CO-LOCATED SATELLITES WITH GROUND BASED PROCESSING

Methods, systems, and devices for co-located satellites with ground based processing are described. A set of co-located satellites may be configured to collect a set of return link signal components, where each co-located satellite includes a first payload configured to receive a respective return link signal component including one or more return link signal transmitted from one or more terminals and a second payload configured to transmit a representation of the respective return link signal component. One or more ground stations may be configured to receive the representations of the respective return link signal components. A central processor may be configured to apply a set of beamforming coefficients to the representations of the respective return link signal components received by the one or more ground stations to obtain one or more return link beam signals corresponding to one or more return link beams from the set of co-located satellites.

BACKGROUND

The following relates generally to communications, including co-located satellites with ground based processing.

Communications devices may communicate with one another using wired connections, wireless (e.g., radio frequency (RF)) connections, or both. Wireless communications between devices may be performed using wireless spectrum that has been designated for a service provider, wireless technology, or both. In some examples, the amount of information that can be communicated via a wireless communications network is based on an amount of wireless spectrum designated to the service provider, and an amount of frequency reuse within the region in which service is provided. Wireless communications (e.g., cellular communications, satellite communications, etc.) may use beamforming and multiple-input multiple-output (MIMO) techniques for communications between devices to increase frequency reuse, however, providing a high level of frequency reuse in some types of communication systems such as satellite communications presents challenges.

SUMMARY

A set of co-located satellites may be configured to collect a set of return link signal components, where at least two pairs of adjacent satellites of the set of co-located satellites along a first dimension have a different inter-satellite spacing, and where each satellite of the set of co-located satellites includes a first payload configured to receive a respective return link signal component including one or more return link signals transmitted from one or more terminals over a first frequency range and a second payload configured to transmit a representation of the respective return link signal component. One or more ground stations may be configured to receive the representations of the respective return link signal components. A central processor may be configured to apply a set of beamforming coefficients to the representations of the respective return link signal components received by the one or more ground stations to obtain one or more return link beam signals corresponding to one or more return link beams from the set of co-located satellites.

DETAILED DESCRIPTION

In some examples, co-located satellites of a satellite swarm (e.g., a geostationary Earth orbit (GEO) swarm) may communicate with a terminal. For instance, the terminal may transmit a signal, where a first signal component of the signal is received by a first satellite of the satellite swarm and a second signal component of the signal is received by a second satellite of the satellite swarm. Processing respective signal components to form a beam signal from the signal components may involve the first and second satellites consuming substantial energy. However, each satellite may have a limited supply or budget of energy to expend on processing. Additionally, malfunction of components used to process the respective signal components at the first and second satellites may be difficult or expensive, for example involving replacing a satellite or repairing a satellite in orbit. In some examples, capability of the satellite swarm may be impacted for a duration of time during which the first and/or second satellites may be incapable of processing the respective signal components.

Accordingly, in some examples, each of the first and second satellites may receive a respective signal component from the terminal via a first payload and may transmit a respective representation of the respective signal component to another device for processing. The other device may include one or more ground stations or may include a central satellite configured to aggregate the representations and transmit the aggregated representations to the one or more ground stations. The one or more ground stations may provide received representations of signal components to a central processor that is configured to apply a set of beamforming coefficients to the representations to obtain one or more beam signals corresponding to one or more beams from the satellite swarm. By processing the representations of the signal components at the central processor, the first and second satellites may conserve more energy. Additionally, since repair or replacement of processing components of a central processor may be simpler and faster, a duration of time during which the central processor may be incapable of processing representations of signal components due to component malfunction may be shorter than a duration of time during which the first and second satellites may be incapable of processing signal components due to component malfunction.

Features of the disclosure are initially described in the context of a satellite communications system and a communications network as described with reference toFIGS.1and2. Features of the disclosure are described in the context of communications schemes as described with reference toFIGS.3-7. These and other features of the disclosure are further illustrated by and described with reference to an apparatus diagram and flowcharts that relate to co-located satellites with ground based processing as described with reference toFIGS.8-10.

FIG.1shows an example of a satellite communications system100that supports co-located satellites with ground based processing in accordance with aspects described herein. Satellite communications system100may include a ground system135, terminals120, and a satellite swarm105. In some cases, satellite swarm may be in a geostationary Earth orbit (GEO). Although discussed with reference to the satellite swarm105including GEO satellites, in some examples the satellites of the satellite swarm105may be in other orbits such as a low Earth orbit (LEO) or medium Earth orbit (MEO). The ground system135may include a network of access nodes140that are configured to communicate with the satellite swarm105. The access nodes140may be coupled with access node transceivers145that are configured to process signals received from and to be transmitted through corresponding access node(s)140. The access node transceivers145may also be configured to interface with a network125(e.g., the Internet)—e.g., via a network device132(e.g., a network operations center, satellite and gateway terminal command centers) that may provide an interface for communicating with the network125.

Terminals120may include various devices configured to communicate signals with the satellite swarm105, where the terminals120may include fixed terminals (e.g., ground based stationary terminals) or mobile terminals such as terminals on boats, aircraft, ground based vehicles, and the like. A terminal120may communicate data and information with an access node140via the satellite swarm105. The data and information may be communicated with a destination device such as a network device132, or some other device or distributed server associated with network125.

The satellite swarm105may include a network of satellites110that are deployed in space orbits (e.g., GEO, MEO, LEO, etc.). One or more satellites110included in the satellite swarm105may be equipped with an antenna array115that includes multiple antennas and/or antennas panels. The antennas, which may also be referred to as antenna elements, of each antenna array115may be evenly distributed or unevenly distributed. Additionally or alternatively, the one or more satellites110may be evenly distributed or unevenly distributed relative to each other. For example, the distribution of the satellites110may be non-harmonic, meaning that inter-satellite spacing is different across the satellite swarm105, and in some the spacing between any two satellites110of the satellite swarm105may be different than the spacing between any other two satellites. In some cases, the spacing between the satellites may be allowed to vary (e.g., over time) based on differences in orbital positioning.

The satellite swarm105may use the one or more satellites110to support multiple-input multiple-output (MIMO) techniques to increase a utilization of frequency resources used for communications—e.g., by enabling wireless spectrum to be reused concurrently in different geographic regions of a geographic area. Similarly, the satellite swarm105may use the one or more satellites to support beamforming techniques to increase a utilization of frequency resources used for communications.

MIMO techniques may be used to exploit multipath signal propagation and increase spectral efficiency by transmitting or receiving multiple signals via different spatial layers. The multiple signals may, for example, be transmitted by a transmitting device (e.g., a satellite110or multiple satellites110of satellite swarm105) via a set of antennas in accordance with a set of weighting coefficients. Likewise, the multiple signals may be received by a receiving device (e.g., a satellite110or multiple satellites110of satellite swarm105) via a set of antennas in accordance with a set of weighting coefficients. Each of the multiple signals may be associated with a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). MIMO techniques include single-user MIMO (SU-MIMO), where multiple spatial layers are used to communicate with one device, and multiple-user MIMO (MU-MIMO), where multiple spatial layers are used to communicate with multiple devices.

To determine weighting coefficients to apply to the set of antennas such that the N spatial layers are formed, an (M×N) MIMO matrix may be formed, where M may represent the quantity of antennas of the set of antennas. In some examples, M may be equal to N. The MIMO matrix may be determined based on a channel matrix and used to isolate the different spatial layers of the channel. In some examples, the weighting coefficients are selected to emphasize signals transmitted using the different spatial layers while reducing interference of signals transmitted in the other spatial layers. Accordingly, processing signals received at each antenna with the set of antennas (e.g., a signal received at the set of antennas) using the MIMO matrix may result in multiple signals being output, where each of the multiple signals may correspond to one of the spatial layers. The elements of the MIMO matrix used to form the spatial layers of the channel may be determined based on channel sounding probes received at satellite swarm105—e.g., from one or more devices. In some examples, the weighting coefficients used for MIMO communications may be referred to as beam coefficients, and the multiple signals or spatial layers may be referred to as beam signals.

Beamforming techniques may be used to shape or steer a communication beam along a spatial path between satellite swarm105and a geographic area. A communication beam may be formed by determining weighting coefficients for antenna elements of an antenna array that result in the signals transmitted from or received at the antenna elements being combined such that signals propagating in a particular orientation with respect to an antenna array experience constructive interference while others experience destructive interference. Thus, beamforming may be used to transmit signals having energy that is focused in a direction of a communication beam and to receive signals that arrive in a direction of the communication with increased signal power (relative to the absence of beamforming). The weighting coefficients may be used to apply amplitude offsets, phase offsets, or both to signals carried via the antennas. In some examples, the weighting coefficients applied to the antennas may be used to form multiple beams associated with multiple directions, where the multiple beams may be used to communicate multiple signals having the same frequency at the same time. The weighting coefficients used for beamforming may be referred to as beam coefficients, and the multiple signals may be referred to as beam signals.

In some examples, beamforming techniques may be used by satellite swarm105to form spot beams that are tiled (e.g., tessellated) across a geographic area. In some examples, the wireless spectrum used by satellite swarm105may be reused across sets of the spot beams for communications between terminals120and the satellite swarm105. In some examples, the wireless spectrum can be reused in spot beams that do not overlap, where a contiguous geographic region can be covered by overlapping spot beams that each use orthogonal resources (e.g., orthogonal time, frequency, or polarization resources). In some examples, satellites of the satellite swarm105may communicate with terminals120via communications beams119within a subarea155of the geographic area150.

Satellites110occupying a geostationary Earth orbit with 0 degrees of inclination relative to the equator of a planet (e.g., Earth) may have no apparent motion from the surface of the planet and may project a stationary (e.g., single point) ground track on the equator. Satellites110with a geosynchronous orbit may have a small inclination relative to the equator and may have apparent periodic motion with a period of one sidereal day and may trace a ground track ellipse around a single point on the equator of the surface of the planet. As the amount of inclination relative to the equator grows (e.g., becomes non-zero), the satellites110may have apparent periodic motion with a period of one sidereal day and may track a ground track analemma (e.g., aFIG.8) around a single point on the equator of the surface of the planet. In some examples, the satellites110of satellite swarm105may include one or more satellites in geostationary Earth orbit or a geosynchronous orbit. For example, satellite swarm105may include one or more satellites in geostationary Earth orbit occupying one or more orbital slots (e.g., as defined along the GEO arc), as well as one or more satellites in a geosynchronous orbit that occupy the same one or more orbital slots, with a small inclination relative to a geostationary Earth orbit.

When the ground track of the geosynchronous satellite across a sidereal day is a single point or an ellipse or analemma with a small size (e.g., a size below a threshold size), the amount of angular deviation or pointing associated with using a ground-based antenna to keep the satellite110in a main beam of the ground-based antenna of maximum signal gain may be zero or below a threshold amount. Accordingly, in such examples, the ground-based antennas may be fixed or may have a scan angle below a threshold amount. As such, the ground-based antennas may refrain from performing continuous tracking of satellites, which may be associated with a higher energy consumption than remaining fixed or moving with the scan angle below the threshold amount.

In some examples, a set of satellites110may be co-located in a satellite swarm105. As used herein, satellites that are co-located may be understood to share an orbital slot, or orbit together such that they stay within an aperture area that can be used for communication with terminals or ground stations. In some cases, the set of satellites110may be in a same geosynchronous orbital slot (e.g., within 0.1 degrees of longitude and 0.1 degrees of latitude relative to the equator of the planet). The geosynchronous orbital slot may have a square shape with equal dimensions for height and width (e.g., 126 km). The satellite swarm105may use ground-based signal processing for ground-based calibration of the location of each element of the satellite swarm105(e.g., each satellite110). Additionally, an array of ground-based antennas receiving raw (e.g., unprocessed) or at least partially processed signal information collected by each satellite110may be present (e.g., multiple ground systems135and/or multiple access nodes140in the ground system135). The signal information may be communicated to a central processor130. In some examples, after calibration, the satellite swarm105, central processor130, and/or a network device132coupled with the ground-based antennas may identify the locations of satellites110within a quarter wavelength of a communication frequency (e.g., a carrier frequency).

In some examples, central processor130may perform a-priori prediction and/or estimation of signal phase-of-arrival on each satellite110and/or each antenna element using geometric modeling. Additionally or alternatively, central processor130may process training data received at the satellites110to discover phase-of-arrival correlation on each satellite110and/or each antenna element. Satellites110of the satellite swarm105may support one or more of multiple MIMO modes that include different levels or types of MIMO processing including channel synthesis from channel sounding probes transmitted by reference terminals (e.g., which may be included in terminals120, or may be separate terminals for transmission of channel sounding probes).

As the speed of satellites within satellite swarm105relative to each other decreases, the amount of recalibrations performed for the satellite swarm105(e.g., such that the positions of the satellites110of the satellite swarm105are identified within a quarter wavelength of the communication frequency) over a fixed duration of time may also decrease. Due to the positions of the satellites110being identified within the quarter wavelength, a system providing a signal processing basis set of two independent means of signal correlation may be realized which may correlate antenna signal energy independently or in combination. The antenna signal energy may correlated so as to algorithmically adapt to supply system benefits depending on user terminal circumstances. For instance, a first independent means of signal correlation may include collecting signal energy by an antenna set and correlating the collected signal energy by a process of using training data to discover the correlation of signals received by the antenna elements using operations (e.g., linear algebra, probability, statistical processing). A second independent means of signal correlation may include collecting signal energy by the antenna set and correlating using a priori knowledge of the user terminal position and the positions of the satellites110(e.g., and/or of antenna elements of the satellites110).

Implementing the satellite swarm105may have one or more benefits as compared to implementing a terrestrial-based system. For instance, the satellite swarm105may have a lower gravitational load as compared to the terrestrial-based system. Additionally, the satellite swarm105may encounter fewer variable weather and temperature conditions. Additionally, the satellite swarm105may encounter fewer environmental disturbances as compared to terrestrial-based system.

In some examples, a multiplicity of satellites110may be assembled in a satellite swarm105in a single geosynchronous orbital slot (e.g., a square with dimensions of 126 km on each side), where each satellite110hosts one or more antenna elements (e.g., arranged in an antenna array115). Each satellite110in the satellite swarm105may have one or more communications systems. For instance, each satellite110may have a first system for in-band-user-terminal communications for user communications services (e.g., communications between the satellite110and a terminal120) and a second system for out-of-user-terminal-band communications for ground-based signal processing (e.g., communications between the satellite110and the ground system135).

In some examples, employing satellite swarms105that use ground-based processing may have one or more advantages over other geosynchronous single-satellite methods. For instance, such satellite swarms105may enable incremental provisioning of services. For instance, to add additional users, additional ground-based signal processing antennas (e.g., additional ground systems135and/or access nodes140) and capacity may be employed and/or additional satellites110may be launched. Employing the additional ground-based antennas and/or launching additional satellites may be associated with using fewer resources than upgrading a capacity of satellites110that are already launched. Additionally, using satellite swarms105with ground-based processing may enable incremental upgrades and replacement. For instance, to upgrade a satellite swarm, a new satellite110may be launched. Additionally, using satellite swarms105with ground-based processing may enable an increase in user density, increased resilience to ground-based and space-based interferers (e.g., beamforming with the satellites110may be used to null ground and space-based interferers), and increased tolerance to fault mechanisms (e.g., kinetic fault mechanisms such as collisions as satellites110are distributed over a dispersed area and service may be provided even after losing one satellite110).

In some examples, a satellite110of the satellite swarm may operate according to a first baseline ground processing mode (e.g., baseline ground processing mode1) in which time domain and/or frequency domain modulation techniques are used to establish total bits per hertz. In other examples, spatial domain modulation techniques as well as time domain and/or frequency domain modulation techniques may be used in a second baseline processing mode (e.g., baseline ground processing mode2) and a third baseline processing mode (e.g., baseline ground processing mode3) to establish total bits per hertz. In some such examples, multiple ground systems135and/or access nodes140may be employed and may be in fixed locations separated by above a threshold amount. For the second baseline processing mode, a frequency reuse from 2 to j (e.g., where j is the number of elements in an aperture) may be employed and calibration using a geometric sweep may be performed. For the third baseline processing mode, a frequency reuse of 2 to n (e.g., where n is the number of satellites in a particular geosynchronous slot) may be employed and calibration using a long training data sequence and MIMO to discover correlation for each physically separate ground station (e.g., ground system135, access node140) may be performed. The first baseline ground processing mode may be associated with a single ground station frequency set per hemisphere (e.g., frequency reuse of 1) and the second and third baseline ground processing modes may be associated with multiple ground stations in each hemisphere with a full frequency set reuse.

FIG.2shows an example of a communications network200that supports beamforming using sparse antenna arrays in accordance with examples described herein.

Communications network200depicts a system for communicating using one or more of MIMO techniques, geometric interpretation techniques, and geometrically-informed MIMO techniques. Communications network200may include a satellite swarm205, satellite210, antennas215-aand215-b, communication link220, ground station225, central processor230, beamforming coefficient component235, beam signal component240, and memory255(including code260). At least a portion (e.g., all) of communications network200may be located within a space segment of communications network200(e.g., in a satellite system). In some examples, a portion of communications network200that is not included in the space segment may be located within a ground segment of communications network200(e.g., in a ground system). For example, satellite swarm205(e.g., including satellite210and antennas215-aand215-b) may be included in a space segment of communications network200, while ground station225and central processor230may be included in a ground segment of communications network200.

Satellite swarm205may be an example of a satellite swarm105as described with reference toFIG.1and satellite210may be an example of a satellite110as described with reference toFIG.1. Antennas215-aand215-bmay represent antennas at a single satellite (e.g., at an antenna array of satellite210) or may represent additional different satellites of satellite swarm205, each having an antenna or antenna array.

Link220may represent an interface over which signals may be exchanged between the satellite swarm205and a central location that may be used to distribute the signal to the signal processing components of communications network200(e.g., beamforming coefficient component235, beam signal component240). Link220may be a wireless interface that is used to wirelessly communicate signaling between satellite swarm205and the signal processing components. Link220may support point to point (e.g., from one satellite to one ground station), or point to multi-point (e.g., from one satellite to multiple ground stations) communication.

Beamforming coefficient component235may apply a set of beamforming coefficients to representations of return link signal components received by the ground station225. Additionally or alternatively, beamforming coefficient component235may apply, at the central processor, a set of forward link beamforming coefficients to one or more forward link beam signals to obtain representations of forward link signal components for transmission by the set of co-located satellites.

Beam signal component240may obtain one or more return link beam signals corresponding to one or more return link beams from the set of co-located satellites based on beamforming coefficient component235applying the set of beamforming coefficients. In some examples, beam signal component240may obtain a first set of return link beam signals corresponding to a first set of return link beams associated with a first set of return link coverage areas, where the first set of return link coverage areas are non-overlapping with each other. Additionally, the beam signal component240may obtain a second set of return link beam signals corresponding to a second set of return link beams associated with a second set of return link coverage areas, where the second set of return link coverage areas are non-overlapping with each other.

Central processor230may include an intelligent hardware device (e.g., a general-purpose processor, a digital signal processor (DSP), a central processing unit (CPU), a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). The central processor230may be configured to execute computer-readable instructions stored in a memory (e.g., memory255) to cause the communications network200to perform various functions (e.g., functions or tasks supporting beamforming using sparse antenna arrays). For example, the communications network200or a component of the communications network200may include a processor247and memory255coupled to or included in the central processor230that are configured to perform various functions described herein.

The memory255may include random access memory (RAM) and/or read-only memory (ROM). The memory255may store code260that is computer-readable and computer-executable. The code260may include instructions that, when executed by the processor247, cause the communications network200to perform various functions described herein. The code260may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some cases, the code260may not be directly executable by the processor247but may cause a computer (e.g., when compiled and executed) to perform functions described herein. In some cases, the memory255may contain, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

Additionally, or alternatively, beamforming coefficient component235, beam signal component240, or various combinations or components thereof, may be implemented in code260(e.g., as communications management software or firmware), executed by central processor230. If implemented in code260executed by processor247, the functions of beamforming coefficient component235, beam signal component240, or various combinations or components thereof may be performed by a general-purpose processor, a DSP, a central processing unit (CPU), an ASIC, an FPGA, or any combination of these or other programmable logic devices (e.g., configured as or otherwise supporting a means for performing the functions described in the present disclosure).

In some examples, a combination of ground-based processing and space-based processing may be employed. For example, a first user capacity may be provided using ground-based processing and a second, reduced user capacity may be provided using space-based processing. For instance, a swarm of satellites (e.g., a swarm including satellite210and additional antennas215-aand215-b, which may be additional satellites) may be in a location (e.g., a geographic region) where it may be advantageous to generate a fewer number of beams or in which links to ground station(s) may be lower capacity. In some such examples, a local processor of the swarm (e.g., a space-based processor) may receive signal components and may perform reduced processing to generate a fewer number of wider beam signals (e.g., as opposed to a greater number of narrower beam signals). Additionally or alternatively, the local processor may process a reduced number of signal components (e.g., forward link signal components, return link signal components) or beamforming coefficients. These fewer signal components may correspond to a lower number of satellites present within the swarm or may correspond to multiple satellites of the swarm (e.g., adjacent satellites) being grouped together for application of beamforming coefficients. For example, for transmission of forward link signal components, the local processor may apply a same beamforming coefficient to a forward link beam signal to obtain forward link signal components for a group of satellites of the swarm, and for reception of return link signal components, the local processor may apply a same beamforming coefficient to the representations of the return link signal components from the group of satellites. Such methods may be employed when the swarm of satellites are over a particular geographic region (e.g., the north pole, the south pole, an ocean where there is a low user density). Additionally or alternatively, such methods may be employed when a number of ground stations available for communication fails to satisfy a threshold and/or when a signal metric associated with one or more of a set of ground stations fails to satisfy a threshold.

FIG.3illustrates an example of a communications scheme300that supports co-located satellites with ground based processing in accordance with aspects described herein. In some examples, communications scheme300may be implemented by one or more aspects of satellite communications system100and/or communications network200. For instance, satellite305may be an example of a satellite110as described with reference toFIG.1and/or a satellite210as described with reference toFIG.2; terminal310may be an example of a terminal120as described with reference toFIG.1; and ground station315may be an example of a ground system135as described with reference toFIG.1and/or a ground station225as described with reference toFIG.2.

Satellite305may include a first payload320, a second payload325, and a processor350. The first payload320may be configured to communicate with terminal310and the second payload325may be configured to communicate with ground station315. For instance, the first payload320may be configured to receive a return link signal component330from terminal310and second payload325may be configured to transmit a representation335of the return link signal component330to ground station315. Additionally or alternatively, the second payload325may be configured to receive a representation340of a forward link signal component345from ground station315and transmit the forward link signal component345to terminal310.

In some examples, satellite305may be one of a set of co-located satellites. In some such examples, the set of co-located satellites may be configured to collect a set of return link signal components. For instance, the satellite305may collect return link signal component330over a first frequency range via the first payload320. Additionally, the set of co-located satellites may be configured to transmit a representation of the respective return link signal component that each satellite receives. For instance, the satellite305may transmit the representation335of the return link signal component330via the second payload325.

In some examples, ground station315may be one of one or more ground stations configured to receive the representations of the respective return link signal components. For instance, ground station315may receive the representation335of the return link signal component330from second payload325. Alternatively, the second payload325may transmit the representation335of the return link signal component330to a central satellite, and the central satellite may transmit the representation335to the ground station315.

In some examples, a central processor (e.g., a central processor230as described with reference toFIG.2) coupled with ground station315may be configured to apply a set of beamforming coefficients to the representations of the respective return link signal components received by the one or more ground stations including ground station315to obtain one or more return link beam signals corresponding to one or more return link beams from the set of co-located satellites including satellite305. Additionally, the central processor may be configured to obtain a first set of return link beam signals corresponding to a first set of return link beams associated with a first set of return link coverage areas. In some such examples, the first set of return link coverage areas may be non-overlapping with each other. In some examples, the central processor may be configured to obtain a second set of return link beam signals corresponding to a second set of return link beams associated with a second set of return link coverage areas. In some such examples, the second set of return link coverage areas may be non-overlapping with each other. Additionally or alternatively, the second set of return link beams may be associated with one or more second return link beams associated with one or more second return link signals transmitted from one or more second terminals over a second frequency range. For instance, terminal310may transmit return link signal component330over a first frequency range that differs from a second frequency range over which another terminal transmits a respective return link signal component.

In some examples, a first ground station (e.g., ground station315) of the one or more ground stations may be configured to receive a first representation of a first return link signal component (e.g., representation335) from a first satellite (e.g.,305) and a second ground station (e.g., another ground station coupled with the central processor) may be configured to receive a second representation of a second return link signal component from a second satellite of the set of co-located satellites. In some such examples, the first and second ground stations may receive the respective representations based on the first satellite being configured to transmit the first representation of the first return link signal component within a first coverage area excluding a second coverage area to which the second satellite is configured to transmit the second representation of the second return link signal component.

In some examples, the second payloads of the set of co-located satellites are configured to receive respective representations of forward link signal components. For instance, the second payload325of satellite305may be configured to receive a representation340of a forward link signal component345. The first payloads of the set of co-located satellites may be configured to transmit the forward link signal components based on the received respective representations of the forward link signal components. For instance, the first payload320of satellite305may be configured to transmit the forward link signal component345based on the received representation340of the forward link signal component345. In some examples, the central processor may be configured to apply a set of forward link beamforming coefficients to the one or more forward link beam signals to obtain the representations of the forward link signal components, and the one or more ground stations coupled with the central processor may be configured to transmit the representations of the forward link signal components to the set of co-located satellites.

In some examples, the central processor may be configured to identify a location of each satellite of the set of co-located satellites and to generate the set of beamforming coefficients based on the identified location. Additionally or alternatively, a central satellite communicating with the satellite305and/or a local processor (e.g., processor350) may be configured to identify the location of each satellite of the set of co-located satellites. In some examples, each satellite305may transmit a ranging signal to a central satellite or other satellites305for determining the location of each satellite of the set of co-located satellites.

In some examples, the inter-satellite spacing of adjacent satellites along the first dimension or a second dimension orthogonal to the first dimension may be greater than a distance that is equivalent to a wavelength of the return link signal components. Additionally or alternatively, the inter-satellite spacing of adjacent satellites of the set of co-located satellites along the first dimension or a second dimension orthogonal to the first dimension may be greater than distance that is equivalent to ten times a wavelength of the return link signal components.

In some examples, the processor350may perform sampling according to a common reference timing. For instance, when satellite305receives return link signal component330, processor350may (e.g., with first payload320) synchronize to a reference timing, perform sampling (e.g., on return link signal component330), format the return link signal component330into the representation335of return link signal component330, or any combination thereof. Additionally or alternatively, when satellite305receives representation340of forward link signal component345, processor350may format (e.g., perform filtering, digital-to-analog conversion, frequency conversion) the representation340into forward link signal component345for transmission via first payload320.

In some examples, the central processor may be configured to apply and/or may apply the set of beamforming coefficients to the representations of the respective return link signal components to obtain the one or more return link beam signals at a first time. Additionally, the local processor350may be configured to obtain representations of respective return link signal components from other satellites of the set of co-located satellites, and may apply a second set of beamforming coefficients to at least a subset of the representations of the respective return link signal components to obtain one or more second return link beam signals at a second time. The local processor350may transmit the one or more second return link beam signals to a ground station.

FIG.4illustrates an example of a communications scheme400that supports co-located satellites with ground based processing in accordance with aspects described herein. In some examples, communications scheme400may be implemented by one or more aspects of satellite communications system100, communications network200, communications scheme300, or any combination thereof. For instance, satellites405-aand405-bmay each be an example of a satellite110as described with reference toFIG.1, a satellite210as described with reference toFIG.2, or a satellite305as described with reference toFIG.3, and ground station410may be an example of a aspects of a ground system135as described with reference toFIG.1, a ground station225as described with reference toFIG.2, or a ground station315as described with reference toFIG.3. Additionally, signal component representations415-aand415-bmay be an example of a representation335of a return link signal component330.

Satellites405-aand405-bmay each be a respective satellite of a set of co-located satellites. In some examples, satellites405-aand405-bmay each communicate with ground station410. For instance, satellite405-amay transmit a first signal component representation415-a(e.g., a representation of a first signal component) and satellite405-bmay transmit a second signal component representation415-b(e.g., a representation of a second signal component) to ground station410. In some examples, satellite405-amay transmit the first signal component representation415-aover a first frequency range420-aand satellite405-bmay transmit the second signal component representation415-bover a second frequency range420-b, where the first frequency range may be different than (e.g., exclusive of) the second frequency range. In some examples, one or both of first frequency range420-aand second frequency range420-bmay be different than (e.g., exclusive of, higher than) a range of frequencies over which satellites405-aand405-bcommunicate with a terminal (e.g., terminals from which satellites405-aand405-bmay receive signal components). Transmitting the respective signal component representations over different frequency ranges may allow multiple signal components415to be received from multiple satellites405concurrently at the same ground station410.

In some examples, a set of satellites including satellites405-aand405-bmay transmit respective signal component representations using spatial multiplexing, frequency multiplexing, or both. For instance, a first subset of the set of satellites may transmit respective signal component representations to a first ground station and a second subset of the set of satellites may transmit respective signal component representations to a second ground station spatially separated from the first ground station. Additionally, each satellite within the first subset of satellites may transmit respective signal component representations over a different frequency range than each other satellite of the first subset of satellites. Similarly, each satellite within the second subset of satellites may transit respective signal component representations over a different frequency range than each other satellite of the second subset of satellites.

A forward link communication scheme may be implemented in a similar manner to that shown for the return link for communication scheme400. In some examples, ground station410may transmit forward link signal component representations to satellites405-aand405-b. For instance, ground station410may transmit a first forward link signal component representation to satellite405-aand a second forward link signal component representation to satellite405-b. In some examples, a central processor coupled with the ground station410may apply a set of forward link beamforming coefficients to beam signals to obtain the first forward link signal component representation and the second forward link signal component representation. In some examples, ground station410may transmit the first forward link signal component representation over first frequency range420-aand may transmit the second forward link signal component representation over second frequency range420-b. Satellite405-amay convert (e.g., to a frequency used for forward link signals to a user terminal) the first forward link signal component representation to a first forward link signal component and satellite405-bmay convert (e.g., to the frequency used for forward link signals to the user terminal) the second forward link signal component representation to a second forward link signal component. Satellite405-amay transmit the first forward link signal component and satellite405-bmay transmit the second forward link signal component. In a similar manner, additional satellites405may transmit additional forward link signal components, and the forward link signal components may result in a forward link beam carrying data for one or more user terminals.

FIG.5illustrates an example of a communications scheme500that supports co-located satellites with ground based processing in accordance with aspects described herein. In some examples, communications scheme500may be implemented by one or more aspects of satellite communications system100and/or communications network200. For instance, central processor505may be an example of a central processor230as described with reference toFIG.2; satellites515-a,515-b, and515-cmay each be an example of a satellite110,210, or305as described with reference toFIGS.1-3; and terminals525-aand525-bmay each be an example of a terminal120as described with reference toFIG.1.

Each of satellites515-a,515-b, and515-cmay be configured to communicate with one or more terminals. For instance, satellite515-amay be configured to communicate with terminal525-avia communication beam520-aand to communicate with terminal525-bvia communication beam520-b; satellite515-bmay be configured to communicate with terminal525-avia communication beam520-cand to communicate with terminal525-bvia communication beam520-d; and satellite515-cmay be configured to communicate with terminal525-avia communication beam520-eand to communicate with terminal525-bvia communication beam520-f. In some examples, each of satellites515-a,515-band515-cmay communicate with the one or more terminals using a respective first payload. Additionally, each of satellites515-a,515-b, and515-cmay be configured to communicate with a central processor505(e.g., via a set of one or more ground stations). For instance, satellite515-amay be configured to communicate with the central processor505via communication link510-a; satellite515-bmay be configured to communicate with the central processor505via communication link510-b; and satellite515-cmay be configured to communicate with the central processor505via communication link510-c.

In some examples, the first payload of each of satellites515-a,515-b, and515-cmay include a respective set of antenna elements (e.g., an antenna array115) and a respective local processor. The respective local processor may be configured to perform beamforming of a set of local component signals received at the set of antenna elements to obtain one or more respective signal components. For instance, terminal525-amay transmit a first signal530-aand terminal525-bmay transmit a second signal530-b. The first signal530-aand the second signal530-bmay be transmitted concurrently over a same frequency range. Satellite515-amay receive respective local component signals of the first signal530-aand the second signal530-bat its set of antenna elements, and may form communication beam520-aand communication beam520-bfrom the respective component signals using a set of local beamforming coefficients to obtain a first local beam signal associated with communication beam520-aand a second local beam signal associated with communication beam520-b. Similarly, satellite515-bmay receive respective local component signals of the first signal530-aand the second signal530-bat its set of antenna elements, and may form communication beam520-cand communication beam520-dfrom the respective component signals using a set of local beamforming coefficients to obtain a third local beam signal associated with communication beam520-cand a fourth local beam signal associated with communication beam520-d. In addition, satellite515-cmay receive respective local component signals of the first signal530-aand the second signal530-bat its set of antenna elements, and may form communication beam520-eand communication beam520-ffrom the respective component signals using a set of local beamforming coefficients to obtain a fifth local beam signal associated with communication beam520-eand a sixth local beam signal associated with communication beam520-f. That is, the local processor of each of satellites515-a,515-b, and515-cmay be configured to obtain a first representation of the respective signal component corresponding to a respective first local beam associated with a first local coverage area from the set of local component signals received at the set of elements and to obtain a second representation of a respective signal component corresponding to a respective second local beam associated with a second local coverage area from the set of local component signals received at the set of elements. In some such examples, the respective first local beam and a the respective second local beam may be associated with at least partially overlapping frequency ranges. In some examples, the central processor505may be configured to obtain a first beam signal based on applying a first set of beamforming coefficients to the first representations obtained by each of satellites515-a,515-b, and515-cand to obtain a second beam signal based on applying a second set of beamforming coefficients to the second representations obtained by each of satellites515-a,515-b, and515-c. For example, the central processor505may apply a set of beamforming coefficients (e.g., which may include M beamforming coefficients, where M corresponds to the number of satellites515applying local beamforming coefficients to obtain a local beam) to obtain beam signals corresponding to beams that are compound beams formed from local beams520associated with a coverage area or terminal525. In one example, the central processor505may apply a first set of beamforming coefficients to the first, third, and fifth local beam signals to obtain a first beam signal associated with the first signal530-aand apply a second set of beamforming coefficients to the second, fourth, and sixth local beam signals to obtain a second beam signal associated with the second signal530-b.

A forward link communication scheme may be implemented in a similar manner to that shown for the return link for communication scheme500. For instance, a central processor may apply beamforming coefficients to a first forward link beam signal and a second forward link beam signal to obtain respective representations of first forward link signal components and respective representations of second forward link signal components, respectively. Each of satellites515-a,515-b, and515-cmay receive a respective representation of the first forward link signal component and a respective representation of the second forward link signal component weighted according to the applied beamforming coefficients and corresponding to each beam. Each of satellites515-a,515-b, and515-cmay apply a set of beamforming coefficients to each received representation (e.g., a different set of beamforming coefficients for each representation or a same set of beamforming coefficients for both representations) to generate local forward link signal components to be transmitted from each antenna element of each of satellites515-a,515-b, and515-cto terminals525-aand525-bto form local beams520. Local beams520may then form communication beams according to the beamforming coefficients applied by the central processor.

FIG.6illustrates an example of a communications scheme600that supports co-located satellites with ground based processing in accordance with aspects described herein. In some examples, communication scheme600may be implemented by one or more aspects of satellite communications system100, communications network200, communications scheme300, or any combination thereof. For instance, satellites605-aand605-band central satellite615may each be an example of a satellite110as described with reference toFIG.1, a satellite210as described with reference toFIG.2, or a satellite305as described with reference toFIG.3. Ground station625may be an example of aspects of a ground system135as described with reference toFIG.1, a ground station225as described with reference toFIG.2, or a ground station315as described with reference toFIG.3. Additionally, signal component representations610-aand610-bmay be an example of a representation335of a return link signal component330as described with reference toFIG.3.

Satellites605-aand605-bmay each be a respective satellite of a set of co-located satellites. Additionally, central satellite615may be one of the set of co-located satellites or a satellite excluded from the set of co-located satellites. For example, central satellite615may be co-located with the set of co-located satellites, but may or may not receive signals directly from terminals. In some examples, satellites605-aand605-bmay each communicate with central satellite615. For instance, satellite605-amay transmit a first signal component representation610-a(e.g., a representation of a first signal component) and satellite605-bmay transmit a second signal component representation610-b(e.g., a representation of a second signal component) to central satellite615. In some examples, satellite605-amay transmit the first signal component representation610-aover a first frequency range630-aand satellite605-bmay transmit the second signal component representation610-bover a second frequency range630-b, where the first frequency range may be different from (e.g., may be exclusive of) the second frequency range.

Central satellite615, after receiving the first signal component representation610-aand the second signal component representation610-b, may combine the signal component representations to generate aggregated signal component representation620. Aggregated signal component representation620may include first signal component representation610-aand second signal component representation610-b, and may be transmitted over a third frequency range different from the first frequency range and the second frequency range. For example, aggregated signal component representation620may be have a bandwidth equal or greater to a bandwidth of N·SRBW, where N may be the number of satellites in the set of co-located satellites and SRBWmay be the bandwidth of each of the signal component representations610. Upon generating the aggregated signal component representation620, the central satellite may transmit the aggregated signal component representation620to ground station625. Ground station625may extract each signal component representation from the aggregated signal component representation620and may apply a set of beamforming coefficients to the signal component representations to obtain one or more return link beam signals corresponding to one or more return link beams from satellites605-aand605-b.

A forward link communication scheme may be implemented in a similar manner to that shown for the return link for communication scheme600. In some examples, a central processor coupled with the ground station625may apply a set of forward link beamforming coefficients to beam signals to obtain the respective representations of forward link signal components. The ground station625may aggregate the respective representations of forward link signal components to form an aggregated forward link signal component representation. In some examples, central satellite615may be configured to receive the aggregated forward link signal component representation from ground station625. Additionally, central satellite615may be configured to separate the aggregated forward link signal component representation into a first forward link signal component representation and a second forward link signal component representation, where the central satellite615may transmit the first forward link signal component representation to satellite605-aand may transmit the second forward link signal component representation to satellite605-b. Satellite605-amay transmit the first forward link signal component and satellite605-bmay transmit the second forward link signal component. Additional satellites605may transmit other forward link signal components, and the forward link signal components may form a communication beam carrying forward link signals for one or more terminals.

FIG.7illustrates an example of a communications scheme700that supports co-located satellites with ground based processing in accordance with examples as disclosed herein. In some examples, communications scheme700may be implemented by one or more aspects of satellite communications system100and/or communications network200. For instance, satellite swarm705may be an example of a satellite swarm105as described with reference toFIG.1; satellites710-a,710-b, and710-cmay each be an example of a satellite110as described with reference toFIG.1, a satellite210as described with reference toFIG.2, or a satellite305as described with reference toFIG.3. Ground stations715-aand715-bmay each be an example of aspects of a ground system135as described with reference toFIG.1, a ground station225as described with reference toFIG.2, or a ground station315as described with reference toFIG.3.

Ground stations715-aand715-bmay be configured to communicate with GEO swarm705. For instance, satellite710-amay transmit a first representation of a signal component, satellite710-bmay transmit a second representation of a signal component, and satellite710-cmay transmit a third representation of a signal component, where each of the first, second, and third representations may be received by multiple ground stations. Ground station715-amay receive the first representation of the signal component as signal720-cand ground station715-bmay receive the first representation of the signal component as signal725-c. Similarly, ground station715-amay receive the second representation of the signal component as signal720-aand ground station715-bmay receive the second representation of the signal component as signal725-b. Additionally or alternatively, ground station715-amay receive the third representation of the signal component as signal720-band ground station715-bmay receive the third representation of the signal component as signal725-a. In some examples, the first, second, and third signal representations may be transmitted over overlapping frequencies and/or may be associated overlapping beams (e.g., generated via a reflector on the corresponding satellite). In such examples, ground stations715-aand715-bmay apply MIMO (e.g., apply beamforming coefficients or coding matrices to distinguish spatial layers) to distinguish between representations (e.g., to extract return feeder link beam signals).

FIG.8shows a flowchart illustrating a method800that supports co-located satellites with ground based processing in accordance with examples as disclosed herein. The operations of method800may be implemented by or its components as described herein. For example, the operations of method800may be performed by. In some examples, may execute a set of instructions to control the functional elements of the device to perform the described functions. Additionally or alternatively, may perform aspects of the described functions using special-purpose hardware.

At805, the method may include receiving, at a set of co-located satellites, a set of return link signal components, where at least two pairs of adjacent satellites of the set of co-located satellites along a first dimension have a different inter-satellite spacing, and where each satellite of the set of co-located satellites receives a respective return link signal component including one or more return link signals transmitted from one or more terminals over a first frequency range and a second payload. The operations of805may be performed in accordance with examples as disclosed herein.

At810, the method may include transmitting, from each satellite of the set of co-located satellites to one or more ground stations, a respective representation of the respective return link signal component. The operations of810may be performed in accordance with examples as disclosed herein.

At815, the method may include applying, at a central processor, a set of beamforming coefficients to the representations of the respective return link signal components received by the one or more ground stations to obtain one or more return link beam signals corresponding to one or more return link beams from the set of co-located satellites. The operations of815may be performed in accordance with examples as disclosed herein.

Aspect 1: The apparatus, including features, circuitry, logic, means, or instructions, or any combination thereof for receiving, at a set of co-located satellites, a set of return link signal components, where at least two pairs of adjacent satellites of the set of co-located satellites along a first dimension have a different inter-satellite spacing, and where each satellite of the set of co-located satellites receives a respective return link signal component including one or more return link signals transmitted from one or more terminals over a first frequency range and a second payload; transmitting, from each satellite of the set of co-located satellites to one or more ground stations, a respective representation of the respective return link signal component; and applying, at a central processor, a set of beamforming coefficients to the representations of the respective return link signal components received by the one or more ground stations to obtain one or more return link beam signals corresponding to one or more return link beams from the set of co-located satellites.

Aspect 2: The apparatus of aspect 1, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for obtaining, at the central processor, a first plurality of return link beam signals corresponding to a first plurality of return link beams associated with a first plurality of return link coverage areas, where the first plurality of return link coverage areas are non-overlapping with each other.

Aspect 3: The apparatus of aspect 2, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for obtaining, at the central processor, a second plurality of return link beam signals corresponding to a second plurality of return link beams associated with a second plurality of return link coverage areas, where the second plurality of return link coverage areas are non-overlapping with each other, and where the second plurality of return link beams are associated with one or more second return link signals transmitted from one or more second terminals over a second frequency range.

Aspect 4: The apparatus of any of aspects 1 through 3, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for receiving, from a first satellite of the set of co-located satellites and at a first ground station of the one or more ground stations, a first representation of a first return link signal component and receiving, from a second satellite of the set of co-located satellites and at a second ground station of the one or more ground stations, a second representation of a second return link signal component based at least in part on receiving the first representation of the first return link signal component within a first coverage area excluding a second coverage area within which the second representation of the second return link signal component is received.

Aspect 5: The apparatus of any of aspects 1 through 4, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for receiving, from a first satellite of the set of co-located satellites and at a ground station of the one or more ground stations, a first representation of a first return link signal component and receiving, from a second satellite of the set of co-located satellites and at the ground station, a second representation of a second return link signal component based at least in part on receiving the first representation of the first return link signal component at a first range of frequencies excluding a second range of frequencies over which the second representation of the second return link signal component is received.

Aspect 6: The apparatus of any of aspects 1 through 5, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for applying, at the central processor, a set of forward link beamforming coefficients to one or more forward link beam signals to obtain representations of forward link signal components for transmission by the set of co-located satellites; transmitting, from the one or more ground stations and to the set of co-located satellites, the representations of the forward link signal components; receiving, at the set of co-located satellites, the respective representations of the forward link signal components; and transmitting, from the set of co-located satellites, the forward link signal components based at least in part on the received respective representations of the forward link signal components.

Aspect 7: The apparatus of any of aspects 1 through 6 where each satellite of the set of co-located satellites includes a plurality of elements and a local processor and the method, apparatuses, and non-transitory computer-readable medium, further includes operations, features, circuitry, logic, means, or instructions, or any combination thereof for performing, at the local processor, beamforming of a plurality of local component signals received at the plurality of elements to obtain the respective signal component.

Aspect 8: The apparatus of aspect 7, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for obtaining, at the local processor of each satellite of the set of co-located satellites, a first representation of the respective signal component corresponding to a respective first local beam associated with a first local coverage area from the plurality of local component signals received at the plurality of elements and obtaining, at the local processor of each satellite of the set of co-located satellites, a second representation of a respective signal component corresponding to a respective second local beam associated with a second local coverage area from the plurality of local component signals received at the plurality of elements, where the respective first local beam and the respective second local beam are associated with at least partially overlapping frequency ranges.

Aspect 9: The apparatus of aspect 8, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for obtaining, at the central processor, a first beam signal based at least on applying a first set of beamforming coefficients to the first representations obtained by each of the set of co-located satellites and obtaining, at the central processor, a second beam signal based at least on applying a second set of beamforming coefficients to the second representations obtained by each of the set of co-located satellites.

Aspect 10: The apparatus of any of aspects 1 through 9, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for collecting, at a central satellite, the respective representation of the respective return link signal component for each satellite of the set of co-located satellites, where the central satellite transmits the respective representation of the respective return link signal component for each satellite of the set of co-located satellites to the one or more ground stations.

Aspect 11: The apparatus of aspect 10, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for receiving, at the central satellite and a from a first satellite of the set of co-located satellites, a first representation of a first return link signal component and receiving, at the central satellite and from a second satellite of the set of co-located satellites, a second representation of a second return link signal component based at least in part on receiving the first representation of the first return link signal component at the first frequency range excluding a second frequency range over which the second representation of the second return link signal component is received.

Aspect 12: The apparatus of any of aspects 10 through 11, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for the central satellite includes one co-located satellite of the set of co-located satellites.

Aspect 13: The apparatus of any of aspects 1 through 12, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for identifying, at the central processor, a location of each satellite of the set of co-located satellites and generating, at the central processor, the set of beamforming coefficients based at least in part on the identified location.

Aspect 14: The apparatus of any of aspects 1 through 13 where the one or more ground stations includes a set of ground stations and the method, apparatuses, and non-transitory computer-readable medium, further includes operations, features, circuitry, logic, means, or instructions, or any combination thereof for forming, via a subset of the set of ground stations, a beam for receiving the representation of the respective return link signal component from one satellite of the set of co-located satellites.

Aspect 15: The apparatus of any of aspects 1 through 14, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for the inter-satellite spacing of adjacent satellites of the set of co-located satellites along the first dimension or a second dimension orthogonal to the first dimension is greater than a distance that is equivalent to a wavelength of the return link signal components.

Aspect 16: The apparatus of any of aspects 1 through 15, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for the inter-satellite spacing of adjacent satellites of the set of co-located satellites along the first dimension or a second dimension orthogonal to the first dimension is greater than a distance that is equivalent to ten times a wavelength of the return link signal components.

Aspect 17: The apparatus of any of aspects 1 through 16, further including operations, features, circuitry, logic, means, or instructions, or any combination thereof for applying, at the central processor, the set of beamforming coefficients to the representations of the respective return link signal components to obtain the one or more return link beam signals at a first time and applying, at a local processor on one of the set of co-located satellites, a second set of beamforming coefficients to at least a subset of the representations of the respective return link signal components to obtain one or more second return link beam signals at a second time.

FIG.9shows a flowchart illustrating a method900that supports co-located satellites with ground based processing in accordance with examples as disclosed herein. The operations of method900may be implemented by or its components as described herein. For example, the operations of method900may be performed by. In some examples, may execute a set of instructions to control the functional elements of the device to perform the described functions. Additionally or alternatively, may perform aspects of the described functions using special-purpose hardware.

At905, the method may include receiving, at a set of co-located satellites, a set of return link signal components, where at least two pairs of adjacent satellites of the set of co-located satellites along a first dimension have a different inter-satellite spacing, and where each satellite of the set of co-located satellites receives a respective return link signal component including one or more return link signals transmitted from one or more terminals over a first frequency range and a second payload. The operations of905may be performed in accordance with examples as disclosed herein.

At910, the method may include transmitting, from each satellite of the set of co-located satellites to one or more ground stations, a respective representation of the respective return link signal component. The operations of910may be performed in accordance with examples as disclosed herein.

At915, the method may include applying, at a central processor, a set of beamforming coefficients to the representations of the respective return link signal components received by the one or more ground stations to obtain one or more return link beam signals corresponding to one or more return link beams from the set of co-located satellites. The operations of915may be performed in accordance with examples as disclosed herein.

At920, the method may include obtaining, at the central processor, a first plurality of return link beam signals corresponding to a first plurality of return link beams associated with a first plurality of return link coverage areas, where the first plurality of return link coverage areas are non-overlapping with each other. The operations of920may be performed in accordance with examples as disclosed herein.

FIG.10shows a flowchart illustrating a method1000that supports co-located satellites with ground based processing in accordance with examples as disclosed herein. The operations of method1000may be implemented by or its components as described herein. For example, the operations of method1000may be performed by. In some examples, may execute a set of instructions to control the functional elements of the device to perform the described functions. Additionally or alternatively, may perform aspects of the described functions using special-purpose hardware.

At1005, the method may include receiving, at a set of co-located satellites, a set of return link signal components, where at least two pairs of adjacent satellites of the set of co-located satellites along a first dimension have a different inter-satellite spacing, and where each satellite of the set of co-located satellites receives a respective return link signal component including one or more return link signals transmitted from one or more terminals over a first frequency range and a second payload. The operations of1005may be performed in accordance with examples as disclosed herein.

At1010, the method may include receiving, from a first satellite of the set of co-located satellites and at a first ground station of one or more ground stations, a first representation of a first return link signal component. The operations of1010may be performed in accordance with examples as disclosed herein.

At1015, the method may include receiving, from a second satellite of the set of co-located satellites and at a second ground station of the one or more ground stations, a second representation of a second return link signal component based at least in part on receiving the first representation of the first return link signal component within a first coverage area excluding a second coverage area within which the second representation of the second return link signal component is received. The operations of1015may be performed in accordance with examples as disclosed herein.

At1020, the method may include applying, at a central processor, a set of beamforming coefficients to the representations of the respective return link signal components received by the one or more ground stations to obtain one or more return link beam signals corresponding to one or more return link beams from the set of co-located satellites. The operations of1020may be performed in accordance with examples as disclosed herein.

Aspect 18: A system, including: a set of co-located satellites configured to collect a set of return link signal components, where at least two pairs of adjacent satellites of the set of co-located satellites along a first dimension have a different inter-satellite spacing, and where each satellite of the set of co-located satellites includes a first payload configured to receive a respective return link signal component including one or more return link signals transmitted from one or more terminals over a first frequency range and a second payload configured to transmit a representation of the respective return link signal component; one or more ground stations configured to receive the representations of the respective return link signal components; and a central processor configured to apply a set of beamforming coefficients to the representations of the respective return link signal components received by the one or more ground stations to obtain one or more return link beam signals corresponding to one or more return link beams from the set of co-located satellites.

Aspect 19: The system of aspect 18, where the central processor is configured to obtain a first plurality of return link beam signals corresponding to a first plurality of return link beams associated with a first plurality of return link coverage areas, the first plurality of return link coverage areas are non-overlapping with each other.

Aspect 20: The system of aspect 19, where the central processor is configured to obtain a second plurality of return link beam signals corresponding to a second plurality of return link beams associated with a second plurality of return link coverage areas, the second plurality of return link coverage areas are non-overlapping with each other, and the second plurality of return link beams are associated with one or more second return link signals transmitted from one or more second terminals over a second frequency range.

Aspect 21: The system of any of aspects 18 through 20, where a first ground station of the one or more ground stations is configured to receive a first representation of a first return link signal component from a first satellite of the set of co-located satellites and a second ground station is configured to receive a second representation of a second return link signal component from a second satellite of the set of co-located satellites based at least in part on the first satellite being configured to transmit the first representation of the first return link signal component within a first coverage area excluding a second coverage area to which the second satellite is configured to transmit the second representation of the second return link signal component.

Aspect 22: The system of any of aspects 18 through 21, where a ground station of the one or more ground stations is configured to receive a first representation of a first return link signal component from a first satellite of the set of co-located satellites and to receive a second representation of a second return link signal component from a second satellite of the set of co-located satellites based at least in part on the first satellite being configured to transmit the first representation of the first return link signal component at the first frequency range excluding a second frequency range over which the second satellite is configured to transmit the second representation of the second return link signal component.

Aspect 23: The system of any of aspects 18 through 22, where: the second payloads of the set of co-located satellites are configured to receive respective representations of forward link signal components; the first payloads of the set of co-located satellites are configured to transmit the forward link signal components based at least in part on the received respective representations of the forward link signal components; the central processor is configured to apply a set of forward link beamforming coefficients to one or more forward link beam signals to obtain the representations of the forward link signal components; and the one or more ground stations are configured to transmit the representations of the forward link signal components to the set of co-located satellites.

Aspect 24: The system of any of aspects 18 through 23, where the first payload of each satellite of the set of co-located satellites includes a plurality of elements and a local processor configured to perform beamforming of a plurality of local component signals received at the plurality of elements to obtain the respective signal component.

Aspect 25: The system of aspect 24, where the local processor of each satellite of the set of co-located satellites is configured to obtain a first representation of the respective signal component corresponding to a respective first local beam associated with a first local coverage area from the plurality of local component signals received at the plurality of elements and to obtain a second representation of a respective signal component corresponding to a respective second local beam associated with a second local coverage area from the plurality of local component signals received at the plurality of elements, and the respective first local beam and the respective second local beam are associated with at least partially overlapping frequency ranges.

Aspect 26: The system of aspect 25, where the central processor is configured to obtain a first beam signal based at least on applying a first set of beamforming coefficients to the first representations obtained by each of the set of co-located satellites and to obtain a second beam signal based at least on applying a second set of beamforming coefficients to the second representations obtained by each of the set of co-located satellites.

Aspect 27: The system of any of aspects 18 through 26, where the system further includes: a central satellite configured to collect the representations of the respective return link signal components and to transmit the representations to the one or more ground stations.

Aspect 28: The system of aspect 27, where the central satellite is configured to receive a first representation of a first return link signal component from a first satellite of the set of co-located satellites and to receive a second representation of a second return link signal component from a second satellite of the set of co-located satellites based at least in part on the first satellite being configured to transmit the first representation of the first return link signal component at a first range of frequencies excluding a second range of frequencies over which the second satellite is configured to transmit the second representation of the second return link signal component.

Aspect 29: The system of any of aspects 27 through 28, where the central satellite includes one co-located satellite of the set of co-located satellites.

Aspect 30: The system of any of aspects 18 through 29, where the central processor is configured to identify a location of each satellite of the set of co-located satellites and to generate the set of beamforming coefficients based at least in part on the identified location.

Aspect 31: The system of any of aspects 18 through 30, where the one or more ground stations includes a set of ground stations, a subset of the set of ground stations is configured to form a beam for receiving the representation of the respective return link signal component from one satellite of the set of co-located satellites.

Aspect 32: The system of any of aspects 18 through 31, where the inter-satellite spacing of adjacent satellites of the set of co-located satellites along the first dimension or a second dimension orthogonal to the first dimension is greater than a distance that is equivalent to a wavelength of the return link signal components.

Aspect 33: The system of any of aspects 18 through 32, where the inter-satellite spacing of adjacent satellites of the set of co-located satellites along the first dimension or a second dimension orthogonal to the first dimension is greater than a distance that is equivalent to ten times a wavelength of the return link signal components.

Aspect 34: The system of any of aspects 18 through 33, further including a local processor on one of the set of co-located satellites, where the central processor is configured to apply the set of beamforming coefficients to the representations of the respective return link signal components to obtain the one or more return link beam signals at a first time and the local processor is configured to apply a second set of beamforming coefficients to at least a subset of the representations of the respective return link signal components to obtain one or more second return link beam signals at a second time

It should be noted that these methods describe examples of implementations, and that the operations and the steps may be rearranged or otherwise modified such that other implementations are possible. In some examples, aspects from two or more of the methods may be combined. For example, aspects of each of the methods may include steps or aspects of the other methods, or other steps or techniques described herein.