A wireless network includes a tunable RF transmitter in wireless communication with a master node to transmit at a first slave frequency; a tunable RF receiver in wireless communication with the master node to receive at a second slave frequency; and an RF oscillator to communicate with the RF receiver and the RF transmitter an RF oscillator frequency to determine and tune the first and second slave frequencies. The RF oscillator is configured to receive calibration information including time information or frequency information, or both, from a reference node. The RF oscillator frequency of the RF oscillator is tuned based on the calibration information from the reference node to enable communication between the slave node and the master node at the tuned RF oscillator frequency.

The present invention relates to the field of wireless communications, and in particular, to an information sending and receiving method, a base station, and a terminal device that are used for uplink timing of a terminal device. In the information sending method, a first base station determines a first time adjustment parameter and a second time adjustment parameter; the first base station sends the first time adjustment parameter and the second time adjustment parameter to a terminal device. According to the solution provided in this application, the base station provides a plurality of time adjustment parameters for the terminal device to perform uplink signal timing, so as to provide flexible and efficient uplink subframe scheduling for the base station, thereby meeting various requirements for uplink timing.

In a mobile communication system using a mobile-type radio relay apparatus that forms a plurality of cells toward the ground or the sea while moving in an upper airspace, a deterioration in communication quality, which is caused by a Doppler shift of a reception signal due to a relative movement of a radio relay apparatus with respect to a terminal apparatus of each of a plurality of cells or a feeder station on the ground or on the sea, is suppressed. The communication system comprises a mobile-type radio relay apparatus that is disposed movably by flying in an upper airspace, forms a plurality of cells from an antenna at a predetermined altitude toward the ground or the sea, and performs a radio communication with a terminal apparatus located in each of the plurality of cells. The communication system comprises an estimation section for estimating a Doppler shift in at least one of a radio communication of a service link between the terminal apparatus located in the cell and the radio relay apparatus and a radio communication of a feeder link between the radio relay apparatus and a feeder station on the ground or on the sea, and a correction section for correcting a frequency of the at least one radio communication based on an estimation result of the Doppler shift.

The present invention is to generate a spatially phase modulated electron wave. A laser radiating apparatus, a spatial light phase modulator, and a photocathode are provided. The photocathode has a semiconductor film having an NEA film formed on a surface thereof, and a thickness of the semiconductor film is smaller than a value obtained by multiplying a coherent relaxation time of electrons in the semiconductor film by a moving speed of the electrons in the semiconductor film. According to the configuration, a spatial distribution of phase and a spatial distribution of intensity of spatial phase modulated light are transferred to an electron wave, and the electron wave emitted from an NEA film is modulated into the spatial distribution of phase and the spatial distribution of intensity of the light. Since the spatial distribution of phase of the light can be modulated as intended by a spatial phase modulation technique for light, it is possible to generate an electron wave having a spatial distribution of phase modulated as intended.

A hopping spread-spectrum wireless network for IoT applications operating in a predetermined frequency band, with mobile device that have unsynchronized local frequency references and receiving gateways that are capable of detecting whether modulated radio signals will collide in frequency in a collision time interval, and blanking the signals in the collision time. Preferably, the frequency band is subdivided into a sub-bands, and the mobile devices adapt the width of the sub-bands used for transmission based on a synchronization status indicative of the frequency error of the local frequency reference.

A radio link monitoring method, the method includes: generating an indication indicating that a reference signal is not detected if the reference signal is not detected; and performing radio link monitoring according to the indication.

Various arrangements for compensating for Doppler shift on a non-terrestrial orthogonal frequency division multiplex (OFDM) network are presented. A received frequency of a downlink satellite message received from a satellite may be determined. A downlink frequency delta between an expected frequency of the downlink satellite message and the received frequency of the downlink satellite message can be calculated. An uplink frequency delta based on the calculated downlink frequency delta may be calculated. An uplink transmission frequency at which an uplink OFDM symbol is transmitted may be calculated based on the calculated uplink frequency delta.

Techniques are provided for providing Doppler correction. In particular, embodiments may provide re-banding circuitry having a reference clock, a mixer, and a compensation circuitry for re-banding and for Doppler correction. The compensation circuitry may be configured to adjust a reference frequency of the reference clock based on signals received from a Global Navigation Satellite System (GNSS) receiver. The mixer may be configured to translate communication signals in a first frequency band to a second frequency band based at least in part on the adjusted reference frequency of the reference clock.

A user terminal (UT) to transmit small amounts of data, the UT including: a packet including the data, where the packet is less than 128 bytes; a frequency synchronizer to synchronize a transmission frequency of an ASCMA return link connecting the UT with a satellite gateway; and an ASCMA transmitter to transmit, without acquiring timing synchronization with the satellite gateway from the UT, the packet modulated over the synchronized transmission frequency as an ASCMA waveform including a preamble to indicate a start of a transmission. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

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.