Abstract: A method can include determining an initial beam configuration by a controller at a satellite in a non-terrestrial network (NTN); applying the initial beam configuration to control an antenna array to transmit a beam to cover a target service area; determining subsequent beam configurations, by the controller, corresponding to a sequence of locations along an orbit of the satellite; and applying the subsequent beam configurations at each of the sequence of locations successively to control the antenna array to transmit respective beams to cover the target service area while the satellite is flying along the orbit. The controller determines the initial beam configuration and the subsequent beam configurations in a way that a variation of beam footprints of the beams is minimized to realize a constant beam footprint corresponding to the target service area.

Abstract: A method can include determining an initial beam configuration by a controller at a satellite in a non-terrestrial network (NTN); applying the initial beam configuration to control an antenna array to transmit a beam to cover a target service area; determining subsequent beam configurations, by the controller, corresponding to a sequence of locations along an orbit of the satellite; and applying the subsequent beam configurations at each of the sequence of locations successively to control the antenna array to transmit respective beams to cover the target service area while the satellite is flying along the orbit. The controller determines the initial beam configuration and the subsequent beam configurations in a way that a variation of beam footprints of the beams is minimized to realize a constant beam footprint corresponding to the target service area.

Abstract: Aspects of the disclosure provide an apparatus for transmitting a circularly polarized signal by linearly polarized antennas. Processing circuitry of the apparatus generates a transmitted baseband signal vector. Based on the transmitted baseband signal vector, power amplifiers (PAs) of the apparatus generates transmitted radio frequency (RF) signals. The transmitted RF signals are received by receiving circuitry of the apparatus to obtain a received baseband signal vector. A controller of the apparatus calibrates the PAs and local oscillator (LO) signals of frequency converters of the apparatus based on the received baseband signal vector. A horizontally polarized antenna and a vertically polarized antenna of the apparatus transmit a circularly polarized signal based on the calibrated PAs and the calibrated LO signals.

Abstract: Provided is an apparatus for transmitting a circularly polarized signal by linearly polarized antennas. A horizontally polarized antenna and a vertically polarized antenna of the apparatus receives a first circularly polarized signal transmitted based on a transmitted baseband signal vector. Based on the first circularly polarized signal, a radio frequency (RF) module of the apparatus generates a received baseband signal vector including a product of the transmitted baseband signal vector and a receiving polarization vector of the transmitted baseband signal vector. Processing circuitry of the apparatus estimates the receiving polarization vector based on the received baseband signal vector and calibrates power amplifiers (PAs) and local oscillator (LO) signals of frequency converters in the RF module based on the estimated receiving polarization vector.

Abstract: Aspects of the disclosure provide an apparatus for receiving a circularly polarized signal by linearly polarized antennas. A horizontally polarized antenna and a vertically polarized antenna of the apparatus receive a circularly polarized signal that is transmitted based on a transmitted baseband signal vector. A radio frequency (RF) module of the apparatus generates a first baseband signal vector based on the received circularly polarized signal. The first baseband signal vector includes a product of the transmitted baseband signal vector and a receiving polarization vector of the transmitted baseband signal vector. Processing circuitry of the apparatus estimates the receiving polarization vector of the transmitted baseband signal vector based on the first baseband signal vector. The processing circuitry derives a second baseband signal vector based on the estimated receiving polarization vector and the first baseband signal vector.

Abstract: The disclosure provides a method including the following steps: receiving, by an electronic device, beacon signals transmitted from access points, and estimating the number of the access points according to the beacon signals; determining by the electronic device whether the electronic device can connect to a base station; when it is determined that the electronic device cannot connect to the base station, estimating the number of connection access points according to the number of the access points and a first data queue by the electronic device; and when it is determined that the electronic device can connect to the base station, determining by the electronic device whether to connect the electronic device to the base station according to the first data queue, and estimating the number of the connection access points according to the number of the access points, the first data queue and a determination result.