Methods, systems, and apparatus, including computer programs encoded on computer storage media, for dynamically reducing an aperture size to reduce overhead. In some implementations, a server can receive a first transmission from a first terminal through a communication network. The server can determine a timing offset associated with the first terminal based on the first transmission. The server can determine an aperture window size for an aperture window for the first terminal based on the determined timing offset associated with the first terminal. The server can generate allocation data that assigns communication resources to one or more terminals that includes the first terminal, the allocation data being based on the determined aperture window size for the first terminal. The server can communicate with the one or more terminals to indicate the communication resources respectively allocated to the one or more terminals.

The invention relates to a method for operating a communication system, the communication system comprising at least two separate transmitting antennas located on Earth and at least two receive antennas located with a distance from Earth, the receive antennas having directional receiving patterns which cover a common region on Earth, the method comprising the following steps: —precoding the symbol sequences before transmission from the transmitting antennas to the receive antennas in order to reduce spatial interference between the symbol sequences, and —simultaneously transmitting symbol sequences from the transmitting antennas to the receive antennas by spatial and frequency multiplexing in a time and phase synchronized fashion, the symbol sequences being transmitted from different transmitting antennas being different from each other but being transmitted on the same frequency. In this way, a high bandwidth method for transmitting data from an Earth transmitting station to a receiving station which is located with a distance from Earth.

Methods and apparatuses for performing predistortion on transmissions to antennas are disclosed. In some embodiments, a method includes obtaining a type and scan angle of a flat panel antenna of a satellite terminal; selecting, based on the type and the scan angle, predistortion to apply to a signal to be transmitted to the flat panel antenna; applying the predistortion to the signal; and transmitting the signal to the flat panel antenna of the satellite terminal.

In one embodiment of the present disclosure, a satellite communication system includes a satellite constellation including a plurality of satellites in non-geosynchronous orbit (non-GEO), wherein at least some of the plurality of satellites travel in a first orbital path at a first inclination, and an end point terminal having an earth-based geographic location, the end point terminal having an antenna system defining a field of regard for communicating with the satellite constellation, wherein the field of regard is a limited field of regard, wherein the field of regard is tilted from a non-tilted position to a tilted position, and wherein the tilt angle of the tilted position is a function of the latitude of the geographic location.

An enhanced L-band Digital Aeronautical Communications System (LDACS) may include LDACS ground stations; and a LDACS airborne stations, each configured to communicate with the LDACS ground stations at a given class of service from among different classes of service. The enhanced LDACS may also include a network controller configured to operate the LDACS ground stations and LDACS airborne stations at the different user classes of service.

A plurality of control signals transmitted in individual frequency bands by a moving transmission station via a plurality of transmission antennas and a plurality of data signals transmitted in a common frequency band by the transmission station via the plurality of transmission antennas in synchronization with the control signals are received by each of a plurality of antennas disposed at different positions. Based on symbol timings of the control signals received by the antenna, a sampling rate error between the plurality of control signals transmitted by the plurality of transmission antennas, respectively, is compensated for. Based on the control signals subjected to the sampling rate error compensation, frame timings of the plurality of data signals transmitted by the transmission station via the plurality of transmission antennas are synchronized. Based on the control signals subjected to the sampling rate error compensation, channels for the plurality of data signals transmitted by the transmission station via the plurality of transmission antennas are estimated. The plurality of data signals with the frame timings synchronized, for the estimated channels are equalized.

In some implementations, a radiofrequency down converter comprises an input port to receive a radiofrequency input signal, and the down converter includes a first bandpass filter configured to filter the input signal. The down converter includes a mixer stage coupled to the bandpass filter, the mixer stage being configured to generate a mixer output signal by processing the filtered input signal using a gain adjustment device, one or more amplifiers, and a mixer. The down converter includes a signal adjustment stage coupled to receive the mixer output signal, the signal adjustment stage comprising: a temperature compensation device configured to compensate for changes in signal gain due to changes in temperature; a second bandpass filter; a gain adjustment device; one or more amplifiers; and a low pass filter. The down converter comprises an output port coupled to output an adjusted mixer output signal from the signal adjustment stage.

A method, including receiving a search query for resources that are configured to establish a connection with a space vehicle, the search query including a first value for a connection parameter; identifying one or more tactic definitions that satisfy the search query, each of the tactic definitions including one or more second values for the connection parameter, wherein at least one of the second values for the connection parameter matches the first value for the connection parameter that is included in the search query; and generating one or more tactic options, each of the tactic options being generated based on a respective one of the tactic definitions, each of the tactic options being associated with a respective resource of the tactic option.

Methods and systems are described for providing end-to-end beamforming. For example, end-to-end beamforming systems include end-to-end relays and ground networks to provide communications to user terminals located in user beam coverage areas. The ground segment can include geographically distributed access nodes and a central processing system. Return uplink signals, transmitted from the user terminals, have multipath induced by a plurality of receive/transmit signal paths in the end to end relay and are relayed to the ground network. The ground network, using beamformers, recovers user data streams transmitted by the user terminals from return downlink signals. The ground network, using beamformers generates forward uplink signals from appropriately weighted combinations of user data streams that, after relay by the end-end-end relay, produce forward downlink signals that combine to form user beams.

A satellite communication system includes a plurality of earth station apparatuses and a control earth station apparatus, the plurality of earth station apparatuses each accommodating a terminal apparatus that establishes a session by using a control message being dedicated to perform communication, the control earth station apparatus transmitting and/or receiving a control signal on a controlling line to an earth station apparatus of the plurality of earth station apparatuses via a relay satellite, and the satellite communication system performing circuit-switching of a communicating line between the plurality of earth station apparatuses that are connected by single-hop connection to allow a plurality of the terminal apparatuses to perform communication with each other. A first earth station apparatus accommodating a first terminal apparatus on an outgoing side among the plurality of earth station apparatuses encapsulates the control message received from the first terminal apparatus in the control signal to transfer the encapsulated resultant through the controlling line to a second earth station apparatus accommodating a second terminal apparatus on an incoming side among the plurality of earth station apparatuses, and performs circuit-switching of the communicating line between the first earth station apparatus and the second earth station apparatus in accordance with the control message. This allows circuit-switching to be performed through satellite channels using a simple transmission frequency fixed assignment scheme.