SATELLITE SYSTEM COMPRISING BEAM JUMP TERMINALS COMMUNICATING WITH MORE THAN ONE GATEWAY

专利摘要:
A satellite communication system includes a satellite configured to provide a first plurality of spot beams adapted for communication with subscriber terminals using time-domain beam switching, and a second plurality of spot beams adapted to communication with bridges. The satellite includes a spectrum routing network that is configured to multiplex, in time, spot beams of the second plurality of spot beams with point beams of the first plurality of spot beams, such that a beam One-off, which implements beam switching, for communication with subscriber terminals, communicates with different power beams (and therefore different gateways) at different times during a switching period.
公开号:FR3049792A1
申请号:FR1752604
申请日:2017-03-28
公开日:2017-10-06
发明作者:William Hreha；Anne Elizabeth Wharton；David Linford Foulke
申请人:Space Systems Loral LLC；
IPC主号:

专利说明:

SATELLITE SYSTEM COMPRISING BEAM JUMPING TERMINALS COMMUNICATING WITH MORE THAN ONE GATEWAY
The present disclosure relates to a technology for satellite communication systems.
Satellite communication systems typically include one or more satellites and a set of ground terminals. Such systems generally operate in accordance with regulations that affect an operating frequency bandwidth for a specific communication service, and specify, among other things, a maximum signal power spectral density of the communication signals radiated to the ground. A growing market exists in the provision of high-speed data communication services to individual consumers and small businesses that may be underserved by conventional terrestrial services, or may not be able to pay for such services services. Satellite communication systems have been proposed to provide such high data rate communication services. However, designing a satellite system to meet these needs is a challenge. To this end, the invention relates to a satellite communication system, comprising a satellite configured to provide a first plurality of spot beams adapted for communication with subscriber terminals using a time domain beam, in a wherein the satellite is configured to provide a second plurality of spot beams adapted for communication with gateways, the satellite includes a spectrum routing network that is configured to time-multiplex spot beams of the second plurality. spot beams with spot beams of the first plurality of spot beams.
According to other advantageous aspects of the present invention, the satellite communications system comprises one or more of the following characteristics, considered alone or in any technically possible combination: the spectrum routing network includes a digital channelizer; - the satellite communication system, in which: - the spectrum routing network includes a digital channelizer; the first plurality of spot beams is divided into switching groups; the satellite further includes an antenna system and a selection matrix in communication with the digital funnel and the antenna system; the antenna system provides the first plurality of spot beams and the second plurality of spot beams; the digital channelizer routes between the first plurality of spot beams and the second plurality of spot beams; and the selection matrix switches a bitrate among the spot beams in the same switching group. the satellite is configured to switch a bitrate among the spot beams, at intervals of one epoch, over a switching period according to a switching plan; and the spectrum routing network is configured to multiplex, in time, spot beams of the second plurality of spot beams with spot beams of the first plurality of spot beams, during a switching period, so that a specific beam of the first plurality of beams receives a bandwidth at multiple times during the switching period, the satellite is configured to route communication between different beams of the second plurality of beams and the specific beam, at different epochs among multiple epochs during the switching period; the satellite is configured to route a communication between different beams of the second plurality of beams and the specific beam at different epochs among multiple epochs during the switching period, while the specific beam remains at a location of specific subscriber terminal; the spectrum routing network is configured to multiplex, in time, point beams of the second plurality of spot beams with point beams of the first plurality of spot beams, providing communication between a specific point beam. of the first plurality of point beams and a first point beam of the second plurality of point beams, during a first set of epochs, while the specific point beam is at a location on a surface of the planet, and providing communication between the specific spot beam and a second spot beam of the second plurality of spot beams, in a second set of one or more epochs, while the specific spot beam remains on replacement on the planet's surface ; the second set of one or more epochs is intertwined with the first set of epochs; the spectrum routing network is configured to multiplex, in time, spot beams of the second plurality of spot beams with spot beams of the first plurality of spot beams, while a specific spot beam of the first set of spot beams; spot beams remain on a specific location; - the satellite is configured to; - switching a rate among the spot beams of the first plurality of spot beams, at intervals of one epoch, over a switching period, according to a switching plan; modifying a configuration of the spectrum routing network during the orbit switching plan while the satellite is moving relative to a coverage area; and modifying, in orbit, the manner in which the spot beams of the second plurality of spot beams are multiplexed with point beams of the first plurality of spot beams; the satellite is configured to: switch a rate among the spot beams, at intervals of one epoch, over a switching period, according to a switching plan; each epoch including a duration of activity, a late arrival window, a payload reconfiguration time and an anticipated arrival window; during the duration of activity of a current epoch, to transmit data for the current epoch; during the late arrival time, transmit data that arrived late for the current time; during the payload reconfiguration time, modifying routing paths in the spectrum routing network for a successive epoch; and during the early arrival window, transmit data that arrived in advance for the next time; - the satellite is a non-geostationary satellite; the satellite further comprises additional satellites which, together with the satellite, form a constellation of non-geostationary satellites which are each configured to provide a first distinct plurality of spot beams adapted for communication with subscriber terminals using a temporal domain beam, and providing a second distinct plurality of spot beams adapted for communication with gateways, the satellites each including a respective spectrum routing network which is configured to multiplex in time spot beams of the respective second plurality of spot beams with spot beams of the respective first plurality of spot beams; each satellite of the constellation has the same beam map; and each satellite of the constellation is configured to move along the same orbital path; The invention also relates to a method of operating a satellite communication system, comprising the steps of: providing a first plurality of spot beams from a non-geostationary satellite to communicate with subscriber terminals as the satellite travels across a surface of the planet; implementing time domain beam switching for the first plurality of spot beams; providing a second plurality of spot beams from the non-geostationary satellite to communicate with gateways as the satellite travels across the surface of the planet; providing communication between a specific spot beam of the first plurality of spot beams and a first spot beam of the second plurality of spot beams during a first set of epochs while the specific spot beam is at a location on the surface of the planet ; and providing communication between the specific spot beam and a second spot beam of the second plurality of spot beams during a second set of one or more epochs, while the specific spot beam remains overwriting on the surface of the planet .
According to other advantageous aspects of the present invention, the method of operating a satellite communications system comprises one or more of the following characteristics, considered alone or in any technically possible combination: the first set of epochs is intertwined with the second set of one or more eras; the step of implementing the time domain beam switching for the first plurality of spot beams induces the step of moving a rate between the spot beams of the first plurality of spot beams, at intervals of an epoch, over a switching period, according to a switching plan; and the method further comprising the step of changing the configuration of the non-geostationary satellite between providing the communication between the specific point beam and the first point beam, and providing the communication between the specific point beam and the second beam punctual, during the switching plan, in orbit, while the satellite is moving away from the surface of the planet; the step of implementing time domain beam switching for the first plurality of point beams includes moving a rate between the spot beams of the first plurality of spot beams, at intervals of an epoch, over a switching period, according to a switching plan; each epoch including a duration of activity, a late arrival window, a payload reconfiguration time, and an anticipated arrival window; and wherein the method further comprises the steps below wherein; during the period of activity of a current epoch, the satellite transmits data for the current epoch; - during the late arrival time, the satellite transmits data that arrived late for the current time; during the payload reconfiguration time, the satellite configures its routing routes for a successive period; and - during the early arrival window, the satellite transmits data that arrived in advance for the next epoch. the steps of providing a first plurality of spot beams, implementing time domain beam switching for the first plurality of spot beams, providing a second plurality of spot beams, providing the spot beam; communication between a specific spot beam of the first plurality of spot beams and a first spot beam, and providing communication between the specific spot beam and a second spot beam, are implemented separately and simultaneously by multiple satellites using the same map of beams and moving along the same orbital trajectory. The invention also relates to a satellite, wherein the satellite is a non-geostationary satellite configured to provide a first plurality of beams adapted for communication with subscriber terminals and to provide a second plurality of beams adapted for communication with gateways, the satellite is configured to implement time domain multiplexing for the first plurality of beams over a switching period, so that a specific beam of the first plurality of beams receives a bandwidth at at multiple times during the switching period, the satellite is configured to route communication between different beams of the second plurality of beams and the specific beam, at different epochs of multiple epochs, during the switching period. .
According to another advantageous aspect of the present invention; the satellite is configured to route a communication between different beams of the second plurality of beams and the specific beam, at different epochs among multiple epochs, during the switching period, while the specific beam of the first set of spot beams stays on a specific location; the first plurality of beams corresponds to spot beams divided into switching groups; the satellite further includes an antenna system, a digital funnel and a selection matrix in communication with the digital funnel and the antenna system; the antenna system provides the first plurality of spot beams; the digital channelizer routes between the first plurality of spot beams and the second plurality of spot beams; and the selection matrix switches a bitrate among the spot beams in the same switching group.
These features and advantages of the present invention will appear more clearly on reading the description which follows, provided solely by way of nonlimiting example and with reference to the appended drawings, in which:
Fig. 1 is a block diagram describing an embodiment of a portion of a satellite communications system;
Fig. 2 is a block diagram illustrating a satellite and its antenna system; Figure 3 illustrates a beam map for a field of view;
Figure 4 is a map of the world showing a constellation of non-geostationary satellites;
Figure 5 is a map of the world, showing the beam maps for eleven non-geostationary satellites;
Fig. 6 is a block diagram of one embodiment of a communication payload for a non-geostationary satellite;
Fig. 7 is a block diagram of an embodiment of a digital channelizer;
Fig. 8 illustrates an exemplary embodiment of an uplink frequency plan for beams remote from the equator;
Fig. 9 illustrates an exemplary embodiment of a downlink frequency plan for beams remote from the equator;
Fig. 10 is a beam map illustrating an embodiment of a color assignment (frequency band + polarization) for spot beams;
Figure 11 illustrates an exemplary uplink frequency plan for beams at the equator;
Figure 12 illustrates an exemplary downlink frequency plan for beams at the equator;
Figure 13 illustrates a beam map;
Fig. 13A is a flowchart describing an embodiment of a satellite constellation operation process with different frequency planes and different switching planes between beams at the equator and beams distant from the equator;
Figures 14A and 14B illustrate exemplary beam polarization maps; Figures 15A, 15B, 15C, 15D, 15E and 15F illustrate exemplary beam maps;
Fig. 15G is a flow chart depicting an embodiment of a satellite communications system operating process, including frequency modification for subscriber terminals, not requiring polarization modification as the satellites move relative to subscriber terminals;
Fig. 15H is a flowchart describing an embodiment of a satellite communications system operating process, including implementation of satellite handoffs;
Figures 16A, 16B and 16C illustrate exemplary beam maps;
Figs. 17A, 17B, 17C, 17D and 17E illustrate exemplary beam maps;
Fig. 18 is a timing diagram describing a time domain beam switching;
Fig. 19 is a flowchart describing an embodiment of a time domain beam switching implementation process;
Fig. 20A illustrates an exemplary beam map showing switching groups far away from the equator;
Figure 20B illustrates an exemplary beam map showing switching groups at the equator;
Fig. 21 illustrates a table providing an exemplary assignment of switching groups remote from the equator;
Figure 22 illustrates a table providing an exemplary assignment of switching groups at the equator;
Fig. 23 illustrates an exemplary beam map showing the field of view, representing a time instant, and graphically indicating which subset of spot beams of the various switching groups is active in the current epoch:
Fig. 24 depicts a portion of an example of a beam switching plane;
Fig. 25 illustrates a timing for one embodiment of a superframe; Fig. 26 illustrates the contents of an embodiment of a superframe;
Fig. 27 illustrates an example of a payload of a superframe;
Figure 28 illustrates a portion of a satellite communication system showing sample transmission times;
Fig. 29 is a flowchart describing an embodiment of a time domain beam switching implementation process with a non-geostationary satellite constellation able to dynamically modify beam switching planes;
Figure 30 depicts a portion of an example of a beam switching plane, and illustrates a time-division multiplexing of gateways;
Fig. 31 is a flowchart describing an embodiment of a time domain beam switching and time division multiplexing implementation process;
Fig. 32 is a flowchart describing an embodiment of a time domain beam switching implementation process on a satellite;
Fig. 33 illustrates a portion of a satellite communication system showing a satellite which is configured to implement a beam switching plan which, during a switching period, provides a bit rate at a first time. punctual beam for an aggregated time duration, based on bandwidth assignments to the first gateway and the first set of subscriber terminals;
Fig. 34 is a flowchart describing an embodiment of a process for implementing time-domain beam switching taking into account the bandwidth requirements of the subscriber terminal and the gateway;
Fig. 35 is a graph depicting an example of capacity sharing by dividing times or units of capacity based on pro-rated bandwidth requirements;
Figure 36 illustrates a portion of a satellite communication system showing a handover of a subscriber terminal between spot beams on the same satellite;
Fig. 37 is a flowchart describing an embodiment of a gateway process for implementing a handover of a subscriber terminal between spot beams on the same satellite;
Fig. 38 is a flowchart describing an embodiment of a gateway process for implementing a handover of a subscriber terminal between spot beams on the same satellite;
Fig. 39 is a flowchart describing an embodiment of a subscriber terminal process for implementing subscriber terminal handoff between point beams on the same satellite;
Fig. 40 is a flowchart describing an embodiment of a subscriber terminal process for implementing a subscriber terminal handover between spot beams on the same satellite;
Fig. 41 illustrates a portion of a satellite communication system showing a handover of a subscriber terminal between point beams of different satellites;
Fig. 42 is a flowchart describing an embodiment of a gateway process for implementing a handover of a subscriber terminal between point beams on different satellites;
Fig. 43 is a flowchart describing an embodiment of a subscriber terminal process for implementing a subscriber terminal handover between point beams on different satellites;
Figure 44 illustrates a portion of a satellite communication system showing two cooperating gateways operating within switching beams and communicating with switching beams.
Fig. 45 is a flowchart describing an embodiment of a process for implementing gateway handoff between satellites, where the gateways operate within switching beams and communicate with switching beams;
Figures 46A, 46B, 46C and 46D illustrate fields of view of the two satellites moving over coverage areas;
Fig. 47 illustrates a portion of a satellite communication system showing a gateway connecting to steerable spot beams of both satellites for implementing intercell handover;
Fig. 48 is a flowchart describing an embodiment of a process for implementing intercell handoff for bridges communicating with orientable spot beams of satellites in the constellation;
Figures 49A, 49B, 49C, 49D and 49E illustrate a field of view of a satellite traveling over coverage regions as the satellite enters orbit around the Earth;
Fig. 50 is a flowchart describing one embodiment of a timing synchronization implementation process for the satellite communication system;
Fig. 51 is a flowchart describing an embodiment of a synchronization process of a gateway with a satellite;
Figure 51A illustrates an exemplary beacon signal;
Fig. 52 is a flowchart describing an embodiment of a synchronization process of a subscriber terminal with a gateway;
Fig. 53 is a flowchart describing an embodiment of a gateway-implemented process for automatically determining a location of a satellite.
System overview
A satellite communication system is provided that includes a constellation of non-geostationary satellites orbiting the Earth, a plurality of gateways and a plurality of subscriber terminals (also referred to as "terminals"). Subscriber terminals communicate with gateways via satellites as the satellites move into orbit. The satellites each provide a plurality of non-articulated point beams that implement switching - in other words, repointing in another direction - of the time domain beam and a plurality of steerable point beams for communicating with the gateways and terminals. subscribers. The system can be used to provide access to the Internet or other networks, telephone services, videoconferencing services, private communications, broadcasting services, as well as other communication services.
In one embodiment, a satellite is configured to provide a first plurality of spot beams adapted for communication with subscriber terminals using time-domain beam switching, and a second plurality of spot beams (beams). power supply) adapted for communication with gateways. The satellite includes a spectrum routing network that is configured to multiplex, in time, spot beams of the second plurality of spot beams with point beams of the first plurality of spot beams, such that a beam punctual, which implements a beam switching, for communication to subscriber terminals, communicates with different power supply beams (and therefore different gateways) at different times, during a switching period.
Figure 1 is a block diagram illustrating a portion of a satellite communications system that includes one or more satellites. Figure 1 illustrates a satellite 201, which is a non-geostationary satellite. A geostationary satellite moves in a geosynchronous orbit (with a rotation period synchronous with that of the Earth's rotation) in the plane of the equator, so that it remains stationary with respect to a fixed point on the surface of the equator Earth. This orbit is often reached at an altitude of 22,300 miles (35,900 km) above the Earth; however, other altitudes may also be used. A non-geostationary satellite is a satellite that is not a geostationary satellite, and is not in an orbit that causes the satellite to remain stationary with respect to a fixed point on the Earth's surface. Examples of non-geostationary satellites include, but are not limited to, low-orbiting satellites ("LEO"), medium-orbiting satellites ("MEO"), or satellites in highly eccentric elliptical orbits ("HEO"). . Although Figure 1 illustrates only one satellite, in some embodiments (as described below), the system will include multiple satellites, in which case the term "satellite constellation" will be used.
In one embodiment, a satellite 210 includes a bus (i.e., a spacecraft), and one or more payloads, including a communication payload. The satellite may also include multiple power sources, such as batteries, solar panels, and one or more propulsion systems, to operate the bus and payload. The satellite includes an antenna system that provides a plurality of beams, including steerable spot beams and non-articulated spot beams, for communicating with subscriber terminals and gateways.
A subscriber terminal is a device that communicates over the air with a satellite, generally intended for use by one or more end users. The term "subscriber terminal" may be used to refer to a single subscriber terminal or to multiple subscriber terminals. A subscriber terminal is adapted for communication with the satellite communication system, in particular the satellite 201. The subscriber terminals may include fixed subscriber terminals and mobile subscriber terminals, in particular, but but not limited to, a cellular telephone, a cordless handset, a wireless modem, a data transceiver, a pager or position finder, or a mobile radiotelephone, a cellular overlay, a trunk, an enterprise computer storage or computing device, an overhead device, a maritime device or a head end of an isolated local network. A subscriber terminal may be portable, portable (including on-board installations in vehicles such as cars, trucks, boats, trains, airplanes, etc.) or fixed, as appropriate. A subscriber terminal may be referred to as a "wireless communication device", "mobile station", "wireless mobile unit", "user", "subscriber", "terminal" or "mobile".
The term "gateway" may be used to refer to a device that communicates over-the-air with a satellite and provides an interface to a network, such as the Internet, a wide area network, a telephone network, or some other type of network. . In some embodiments, the gateways manage the subscriber terminals.
Figure 1 also illustrates a network control center 230, which includes an antenna and a modem for communicating with the satellite 201, as well as one or more processors and one or more data storage units. The network control center 230 provides instructions for controlling and operating the satellite communication payload 201, as well as all other satellite communication payloads in the constellation. The network control center 230 may also provide instructions to any of the gateways (via a terrestrial network or satellite) and / or to subscriber terminals.
In one embodiment, the satellite 201 is configured to provide two hundred fixed point beams, (i.e., non-articulated beams so that they are fixed relative to the satellite 201), which uses a time domain beam switching among the spot beams. In other embodiments, plus or minus two hundred point beams may be used for time domain beam switching. In one embodiment, the two hundred switching beams are divided into thirty-six switching groups so that only one beam in each group is active at a given time; therefore, thirty-six of the two hundred punctual beams are active at one instance in time. In addition to the two hundred non-articulated spot beams that implement time-domain beam switching, an embodiment of the satellite 201 includes eight 4.2 degree orientable spot beams used to communicate with gateways. In other embodiments, plus or minus eight beams may be used. In addition, the satellite 201 includes six steerable spot beams at 2.8 degrees that may have a dual function, namely to communicate with gateways and / or provide high capacity communication for subscriber terminals which would otherwise fall into switching beams. two hundred spot beams implementing a beam switching in the time domain. Other embodiments may use spot beams sized differently. For illustrative purposes only, FIG. 1 illustrates five spot beams: 202, 206, 210, 214 and 218. The spot beam 202 is a 4.2 degree orientable spot beam that illuminates, or illuminates, a coverage area 204, to communicate with one or more gateways 205 through a downlink 202d and an uplink 202u. The spot beam 206 is a 2.8 degree steerable bivalent beam that illuminates the coverage area 208 to communicate with one or more gateways 209 and one or more subscriber terminals, ST, through the 206d downlink. and uplink 206u. The spot beam 210 is a steerable point beam of 2.8 degrees that could be used to communicate with gateways or subscriber terminals, ST, but in the example of FIG. 1, the spot beam 210 illuminates the coverage area 212 for communicating with one or more gateways 213 through the downlink 21 Od and the uplink 21 Or. The two hundred point beams that implement time domain beam switching can be used to communicate with subscriber terminals or gateways. Spot beams 214 and 218 are two examples of the two hundred non-articulated point beams that have implemented time domain beam switching. The spot beam 214 illuminates the coverage area 216 to communicate with one or more gateways 217 and one or more subscriber terminals, ST, through the downlink 214d and the uplink 214u. The spot beam 218 illuminates the coverage area 220 to communicate with subscriber terminals, ST, through the downlink 218d and the uplink 218u.
Fig. 2 is a block diagram showing in more detail one embodiment of a satellite antenna system 201. For example, Fig. 2 illustrates antennas 252, 254, 258 and 260 which provide the two hundred beams. which implement beam switching in the time domain. Each of the antennas 252, 254, 258 and 260 provides fifty spot beams. FIG. 2 illustrates a cluster of power sources 262 pointed at the antenna 252, a power source cluster 264 pointed at the antenna 254, a power source cluster 266 pointed at the antenna 258, and a In addition, satellite 201 includes six steerable antennas of 2.8 degrees to communicate with gateways and / or to provide high-capacity bundles for terminal terminals. subscribers, namely the antennas 286, 288, 290, 292, 294 and 296. The satellite 201 also includes eight directional antennas of 4.2 degrees to communicate with gateways, namely the antennas 270, 272, 274, 276, 278, 280, 282 and 284. In one embodiment, the antennas are mechanically steerable. In another embodiment, a phased array antenna or other means may be used to electronically orient the spot beams. The satellite 201 also includes an antenna 298 for communicating with the network control center 230 to provide telemetry data and instructions to the satellite 201, and to return status data and other data to the command center. 230. The antenna 298, or any of the other antennas, may also be used to provide a beacon signal. In some embodiments, the satellite 201 may include an additional antenna for providing the beacon signal. In conventional satellites, the beacon signal provides the subscriber terminals and gateways with a gauge to determine the amount of energy to be used. A ground terminal can transmit a signal that the satellite will use to generate a corresponding downlink, which can then be compared to the beacon signal strength, and it can then adjust its power up or down to to obtain a correspondence with the beacon signal. The beacon signal can also be used to determine when a satellite is not operational. In addition, beacon signals may be used to compensate for the Doppler shift. Since the terminal knows that the beacon signal is supposed to be on a certain frequency, it can calculate its Doppler shift on the basis of the current reception of the beacon signal.
Figure 3 provides an exemplary beam map for the two hundred non-articulated point beams of the satellite 201 that implement time-domain beam switching. In one embodiment, these spot beams have a fixed direction relative to the satellite 201. As can be seen, the two hundred spot beams shown in FIG. 3 are numbered from 1 to 200. In one embodiment, the spot beams overlap; for example, the -5 dB contour of each spot beam overlaps the -5 dB contour with other nearby spot beams. All spot beams together constitute the field of view of the satellite 201. The field of view of the satellite is different from the visual field of the satellite. For example, the field of view represents the target area that the satellite can see / communicate based on its position. Thus, the entire beam map of Figure 3 corresponds to the field of view. On the other hand, the visual field corresponds to the zone that the payload of the satellite can actually see to an instance in the time. For example, when implementing a time domain beam switching, only a subset of these spot beams shown in Figure 3 is active at a given time. The visual field is therefore inferior to the field of vision.
In one embodiment, the satellite 201 corresponds only to a satellite of a larger constellation of satellites implementing the satellite communication system. In an exemplary embodiment, the satellite constellation includes eleven satellites, where each satellite has the same structure as that of the satellite 201.
However, each of the satellites is independently programmable to implement identical or different time domain beam switching plans, as will be explained below. Figure 4 is a map of the world illustrating eleven MEO satellites 302, 304, 306, 308, 310, 312, 314, 316, 318, 320 and 322. In one embodiment, the eleven satellites are all in orbit around the planet. equator. In one example, the eleven satellites all move in the same orbital direction along the same orbital path and are spaced evenly from one another. Since the satellites are in MEO orbit, they are "non-geostationary", which means they will move relative to any location on the Earth. As the satellites move into orbit, the coverage areas of the pedestrian bridge and user beams will drift across the Earth's surface with the satellites. In one example, there will be a drift rate of 360 degrees of longitude every six hours, or one degree per minute. In such an embodiment, each satellite will be in orbit, once past the same land position, in six hours, or four times per day. In one embodiment, the time required to drift over the width of a spot beam covering subscriber terminals (one of two hundred spot beam switching beams) is about 2.8 minutes (168 seconds). ).
Figure 5 illustrates the same world map as that of Figure 4, where the beam maps (the field of view) for each of the satellites are shown on the map. For example, the satellite 302 projects the beam map 350, the satellite 304 projects the beam map 352, the satellite 306 projects the beam map 354, the satellite 308 projects the beam map 356, the satellite 310 projects the map. 358, the satellite 312 projects the beam map 360, the satellite 314 projects the beam map 362, the satellite 316 projects the beam map 365, the satellite 318 projects the beam map 366, the satellite 320 projects the map. beams 368, and the satellite 322 projects the beam map 370. Note that the satellites 302-322 are constantly moving from west to east; therefore, the 350-370 beam maps also move from west to east, and are never stationary (in one embodiment). As can be seen, adjacent satellites have adjacent beam maps and adjacent fields of view when operating the satellites. In one embodiment, the adjacent satellite beam maps overlap so that, among the satellites in the constellation, there is continuous coverage across the globe; however, there may be gaps without coverage at the North and South Poles (where demand is low). In other words, the beam map of each satellite is adjacent to a beam map on the adjacent satellite to provide a composite beam map that goes around the Earth.
Fig. 6 is a block diagram of one embodiment of a communication payload for the non-geostationary satellite 201. In one embodiment, each of the satellites 302-322 implements the same structure and the same design. that the satellite 201; therefore, the payload of Figure 6 will be implemented on each of the satellites 302-322. Traditionally, the communication path from the gateway to the subscriber terminal via the satellite is referred to as the "one way", and the communication path of the subscriber terminals to the gateway through the satellite is called the "path back ". When a satellite is used to provide connectivity to the Internet, a user on a computer connected to a subscriber terminal will send a request for content over the Internet to the gateway through the satellite, and the gateway will provide, in response to this request, access to the Internet. The response from the Internet will be provided to the gateway and then transmitted to the subscriber terminal via the satellite.
The structure of Figure 6 implements both the outward and return paths. The uplink beams are received at the left side of the components of Fig. 6 and the downlink beams are provided at the right periphery of the components of Fig. 6. For example, Fig. 6 illustrates eight antennas in FIG. 400 gateways dual steerable polarization and six 402 dual-polarization high capacity subscriber / gateway steerable antennas for receiving uplink beams. Figure 6 also illustrates the two hundred non-articulated point beams divided into two groups; one hundred and seventy spot beams 404 illuminating areas far from the equator and thirty spot beams 406 illuminating areas at the equator.
The eight steerable spot beams of 4.2 degrees of gateways 400 provide sixteen signals, namely eight signals in each polarization (left / right or horizontal / vertical). Six of these sixteen signals are provided to a selection matrix 410 which includes a set of switches that selects two of the six input signals and provides these two selected signals to a low noise amplifier 412. Ten of the sixteen dual polarized signals from antennas 400 are applied directly to a bank of low noise amplifiers 412 including low noise amplifiers. Note that the antennas 400 of Figure 6 correspond to the antennas 270-284 of Figure 2. Similarly, the antennas 402 of Figure 6 correspond to the antennas 286-296 of Figure 2. The six steerable antennas bridges 402 provide twelve signals (six signals in two polarizations). Six of these signals are supplied directly to the low noise amplifier bank 412, the other six signals are supplied to a "6: 2" selection matrix, 414, which selects two of the signals to be supplied to the bank. 412 low noise amplifiers. Note that the satellite payload will include a processor (not shown) that controls each of the selection matrices described herein. Alternatively, a satellite bus will include a processor that will control the selection matrices. As described above, the low noise amplifier bank 412 has twenty input signals and thus twenty output signals. Fourteen of the signals outputted from the low noise amplifier bank 412 are supplied to separate separators 416. In other words, there are fourteen separators 416. Each separator separates the incoming signal into four copies, noted; F1 / 3, F2 / 4, F5 / 6 and F7 / 8. The remaining six outputs of the LNA amplifier 412 are provided to a different set of separators 418 separating the signal into four labeled copies; F1 / 3, F2 / 4, F7 / 8 and R-HC. The seven separator outputs starting with an "F" are part of the one-way trip. The single output of separator 418 labeled "R-SC" is part of the return path from a high-capacity steerable point beam used to connect to subscriber terminals. In one embodiment, the separators 416 and 418 include filters for passing the frequency bands of the tagged output and interrupting all other frequencies.
After the separators 416 and 418, the signals are sent to appropriate matrices 420, 422, 424, 426 and 428 to select the bands to be used. The selection matrix 420 receives the signal F1 / 3. The selection matrix 422 receives the signal F2 / 4. The selection matrix 424 receives the signal F5 / 6. The selection matrix 426 receives the signal R-8C. The selection matrix 428 receives the signal F7 / 8. Eleven signals from the output of the selection matrix 420 are provided to a downconverter 440, which outputs to channel 442. The eleven signals from the output of the select matrix 422 are provided to the downconverter 444, which provides its output to a funnel 442. The output of the selection matrix 424 includes seven signals which are provided to the down converter 446, which outputs to the funnel 442. The output of the selection matrix 426 includes six signals which are supplied to the receiver. step-down converter 446, which outputs to channel 442. The output of selection matrix 428 includes eleven signals which are supplied to down-converter 448, which outputs to channel 442. Each of the selection matrices includes a series of programmable switches for routing a subset of inputs to the output ports.
The one hundred and seventy non-equatorial point beams 404 are provided to a selection matrix 443 that selects twenty-eight point beams from the one hundred and seventy point beams. That is, a beam of each of the twenty-eight beam switching groups (see below) is selected. These twenty-eight signals are sent to a low-noise amplifier 444. Half of the signals outputted from the low-noise amplifier 444 are supplied to the separators 446. The other half of the signals are supplied to the separators 448. Each of the fourteen separators 446 makes three copies of the signal and outputs these three copies as the F1 / 3, F2 / 4 and RTN signals. Each of the fourteen separators 448 makes three copies of its respective incoming signals and outputs them as the F5 / 6, F7 / 8 and RTN signals. Note that the signals F1 / 3, F2 / 4, F5 / 6 and F7 / 8 are part of the forward path representing the communication from a gateway in one of the one hundred seventy switching beams. The RTN signal is part of the return path from the subscriber terminals. Note that in some embodiments, each of the separators has appropriate bandpass filters. In some embodiments, each of the selection arrays has appropriate bandpass filters at respective inputs and / or outputs.
FIG. 6 illustrates the thirty non-articulated spot beam switching beams close to the equator that are provided to the selection matrix 454. The eight selected signals are supplied to the low noise amplifier 456, which outputs a signal labeled "RTN". Note that, in some embodiments, each of the low noise amplifiers 456, 444, and 412 has bandpass filters at its input and / or output. In addition, bandpass filters may be used at each of the antennas 400, 402, 404 and 406. Based on the output of the separators 448 and the low noise amplifier 456, thirty-six signals labeled " RTN "are combined in frequency in a multiplexer 450 which outputs nine signals. The output of the multiplexer 450 is supplied to a downconverter 452. The output of the downconverter 452 is supplied to a funnel 442. Each of the selection matrices 410, 414, 420, 422, 424, 426, 428, 443 and 454 includes switches that are used to switch the rate between the different spot beams in the switching groups or between different bands from the high capacity steerable gateways and spot beams. The selected signals are provided to funnel 442 which is used to route spectrum between uplinks and downlinks. In one embodiment, funnel 442 is a digital channelizer that is fully programmable in orbit. Additional details on the funnel 442 are provided below with respect to FIG. 7. The funnel 442 may be considered a giant switching or routing matrix that is fully programmable. FIG. 6 shows that funnel 442 provides fourteen outputs to upconverter 460, fourteen outputs to upconverter 472, eight outputs to upconverter 480, eight outputs to upconverter 490, and twenty outputs to upconverter 502. that the upconverers 460, 472, 480 and 490 (all for increasing the signal frequency) are provided as part of the forward path, while the upconverter 502 is provided for the return path. The output of each of fourteen inverters 460 is supplied to filters 462. The output of each of the fourteen filters 462 is supplied to solid state power amplifiers (SSPAs) 464. The output of each of the fourteen SSPA amplifiers is supplied to the multiplexer 466. The output of the multiplexer 466 is supplied to a "28: 170" type selection matrix, 468. The 170 outputs of the selection matrix 468 are provided as one hundred and seventy non-equatorial spot beams. non-articulated beam switching 470.
The respective outputs of the fourteen upconverters 472 are provided to individual filters 474. The output of each of the fourteen filters 474 is provided to individual SSPA amplifiers 476. The output of each of the fourteen SSPA amplifiers 476 is provided to the multiplexer 478. The Multiplexer output 478 is supplied to the select matrix 468. The output of the eight upconverters 480 is supplied to the filters 482. The output of the eight filters 482 is provided to the individual SSPA amplifiers 484. The output of the SSPA amplifiers 484 is provided to the selection matrix 486. The output of the selection matrix 486 is provided in the form of the thirty equatorial region non-articulated beam switching point beams 488. Note that the SSPA amplifiers can be deactivated (for example, when the satellite is over the ocean or other uninhabited area) to save energy.
The output of the upconverters 490 (which may be part of the forward path or the return path) is provided to the filters 492. The output of the eight filters 492 is supplied to the SSPA amplifiers 494. The output of the eight SSPA amplifiers 494 is provided to the selection matrix 496. The twelve output signals from the selection matrix 496 are provided to the multiplexer 498. The output of the multiplexer 498 is provided in the form of the six steerable high capacity subscriber gateway / terminal point beams of 2.8 degrees, with double polarization.
The respective output of the upconverters 502 is supplied to the individual filters 504. The respective output of the twenty filters 504 is supplied to the individual SSPA amplifiers 506. The respective output of the twenty SSPA amplifiers 506 is supplied to the selection matrix 508, which supplies 42 exits. Twelve of the 42 outputs are provided to the multiplexer 498, fourteen of the 42 outputs are provided to the multiplexer 466 and the multiplexer 478, and sixteen of the 42 outputs are provided in the form of the eight steerable gateway dual polarization spot beams described above.
In an alternative embodiment, all or part of the selection matrices can be eliminated by selecting / switching by the funnel 442. In some embodiments, the payload of FIG. 6 can be fully implemented simply by a funnel to use to switch, route and filter.
FIG. 7 is a block diagram describing an exemplary implementation of funnel 442. The technologies described herein are limited to any particular architecture or implementation of funnel 442. The embodiment of FIG. that a relevant example for the technology described here and many other configurations are also usable. Inputs applied to the funnel 442 are provided to a receive module 550, where the signals can be filtered, amplified, stored or simply received. The output of the receiving module 550 is supplied to a switching network and beam shaping network 552. The output of the switching network and beam shaping network 552 is supplied to a transmission module 554 which provides the outputs of the tracer 442. The funnel 442 also includes an auxiliary module 556, a control unit 558 and a clock generator 560, all of which are connected to the receive module 550, to the switching network / beam shaping network 552 and to the transmission module. 554. In one embodiment, the control unit 558 includes one or more processors used to program the switching network / beamforming network 552. The clock generator 560 provides a clock signal for the delay within the funnel 442. In one embodiment, the auxiliary module 556 is used to control the switches of the r switching network, adjusting beams, providing spectrum analysis and providing uplink and downlink modems.
In one embodiment, the non-geostationary satellites 302-322 are each configured to provide a plurality of spot beams (described above) implementing a first frequency plane at the Earth's equator and a second plane of frequency distant from the equator of the Earth, where the first frequency plane is different from the second frequency plane. Thus, during the operation of the non-geostationary satellite constellation, several or all of these satellites within the constellation will communicate with a terminal or multiple terminals at the equator using spot beams for implementing the first frequency plane, and a plurality of satellites or all the satellites of the constellation will communicate with one or more terminals remote from the equator using spot beams which implement the second frequency plane.
In one embodiment, the frequency planes at the equator and the frequency planes far from the equator all use the band KA; however, other bands may also be used. Figures 8 and 9 provide the frequency plan for the areas distant from the Earth's equator, while Figures 11 and 12 provide the frequency plan for the areas at the equator. Specifically, Figure 8 provides the frequency plane distant from the equator for uplinks. Figure 8 shows the uplink using between 27.50 GHz and 30.00 GHz. The frequency plan includes three components. The first component corresponds to the "go" uplink used by gateways including eight colors (frequency band + polarization) each comprising a 500 MHz frequency band in a polarization (left circular polarization, LHCP, or right circular polarization, RHCP ), labeled "FWD1 UL", "FWD2 UL", "FWD3 UL", "FWD4 UL", "FWD5 UL", "FWD6 UL", "FWD7 UL", "FWD8 UL". The second component of Figure 8 includes the return path used by subscriber terminals, which includes eight colors, each of which corresponds to a frequency band of 100 MHz in a polarization, labeled "RI", "R2", " R3 "," R4 "," Ria "," R2a "," R3a "and" R4a ". Figure 8 also illustrates a frequency plan for the return path used by subscriber terminals in the high capacity steerable beams which comprise four colors, each of which corresponds to a 225 MHz frequency band and a polarization (LHCP or RHCP), labeled "RI HC UL", "R2 HC UL", "R3 HC UL" and "R4 HC UL". The arrow labeled "TC" indicates the frequency assigned for control and telemetry signals.
Figure 9 illustrates the frequency plan for the downlink in regions far away from the equator. The frequency plan for communicating a downlink beam to the subscriber terminals uses four colors, each of which has a 500 MHz frequency band in a polarization (LHCP or RHCP), labeled "FWD DI DL", "FWD D2 DL" "," FWD D3 DL "and" FWD D4 DL ". As mentioned above, the one hundred and seventy non-articulated point beams that implement time-domain beam switching can also serve gateways using four colors, each of which corresponds to 180 MHz frequency bands. a polarization, and labeled, in Figure 9, "RI FB DL", "R2 FB DL", "R3 FB DL" and "R4 FB DL". As discussed above, the satellite can include steerable beams of high capacity that can serve both gateways and subscriber terminals. The downlink to the subscriber terminals in these high-capacity steerable beams uses four colors, each of which has a frequency band of 400 MHz in a polarization, labeled in Figure 9 as "FWD HCl DL". FWD HC2 DL "," FWD HC3 DL "and" FWD HC4 DL ". As discussed above, the satellite may include 4.2 degree steerable spot beams that communicate with gateways. These beams will use two colors each of which includes a frequency band of 400 MHz in a polarization, and having eight sub-channels which are labeled, in Figure 9, "R1", "R2", "R3", "R4", "R1a", "R2a", "R3" and "R4a". When high capacity steerable beams are used, the downlink may also be part of the 4.2 degree steerable spot beam return path, and includes a 225 MHz frequency band in a polarization, within the 400 available spectra. , and labeled "R1 / 2/3/4 HC DL". Note that, in one embodiment, the uplink frequency plan and the downlink frequency plan are constructed so that the subscriber terminals and gateways use different frequencies. When a specific spot beam among the spot beams implementing time domain beam switching serves a gateway and subscriber terminals, the subscriber terminals and the gateway use different frequencies. The arrow labeled "TM" (which may be in-band or out-of-band) represents control and telemetry signals. Note that although the exemplary embodiment shown in FIGS. 8 and 9 illustrates the two polarizations in the form of a left circular polarization, LHCP, or a right circular polarization, RHCP, other embodiments may use circular and linear right and left polarizations. Some embodiments of satellite communication systems use vertical and horizontal polarization.
FIG. 10 is a beam map illustrating the same field of view as FIG. 3, and therefore the same beam map as FIG. 3. However, instead of representing numbers in each of the spot beams on FIG. beam map, Figure 10 gray each beam. The shading of FIG. 10 corresponds to the shading in FIG. 9. Thus, each of the spot beams is assigned a downlink color (frequency band and polarization) using the frequency plane of FIG. 9. For example , the leftmost lower beam in row 1 has vertical shading and therefore corresponds to "FWD D3 DL" and the right upper beam in row 22 has sloping shading that corresponds to "FWD DI DL". Figure 10 illustrates a four-color reuse plan.
Figures 11 and 12 illustrate the frequency plan for the area at the equator. In one embodiment, different frequency planes are used at the equator since it is necessary to avoid interference with geostationary satellites. Figure 11 shows the frequency plan for the uplink. In one embodiment, none of the orientable spot beams will be used in the area close to the equator. Therefore, the area close to the equator will only be served by non-articulated spot beams that implement time-domain beam switching. The uplink in the Equator region will include eight colors, each of which has a frequency band of 100 MHz in one polarization, so that four colors are left polarized and between 28.60 GHz and 29.10 GHz. The eight colors of the uplink in the Equator region are labeled "RI", "R2", "R3", "R4", "RI a", "R2a", "R3a" and "R4a". These frequency bands are each used as part of the return path implementing the communication of the subscriber terminals to the satellite.
Figure 12 illustrates the frequency plan for the downlink in the equator area and represents four colors used for the "go" downlink. Each of the colors includes 250 MHz frequency bands in a polarization, labeled "FWD El", "FWD E2", "FWD E3" and "FWD E4". The four colors are between 18.80 GHz and 19.3 GHz.
Therefore, differences in the downlink at the equator to the downlink far from the equator include downlink colors far away from the non-equatorial zone with twice as large frequency ranges. . For example, FWD DI DL corresponds to 500 MHz between 18.8 GHz and 19.3 GHz compared to FWD El which corresponds to 250 MHz between 18.8 GHz and 19.05 GHz. FWD D2 DL corresponds to 500 MHz between 19.3 GHz and 19.8 GHz compared to FWD E2 which corresponds to 250 MHz between 19.05 GHz and 19.3 GHz; FWD D3 DL corresponds to 500 MHz between 18.8 GHz and 19.3 GHz whereas FWD E3 corresponds to 250 MHz between 18.8 GHz and 19.05 GHz; and FWD D4 DL corresponds to 500 MHz between 19.3 GHz and 19.8 GHz compared to FWD E4 which corresponds to 250 MHz between 19.05 GHz and 19.3 GHz. While the return links in the equatorial region and the non-equatorial region both correspond to 100 MHz bands, the frequency bands for the equator region are shifted upwards in frequency; for example, RI in Figure 8 starts at 28.54 GHz while RI in Figure 11 starts at 28.6 GHz.
As can be seen from FIGS. 8, 9, 11 and 12, the frequency plane distant from the equator includes frequency ranges that are not in the frequency plane at the equator; the frequency plane at the equator includes uplink frequency ranges different from those of the second frequency plane; the frequency plane distant from the equator includes frequency ranges larger than those of the frequency plane at the equator; the frequency plane distant from the equator includes more frequency ranges than the frequency plane at the equator; and the frequency plane distant from the equator includes a bandwidth greater than that of the frequency plane at the equator. Spot beams at the equator consist only of spot beams that are non-articulated with respect to the satellite, and point beams distant from the equator include point-like beams that are non-articulated with respect to the satellite, and point-oriented beams.
When operating the non-geostationary satellite constellation 302-322, multiple satellites in the constellation communicating with a first terminal at the equator use spot beams that implement the frequency plane for the equator and multiple satellites in the constellation communicating with a second terminal far from the equator use point beams that implement the frequency plane for regions far from the equator (for example, using adjacent fields of view for the constellation).
Figure 13 illustrates the same field of view and the same beam map as those of Figure 3 and Figure 10; however, Figure 13 illustrates the equatorial zone and the non-equatorial zone (far away from the equator). The equatorial zone corresponds to the frequency plane of FIGS. 11 and 12 and the non-equatorial zone corresponds to the frequency plane of FIGS. 8 and 9. It should be noted that FIG. 13 uses shading for the equatorial zone. If the rows of the beams in the beam map of Figures 3, 10 and 13 were to be numbered, as shown in Figures 10 and 13, the rows 10, 11 and 12 would refer to the equatorial area. Note that Figure 12 uses shading for the four colors of the frequency plane. This shading is also used to assign each of the colors to the various spot beams in the equatorial zone, as shown in Figure 10.
Fig. 13A is a flowchart describing an embodiment of a satellite constellation operating process using different frequency planes and switching planes (described below) between spot beams at the equator and spot beams distant from the equator. In step 580, the system exploits the constellation of non-geostationary satellites in an orbit at the equator. In other embodiments, other orbits may be used. In step 582, each satellite of the constellation provides a first set of spot beams that illuminates a region on the equator using a frequency plane for the equator, for example, the frequency plane of FIGS. 12. In step 584, each satellite in the constellation provides a second set of spot beams that illuminates a region distant from the equator using a frequency plane for non-equatorial areas. For example, step 584 may include using the frequency planes of Figs. 8 and 9 in the non-equatorial area of Fig. 13. Step 582 may include using the frequency plans of Figs. 11 and 12 in the equatorial zone of FIG. 13. In step 586, each of the satellites of the constellation flies over a terminal at or near the equator as it travels its orbital path along the equator. As it flies over this terminal, it communicates with the terminal using the first set of spot beams and the frequency plane for the equator. In step 588, as each satellite in the constellation flies over a terminal in a region far from the equator, it communicates with that terminal using the second set of spot beams and the frequency plane for non-equilibrium areas. equatorial (for example, the non-equatorial zone). As discussed above, each of the eleven satellites of the exemplary constellation illustrated in Figure 4 crosses the same orbit four times a day and, therefore, each of the satellites will have the ability to communicate with each terminal potentially four times a day. (if this terminal is stationary and always undervoltage), using the equatorial zone or non-equatorial zone frequency plan. The process of Figure 13A is not necessarily implemented in the order or sequence shown in Figure 13A, and other sequences may be implemented. For example, step 580 may be considered to synthesize the entire operation of the system and may encompass all the other steps, and steps 582 and 584 may be implemented in parallel.
As discussed above, the high capacity steerable beams can serve subscriber terminals as well as gateways. Satellites can support fully meshed networks between subscriber terminals in high capacity steerable beams. For example, two subscriber terminals in the same steerable beam of high capacity can communicate with each other directly via the satellite without going through a gateway. In addition, two subscriber terminals in different high capacity steerable beams can communicate with each other directly via the satellite without going through a gateway. These subscriber terminals in steerable beams of high capacity, and steerable beams of high capacity, do not implement a beam switching in the time domain. In addition, the gateways can communicate with subscriber terminals in the high capacity beams without the use of time domain beam switching. Another embodiment is to configure beam assignments in the articulated network, so that continuous connectivity is provided to geographical locations, so that no beam switching is required by the gateway or the terminals. of subscribers in each subscriber terminal uplink feed beam.
Single polarity through a spot beam path As the eleven satellites 302-322 move along their orbital path from west to east at the equator, the spot beams (including the entire field of view) will move over the surface of the Earth from west to east. As the spot beams move over a subscriber terminal, this subscriber terminal will first connect with an east spot beam in the field of view and then move slowly to the beams. punctual from the west while the spot beams move in their entirety (see Figure 3) from west to east. For example, a subscriber terminal may first connect to the spot beam 199. Subsequently, the subscriber terminal will move through the spot beams 129, 130, 131, 132, 133, 134, 135, 136, and 137. .
In one embodiment, each of the non-geostationary satellites 302-322 provides the plurality of point beams (e.g., the beam map in the field of view of Figure 3) to use multiple frequencies and multiple polarities (e.g. , two), so that all spot beams on a path entirely traversing the plurality of point beams in the orbital direction communicate using a common polarization. In the example described above, the path entirely traversing the plurality of spot beams ranged from the point beam 199 to the point beam 137. This path is in the orbital direction since the satellite travels from west to east along the the equator. In this embodiment, all spot beams in the path through the beams 199, 129, 130, 131, 132, 133, 134, 135, 136 and 137 are configured to have the same polarity. In this way, as the field of view moves above and beyond a subscriber terminal, this subscriber terminal will not need to change polarity when it transfers between spot beams or between satellites. The subscriber terminal may have to modify frequencies when it changes the spot beam, but it will not need to change the polarities. This is shown more graphically in Fig. 14A, which illustrates a field of view (or part of a field of view) including spot beam polarity. In each spot beam, a letter "L" or a letter "R" indicates whether the spot beam has a left polarization or a right polarization. Arrow 573 represents a path completely traversing the plurality of point beams in the orbital direction and illustrates an example of how this path will traverse only point beams having a left polarization.
Fig. 14B illustrates another embodiment of a plurality of spot beams, where the path completely traversing the plurality of spot beams in the orbital direction is on a diagonal, as indicated by the arrow 575. Arrows 573 and 575 Figs. 14A and 14B show the path taken by a subscriber terminal when the subscriber terminal is stationary and when the spot beams pass through the subscriber terminal or pass over the subscriber terminal. Note that the technology described here can be used with equatorial orbits and non-equatorial orbits (ie orbits that do not follow the equator), including elliptical orbits.
Figs. 15A-F provide another example of a subscriber terminal completely traversing the plurality of spot beams in the orbital direction using a single polarization. For example, in Figure 15A, spot beams 1-11 are shown. Next to each spot beam number, an "L" or "R" indicates whether it is a left polarization or a right polarization. The initial position of the subscriber terminal is indicated by "S". As seen in Figure 15A, the field of view is expected west of the subscriber terminal S. As can also be seen in Figure 8, each spot beam is configured to communicate in at least one range. frequency and polarity. Polarizations are assigned to the spot beams so that all point beams that illuminate and are configured to communicate with the subscriber terminal S at a location on the ground use the same polarity, while other point beams in the field of view, which do not illuminate the subscriber terminal S, may use another polarity. For example, Figures 15B-F illustrate the field of vision moving from west to east. In Fig. 15B, the field of view has moved so that the subscriber terminal S is now within the point beam 7 and communicates with the spot beam 7 using a right polarization. In parallel, the spot beams 1,2, 3 and 8-11 communicate with other subscriber terminals using a left polarization. In Fig. 15C, the field of view has moved so that the subscriber terminal S communicates with the spot beam 6, also using a right polarization. In Fig. 15D, the field of view has moved so that the subscriber terminal S is not in communication with the spot beam 5 by using a right polarization. In Fig. 15E, the field of view has moved so that the subscriber terminal S is in communication with the spot beam 4, using a right polarization. In FIG. 15F, the field of view has moved to the east of the subscriber terminal S and consequently the subscriber terminal S is no longer in communication with any of the spot beams or the field of view. vision shown in Figure 15F. As can be seen, as the spot beams have passed through or past the subscriber terminal S, the subscriber terminal S has continued to communicate only by using the straight scrubbing. In one embodiment, the spot beams 4, 5, 6 and 7 each use different frequency bands. In other embodiments, the spot beams 5 and 7 may use the same frequency band, and the spot beams 4 and 6 may use the same frequency band. Therefore, as the field of view passes above or beyond the subscriber terminal, the subscriber terminal will have to change frequency between the spot beams, but it will not change the polarizations. The fact of not modifying the polarization accelerates the handover process and allows a simpler and cheaper design of the subscriber terminal.
Fig. 15G is a flowchart describing an embodiment of a subscriber terminal operating process, including frequency modification for subscriber terminals, but without any required change in polarization as the satellite moves relative to the subscriber terminal. In step 602, the subscriber terminal communicates with the current satellite using the current spot beam at a current frequency and a fixed polarization while the current satellite is in orbit. Step 602 continues to be implemented until the subscriber terminal reaches the periphery of the point beam. At this point, an intercell transfer must take place to the successive spot beam. It is determined whether the successive spot beam is located in a new satellite or in the current satellite (step 604). If it is not located in a new satellite (ie, if it is located in the current satellite), then the subscriber terminal automatically replaces its communication frequency with a frequency used for the adjacent adjacent spot beam. on the current satellite without polarization change (step 606). The process then proceeds to step 602. However, if the next adjacent spot beam is for a new satellite (step 604), then in step 610 the subscriber terminal automatically replaces its communication frequency with the frequency for the first spot beam on the successive satellite, without change of polarization. Therefore, even when the subscriber terminal is transferring from one satellite to another satellite, it will not need to change the polarization. Thus, the subscriber terminal will maintain a polarization across the path of spot beams, including on multiple satellites. During the step 612, the subscriber terminal will establish a communication with the successive satellite, and the successive satellite will then become the current satellite. After step 612, the process returns to step 602.
FIG. 15H is a flowchart describing an embodiment of a satellite communication system operating process, including the implementation of handoffs between point beams, so that a subscriber terminal There is no need to change the polarities for the handover. The process of Figure 15H is implemented by a non-geostationary satellite orbiting the Earth, which is configured to provide a plurality of spot beams in the field of view, where the plurality of spot beams use multiple frequencies and multiple polarities, each spot beam of the plurality of spot beams being configured to communicate in at least one frequency range and one polarity. The satellite will communicate with a terminal using different spot beams and a common polarity while the terminal is in the field of view as the first non-geostationary satellite moves relative to the Earth and the terminal changes point beams. For example, in step 640, the satellite will communicate with a subscriber terminal (ground or air location) using the current spot beam and the common polarity for the path this subscriber terminal will follow through. the field of vision. In step 642, it is determined whether the satellite has moved too far, so that the subscriber terminal is no longer located in the current spot beam. If this is not the case, the process proceeds to step 640. If, however, the satellite has moved too far so that the subscriber terminal is located on the periphery of a spot beam, then is then determined whether the subscriber terminal is located at the periphery of the beam map (step 644). If the subscriber terminal is not on the periphery of the beam map, then the subscriber terminal will be transferred to the next adjacent spot beam in the orbital direction which uses the same common polarity in step 646 Subsequently, the process proceeds to step 640. If, however, the subscriber terminal was at the periphery of the bundle card, then at step 648, the subscriber terminal is transferred to a spot beam on the adjacent satellite, also using the same common polarity as that used by the subscriber terminal to communicate.
Beam switching
As described above, satellites 302-322 are each non-geostationary satellites configured to provide a plurality of spot beams using time-domain beam switching between point beams. In one embodiment, time-domain beam switching includes multiple spot beams sharing a frequency bandwidth or bit rate, so that different spot beams can use the same frequency bandwidth or bit rate. at different times since the shared bandwidth or the shared rate switches between the spot beams, where only a subset of spot beams is active at a time. Thus, the satellite is configured to switch the rate between the spot beams in the same switching group. Time-domain beam switching allows the field of view to be much larger without the use of time-domain beam switching. Thus, the satellite can have a much larger coverage area. One of the challenges of time-domain beam switching with a non-geostationary satellite is that the coverage area is constantly changing. In addition, the demand for services over time is changing. There are therefore two changing variables, namely the demand and the coverage area, which complicates the task of designing a non-geostationary satellite communication system.
To implement time-domain beam switching, the two hundred non-articulated point beams of the satellite are divided into beam switching groups. Each beam switching group includes several spot beams. At any time instance, only one beam (or a subset of one or more beams) of one switching group will be active, while the other beams of the switching group will be inactive. In one embodiment, all the beams of the switching group use the same frequency and the same polarization. In another embodiment, the beams of a switching group use the same frequency and mixed polarizations. The system will therefore create the notion of a switching period divided into a number of intervals, called "epochs". Each beam will be assigned one or more epochs during the switching period. Assigning different numbers of epochs to different spot beams allows the variation of the transit time among spot beams in a switching group. In some embodiments, the switching plans take into account the amount of time required for the particular application. For example, "voice over IP" communication may require twenty to thirty milliseconds of time to prevent quality degradation.
Switch groups can be assigned to spot beams based on various and varied strategies. In one example, all the beams of a switching group are side by side. For example, Figure 16A illustrates a portion of the field of view of Figure 3, including twenty-five spot beams divided into five switching groups of five spot beams each. Each of the switching groups is greyed out using a different type of shading. The switching group 1 includes the beams 3, 4, 5, 11 and 12. The switching group 2 includes the beams 6, 7, 13, 14 and 15. The switching group 3 includes the beams 20, 21, 29, 38 and 39. The switching group 4 includes the beams 22, 30, 31, 40 and 41. The switching group 5 includes the beams 23, 24, 32, 33 and 42. In some embodiments, the switching planes between the switching groups with point beam elements adjacent to the spot beam elements of other switching groups are planned so as to avoid interference between the beams.
In other embodiments, each of the beams of a switching group is uniformly or unevenly distributed over the field of view. For example, in this embodiment, it is possible for each of the spot beams of a switching group to use the same frequency range. The polarization may be different between the beams. Figure 16B illustrates part of the field of view of Figure 3, including twenty-five spot beams divided into five switching groups. Each of the beams of a switching group is grayed out using the same type of shading, so that different shading is used for different switching groups. For example, the switching group 1 includes the beams 3, 14, 22, 32 and 38. The switching group 2 includes the beams 4, 14, 21, 33 and 41. The switching group 3 includes the beams 5, 11 , 24, 33 and 39. The switching group 4 includes the beams 6, 15, 20, 30 and 42. The switching group 5 includes the beams 7, 13, 23, 29 and 40.
In another embodiment, the switching groups are arranged consecutively along a path traversed by a subscriber terminal. For example, Fig. 16C illustrates part of the field of view of Fig. 3, with an arrow indicating the orbital direction. Each row of spot beams includes spot beams in the same switching group. In this embodiment, adjacent rows would have different frequency ranges or different polarizations. In the embodiment of FIG. 16C, the switching group 1 includes the spot beams 3, 4, 5, 6 and 7. The switching group 2 includes the beams 11, 12, 13, 14 and 15. The group of switching 3 includes the beams 20, 21, 22, 23 and 24. The switching group 4 includes the beams 29, 30, 31, 32 and 33. The switching group 5 includes the beams 38, 39, 40, 41 and 42 .
In order to graphically represent beam switching in the time domain, Figs. 17A-17E show five different times in a switching period for the embodiment of Fig. 16B. In each of Figs. 17A-E, the spot beam that is active for each switching group is greyed out and the spot beams that are inactive for each of the switching groups are not greyed out. In the first epoch, illustrated by FIG. 17A, the spot beams 4, 11, 22, 29 and 42 are active, while the other spot beams are inactive. In the second epoch, illustrated by FIG. 17B, the spot beams 5, 12, 23, 50 and 41 are active, while the other spot beams are inactive. In the third epoch, illustrated by FIG. 17C, the spot beams 3, 14, 20, 24 and 40 are active, while the other spot beams are inactive. In the fourth epoch, illustrated by FIG. 17D, the spot beams 7, 15, 21, 31 and 38 are active, while the remaining spot beams are inactive. In the fifth epoch, illustrated by Figure 17E, the spot beams 6, 13, 32, 33 and 39 are active, while the other spot beams are inactive. It is contemplated that in some embodiments a switching period has more than five epochs. However, no specific number of epochs are required in a specific switching period.
In some embodiments, the switching period is fully configurable and programmable, while the satellites are in orbit. This concept is shown in Figure 18, which illustrates a series of epochs divided into switching periods. In this embodiment, each switching period includes N epochs. After N epochs, the successive switching period is implemented. In some embodiments, consecutive switching periods will implement the same switching scheme (for example, the same assignment of spot beams at times) until a satellite is programmed to change switching planes ( for example, as a result of changing demand). During each switching period, as shown in FIGS. 17A-17E, only one spot beam of each switching group is active. As a result, only part of the field of view is active. These spot beams that are active are called "visual field". Since the number of active spot beams is less than the total number of spot beams in the beam map, each of the non-geostationary satellites 302-322 has a field of view that is greater than its field of view at any instance in time.
As discussed above, satellites 302-322 each provide a plurality of spot beams as satellites traverse the planet's surface. In order to implement beam switching in the time domain, the spot beams are divided into switching groups. The satellite uses the selection matrices described above, together with the digital funnel, to implement time domain beam switching. Fig. 19 is a flowchart that describes an embodiment of a satellite process implementing time domain beam switching. In step 670, the satellite reconfigures the selection matrices for routing energy and making a connection with the applicable gateway beam to a successive set of beams in the switching groups according to the switching in progress. In step 672, the satellite will allow communication during epoch 0 (see FIG. 18), sending only power and making the gateway connection to the predetermined beam subset in each group. In step 674, the satellite will reconfigure the selection matrices to route energy to the next set of beams in the switching groups according to the current switching plane. In step 676, the satellite will communicate at time 1, sending only power to a predetermined set of beams in each switching group according to the switching plan. In step 678, the satellite will reconfigure the selection matrices for routing energy to the successive spot beam set in the switching groups according to the current switching plane. In step 680, the satellite will allow communication during epoch 2, by sending only energy to a predetermined subset of beams in each switching group. This process will continue for each epoch, as shown in Figure 18, until the last epoch (called "epoch N" in Figure 18). During step 682, the satellite will reconfigure the selection matrix in order to route energy to the successive switching group beam sequence according to the current switching plane. In step 684, the satellite will allow communication during period N, by sending only energy to a predetermined subset of beams in each switching group. In step 686, the satellite may (optionally) access a new switching plan that takes into account the movement of the non-geostationary satellite. In step 688, the new switching plan is loaded and becomes the current switching plan, so that the process proceeds to step 670. Thus, the process of Fig. 19 describes the operation in which the non-geostationary satellite implements time-domain beam switching during a switching period. In one embodiment, the switching plan may change at the end of each switching period. In other embodiments, the switching plan may change after a fixed number or a dynamic number of switching periods. In other embodiments, the switching period may change after any switching period; however, there is no requirement that a switching plan change after any switching period.
In an exemplary embodiment, the switching period lasts 90 seconds and a time lasts 1.286334 milliseconds. In this embodiment, the total drift time of a spot beam across a subscriber terminal corresponds to about 2 switching periods (168 seconds).
In an exemplary embodiment that utilizes time-domain beam switching for the uplink and downlink of the two hundred non-articulated spot beams, the two hundred non-articulated spot beams are divided into thirty-six switching groups. Twenty-eight switching groups include six or seven spot beams that are not in the equator zone. Eight switching groups include three or four spot beams that illuminate areas at the equator. In one embodiment, the assignment of the switching groups is defined and immutable in the satellites. In other embodiments, the membership of the switching groups can be dynamically changed into orbit.
In one embodiment, the two hundred non-articulated point beams are divided into zones, so that each switching group may have a beam in each zone (some switching groups may have two beams in one zone). In an exemplary embodiment, the non-equatorial switching groups will switch by jumping through six zones arranged in a north / south grid. This takes advantage of the traffic pattern of each continent to focus along a specific latitude. This also reduces the likelihood that a high demand is needed on a switchgroup in two different locations, and this allows the switching groups to focus on any extended geographic area with high traffic demands. For example, FIG. 20A illustrates the same field of view as that of FIG. 3 and indicates the equatorial zone (rows 10, 11 and 12). The rest of the field of view, distinct from the equatorial zone, corresponds to the non-equatorial region. These spot beams in the non-equatorial region are grayed out to indicate six zones. Each switching group will include at least one beam in each zone. Figure 20B illustrates the zones for the equatorial zone. Namely, each of the spot beams in the equatorial zone is grayed out using one of four shading types to indicate which zone is each point beam among the four zones. Each of the switching groups for the equatorial zone will include at most one beam in each zone. Thus, the equatorial zone and the non-equatorial region have distinct zones in order to form switching groups. As such, the beam switching is implemented in the equatorial zone differently from the beam switching in the non-equatorial region. In one embodiment, a different switching plane than that used for the non-equatorial region is used for the equatorial zone.
Fig. 21 is a table illustrating an example of the twenty-eight switching groups used for the 170 non-articulated point beams of the field of view, in Figs. 20A and 20B, which are not in the equatorial zone. The left column shows the numbers of the switching groups HG1-HG28. The remaining seven columns indicate beam numbers for the beams in the relative switching group. Fig. 22 is a table which describes the membership of switching groups for the equatorial zone. The left column shows the numbers of the switching groups EHG1-EHG8 and the other four columns indicate the beam numbers for these beams in the relative switching groups.
Fig. 23 illustrates the field of view of Fig. 3 (and Figs. 20A and 20B) during an epoch. Each of the switching groups shown in Figs. 21 and 22 has an active beam during that specific time. Each of the active beams is grayed out. These shaded active beams represent the satellite's visual field during this time, while the entire beam represents the field of view. As can be seen, the field of view for the satellite is superior to the visual field during that time.
Figure 24 graphically illustrates how epochs are assigned to a set of switching beams in an HG2 switching group (see Figure 21) over a portion of the switching period. As can be seen, at no time instance will any two beams be active in the switching group. In other words, only one beam is active at a time; however, the power harness that communicates with the gateway supporting beams 2, 24, 56, 79, 131, 154, and 190 is still active in each epoch. In other words, at each switching, a source beam and the power beam are active for communication. The power harness is not part of the switching group, but in some embodiments connectivity with the power harness may be changed at each switching. Thus, the gateways in the power supply beams are assigned time periods to manage the terminals within them.
Figure 25 illustrates a superframe, which corresponds to the data format used during an epoch. In one embodiment, the superframe is based on the DVB-S2X standard. Other formats of superframes or frames may also be used. Each superframe includes a usable portion 720 and an unusable portion. During the usable part (or duration of activity), data is transmitted. During the unusable portion, no data is transmitted. In one embodiment, the usable portion lasts 1.2852 milliseconds. The unusable portion includes a late arrival window 724, a payload transition time 722 and an anticipated arrival window 726. The late arrival window 724 is 0.0665 ps and takes into account the communication that arrives at the satellite level a bit later than it should. The early arrival window 726 allows 0.0665 ps and takes into account any data for the successive epoch that arrive slightly early. The payload transition time 722 lasts 1,001 psec. During the payload transition time 722, the satellite is not available to communicate along its various communication paths since the various selection matrices and / or the digital funnel adjust / reconfigure for each other. successive era. As can be seen, the entire epoch lasts 1.286334 milliseconds. The technology described in this document is not limited to a specific timer; therefore, other timers for superframe and transmission may also be used.
An alternative embodiment includes adding a beam switching transition time between the superframes. This could also be in terms of the integer number of symbols to help the clocks stay synchronized, if any. Indeed, it adds stuffing time between defined superframes, in order to configure the transition time.
Fig. 26 also illustrates the same superframe as that of Fig. 25, but indicating data contents. The unusable part of the superframe, which includes the late arrival window 724, the payload transition time 722 and the anticipated arrival window 726, uses the transmission time of 540 symbols. However, no real data symbol will be intentionally transmitted during these time periods by the satellite. The usable portion 720 of the superframe includes a header and a payload. The header, which uses 720 symbols, contains two fields: "SOSF" and "SFFI". In one embodiment, the SOSF field corresponds to a start of a superframe preamble that corresponds to a unique combination of bits to indicate that a superframe begins. In one embodiment, the SFFI field is a superframe format indicator that indicates which of the different superframe formats is implemented by that specific superframe. In one embodiment, more than one superframe format may be used for different types of communication. In some embodiments, only one format will be used for the communication system. In one embodiment, the payload is divided into a set of capacity units (CU). In one embodiment, each CU corresponds to 90 symbols and represents a time slot in the payload. In exemplary implementation, the capacity units may be distributed among the subscriber terminals within a point beam, so that different subscriber terminals will receive communication in different capacity units. This allows a type of time domain multiplexing of the data path. As illustrated in Figure 27, one embodiment of the payload includes CU9 - CU6800 units.
Figure 28 depicts part of the delay involved in the satellite communication system described here. For example, Figure 28 indicates that the propagation delay between the gateway and the satellite (propagation delay SB) is about 54-72 msec. The processing time of the communication through the satellite is about 20-30 psec. The propagation delay of the satellite at the subscriber terminal for the implementation of time-domain beam switching by the non-articulated point beams (HB propagation delay) is about 54 to 72 msec. Therefore, the satellite will transmit, to a subscriber terminal, in a switching beam, data that was sent by the gateway between 74 and 102 milliseconds before that. In other words, the satellite is configured to receive data, for a specific epoch, that were sent before a specific period beginning, a period of time that is significantly greater than the length of time it was. -even. For example, the data for the specific epoch can be sent to the satellite before the start of the specific epoch to transmit the data, a period of time that is greater than 10 or 30 times the length of the epoch. This requires a very precise delay by the gateway.
There is a delay across the satellite payload so that the portion of the superframe (see Figures 25 and 26) corresponding to the payload transition time 722 enters the payload 20-30 psec before leaving the load useful. Thus, the portion of the superframe corresponding to the payload transition time 722 is perceived / implemented by different parts of the payload at different times. Figure 6 illustrates an example of a payload that includes various selection matrices and a digital funnel. Other switching components can also be used on the satellite. Different selection matrices and the digital channelizer can perceive and implement the payload transition time 722 at different times in time. In one embodiment, the payload components must delay their reconfigurations so that the payload transition time 722 arrives at the component level when reconfiguration is required. Thus, the payload transition time 722 is implemented by different groups of switching components at different times, so that different groups of switching components reconfigure for a new switching plane at different times.
Fig. 29 is a flowchart describing an embodiment of a time domain beam switching implementation process, as discussed above. In step 800, the system operates the non-geostationary satellite constellation along the same orbital path using the same beam map. The beam map of each satellite is adjacent to a beam map on the adjacent satellite to provide a composite beam map that encompasses the Earth's turn. Each satellite provides a plurality of spot beams as the satellites move across the surface of the planet. In step 802, a subset of satellites or all of the satellites receive in-orbit instructions that include one or more switching planes or switching patterns, as well as one or more beam connectivity plans. Gateway beam user. All gateways receive satellite-dependent assignments and the bandwidth time frequency of one or more gateway beams aligned with switched-on gateway and satellite user beam switching patterns. In step 804, on the basis of the instructions received at step 802, one or more satellites reconfigure its gateway user beam connectivity (e.g., the selection matrices or the digital channelizer) and / or updates its / their switching plan based on the new received switching pattern (eg, programming a non-geostationary satellite to assign any combination of epochs in a plan switching between spot beams of the same switching group). In step 806, each satellite simultaneously implements time-domain beam switching for the plurality of non-articulated point beams, based on the switching group, so that a subset of spot beams in each switching group is active at any given time. In one embodiment, steps 800-806 are each implemented continuously, and the process of Figure 29 is implemented repeatedly. In one embodiment, each gateway implements sub-assignment and TDMA connectivity according to its satellite-dependent, time-dependent and user-beam dependent gateway beam assignments. This gateway TDMA enablement is implemented as part of an independent time synchronization with each of said one or more satellites to which the gateway beam assignments are provided.
In one embodiment, the non-geostationary satellites described above include a forward path and a return path, so that the forward path has different switching planes than the return path. In other words, the beam switching for the forward path may be different from the beam switching for the return path. For example, the outward path may have switching groups, sequences and / or passage times that are different from those of the return path.
Multiplexing gateways
Referring again to FIG. 24, all the beams of a switching group are switched so that, in any given epoch, one of the beams of the switching group is in communication with a power harness. . In another embodiment, the switching group may be in communication with a plurality of power beams that are multiplexed in time. For example, Figure 30 illustrates non-articulated spot beams implementing time domain beam switching, including point beams 2, 24, 56, 79, 130, 154, and 190. At any given time, only the one of these spot beams of beam switching in the time domain will be active. Figure 30 illustrates two power supply beams, FBI and FB2. The FBI bundle connects to a gateway. The FB2 beam connects to a second gateway. Thus, Fig. 30 illustrates a first plurality of spot beams (2, 24, 56, 79, 130, 154 and 190) and a second plurality of spot beams (FBI and FB2). At any one time, a spot beam of the switching beams is active and a spot beam of the power beams is active so that the two active beams communicate. Thus, satellites 302-322 are each configured to provide a first plurality of spot beams (e.g., point beams 24, 56, 79, 130, 154, 190) for communication with subscriber terminals using time-domain beam switching for moving the rate between spot beams of the first plurality of spot beams and a second plurality of spot beams (for example, FBI and FB2) adapted for communication with gateways. The satellites each include a spectrum routing network (one or more of the selection matrices and / or the funnel) that is configured to multiplex in time the spot beams of the second plurality of spot beams with spot beams of the first plurality of spot beams. In other words, each switching beam in the active time can communicate with any one of the power beams during different epochs. For example, the spot beam 130 communicates with the beam FB2 during the epoch E4 and with the beam FBI during the epochs E5 and E6, all while the spot beam 130 remains on a subscriber terminal location. the surface of the planet. Similarly, the spot beam 2 communicates with the FBI beam during EO, E1, E2 and E3 and communicates with the FB2 beam during E7 and E8, all while the spot beam 2 remains on a location of subscriber terminal on the surface of the planet. In one embodiment, the communication of a spot beam with a first gateway may be interleaved with its communication with a second gateway so that the respective sets of epochs are interlaced (set of epochs 18, 19, and 23 interspersed with the set of times 20, 21, 22 and 24). When more than one gateway is supported in a power harness, the N gateways can operate on different frequencies or on the same frequency. If operating on the same frequency, each gateway will have a separate epoch assigned for transmission and reception.
Fig. 31 is a flowchart that describes an embodiment of a time-domain beam switching implementation process with gateway time multiplexing, as shown in Fig. 30. The process of Fig. 31 is implemented continuously by each of the satellites 302-322. In step 840, each satellite provides a first plurality of spot beams for communicating with subscriber terminals as satellites traverse the planet's surface. In step 842, the satellites will implement time-domain beam switching for the first plurality of spot beams. In step 844, each of the satellites provides a second plurality of spot beams to communicate with the gateways as the satellites traverse the surface of the planet. In step 846, each satellite provides time-multiplexing of the spot beams of the second plurality of spot beams with the spot beams of the first plurality of spot beams while a specific spot beam of the first set of spot beams. remains at a specific location (for example, a routing of communications between different beams of the second plurality of spot beams and a specific beam of the first plurality of spot beams at different epochs among multiple epochs during the switching period).
Figure 31 illustrates an exemplary implementation of step 846, including steps 846A and 846B. In step 846A, a satellite provides communication between a specific spot beam of the first plurality of spot beams and a first spot beam of the second plurality of spot beams during a first set of epochs, while the specific point beam is located at a location on the surface of the planet (for example, while illuminating a set of one or more subscriber terminals). In step 846B, the satellite provides communication between the specific spot beam and a second spot beam of the second plurality of spot beams during a second set of one or more epochs, while the specific spot beam stays on the location on the surface of the planet. Thus, during a specific switching period, a switching beam can communicate with different power supply beams.
Figure 32 provides a flowchart describing an embodiment of a time domain beam switching implementation process on a satellite, which includes gateway multiplexing as described above. In step 860, the satellite transmits data for the current epoch, for the current set of serving beams and power beams, as routed by the funnel and the various selection matrices. . In step 862, the satellite transmits data arriving late for the current epoch, for the current set of serving beams and power beams as routed through the funnel and the dies. selection. In one embodiment, step 860 corresponds to the transmission of the payload of a superframe and step 862 corresponds to the transmission of the late arrival window 724 of a superframe (see FIG. 26). In step 864 of FIG. 32, the satellite reconfigures the routing of all or part (or none) of the routing paths of the funnel and selection matrices in order to establish communication for the serving beams with one or more different power supplies, and it reconfigures the selection matrices for the next switching input. In one embodiment, step 864 corresponds to reconfiguration time 722. In step 866, the satellite transmits data that has arrived in advance for the succeeding epoch for the new set of serving beams. feeding beams as routed through the funnel and selection matrices. In one embodiment, step 866 corresponds to the anticipated arrival window 726. Steps 860-866 correspond to an epoch. If this time is not at the end of a switching period (step 868), then the process continues by returning to step 860 to implement the data transmission for the next time. However, if this epoch is the last epoch of the switching period (step 868), the satellite can load a new switching scheme and a new gateway multiplexing scheme. In one embodiment, step 870 is optional. After step 870, the process returns by a loop in step 860 and executes the next epoch for the next switching period.
Flow assignment
As discussed above, the switching scheme affects different times at different beams of the switching group. Thus, the system can assign different amounts of bit rate, ie bandwidth, to each beam of the switching group, where the amount of bit rate allocated corresponds to the number of epochs assigned to the specific beam of the switching group. In one embodiment, the amount of flow (the amount of time) assigned to each switching beam is based on user demand within the coverage area during a given switching period. In some embodiments, as discussed above, the non-articulated point beams may be used to serve subscriber terminals and gateways. In this situation, the bit rate assignment to a spot beam may be based on the gateway speed requirements in the spot beam as well as the subscriber terminals in the spot beams. Thus, the number of epochs assigned to this point beam is based on the needs of the gateway and the needs of all subscriber terminals. Note that the epochs assigned to a beam for a switching plane may be continuous or discontinuous (spaced in time).
Fig. 34 illustrates an embodiment where a satellite is configured to provide a plurality of spot beams adapted for time-domain beam switching communication to switch the rate between spot beams of a group of nodes. switching, wherein the plurality of spot beams includes at least one spot beam which illuminates and communicates with a gateway and a plurality of subscriber terminals. A satellite is configured to implement a beam switching scheme which, during a switching period, provides a bit rate to the first spot beam for an aggregated time duration (e.g., a number of epochs), based on the bandwidth assignments to the gateway and the plurality of subscriber terminals. It should be noted that the implementation of time-domain beam switching for the spot beam includes providing a spot beam rate for a non-continuous set of multiple epochs that form the aggregated time duration. For example, Fig. 33 illustrates the satellite 201 providing the spot beams 950, 952 and 954 in the switching group A and the spot beams 956, 958 and 960 in the switching group B. The satellite 201 also provides a beam of A non-articulated spot beam 950, at this point, illuminates and communicates with subscriber terminals, ST, and a gateway, GW. The spot beam 952 also communicates with subscriber terminals, ST, and a gateway, GW. The spot beam 954 only communicates with subscriber terminals, ST. Spot beams 956, 958 and 960 communicate only with subscriber terminals, ST. Since the spot beams 950, 952 and 954 are located in the same switching group, the satellite 201 implements a time domain beam switching so that only one of these three spot beams is active at a given moment. given. This means that only one of the gateways 950 and 952 can be active at the same time. Thus, the implementation of time-domain beam switching for the plurality of spot beams includes providing multiple gateways over time, which are geographically separated from one another, since they are located in separate spot beams. In the embodiment shown in Fig. 33, the bit rate supplied to the spot beam 950 (e.g., the number of epochs affected) is based on the throughput requirements of the subscriber terminals, as well as the requirements in terms of gateway throughput in the spot beam 950. The amount of throughput provided to the spot beam 952 (for example, the number of epochs affected in the switching plan) includes sufficient throughput (eg, epochs) to serve the subscriber terminals, ST, in the spot beam 952, as well as to serve the gateway, GW, in the spot beam 952. Note that the spot beam 954 does not include a gateway. In one embodiment, each of the subscriber terminals in the spot beam 954 may communicate with the gateway in the spot beam 950 or with the gateway in the spot beam 952 by multiplexing between the two gateways as described above. .
Fig. 34 is a flowchart that describes an embodiment of a process for the evaluation of a hardware that includes implementing time domain beam switching for the plurality of spot beams, including implementing a beam switching scheme which, during a switching period, provides a bit rate to the first spot beam for an aggregate time duration based on gateway and subscriber terminal bandwidth assignments in this punctual beam. In step 902, the system will determine the demand over time for the subscriber terminals. This can be implemented at the network control center. In step 904, on the basis of the beam map, gateways are assigned to various switching groups. In step 906, the system determines the bandwidth requirements of the serving links (communication with the subscriber terminals) based on the demand over time of the subscriber terminals. In step 908, the bandwidth requirements of the power links (gateway communication) in the switching beams are determined based on the demand of the subscriber terminals in communication with the gateways. In step 910, the bandwidth will be determined for the power links in dedicated power beams (for example, the steerable beams as opposed to the non-articulated beams that are shared between the subscriber terminals and the subscriber terminals). gateways). In step 912, a beam switching plan will be created for the multiple / different switching periods. In step 914, the created switching plans are transmitted to all satellites, while the satellites are in orbit. For example, the network control center will transmit the switching plans to the satellite when the satellites pass over the network control center or through the network control center. These switching plans are received by the satellites and stored in the memory for the satellites. In step 916, each satellite updates or modifies its current switching plan so that a new switching plan is implemented in a timely manner. The satellites each implement a time-domain beam switching of the plurality of non-articulated point beams and implement, in particular, a beam switching scheme then in effect, which, during a switching period, provides a bit rate. to one or more spot beams for aggregate time duration based on gateway and subscriber terminal bandwidth assignments.
Figure 35 is a diagram describing an example of capacity sharing by epoch division, or CL units, at that time, based on pro-rate flow requirements. For example, Figure 35 illustrates the sharing of CD units or epochs for a switching group A, a switching group B and the beam 962 of Figure 33. Since the beam 962 includes only one single gateway, the entire time is available for this gateway. In some embodiments, there may be multiple gateways in the point beam 962 so that the point beam rate 962 must be distributed among the multiple gateways. Switchgroup B includes three bundles that include only subscriber terminals. The amount of flow (or times) supplied to the beam 956 is shown in Fig. 35 as "956S". The amount of flow supplied to the beam 958 is represented by the reference "958S". The quantity of flow supplied to the spot beam 960 is represented by the reference "960S" in Figure 35. As can be seen, the quantity of flow or the number of epochs is not evenly distributed. between the three spot beams. In Figure 35, the amount of rate or timing provided to the point beam 954 (which does not include a gateway) is represented by the reference "954S". The amount of rate or timing provided to the spot beam 95δ is represented by two components: a "950S" component representing the rate assignment to subscriber terminals and a second "950G" component representing the rate assignment to the gateway in the spot beam 950. Since in the beam 950 the gateway may use a different frequency than the users, the first and second components may coexist. The amount of bit rate or timing provided to the spot beam 952 includes two components: the "952S" component represents the bit rate allocation for the subscriber terminals and the "952G" component represents the bandwidth allocation for Gateway. Since in the beam 952 the gateway may use a different frequency than the users, the first and second components may coexist.
As mentioned above, in some embodiments there may be multiple gateways in a gateway cluster. These multiple gateways can support (i.e., communicate with) different sets of subscriber terminals in one or more identical spot beams that implement time-domain beam switching, or can support (That is, communicating with) different sets of subscriber terminals in one or more different spot beams that implement time-domain beam switching. In another alternative, these multiple gateways can support (i.e., communicate with) the same subscriber terminals. The multiple gateways in the same point beam will use different times to communicate with the subscriber terminals.
In some embodiments, a satellite has two or more spot beams in a switching group that illuminate and communicate with gateways and subscriber terminals, where the gateways are geographically separated from one another. For multiple spot beams that illuminate and communicate with gateways and subscriber terminals, they are all individually assigned a frequency rate for a total duration based on the respective gateway and subscriber terminal rate assignments. Accordingly, the satellite implements time-domain beam switching, including providing multiple gateways over time, which are geographically separated from one another.
With respect to the 302-322 satellite constellation, the provision of a plurality of spot beams, and the implementation of time-domain beam switching for the plurality of spot beams, are performed separately and simultaneously by multiple satellites using the same beam map and moving along the same orbital path.
In one embodiment, the satellite is configured to switch the rate over a number of epochs based on the uplink and downlink request of the user terminals in the group beam elements. of commutation. In another embodiment, the satellite is configured to switch the rate over a number of epochs based on the uplink and downlink request of the user terminals and gateways in the elements. of groups of switching groups.
Beam Harness Transfer As each of the 302-322 satellites moves into orbit, their fields of vision move, causing each of the spot beam coverage areas to move. When a subscriber terminal reaches the periphery of a spot beam, it must be transferred to the successive spot beam on the same satellite. As a general rule, the handover will take place from a spot beam in a first switching group to a spot beam in a different switching group. This may result in the updating of switching plans to account for a possible switching group change of the subscriber terminal (s). When the subscriber terminal reaches the periphery of a spot beam at the periphery of the field of view, then the subscriber terminal is transferred to the succeeding satellite.
Figure 36 illustrates a portion of the satellite communication system, showing a subscriber terminal handover between point beams of the same satellite. For example, FIG. 36 illustrates the satellite 201 moving in the orbital direction 201A providing the spot beam 980 and the spot beam 982. As the satellite 201 moves in the direction 201A, the subscriber terminal, ST, will pass from point beam 980 to point beam 982; therefore, a transfer procedure must occur. Figure 36 illustrates the point beam 201 in communication with the gateway 984 (which includes the antenna 986). In one embodiment, the gateway 984 includes the modem 990 connected to the antenna 986, the network interface 994 connected to the network 988 (which may be the Internet or another network), and the gateway processor 992 which is connected to the modem 990 and the network interface 994. In one embodiment, the gateway processor 992 may be a computing device that includes one or more microprocessors, a memory, a nonvolatile storage memory, and so on. Since the subscriber terminal, ST, is transferred from the point beam 980 to the point beam 982, the gateway processor 992, which receives messages from the network 988, which are to be sent to the subscriber terminal, ST, must communicate these messages via the relevant spot beam. For example, Figure 36 illustrates the gateway 984 communicating the messages A, B, C and D. Given the timing of message transmission (given the switching plan), the message A and the message B will be transmitted from the satellite 201 to the subscriber terminal, ST, while the subscriber terminal, ST, is in the spot beam 980. The message C and the message D will be transmitted from the satellite 901 to the subscriber terminal, ST, while the terminal The subscriber, ST, is in the spot beam 982. Note that the spot beam 980 and the spot beam 982 are among the non-articulated point beams that implement time-domain beam switching. On the other hand, the spot beam 980 has a frequency range different from that of the spot beam 982, but the two spot beams use the same polarization. In other switching arrangements, the spot beams 980 and 982 may have the same frequency range or overlapping frequency ranges.
Fig. 37 is a flowchart describing an embodiment of a process implemented by the gateway for implementing a subscriber terminal handover between point beams on the same satellite. In step 1002, gateway processor 992 determines new handshake times for all terminals connected to that specific gateway, based on the location of the satellite, the known beam pattern, and the one or more planes. known beam switching, as well as the position of the terminals (or the feedback of the signal strength received by the subscriber terminals from the satellite). In step 1004, the gateway processor 992 determines (i.e., calculates or searches in a database) one or more new switching plans for the spot beams based on the updated terminals and the beams. For example, when the subscriber terminal, ST, transitions from the beam 980 to the beam 982, this may affect the switching plane due to a change in the demand. In step 1006, the gateway 984 will broadcast the handoff information to all the terminals in all the spot beams that communicate with the gateway 984. The handover information includes a set of records, where each record includes a identifier, ID, terminal for the subscriber terminal, the old spot beam, the new spot beam and the time of the handover. Other information could also be provided. In step 1008, the gateway broadcasts the new switching plan to the terminals and the satellite. In one embodiment, the satellite already has the switching plan and it is not communicated from the gateway.
Fig. 38 is a flowchart describing an embodiment of a process implemented by the gateway to implement a handover of the subscriber terminal at the time of handover. In step 1040, the gateway processor 992 receives data from the network 988, which data is to be transmitted to the subscriber terminal, ST. During step 1042, the gateway processor 992 determines the time required for the transmission of this received data, from the satellite 201 to the subscriber terminal, ST. In step 1044, gateway processor 992 verifies the most recent handoff information (see step 1006 in FIG. 37). In step 1046, the gateway processor 992 determines whether the time when the satellite will transmit the data to the subscriber terminal is close to the time of the handover. If this time is not close to the handover time, then in step 1048, the gateway processor 992 communicates the received data using the current switching plane and the current switching group as well as normal margins for an adaptive modulation and coding (ACM) procedure and a time domain (MW) beam switching procedure. In one embodiment, the margins for TDM switching are related to the size or timing of the late arrival window and the anticipated arrival window. If the time for transmission from the satellite is close to the handover time, but is earlier than the time of inter-cell transfer, then in step 1050, the gateway processor 992 communicates data to the handoff time. terminal using intercellular pre-handover switching group of intercellular pre-handover switching group and wider margins (if necessary) for ACM modulation and TDM switching. If the time for transmitting the satellite to the terminal is later than the handover time, then the gateway processor 992 communicates the data using the intercellular post-handover switching group of the intercellular post-transfer switching group and wider margins (if necessary) for ACM modulation and TDM switching.
Fig. 39 is a flowchart describing an embodiment of a processor implemented by a subscriber terminal with respect to the transfer of the subscriber terminal between point beams. The process of Figure 39 is implemented in response to the implementation of the Figure 37 process by the gateway. In step 1060 of Fig. 39, the terminal receives broadcast handoff information (see step 1006 of Fig. 37). In step 1062, if the received broadcast includes handover information for that terminal, then that terminal stores the information and will configure it during a time when the beam is not active or during payload transition time. Note that the processes of Figures 37 and 39 are implemented continuously.
Fig. 40 is a flowchart describing an embodiment implemented by a subscriber terminal at the time of intercell handover between spot beams. It should be noted that in step 1062, an interrupt is configured. This interruption will trigger the execution of the process of FIG. 40. In step 1070, it is determined whether the terminal is at or near a time of a handover. If not, and if the terminal receives data in step 1072 (in response to step 1048 of Fig. 38), then the terminal decodes this data in step 1074 using normal margins for ACM modulation and TDM switching. The data is reported to a client device during step 1076. A client device for a subscriber terminal may be a computing device, a smart device, and so on. If, during step 1070, it is determined that the terminal is close to a handover time, but prior to the handoff time, then in step 1080 the terminal will receive data from the satellite and decode this data, at step 1082, using the wider margins for ACM modulation and TDM switching. The data will then be reported in step 1076. If the terminal is at a handover time, then in step 1086 the terminal again tunes its local oscillator to replace the frequency or frequencies by the master frequency for the new spot beam. In other words, with reference again to FIG. 36, the subscriber terminal, ST, will again tune its local oscillator, from the frequency corresponding to the point beam 980 to the frequency corresponding to the spot beam 982. During the step 1088, the switching plan will be updated. In some embodiments, the terminal keeps track of the switching plan. In other embodiments, the terminal does not keep track of the switching plan. In one embodiment, a subscriber terminal will include an antenna and an oscillator. In other embodiments, the subscriber terminal includes two antennas and two oscillators, for alternating use of the terminals and oscillators between the spot beams.
Figure 41 illustrates a portion of a satellite communication system representing a handoff of a subscriber terminal between point beams of different satellites. For example, Figure 41 illustrates the satellite 1100 and the satellite 1102, which may be any pair of adjacent satellites of the satellites 302-322. The satellite 1102 provides the spot beam 1106. The satellite 1100 provides the spot beam 1104. The subscriber terminal 1108 includes two antennas 1110 and 1112, two modems 1114 in communication with the antenna 1110, and a modem 1116 in communication with the antenna 1112, terminal processor 1116 and network interface 1118 which is connected to a local area network (LAN). Terminal processor 1116 may be any suitable computer device that includes a processor, memory, nonvolatile memory, and appropriate communication interfaces.
In Fig. 41, the subscriber terminal 1108 is positioned in a region which represents where the spot beam 1106 overlaps with the spot beam 1104. The gateway 1120 is in communication with the satellites 1100 and 1102. The gateway 1120 includes a first antenna 1124 for communicating with the satellite 1100. The gateway 1120 includes the antenna 1122 for communicating with the satellite 1102. The gateway 1120 includes a first modem 1128 connected to the antenna 1124 and a second modem 1126 connected on the air 1122. The gateway 1128 includes the gateway processor 1130 connected to both the modem 1126 and the modem 1128. The gateway processor 1130 is also connected to the network interface 1132, which can communicate with the Internet network. or another network. Since the gateway 1120 is in communication with the two satellites, and it uses a processor 1130, when the subscriber terminal transfers from the satellite 1102 to the satellite 1100, the communication between the subscriber terminal 1108 and the Gateway 1128 will not be broken. Therefore, as the satellites 1102 and 1100 move from west to east, causing the transition of the subscriber terminal 1108 from the point beam 1106 on the satellite 1102 to the point beam 1104 on the satellite 1100, the communication path between the subscriber terminal 1108 and the gateway 1128 will be modified, so that it will pass through the satellite 1100 instead of passing through the satellite 1102. The gateway 1120 will implement the process of Figure 37 described ci above, to identify and communicate the handover information.
In addition, the gateway will implement the process shown in Figure 42 to transfer a subscriber terminal between point beams of different satellites. In step 1200, the gateway processor 1130 communicates with the current satellite through the first antenna (e.g., the antenna 1122). In step 1202, the gateway 1120 establishes communication with the new satellite through a second antenna 1124. In step 1204, the gateway determines when to switch the terminals to the satellite based on the intercell transfer information described above. The gateway 1120 will inform the satellites and subscriber terminals according to the process of FIG. 37. In another embodiment, the satellites are preprogrammed so that it is the relevant time for switching. In another embodiment, the gateway informs the network control center. In step 1206, the gateway communicates with the terminate through the current sateilite (e.g., through the satellite 1102) to the intercell handover time, by implementing the handoff process. Figure 38 using the first antenna (antenna 1122) and the current beam switching plane. In step 1208, the gateway communicates with the terminal through the new satellite (the satellite 1100) after the handover time using the new switch plane, implementing the process of FIG. using the second antenna (for example, antenna 1124). The subscriber terminal will implement the process of Figure 39, as described above, to receive the new handover information. In addition, the subscriber terminals will implement the process of Figure 43 at the handover time. In step 1250, the gateway determines whether the subscriber terminal is at or near the satellite handover time. If the subscriber terminal is not at or near a satellite handoff time, then, in step 1252, data will be communicated with the satellite through its first antenna (eg for example, the antenna 1110). In step 1254, the gateway will decode the received data using normal margins for ACM modulation and TDM switching. In step 1256, the received data will be reported to the client device. Note that the data that is transmitted will not have to be decoded and reported, but rather will have to be coded.
If, in step 1250, it is determined that the subscriber terminal is close to the handover time, then, in step 1260, the terminal will establish or maintain a connection with the gateway by through the second antenna and the second satellite. In step 1262, the subscriber terminal will continue to exchange data with the satellite through the first antenna. In step 1264, the received data will be decoded by the gateway using wider margins for ACM modulation and TDM switching. In step 1266, the received data will be reported. The data that is transmitted will be encoded using wider margins for ACM modulation and TDM switching, if ACM modulation is used on the uplink for the return path.
If, in step 1250, it is determined that the subscriber terminal is at handover time, then, in step 1270, the subscriber terminal switches to a data communication with the second satellite or the new satellite through the second antenna. In step 1272, a new switching plan will be implemented. In one embodiment, the subscriber terminal is not aware of the nature of the switching plan and only responds to the data from the gateway, and therefore will not be aware of the new switching plan. In step 1274, the received data will be decoded using a wider margin for ACM modulation and TDM switching. The transmitted data will use wider margins for ACM modulation, if ACM is used. The received data will be reported in step 1276.
The above description of beam bundle interconnect includes communication at a ground terminal with a non-geostationary satellite constellation using a first point beam of the non-geostationary satellite constellation and the first plane. beam switching, and includes modifying, by the ground terminal, communication with the non-geostationary satellite constellation, to use a second spot beam of the non-geostationary satellite constellation in a second switching beam .
Intercellular transfer for multiple gateways
As described above, some of the non-articulated 1-200 spot beams for each of the 302-322 satellites may be used to serve subscriber terminals and gateways. In some embodiments, subscriber terminals in the non-articulated point beams are configured to communicate with gateways in the non-articulated point beams. In these embodiments, the group of subscriber terminals communicating with the gateway and the non-articulated beams will communicate with at least two gateways. In one implementation, the two gateways communicating with the subscriber terminal group are located in the same country as the subscriber terminals in order to comply with local laws restricting cross-border communications. In other embodiments, the two gateways may be located in different countries.
Figure 44 illustrates an exemplary configuration where two gateways 986 and 988 communicate with the subscriber terminal ST and serve it through the satellite 1. Each gateway has its own antenna and its own modem. For example, the 986 gateway includes the 991 modem and the 988 gateway includes the 993 modem. None of the gateways include a gateway processor. The modems 991 and 993 rather communicate with a central processor 992 which is in communication with the network interface 984 for communication on the network 988 (for example, the Internet). The sharing of a central processor 992 allows the communication flows between the subscriber terminal ST and the entities on the network 988 to be maintained in a certain manner without apparent interruption. In one embodiment, the gateway 986 is located at the western periphery of the subscriber terminals and the gateway 988 is located at the eastern edge of the subscriber terminals. Therefore, these bridges can be called the "East Bridge" and the "West Gateway". The location of the bridges, on the western periphery and the eastern periphery, is motivated by the fact that the 302-322 satellites move from west to east, and the location of the bridges at the western periphery and at the periphery is (separated in the orbital direction) allows efficient intercellular transfers. In other embodiments where the satellites move in another orbital direction, the gateways are located in different locations that are separated from each other by different orbital directions. In other words, the first gateway will be at a first location, the second gateway will be at a second location, and the second location will be separated from the first location in the orbital direction.
Figure 45 is a flowchart describing an embodiment of a handover process between satellites, using east and west bridges, where the gateways operate within and communicate with spot beams implementing a beam switching in the time domain. Note that instead of using east and west gateways, the same process can be used for two different gateways at two different locations separated in the orbital direction. In step 1350, all the subscriber terminals, or a subset of the subscriber terminals, communicate with the east gateway through the satellite 1 as the non-articulated point beam implementing the Time domain beam switching traverses the region where the subscriber terminals are located. Fig. 46A indicates the time when step 1350 is implemented. The field of view for the satellite 1 completely covers the spot beams A, B, C, D, J, F and G, which correspond to the spot beams for which the subscriber terminals are located. At the eastern periphery of the point beam C is located the east gateway E. At the western periphery of the point beam J is the west gateway W.
In step 1354, the west gateway W transfers to satellite 2 as soon as possible (or as close as possible). For example, FIG. 46B shows that the field of view for the satellite 2 is very close to the point beam J, close enough to allow the west gateway W to connect to the satellite 2.
In step 1356, as the field of view for the satellite 2 passes over the spot beams, the subscriber terminals in the spot beams under the field of view for the satellite 2 begin to connect to the satellite. Satellite 2. As discussed above, subscriber terminals will be notified in advance regarding handover information. Thus, when the subscriber terminals perform a handover to the satellite 2, they begin to connect to and communicate with the west gateway through the satellite 2. For example, Figure 46J illustrates part of the field of view for satellite 2 above point beams A, J and G and the field of view for satellite 1 above point beams A, G, D, B, C and F. Subscriber terminals in beams A, J and G will have already connected to the satellite 2 and will have started to communicate with the gateway W via the satellite 2. Since all the terminals in the spot beams A, B, C, D, J, F and G have transferred to satellite 2 and are communicating with the west gateway, the gateway is E is hand-over to satellite 2. For example, Figure 46D illustrates all five spot beams in the vision for the satellite 2; therefore, all subscriber terminals have been transferred and connected to the satellite 2 and are in communication with the west gateway through the satellite 2. In step 1360, in response to instructions from the central processor 992, all the subscriber terminals will then switch to a communication with the gateway is E through the satellite 2. The process of Figure 45 will then be implemented again with the satellite 3 (not shown), then with the satellite 4 (not shown), etc. In this manner, the plurality of subscriber terminals may be configured to communicate with the central processor 992, via non-geostationary satellites, via the first east gateway or the west gateway. The central processor 992 is configured to allocate each subscriber terminal to communicate with the central processor 992 through the east gateway or west gateway based on the location of the appropriate non-geostationary satellite.
In some embodiments, the gateway is (and some subscriber terminals) and the west gateway (and some subscriber terminals) are in different non-articulated point beams that implement time-domain beam switching and that are located in identical switching groups or in different switching groups, implementing the same switching plans or switching planes.
Steerable walkway bundles
As discussed above with respect to Figure 2, the 302-322 satellites each include eight 4.2 degree steerable gateway beams and six steerable high capacity subscriber gateway / terminal beams of 2.8 degrees. In addition, the non-geostationary constellation satellites are each configured to provide a first plurality of two hundred non-articulated spot beams that include the field of view. Orientable spot beams can be oriented to establish communication with a gateway outside and in front of the field of view, and to maintain this communication as the satellite and the field of vision move over and beyond the gateway, including when the gateways are outside and behind the field of view for the respective satellite. This allows the gateways to establish a connection with the satellite before the spot beams cover the subscriber terminals, and then maintain the connection to the satellite while the subscriber terminals handover to the satellite and while the subscriber terminals perform an intercell handover to the successive satellite, to allow smooth communication for the subscriber terminals. This configuration is represented graphically in FIG. 47 which illustrates the satellite 1400 and the satellite 1402. The satellite 1400 provides the non-articulated point beam 404 which implements a time domain beam switching to communicate with the plurality of terminals. subscribers, ST. Satellite 1402 provides the non-articulated point beam 1406 which implements time-domain beam switching for communication with a plurality of subscriber terminals, ST. It is possible that the satellites 1400 and 1402 are simultaneously communicating with the gateway 1120. In another embodiment, time assignments are assigned to the non-articulated beams so that no beam switching is required in a geographical area.
In one embodiment, the gateway 1120 includes two antennas, namely the antenna 1122 for communicating with the satellite 1402 (the east satellite) and the antenna 1124 for communicating with the satellite 1400 (the west satellite). . As the satellites in the constellation move from west to east, the gateway antennas communicate with different pairs of satellites. The gateway 1120 includes the modem 1126 in communication with the antenna 122 and the modem 1128 in communication with the antenna 1124. The gateway 1120 also includes the gateway processor 1130 which is in communication with the modem 1126, the modem 1128 and the modem 1128. 1132 network interface (which connects to the Internet or another network). The spot beams that satellites 1402 and 1400 use to connect to gateway 1120 are steerable so that they can remain pointed at the gateway as satellites and fields of view move. This is described in more detail with respect to the flowchart of Fig. 48 and the graphs of Figs. 49A-E.
During the step 1430 of FIG. 48, the gateway is connected to the satellite 1, via the orientable spot beam for the satellite 1, in order to communicate with its subscriber terminals via the satellite 1. from step 1432, while the gateway communicates with subscriber terminals via satellite 1 (for example, the gateway is located in the satellite's field of view 1) and while the gateway is not located in the field of view of the satellite 2 since the gateway is in the east (opposite) of the satellite 2, the gateway establishes a synchronization with the satellite 2 by using the time tag signal for the satellite 2 (the timing synchronization aligns the direct gateway burst with the assigned time slot reference on the satellite). In step 1434, the satellite 2 moves its steerable beams (for example, the beams 286, 288, 290, 292, 294, 296, 270, 272, 274, 276, 278, 280, 282 or 284 of the Figure 2) so that they point to the gateway, and the gateway initiates a direct link, or forward link, for communication with the subscriber terminals. Figure 49A depicts the situation as it exists at the time of step 1434.
Figure 49A shows the GW gateway surrounded by five coverage areas B1, B2, B3, B4 and B5, where these coverage areas B1-B5 each include a plurality of subscriber terminals that are supported by the gateway and are in communication with the bridge. Figure 49A shows that the field of view for satellite 2 is located east of the gateway and coverage areas B1-B5, so that it does not cover or overlap with gateway or coverage areas B1-B5. Although the gateway is outside the field of view for satellite 2, satellite 2 points / moves one of its steerable beams to cover (point to) the gateway and communicate with the gateway.
In step 1436, the satellite 2 establishes an internal connectivity to serve the gateway, and in particular provides an initial bandwidth to the steerable spot beam for establishing communication. Satellite 2 provides connectivity to allow the gateway to communicate through the steerable spot beam with subscriber terminals. In step 1438, as the non-articulated spot beams that implement time-domain beam switching (and as the field of view) traverse the coverage area supported by the gateway, additional terminals perform a handover to satellite 2 and restore communication with the gateway. For example, Figure 49B illustrates a portion of the field of view for satellite 2 covering and including coverage areas B1 and B5. As a result, the subscriber terminals in coverage areas B1 and B5 will have transferred to satellite 2 and will have established communication with the GW gateway via satellite 2.
As discussed above, the steerable beams may include a single function beam that communicates only with gateways, or they may include dual beams able to communicate with gateways and subscriber terminals. If the steerable point beam that is pointed at and communicates with the bridge is a bivalent spot beam, then, as this bivalent spot beam travels the field of view, including non-articulated point beams implementing beam switching in In the time domain, the system may optionally use the steerable spot beam to communicate with the subscriber terminals. If the system uses the steerable spot beam to communicate with the subscriber terminals, then the non-articulated spot beams implementing the time domain beam switching that overlap with the steerable spot beam will (optionally) be off while they overlap with the steerable spot beam.
When the non-articulated spot beams are de-energized, said one or more times that would have been assigned to them in the switching plane are then supplied to other spot beams in the same switching group in step 1440. In step 1442, as other subscriber terminals establish communication with the gateway (as a result of the movement of the satellite 2), the satellite 2 provides more bandwidth to the gateway, which includes updating internal connectivity to provide additional bandwidth. In other words, the orientable spot beam may be able to communicate using multiple colors, ie multiple chrominances (see the frequency plan described above). Initially a color can be provided to the spot beam. As more subscriber terminals connect to the gateway, additional colors can be added to the non-articulated spot beam frequency assignment. Figure 49C illustrates the field of view for satellite 2 encompassing the gateway in coverage regions B1-B5. Therefore, all subscriber terminals that are supported by the GW gateway now communicate with the GW gateway via the satellite 2. When the satellite 2 moves from its position in Figure 49A to its position in In FIG. 49, it adjusts the pointing of the orientable spot beams, so that the orientable spot beams continue to point towards the gateway GW. During the step 1442, the gateway breaks its connection with the satellite 1 since the satellite 1 has moved to the orbital position where it can no longer serve subscriber terminals supported by the gateway, releasing and the orientable beam that the satellite 1 used to point to the gateway so that it is used for another gateway.
During the step 1446, while the field of view for the satellite 2 leaves the region supported by the gateway, additional subscriber terminals begin handover to the satellite 3 for communication. 3. Note that between steps 1444 and 1446, there is an arrow 1445. This arrow indicates when the process of Figure 48 is restarted for satellites 2 and 3 (instead satellites 1 and 2). In step 1448, while most subscriber terminals terminate communication with the gateway through sateiiite 2, satellite 2 provides less bandwidth to the gateway, including the configuration of internal connectivity (select matrices and digital channelizer) to reduce the provisioned bandwidth for the steerable spot beam pointing to the GW gateway. Figure 49D illustrates the field of view of the satellite 2 moving east of the GW gateway and covering only the coverage areas B2 and B3, as well as a small portion of the coverage area B4. At this point, the subscriber terminals in coverage areas B1 and B5 have already transferred to the succeeding satellite. The gateway remains in contact with the satellite 2 as long as the satellite 2 is in an orbital position making it possible to serve any of the subscriber terminals supported by the gateway, even if the satellite 2's field of vision does not illuminate. not the gateway since the gateway is located behind the field of view, as shown in Figure 49D (step 1450). During the step 1452, the gateway interrupts the connection with the satellite 2, if the satellite 2 has moved to an orbital position where it can no longer serve any terminal supported by the gateway. For example, Figure 49E illustrates a field of view of satellite 2 east of coverage areas B1, B2, B3, B4 and B5.
Synchronization
Because of the timing, as discussed above, it is essential that satellites, subscriber terminals and gateways all remain tightly synchronized. In one embodiment, a master clock is maintained and is accessible at a terrestrial location. For example, the master clock can be maintained by or at the network control center. As each satellite passes over or near the network control center, the satellites synchronize with the network control center, or they synchronize with the master clock. The gateways then synchronize with each satellite before any connection with the satellite, so that the gateways are now in synchronization with the satellite with which they communicate. The subscriber terminals are then responsible for maintaining synchronization with the gateways. In this system, each satellite includes an antenna system that is configured to receive instructional information from a ground center (e.g., a network control center), including a control instruction. adjusting a clock on the satellite to synchronize the satellite with a master clock. The satellite also sends a beacon signal to Earth (that is, to multiple gateways). The beacon signal includes timing information for synchronizing the gateway with the satellite. The gateways are configured to communicate with the satellite and the terminals via the satellite. The gateway is configured to receive the beacon signal from the satellite and to synchronize with the satellite based on the beacon signal. The gateway is configured to send the communication to the terminal via the satellite. The communication includes timing data allowing the terminal to synchronize with the gateway.
Fig. 50 is a flowchart describing one embodiment of a timing synchronization implementation process for the satellite communication system. In step 1502, the network control system 230 (FIG. 1) maintains a master clock. In step 1504, as the satellite passes over or near the network control center (or at the location closest to the network control center in its orbit), the center of Network Control sends a timer message that includes an instruction to set the clock on the satellite. The network control center can also send one or more switching plans. In one embodiment, the master clock is maintained at the network control center. In another embodiment, the master clock is held at another location, but the network control center can access the master clock and send the instruction to the satellite. This instruction can set the satellite clock on the master clock or adjust the satellite clock accordingly. In step 1506, in response to receiving the instruction, the satellite clock sets, or otherwise updates, its clock on the master clock, thereby synchronizing the satellite with the master clock (and synchronizing the satellite with the network control center).
In step 1508, the satellite transmits a beacon signal that includes timing information. The beacon signal is a broad beam covering the entire part of the planet that can be seen by the satellite. In step 1510, before establishing communication with the satellite (before establishing communication with subscriber terminals via the satellite) for the current orbit, the gateway synchronizes with a satellite using the satellite beacon signal (timing synchronization aligns the direct gateway burst with the assigned time slot reference on the satellite while taking into account a possible delay and the Doppler effect - see step 1432 of Figure 48). The gateway will then establish communication with the satellite to implement connections between the gateway and a plurality of subscriber terminals via the satellite. In step 1512, the gateway sends a communication to the subscriber terminals via the satellite, said communication including timing data. In step 1514, the subscriber terminals synchronize with the gateway during communication, based on the timing data, aligning the time delay of the subscriber terminals with the satellite clock. In one embodiment, the communication includes user data, so that the subscriber terminal synchronizes with the gateway during the communication of the user data with the gateway.
Figure 51 is a flowchart that describes in more detail the gateway synchronization process. In one embodiment, the process of Fig. 51 corresponds to an exemplary implementation of step 1510 of Fig. 50. In step 1532, the satellite transmits, and the gateway receives, the beacon signal. of high frequency that has been scattered all over the visible surface of the planet. The beacon signal indicates the beginning of an epoch and a number of eras since midnight. In one embodiment, the complete satellite communication system has a midnight time agreed in advance. Note that midnight occurs at different times on the planet (ie in different spindles). Therefore, in one embodiment, the system selects a unique time reference as the official midnight time of the satellite system. In step 1534, using satellite ephemeris data (satellite orbit and earlier timestamped locations), the gateway determines where the satellite is at that instant. In step 1536, on the determined replacement basis, the gateway calculates the current time of day for the gateway (relative to the epoch and count of epochs in the "midnight" system). In step 1540, the gateway uses the timer beacon signal to further adjust its clock based on the calculated current time of day. In step 1542, the gateway receives one or more new switching plans over the Internet (or other network) from the network control center to be implemented in the future.
Figure 51A provides an example of a beacon signal. In an exemplary embodiment, the beacon signal includes a set of pulses, where the pulse period is one epoch, as shown in Fig. 51A. The beacon signal also includes a message block that indicates the time distance from the system midnight time. The message block completes each set of a period of time so that the gateway knows, at what time, in the time of day window, the epoch corresponds. In this case, it is a hundred times (century). Thus, the first impulse after a message block corresponds to the beginning of a new century. Each message block identifies which century it is in. Therefore, the gateway, after receiving a message block, is able to determine the number of epochs since midnight. In addition, the gateway can use the timing of the pulses to determine when a period begins, and therefore can adjust its clock accordingly.
In one embodiment, the gateway does not indicate to the subscriber terminals in what era it can communicate. This process is described in more detail by the flow chart of Fig. 52, which is an example of implementation of step 1514 of Fig. 50. In step 1560, the subscriber terminal constantly searches the header of a superframe in the downlink. The header contains a single bit sequence. Therefore, in one embodiment, the subscriber terminal does not need to know the switching scheme, since the subscriber terminal constantly searches for the unique bit sequence. When the subscriber terminal beam is not active, the subscriber terminal does not detect this unique bit sequence. In step 1562, the subscriber terminal detects the header of the superframe in the downlink. In step 1564, the subscriber terminal uses the symbol phases in the header to adjust its timing / delay, so that the subscriber terminal is now in synchronization with the subscriber terminal. bridge. In some cases, the gateway includes clock information, date information, or other timing information in the payload of the superframe. If the time of day is included in the superframe, the subscriber terminal will calculate the current time of day from the subscriber terminal based on the time of day in the superframe and the transmission delay. In step 1570, the calculated current time is used to adjust the clock for the subscriber terminal. If the time of day is not included in the superframe, no further adjustment is made for the timer (step 1572).
In one embodiment, the gateway will indicate, by instruction, to the subscriber terminal, when to transmit on the uplink and what frequency to use. This will allow the subscriber terminal to transmit when its switching beam is active, without having to know the switching plan as a whole.
In one embodiment, when a subscriber terminal is connected to multiple gateways, the subscriber terminal establishes an independent timer, even if the gateways communicate on the same satellite. Thus, a first gateway and a second gateway connected to the same subscriber terminal through the same satellite are configured to establish an independent (i.e., distinct) delay with the subscriber terminal.
Note that in the discussion of Figure 51, the gateway used ephemeris data to calculate the current location of the satellite. Fig. 53 is a flowchart describing an embodiment for a plurality of gateways, for determining ephemeris data for a satellite. The process of Figure 53 can be implemented for each satellite several times a day. In step 1580, multiple gateways receive a GPS signal from multiple GPS satellites. During step 1582, these gateways identify the GPS time based on these received GPS signals, using known methods. In step 1584, the multiple gateways receive the beacon signal from a particular satellite. Each gateway will determine the time of reception of this beacon signal in GPS time. All gateways transmit (via the Internet or another network) their respective reception times (in GPS time) of this beacon signal to other gateways. The gateways each calculate the location and speed of the satellite based on the beacon signal receipt times at each gateway and the known locations of each gateway. This assumes that the gateways are not mobile. This process can also use multiple samples of the beacon signal. By knowing the location of a gateway and the time required to transmit a beacon signal from the satellite to the gateway, it is possible to calculate how far the satellite is from the gateway. This creates a sphere around the bridge, the satellite can be anywhere on the surface of this sphere. But since this known sphere exists for multiple gateways, there will be an intersection point that intersects all spheres, which point represents the location of the satellite at that moment in time. By calculating the satellite several times, the satellite's location and speed can be calculated. By knowing the proposed orbit and a group of location and speed samples, the gateway can predict the location of the satellite at a given time. If the process of Figure 53 is implemented multiple times a day, then Gateway Ephemeris data will remain current.
One embodiment also includes determining the Doppler effect on the satellite, and in particular receiving the beacon signal at the ground gateway, determining the frequency offset over time of the beacon signal at the level of the gateway. the footbridge on the ground; and calculating the Doppler effect on the satellite using the beacon signal frequency shift history.
As described above, in one embodiment, non-geostationary satellites are configured to provide steerable bridge beams and non-articulated gateway beams. The non-geostationary satellite includes a beam switching plane for the plurality of spot beams using time domain beam switching, a beam orientation plane for steerable bridge beams, an orientation plane for high-capacity beams; and a connectivity scheme for on-board routing between the gateway beams and the plurality of spot beams using time-domain beam switching. The switching plan and the connectivity plan are structured in a sequence of epochs.
In some embodiments, the satellite clock is adjusted during the reconfiguration time, and / or the clock on the satellite is adjusted by a terrestrial location (for example, the network control center 230, a gateway or another terrestrial location) in bursts of small increments periodically while the satellite is in view.
Note that the foregoing discussion introduces many distinct features and many embodiments. It should be understood that the embodiments described above are not all mutually exclusive. In other words, the features described above (including when described separately or individually) may be combined in one or more embodiments.
An embodiment includes a satellite communication system, comprising; a satellite configured to provide a first plurality of spot beams adapted for communication with subscriber terminals using a time domain beam, wherein the satellite is configured to provide a second plurality of spot beams adapted for a In communication with gateways, the satellite includes a spectrum routing network that is configured to time-multiplex spot beams of the second plurality of spot beams with point beams of the first plurality of spot beams.
One embodiment includes a method of operating a satellite communication system, comprising the steps of: providing a first plurality of spot beams from a non-geostationary satellite to communicate with subscriber terminals as the satellite moves across a surface of the planet; implementing time domain beam switching for the first plurality of spot beams; providing a second plurality of spot beams from the non-geostationary satellite to communicate with gateways as the satellite travels across the surface of the planet; providing communication between a specific spot beam of the first plurality of spot beams and a first spot beam of the second plurality of spot beams during a first set of epochs while the specific spot beam is at a location on the surface of the planet ; and providing communication between the specific spot beam and a second spot beam of the second plurality of spot beams during a second set of one or more epochs, while the specific spot beam remains at the location on the surface of the the planet.
An embodiment includes a satellite communication system, comprising: a non-geostationary satellite configured to provide a first plurality of beams adapted for communication with subscriber terminals and to provide a second plurality of beams adapted for communication with gateways, the satellite is configured to implement time-domain multiplexing for the first plurality of beams over a switching period, so that a specific beam of the first plurality of beams receives a bandwidth of During the switching period, the satellite is configured to route a communication between different beams of the second plurality of beams and the specific beam, at different epochs among multiple epochs, during the switching period.
For the purposes of this document, it should be noted that the dimensions of the various features shown in the figures are not necessarily scaled.
For purposes of this document, any reference, in the specification, to "an embodiment," "a single embodiment," "certain embodiments," or "another embodiment", may be used to describe different embodiments or the same embodiment.
For the purposes of this document, a connection may be a direct connection or an indirect connection (for example, through one or more other parties). In some cases, when an element is referenced as being connected or coupled to another element, the element may be directly connected to the other element, or indirectly connected to the other element through intermediate elements. When an element is referenced as directly connected to another element, there are therefore no intermediate elements between the element and the other element. Two devices are "in communication" if they are directly or indirectly connected so that they can exchange electronic signals mutually.
For the purposes of this document, the term "based on" (or "on the basis of") may be read as "based at least in part on" (or "on the basis at least in part of ").
For the purposes of this document, and without additional context, the use of numerical terms such as a "first" object, a "second" (or "second") object, and a "third" object may not suggest a ranking objects, but can instead be used for identification purposes in order to identify different objects.
For the purposes of this document, the term "set" of objects may refer to a "set" of one or more objects.
The detailed description above has been presented for illustration and description purposes. It is not intended to be exhaustive or to limit the subject matter of this document to the specific form or forms disclosed. Many modifications and variations are possible in light of the above teachings. The described embodiments have been chosen to best explain the principles of the disclosed technology and its practical application to enable others in the art to make the best use of the technology in various embodiments and with various relevant changes for the particular use envisaged. It is intended that the scope be defined by the appended claims.

权利要求:
Claims (20)
[1" id="c-fr-0001]
A satellite communication system, comprising: a satellite configured to provide a first plurality of spot beams adapted for communication with subscriber terminals using a time domain beam, wherein the satellite is configured to providing a second plurality of spot beams adapted for communication with gateways, the satellite includes a spectrum routing network which is configured to multiplex in time spot beams of the second plurality of spot beams with spot beams of the first plurality of spot beams.
[2" id="c-fr-0002]
The satellite communication system of claim 1, wherein: the spectrum routing network includes a digital channelizer.
[3" id="c-fr-0003]
The satellite communication system of claim 1, wherein: the spectrum routing network includes a digital channelizer; the first plurality of spot beams is divided into switching groups; the satellite further includes an antenna system and a selection matrix in communication with the digital funnel and the antenna system; the antenna system provides the first plurality of spot beams and the second plurality of spot beams; the digital channelizer routes between the first plurality of spot beams and the second plurality of spot beams; and the selection matrix switches a rate among the spot beams in the same switching group.
[4" id="c-fr-0004]
The satellite communication system of claim 1, wherein: the satellite is configured to switch a rate among the spot beams at one-time intervals over a switching period in accordance with a switching plan; and the spectrum routing network is configured to multiplex, in time, spot beams of the second plurality of spot beams with spot beams of the first plurality of spot beams, during a switching period, so that a specific beam of the first plurality of beams receives a bandwidth at multiple times during the switching period, the satellite is configured to route communication between different beams of the second plurality of beams and the specific beam, at different epochs among multiple epochs during the switching period.
[5" id="c-fr-0005]
The satellite communication system according to claim 4, wherein: the satellite is configured to route communication between different beams of the second plurality of beams and the specific beam at different epochs of multiple epochs during the course of time. switching period, while the specific beam remains on a specific subscriber terminal location.
[6" id="c-fr-0006]
The satellite communication system of claim 1, wherein: the spectrum routing network is configured to multiplex, in time, spot beams of the second plurality of spot beams with point beams of the first plurality of point beams, providing communication between a specific spot beam of the first plurality of spot beams and a first spot beam of the second plurality of spot beams, during a first set of epochs, while the spot beam specific is on a location on one surface of the planet, and providing communication between the specific point beam and a second spot beam of the second plurality of spot beams, during a second set of one or more epochs, while that the specific point beam remains on the location on the surface of the planet.
[7" id="c-fr-0007]
The satellite communication system of claim 6, wherein: the second set of one or more epochs is interlaced with the first set of epochs.
[8" id="c-fr-0008]
The satellite communication system of claim 1, wherein: the spectrum routing network is configured to multiplex, in time, spot beams of the second plurality of spot beams with point beams of the first plurality of spot beams, while a specific spot beam of the first set of spot beams remains at a specific location.
[9" id="c-fr-0009]
The satellite communication system of claim 1, wherein; the satellite is configured to switch a rate among the spot beams of the first plurality of spot beams, at intervals of one epoch, over a switching period, according to a switching plan; the satellite is configured to change a configuration of the spectrum routing network during the orbit switching plane as the satellite moves relative to a coverage area; and the satellite is configured to orbit the manner in which the spot beams of the second plurality of spot beams are multiplexed with point beams of the first plurality of spot beams.
[10" id="c-fr-0010]
The satellite communication system of claim 1, wherein: the satellite is configured to switch a rate among the spot beams, at one-time intervals, over a switching period, according to a switching plan; each epoch includes a duration of activity, a late arrival window, a payload reconfiguration time and an anticipated arrival window; during the duration of activity of a current epoch, the satellite is configured to transmit data for the current epoch; during the late arrival time, the satellite is configured to transmit data that has arrived late for the current epoch; during the payload reconfiguration time, the satellite is configured to modify routing paths in the spectrum routing network for a successive epoch; and during the early arrival window, the satellite is configured to transmit data that has arrived in advance for the next epoch.
[11" id="c-fr-0011]
The satellite communication system of claim 1, wherein: the satellite is a non-geostationary satellite.
[12" id="c-fr-0012]
The satellite communication system of claim 1, further comprising: additional satellites which, together with the satellite, form a constellation of non-geostationary satellites which are each configured to provide a first distinct plurality of spot beams adapted to communicating with subscriber terminals using a time domain beam, and providing a second distinct plurality of spot beams adapted for communication with gateways, the satellites each including a respective spectrum routing network which is configured to in time-multiplexing manner of spot beams of the respective second plurality of spot beams with spot beams of the respective first plurality of spot beams.
[13" id="c-fr-0013]
The satellite communication system of claim 12, wherein: each satellite of the constellation has the same beam map; and each satellite in the constellation is configured to move along the same orbital path.
[14" id="c-fr-0014]
A method of operating a satellite communication system, comprising the steps of: providing a first plurality of spot beams from a non-geostationary satellite to communicate with subscriber terminals; as the satellite moves across a surface of the planet; implementing time domain beam switching for the first plurality of spot beams; providing a second plurality of spot beams from the non-geostationary satellite to communicate with gateways as the satellite travels across the surface of the planet; providing communication between a specific spot beam of the first plurality of spot beams and a first spot beam of the second plurality of spot beams during a first set of epochs while the specific spot beam is at a location on the surface of the planet ; and providing communication between the specific spot beam and a second spot beam of the second plurality of spot beams during a second set of one or more epochs, while the specific spot beam remains overwriting on the surface of the planet .
[15" id="c-fr-0015]
The method of claim 14, wherein: the first set of epochs is interlaced with the second set of one or more epochs.
[16" id="c-fr-0016]
The method of claim 14, wherein: the step of implementing the time domain beam switching for the first plurality of spot beams includes the step of moving a rate between the spot beams of the first plurality of spot beams, at intervals of one epoch, over a switching period, according to a switching plan; and the method further comprising the step of changing the configuration of the non-geostationary satellite between providing the communication between the specific point beam and the first point beam, and providing the communication between the specific point beam and the second beam punctual, during the switching plane, into orbit, while the satellite moves relative to the planet's surface.
[17" id="c-fr-0017]
The method of claim 14, wherein: the step of implementing time domain beam switching for the first plurality of spot beams includes moving a rate between the spot beams of the first plurality of spot beams, at intervals of one epoch, over a switching period, according to a switching plan; each epoch includes an activity duration, a late arrival window, a payload reconfiguration time, and an anticipated arrival window; during the duration of activity of a current epoch, the satellite transmits data for the current epoch; during the late arrival time, the satellite transmits data that arrived late for the current epoch; during the payload reconfiguration time, the satellite configures its routing paths for a successive period; and during the early arrival window, the satellite transmits data that has arrived in advance for the next epoch.
[18" id="c-fr-0018]
18. The method of claim 14, wherein: the steps of providing a first plurality of spot beams, implementation of the beam switching in the temporei domain for the first pi-beam pientraiité, providing a second plurality of spot beams, providing communication between a specific spot beam of the first plurality of spot beams and a first spot beam, and providing communication between the specific spot beam and a second spot beam, are implemented. separately and simultaneously by multiple satellites using the same beam map and moving along the same orbital path.
[19" id="c-fr-0019]
19. Satellite, wherein the satellite is a non-geostationary satellite configured to provide a first plurality of beams adapted for communication with subscriber terminals and to provide a second plurality of beams adapted for communication with gateways, the satellite is configured to implement time domain multiplexing for the first plurality of beams over a switching period, so that a specific beam of the first plurality of beams receives a bandwidth at multiple epochs during During the switching period, the satellite is configured to route communication between different beams of the second plurality of beams and the specific beam at different epochs of multiple epochs during the switching period.
[20" id="c-fr-0020]
The satellite of claim 19, wherein: the satellite is configured to route communication between different beams of the second plurality of beams and the specific beam, at different epochs of multiple epochs, during the switching period. , while the specific beam of the first set of spot beams remains at a specific location; the first plurality of beams corresponds to spot beams divided into switching groups; the satellite further includes an antenna system, a digital funnel and a selection matrix in communication with the digital funnel and the antenna system; the antenna system provides the first plurality of spot beams; the digital channelizer routes between the first plurality of spot beams and the second plurality of spot beams; and the selection matrix switches a rate among the spot beams in the same switching group.

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