Abstract: Techniques are described herein for non-terrestrial network (NTN) communications via one or more transparent-mode non-geosynchronous (NGSO) satellites. Embodiments extend a terrestrial wireless network (TWN), such as 5G NR, for use with the satellites. Analog feeder uplink and downlink waveforms are formatted to carry forward and return direct-to-device (DtD) signals over respective subchannel channels, and the subchannels can be assigned with time and frequency dimensions that are compatible with resource block assignments of the TWN protocols. Use of the analog subchannels and time-division multiplexing with beam-hopping facilitates satellite communication of the DtD signals effectively as an extension of the TWN. Embodiments also support communication of satellite control signals as part of the analog feeder uplink waveform, and inter-satellite link (ISL) routing and communication on-board the satellite.

Abstract: Techniques are described herein for non-terrestrial network (NTN) communications via one or more transparent-mode non-geosynchronous (NGSO) satellites. Embodiments extend a terrestrial wireless network (TWN), such as 5G NR, for use with the satellites. Analog feeder uplink and downlink waveforms are formatted to carry forward and return direct-to-device (DtD) signals over respective subchannel channels, and the subchannels can be assigned with time and frequency dimensions that are compatible with resource block assignments of the TWN protocols. Use of the analog subchannels and time-division multiplexing with beam-hopping facilitates satellite communication of the DtD signals effectively as an extension of the TWN. Embodiments also support communication of satellite control signals as part of the analog feeder uplink waveform, and inter-satellite link (ISL) routing and communication on-board the satellite.

Abstract: Systems and methods are described herein for providing a direct radiating antenna (DRA) for installation on a communication satellite. The DRA is a phased array of microstrip patch antennas implemented in a very compact profile on a planar substrate. Embodiments of array are implemented as an array of radiating element configurations, each having a microstrip radiating element (e.g., a square patch) coupled to a first side of the planar substrate, amplifiers coupled to a second side of the planar substrate, and filters (e.g., diplexers) coupled between the radiating elements and amplifiers. A thermal conduction layer (e.g., a graphoil or vapor chamber layer) is thermally coupled with the second side of the planar substrate, and a thermal radiation layer (e.g., an optical solar reflector) is thermally coupled with the thermal conduction layer.

Abstract: Methods, systems, and apparatus for transmodulation in multi-beam satellite communication systems. In some implementations, a gateway receives bitstreams for transmission on different forward links from a satellite to terminals. The gateway is configured to modulate data for transmission on a feeder link for transmissions from the gateway to a satellite, including using a same symbol constellation to modulate data to provide different numbers of bits per symbol. The gateway can be configured to select symbols for transmission from among different subsets of the symbols in the symbol constellation to achieve different numbers of bits per symbol. The gateway can also be configured to select symbols for transmission from among one of the subsets determined based at least in part on a measure of signal strength for the feeder link.

Abstract: A system and method for beamforming beams including: matching weights T to a distribution of resources for each of the beams based on a traffic variation for each of the beams; calculating, with a signal processor for each of the beams based on the weights T, a power scalar ? and a weighted minimum mean squared error (WMMSE) matrix WWMSE; and transmitting/receiving the beams based on the power scalar ? and the WMMSE matrix WWMSE, where the power scalar ? satisfies a total power constraint of an antenna subsystem.

Abstract: A system and method for scheduling a variable stayout distance when beam hopping, the method including providing an illumination area of a satellite and candidate beam centers disposed in the illumination area; measuring a respective scan angle from an antenna boresight to a respective beam center of the candidate beam centers; and determining a reuse factor k for each of the candidate beam centers, based on a proportion of the respective scan angle to a maximum scan angle. Each candidate beam center may be processed sequentially. Prior to adding each candidate beam center to a current beam center set, checking whether a candidate beam center meets the stayout distance criteria from all beam centers already in the beam center set.

Abstract: A system and method for scheduling a variable stayout distance when beam hopping, the method including providing an illumination area of a satellite and candidate beam centers disposed in the illumination area; measuring a respective scan angle from an antenna boresight to a respective beam center of the candidate beam centers; and determining a reuse factor k for each of the candidate beam centers, based on a proportion of the respective scan angle to a maximum scan angle. Each candidate beam center may be processed sequentially. Prior to adding each candidate beam center to a current beam center set, checking whether a candidate beam center meets the stayout distance criteria from all beam centers already in the beam center set.

Abstract: A system and method for scheduling a variable stayout distance when beam hopping, the method including providing an illumination area of a satellite and candidate beam centers disposed in the illumination area; measuring a respective scan angle from an antenna boresight to a respective beam center of the candidate beam centers; and determining a reuse factor k for each of the candidate beam centers, based on a proportion of the respective scan angle to a maximum scan angle. Each candidate beam center may be processed sequentially. Prior to adding each candidate beam center to a current beam center set, checking whether a candidate beam center meets the stayout distance criteria from all beam centers already in the beam center set.

Abstract: A system and method for beamforming beams including: matching weights T to a distribution of resources for each of the beams based on a traffic variation for each of the beams; calculating, with a signal processor for each of the beams based on the weights T, a power scalar ? and a weighted minimum mean squared error (WMMSE) matrix WWMSE; and transmitting/receiving the beams based on the power scalar ? and the WMMSE matrix WWMSE, where the power scalar ? satisfies a total power constraint of an antenna subsystem.

Abstract: A system and method for beamforming beams including: matching weights T to a distribution of resources for each of the beams based on a traffic variation for each of the beams; calculating, with a signal processor for each of the beams based on the weights T, a power scalar ? and a weighted minimum mean squared error (WMMSE) matrix WWMSE; and transmitting/receiving the beams based on the power scalar ? and the WMMSE matrix WWMSE, where the power scalar ? satisfies a total power constraint of an antenna subsystem.

Abstract: A system and method for beamforming beams including: matching weights T to a distribution of resources for each of the beams based on a traffic variation for each of the beams; calculating, with a signal processor for each of the beams based on the weights T, a power scalar ? and a weighted minimum mean squared error (WMMSE) matrix WWMSE; and transmitting/receiving the beams based on the power scalar ? and the WMMSE matrix WWMSE, where the power scalar/3 satisfies a total power constraint of an antenna subsystem.

Abstract: A system and method for scheduling a variable stayout distance when beam hopping, the method including providing an illumination area of a satellite and candidate beam centers disposed in the illumination area; measuring a respective scan angle from an antenna boresight to a respective beam center of the candidate beam centers; and determining a reuse factor k for each of the candidate beam centers, based on a proportion of the respective scan angle to a maximum scan angle. Each candidate beam center may be processed sequentially. Prior to adding each candidate beam center to a current beam center set, checking whether a candidate beam center meets the stayout distance criteria from all beam centers already in the beam center set.

Abstract: A system and method for timing synchronization of satellite switching instants with gateway switching instants is described.

Abstract: A system and method for timing synchronization with a modified DVB-S2X waveform for a forward beam hopping satellite is described. The method includes: transmitting a channel including a plurality of beams per a Beam Hopping Time Plan (BHTP), wherein each beam includes a discontinuous signal including a superframe including timing markers and a Beam Hopping Forward Synchronization Pattern (BHFSP); receiving a synchronization information, without a loopback beam, for one of the plurality of beams; determining an adjustment period and an adjusted symbol rate for generation of terrestrial switching instants, based on the synchronization information, for a transmission of the plurality of beams such that at least a portion of a respective BHFSP of one of the beams aligns with one of satellite switching instants; and adjusting a timing and symbol rate of the transmission according to the adjustment period and the adjusted symbol rate, respectively.

Abstract: A system and method for timing synchronization with a modified DVB-S2X waveform for a forward beam hopping satellite is described. The method includes: transmitting a channel including a plurality of beams per a Beam Hopping Time Plan (BHTP), wherein each beam includes a discontinuous signal including a superframe including timing markers and a Beam Hopping Forward Synchronization Pattern (BHFSP); receiving a synchronization information, without a loopback beam, for one of the plurality of beams; determining an adjustment period and an adjusted symbol rate for generation of terrestrial switching instants, based on the synchronization information, for a transmission of the plurality of beams such that at least a portion of a respective BHFSP of one of the beams aligns with one of satellite switching instants; and adjusting a timing and symbol rate of the transmission according to the adjustment period and the adjusted symbol rate, respectively.

Abstract: An RF communications transmitter system comprising a processor, a switch and a plurality of feedhorns. The switch is configured to receive a feed signal of a frequency bandwidth. The processor is configured to control the switch to provide the feed signal to each of at least two of the feedhorns for a respective time period. Each of the at least two feedhorns is configured to generate a beam during the respective time period that the feed signal is provided thereto, wherein the beam is formed based on the feed signal and is transmitted to cover a geographic area of the Earth. The formation and transmission of the beams by the feedhorns is controlled by the processor to provide a time-based allocation of bandwidth amongst the beams based on the time period that the feed signal is provided to each of the feedhorns and a respective frequency/polarization reuse scheme.

Abstract: A method for determining routes for a data circuit between source and destination terminals, where the circuit is formed via satellites traveling in respective non-geostationary orbits, and a total time during which the circuit is active is divided into time intervals. The determination of each route comprises, for each time interval, (i) selecting an uplink satellite to service the source terminal as an ingress node for the circuit, and (ii) determining a series of inter-satellite links connecting the uplink satellite to a downlink satellite servicing the destination terminal during the respective time interval, wherein the series of links is determined to be valid during the respective time interval. Each of the plurality of time intervals is of a duration based on a validity time, based on the satellites traveling in their respective orbits, for the inter-satellite link of all of the routes that is of the shortest duration.

Abstract: A system and method for timing synchronization of satellite switching instants with gateway switching instants is described.

Abstract: An RF communications transmitter system comprising a processor, a switch and a plurality of feedhorns. The switch is configured to receive a feed signal of a frequency bandwidth. The processor is configured to control the switch to provide the feed signal to each of at least two of the feedhorns for a respective time period. Each of the at least two feedhorns is configured to generate a beam during the respective time period that the feed signal is provided thereto, wherein the beam is formed based on the feed signal and is transmitted to cover a geographic area of the Earth. The formation and transmission of the beams by the feedhorns is controlled by the processor to provide a time-based allocation of bandwidth amongst the beams based on the time period that the feed signal is provided to each of the feedhorns and a respective frequency/polarization reuse scheme.

Abstract: A triple use satellite system includes a VSAT population including a VSAT, and a satellite including a broadcast beam for a broadcast service and spot beams for a broadband service, where each of the spot beams provides broadband service to VSATs in separate coverage areas in a geographic region and the broadcast beam provides a broadcast service to the VSAT population in the geographic region.