baseband controller communicatively coupled to a plurality of radio points (RP) via a fronthaul network. Each of the plurality of RPs are configured to exchange radio frequency (RF) signals with at least one user equipment (UE). At least one of the RPs is configured to determine a timing difference while synchronizing to the baseband controller; and determine a frequency error, between the RP and a neighboring base station, based on a radio environment monitoring (REM) procedure. A phase error is determined, between the baseband controller and the neighboring base station, phase error is determined based on the timing difference for the RP and baseband controller, and the frequency error for the RP and the neighboring base station.

Systems and methods are described herein for multi-mode compensation of frequency errors within signals transmitted and received by a mobile terminal. The frequency error can be due to Doppler shift and oscillator error, which introduce opposite frequency shifts. In an acquisition mode, the mobile terminal initially compensates for the oscillator error while transmitting a signal to a communication system that contains the Doppler shift. Upon receiving a message from the communication system indicating the Doppler shift contained in the transmit signal, the mobile terminal can then switch to a tracking mode that can compensate for both Doppler shift and oscillator error.

A method for determining an angle of arrival (AOA) of a received signal is disclosed, comprising: generating a baseband information signal by mixing a received signal with a local oscillator (LO) signal, the received signal being an in-phase signal and quadrature signal uncorrelated with each other and derived from different input data sets; obtaining baseband signal samples of the baseband information signal having an in-phase signal sample and a quadrature signal sample; determining a transmitter phase offset based on an estimated correlation between the in-phase signal samples and the quadrature signal samples; performing a plurality of phase measurements using a plurality of antennas to obtain a plurality of phase measurements; correcting the plurality of phase measurements based on the transmitter phase offset to produce a plurality of corrected phase measurement; and calculating an AOA of the received signal based on the difference between the plurality of corrected phase measurements.

A device for wireless communication using a plurality of antennas including a first local oscillation generator configured to generate a first local oscillation signal for up-converting a first transmission signal, a second local oscillation generator configured to generate a second local oscillation signal for up-converting a second transmission signal, and a phase difference detector configured to, detect a first phase difference between the first local oscillation signal and the second local oscillation signal, and generate a first phase compensation signal based on the first phase difference for adjusting a phase of at least one of the first transmission signal or the second transmission signal.

Various arrangements for compensating for Doppler shift on a non-terrestrial orthogonal frequency division multiplex (OFDM) network are presented. An absolute location of the UE instance may be determined. A relative velocity of the UE instance with respect to a satellite of the non-terrestrial OFDM network may be determined. A frequency delta due to Doppler shift may be determined. A transmission frequency at which an uplink OFDM symbol is to be transmitted to the satellite of the non-terrestrial OFDM network may be determined using the frequency delta.

Disclosed are a method and an apparatus for transmitting and receiving a synchronization signal in a communication system. According to an exemplary embodiment of the present disclosure, a method of transmitting a first synchronization signal, performed by a base station in the communication system, may comprise generating a base sequence; generating a modified sequence by inverting polarity of the base sequence; mapping the base sequence and the modified sequence to a first frequency region having a frequency higher than a center subcarrier and a second frequency region having a frequency lower the center subcarrier, so that the base sequence and the modified sequence are symmetric centering the center subcarrier located at a center frequency of a frequency domain of the synchronization signal; and transmitting the synchronization signal comprising the base sequence and the modified sequence to a terminal. Therefore, performance of the communication system can be improved.

A resource configuration method and an apparatus are provided. The resource configuration method includes: receiving, by user equipment, configuration information sent by a network device, where the configuration information is used to indicate at least one time interval and at least one time-frequency resource unit within the time interval, and the time-frequency resource unit includes a first time-frequency resource subunit and/or a second time-frequency resource subunit; and reconfiguring, by the user equipment, a resource mapping manner and/or a rate matching manner based on the configuration information, so that no downlink receiving or uplink sending is performed by the user equipment on the first time-frequency resource subunit, and adjusting a timing offset of the second time-frequency resource subunit to perform downlink receiving or uplink sending on the second time-frequency resource subunit obtained by adjusting the timing offset. Resource utilization can be improved while ensuring that the user equipment correctly receives data.