Viasat, Inc.

Methods and devices for radio frequency (RF) loopback for transceivers are described. A transceiver for communicating RF signals with a target device may transmit signals at a transmit frequency and receive signals at a (different) receive frequency. The transceiver may include a waveguide diplexer for separating and combining signals based on frequency. The transceiver may be configured to couple a loopback signal from a common port of the waveguide diplexer; the loopback signal may be based on a transmit signal. The transceiver may include a loopback translator to translate the loopback signal from the transmit frequency to the receive frequency and provide the translated loopback signal to a receiver used for receiving signals from the target device. The receiver may compare the translated loopback signal with a representation of the transmit signal to generate a compensation signal. A transmitter may use the compensation signal to adjust subsequent transmit signals.

Described herein are technologies that utilize full duplex gateway terminals in satellite networks with half duplex user equipment. The disclosed scheduling technologies incorporate the knowledge of the propagation delay between a gateway terminal and each UE in communication with the gateway terminal. Based on this propagation delay, a scheduler can allocate DL and UL time slots in a scheduling frame in a way that avoids allocating overlapping DL and UL time slots at each UE.

Systems and methods are described that enable user terminals to eliminate or reduce the number of dummy bursts (or bursts with no data) they send. The systems and methods use two burst detectors, a first burst detector that analyzes the physical structure of the signal, and a second burst detector that analyzes the informational structure of the signal. Output from the first burst detector can be used to control operation of a signal decoder that decodes received signals. The second burst detector analyzes output from the signal decoder to determine the second burst indicator. In other words, the first burst detector can be implemented prior to decoding the received signal to provide a first estimate related to the presence or absence of a burst. This can then be used to limit the amount of processing performed by the signal decoder.

One example includes a self-synchronizing TDD antenna system. The system includes an antenna to communicate transmit and receive signals and an antenna circuit coupled to a user communication system via a transmission line cable. The antenna circuit includes a transmission line measurement circuit to determine signal loss through the transmission line cable and an amplitude adjustment circuit to adjust amplitude of the transmit and/or receive signals based on the determined signal loss. The antenna circuit also includes a transmit detection circuit to monitor signal power of the transmit signal, and a controller to switch the amplitude adjustment circuit from a receive mode to a transmit mode in response to the monitored signal power exceeding a predetermined threshold. In the receive mode, the adjustment circuit applies a receive amplitude adjustment to the receive signal, and in the transmit mode the adjustment circuit applies a transmit amplitude adjustment to the transmit signal.

Described herein are technologies that utilize full duplex gateway terminals in satellite networks with half duplex user equipment. The disclosed scheduling technologies incorporate the knowledge of the propagation delay between a gateway terminal and each UE in communication with the gateway terminal. Based on this propagation delay, a scheduler can allocate DL and UL time slots in a scheduling frame in a way that avoids allocating overlapping DL and UL time slots at each UE.

Systems and methods are described that enable user terminals to eliminate or reduce the number of dummy bursts (or bursts with no data) they send. The systems and methods use two burst detectors, a first burst detector that analyzes the physical structure of the signal, and a second burst detector that analyzes the informational structure of the signal. Output from the first burst detector can be used to control operation of a signal decoder that decodes received signals. The second burst detector analyzes output from the signal decoder to determine the second burst indicator. In other words, the first burst detector can be implemented prior to decoding the received signal to provide a first estimate related to the presence or absence of a burst. This can then be used to limit the amount of processing performed by the signal decoder.

Described herein are technologies that utilize full duplex gateway terminals in satellite networks with half duplex user equipment. The disclosed scheduling technologies incorporate the knowledge of the propagation delay between a gateway terminal and each UE in communication with the gateway terminal. Based on this propagation delay, a scheduler can allocate DL and UL time slots in a scheduling frame in a way that avoids allocating overlapping DL and UL time slots at each UE.

Described herein are technologies that coordinate operation of access nodes in a communications system to enable the efficient use of TDD systems (e.g., cellular equipment) in an FDD network (e.g., a satellite network). Two access nodes can be configured with complementary schedules so that the forward link slots of a first access node correspond to the return link slots of a second access node and vice versa. In this arrangement, all time slots of a satellite network are utilized except for a switching time gap. Advantageously, although the cellular equipment implements TDD schemes, coordinated operation of the access nodes allows the satellite network to operate in full duplex and the duration of a switching time gap in the schedules can be made relatively small. That is, the switching time gap is not influenced by the propagation delay of the signal through the satellite network.

Methods and devices for radio frequency (RF) loopback for transceivers are described. A transceiver for communicating RF signals with a target device may transmit signals at a transmit frequency and receive signals at a (different) receive frequency. The transceiver may include a waveguide diplexer for separating and combining signals based on frequency. The transceiver may be configured to couple a loopback signal from a common port of the waveguide diplexer; the loopback signal may be based on a transmit signal. The transceiver may include a loopback translator to translate the loopback signal from the transmit frequency to the receive frequency and provide the translated loopback signal to a receiver used for receiving signals from the target device. The receiver may compare the translated loopback signal with a representation of the transmit signal to generate a compensation signal. A transmitter may use the compensation signal to adjust subsequent transmit signals.

Methods and devices for radio frequency (RF) loopback for transceivers are described. A transceiver for communicating RF signals with a target device may transmit signals at a transmit frequency and receive signals at a (different) receive frequency. The transceiver may include a waveguide diplexer for separating and combining signals based on frequency. The transceiver may be configured to couple a loopback signal from a common port of the waveguide diplexer; the loopback signal may be based on a transmit signal. The transceiver may include a loopback translator to translate the loopback signal from the transmit frequency to the receive frequency and provide the translated loopback signal to a receiver used for receiving signals from the target device. The receiver may compare the translated loopback signal with a representation of the transmit signal to generate a compensation signal. A transmitter may use the compensation signal to adjust subsequent transmit signals.