Abstract: In an embodiment, a method includes determining a first beam pointing vector associated with an antenna assembly by searching for a satellite from a plurality of satellites. The method includes maintaining a communication link with the satellite by determining a plurality of beam pointing vectors that converge to a signal quality value. The method includes obtaining, from the satellite, satellite ephemeris information of the satellite and one or more of remaining satellites of the plurality of satellites. The method includes determining an estimated orientation of the antenna assembly based on one or more of the satellite ephemeris information and the plurality of beam pointing vector. The method includes determining a second beam pointing vector based on the estimated orientation, the satellite ephemeris information, and an approximate position information of the antenna assembly.

Abstract: Systems, methods, and non-transitory media are provided for timing half-duplex transmissions in a wireless communication system. An example method can include receiving, by a user terminal (UT), a radio frame transmitted by a satellite to a group of UTs; identifying an offset delay defined in the radio frame for scheduling transmissions between the satellite and each UT in the group of UTs, the offset delay providing non-overlapping time intervals for receive, process, and transmit operations at each UT; determining, based on the offset delay and a time when the radio frame was received by the UT, a time for transmitting an uplink radio burst to the satellite, wherein the uplink radio burst transmitted at the time is estimated to arrive at the satellite within a same radio frame interval as uplink radio bursts from other UTs; and transmitting, to the satellite, the uplink radio burst at the time.

Abstract: In an embodiment, an apparatus includes an antenna assembly, a modem, and a beam steering controller. A beam steering controller is configured to determine a beam pointing direction of the antenna assembly to be able to one or both of switch a first communication link with a first satellite to a second communication link with a second satellite or establish and maintain the first communication link with the first satellite. At a start of a determination of the beam pointing direction, one or more of an orientation of the antenna assembly is unknown, positions of a plurality of satellites are unknown, or downlink frequencies of the plurality of satellites are unknown.

Abstract: A wireless communications system includes a pre-distortion actuator configured to receive a carrier-modulated signal and convert the carrier-modulated signal into an output signal, the pre-distortion actuator comprising a behavioral model that models a transmit chain of the system including at least one amplifier and at least one antenna and predict an input-output relationship of the transmit chain of the system between an input to the transmit chain to an output of the transmit chain. The system includes a phased antenna array configured to transmit the output signal. The phased antenna array includes a plurality of antenna elements, each antenna element electrically coupled to a respective power amplifier. The pre-distortion actuator is configured to generate the output signal by applying a correction to the carrier-modulated input signal that cancels out nonlinearities The behavioral model is updated based on feedback from a receiver from a previous output signal transmitted to the receiver.

Abstract: A wireless communications system includes a pre-distortion actuator configured to receive a carrier-modulated signal and convert the carrier-modulated signal into an output signal. The system includes one or more antennas configured to receive the output signal and transmit the output signal, one or more power amplifiers electrically coupled between the pre-distortion actuator and the one or more antennas and a receiver configured to receive the output signal over-the-air and generate feedback based on the output signal. The pre-distortion actuator is configured to generate the output signal by applying a correction to the carrier-modulated signal that cancels out nonlinearities associated with the one or more antennas and/or the one or more power amplifiers. The pre-distortion actuator is configured based on the feedback.

Abstract: In an embodiment, a cross-polarization interference compensation module is included in a receiver of a wireless communication system. The module includes first and second input lines configured to receive respective first and second down-converted digital polarized signals based on receipt of a wireless transmission. The module further includes first and second output lines electrically coupled to at least one modem. The module further includes a first complex finite impulse response (FIR) filter configured to receive the second down-converted digital polarized signal and generate a correction factor that cancels cross-polarization components in the first down-converted digital polarized signal. The module further includes a first filter coefficient engine in communication with the first complex FIR filter and configured to adapt the first complex FIR filter over time based on the first and second down-converted digital polarized signals.

Abstract: A wireless communications system includes a pre-distortion actuator configured to receive a carrier-modulated signal and convert the carrier-modulated signal into an output signal. The system includes one or more antennas configured to receive the output signal and transmit the output signal, one or more power amplifiers electrically coupled between the pre-distortion actuator and the one or more antennas and a receiver configured to receive the output signal over-the-air and generate feedback based on the output signal. The pre-distortion actuator is configured to generate the output signal by applying a correction to the carrier-modulated signal that cancels out nonlinearities associated with the one or more antennas and/or the one or more power amplifiers. The pre-distortion actuator is configured based on the feedback.

Abstract: A wireless communications system includes a pre-distortion actuator configured to receive a carrier-modulated signal and convert the carrier-modulated signal into an output signal. The system includes one or more antennas configured to receive the output signal and transmit the output signal, one or more power amplifiers electrically coupled between the pre-distortion actuator and the one or more antennas and a receiver configured to receive the output signal over-the-air and generate feedback based on the output signal. The pre-distortion actuator is configured to generate the output signal by applying a correction to the carrier-modulated signal that cancels out nonlinearities associated with the one or more antennas and/or the one or more power amplifiers. The pre-distortion actuator is configured based on the feedback.

Abstract: A wireless communications system includes a stochastic pre-distortion actuator configured to receive a carrier-modulated signal and convert the carrier-modulated signal into an output signal. The system includes one or more antennas configured to receive the output signal and transmit the output signal, one or more power amplifiers electrically coupled between the pre-distortion actuator and the one or more antennas and a receiver configured to receive the output signal over-the-air and generate feedback based on the output signal. The pre-distortion actuator is configured to generate the output signal by applying a correction to the carrier-modulated signal that cancels out nonlinearities associated with the one or more antennas and/or the one or more power amplifiers. The pre-distortion actuator is configured based on the feedback.

Abstract: Apparatus and methods for transceiver calibration are provided. In certain configurations, a transceiver includes a transmit channel and an observation channel. The transmit channel includes a transmit mixer that up-converts a transmit signal by a first or transmit local oscillator frequency. The observation channel includes an observation mixer that down-converts an observed signal from the transmit channel by a second or observation local oscillator frequency that is offset from the first local oscillator frequency. By observing the transmit channel using a local oscillator frequency that is offset relative to the transmit channel's local oscillator frequency, the observation channel can observe transmit channel impairments substantially independently from observation channel impairments.

Abstract: Apparatus and methods for transceiver calibration are provided. In certain configurations, a transceiver includes a transmit channel and an observation channel. The transmit channel includes a transmit mixer that up-converts a transmit signal by a first or transmit local oscillator frequency. The observation channel includes an observation mixer that down-converts an observed signal from the transmit channel by a second or observation local oscillator frequency that is offset from the first local oscillator frequency. By observing the transmit channel using a local oscillator frequency that is offset relative to the transmit channel's local oscillator frequency, the observation channel can observe transmit channel impairments substantially independently from observation channel impairments.