# US 9,882,632 B1 · Satellite constellation switching

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- Number: US 9,882,632 B1
- Document ID: US9882632B1
- Status: Granted
- Kind: B1
- Application number: 15/388,269
- Filed: 2016-12-22
- Granted: 2018-01-30
- Earliest claimed: 2016-12-22
- Assignees: Space Systems/Loral, Inc.
- Applicants: Space Systems/Loral, LLC
- Inventors: Jun Fang
- Web page: https://patentgrep.com/patent/US9882632B1

## CPC

- H04B 7/18521: {Systems of inter linked satellites, i.e. inter satellite service (for optical links between satellites H04B10/118)}
- H04B 7/18584: {Arrangements for data networking, i.e. for data packet routing, for congestion control (data switching networks H04L12/00)}
- H04B 7/195: Non-synchronous stations
- H04B: TRANSMISSION

## Abstract

A constellation of satellites form a communication system that includes communication between satellites and ground terminals as well as communication between satellites. The inter-satellite communication is implemented via wireless network comprising a first set of rings in a first orientation and a second set of rings in a second orientation. Each ring of the first set of rings and the second set of rings comprises two ringlets transmitting in opposite directions. Each satellite of the plurality of satellites is configured to communicate in a ring of the first set of rings and communicate in a ring of the second set of rings.

## Claims

### Claim 1

A satellite communication system, comprising:
a plurality of satellites, each of the satellites is configured to wirelessly communicate with ground terminals, each of the satellites is configured to wirelessly communicate with other satellites to form a wireless network comprising a first set of rings in a first orientation and a second set of rings in a second orientation, each ring of the first set of rings and the second set of rings comprises two ringlets transmitting in opposite directions, each satellite of the plurality of satellites is configured to communicate in a ring of the first set of rings and communicate in a ring of the second set of rings, each of the satellites of the plurality are configured to automatically detect a portion of the wireless network being unavailable, and to alert other satellite that the portion of the wireless network being unavailable.

### Claim 2 (depends on 1)

The satellite communication system of claim 1, wherein:
the satellites are configured to travel in a set of planes;
the first set of rings are intra-plane rings; and
the second set of rings are inter-plane rings.

### Claim 3 (depends on 1)

The satellite communication system of claim 1, wherein:
the first set of rings are oriented South-North; and
the second set of rings are oriented East-West.

### Claim 4 (depends on 1)

The satellite communication system of claim 1, wherein:
the first set of rings are orthogonal to the second set of rings.

### Claim 5 (depends on 1)

The satellite communication system of claim 1, wherein:
each satellite of the plurality of satellites is configured to communicate with four neighbors, with two of the neighbors being in a same plane and two of the neighbors being in neighboring planes.

### Claim 6 (depends on 1)

The satellite communication system of claim 1, wherein:
the plurality of satellites comprise a constellation of satellites orbiting the Earth;
as each satellite of the constellation orbits the Earth, it is handed-off between ground terminals in different locations; and
the plurality of satellites configured to determine a target satellite of the constellation of satellites orbiting the Earth that will be in orbital position to service a destination of a message at a future time of delivery of the message to the destination and transmit the message toward the identified target satellite.

### Claim 7 (depends on 1)

The satellite communication system of claim 1, wherein:
the plurality of satellites are Low Earth Orbit satellites or Medium Earth Orbit satellites.

### Claim 8 (depends on 1)

The satellite communication system of claim 1, wherein:
the satellites are configured to wirelessly communicate with other satellites via RF communication.

### Claim 9 (depends on 1)

The satellite communication system of claim 1, wherein:
the satellites are configured to wirelessly communicate with other satellites via optical communication.

### Claim 10 (depends on 1)

The satellite communication system of claim 1, wherein:
each of the satellites of the plurality include routing data structures that indicate an exit ringlet for sending messages to other satellite; and
each of the satellites of the plurality are configured to update the routing data structures in response to the portion of the wireless network being unavailable.

### Claim 11

A satellite communication system, comprising:
a spacecraft; and
a communications payload comprising a ground communication interface configured to communicate with one or more ground terminals and an inter-satellite communication interface configured to communicate with other satellites via two network rings, each network ring comprises two ringlets transmitting in opposite directions, the ground communication interface is connected to the inter-satellite communication interface, and the inter-satellite communication interface comprises:
a MAC client;
a first controller for the first ring in communication with the MAC client; and
a second controller for the second ring in communication with the MAC client.

### Claim 12 (depends on 11)

The satellite communication system of claim 11, the inter-satellite communication interface comprises:
a first interface for an intra-plane ring in communication with the MAC client; and
a second interface for an inter-plane ring in communication with the MAC client.

### Claim 13 (depends on 11)

The satellite communication system of claim 11, the inter-satellite communication interface comprises:
a first Ring Select for the first ring, the first Ring Select in communicating with the MAC client and the first controller;
a first Ringlet Data Path for a first ringlet of the first ring, the first Ringlet Data Path in communication with the first Ring Select and the MAC client;
a second Ringlet Data Path for a second ringlet of the first ring, the second Ringlet Data Path in communication with the first Ring Select and the MAC client;
a second Ring Select for the second ring, the second Ring Select in communicating with the MAC client and the second controller;
a third Ringlet Data Path for a first ringlet of the second ring, the third Ringlet Data Path in communication with the second Ring Select and the MAC client; and
a fourth Ringlet Data Path for a second ringlet of the second ring, the fourth Ringlet Data Path in communication with the second Ring Select and the MAC client.

### Claim 14 (depends on 11)

The satellite communication system of claim 11, wherein:
the inter-satellite communication interface is configured to access a message for communication to a destination, identify a target spacecraft of a constellation of spacecraft orbiting the Earth that will be in orbital position to service the destination at a future time of delivery of the message to the destination, choose a ringlet to transmit the message based on the identified target spacecraft, and send the message toward the identified target satellite via the chosen ringlet.

### Claim 15 (depends on 11)

The satellite communication system of claim 11, wherein:
the inter-satellite communication interface is configured to discover that at least a portion of a ringlet is not available, send out a control packet on one or both of the network rings identifying the portion of the ringlet that is not available and updating a routing data structure based on the portion of the ringlet is not available.

### Claim 16 (depends on 11)

The satellite communication system of claim 11, wherein:
the ground communication interface is configured to receive a message from a ground terminal; and
the inter-satellite communication interface is configured to encapsulate the message into a layer two packet and transmit the layer two packet on one of the ringlets.

### Claim 17 (depends on 11)

The satellite communication system of claim 11, wherein:
the inter-satellite communication interface is configured to operate as a layer two switch for communication with other satellites via two network rings.

### Claim 18 (depends on 11)

The satellite communication system of claim 11, wherein:
the two network rings comprise an intra-plane ring and an inter-plane ring.

### Claim 19 (depends on 11)

The satellite communication system of claim 11, wherein:
the two network rings comprise a first ring at a first orientation and a second ring at a second orientation.

### Claim 20 (depends on 11)

The satellite communication system of claim 11, wherein:
the spacecraft is a bus of a satellite.

### Claim 21

A method for operating a satellite communication system, comprising,
accessing a message for communication to a destination via a constellation of satellites orbiting the Earth, each of the satellites configured to wirelessly communicate with other satellites to form a wireless network comprising a first set of rings and a second set of rings such that each satellite of the constellation of satellites is configured to communicate in a ring of the first set of rings and communicate in a ring of the second set of rings, each ring of the first set of rings and the second set of rings comprises two ringlets transmitting in opposite directions;
identifying a target satellite of the constellation of satellites orbiting the Earth that will be in orbital position to service the destination at a future time of delivery of the message to the destination;
operating a network switch on one or more satellites of the constellation of satellites orbiting the Earth to send the message toward the identified target satellite;
transmitting the message from the identified target satellite to the destination;
automatically discovering that at least a portion of the wireless network is not available; and
sending out one or more control packets on the first set of rings and the second set of rings identifying the portion of the wireless network that is not available.

### Claim 22 (depends on 21)

The method of claim 21, wherein:
the satellites are configured to travel in planes;
the first set of rings are inter-plane rings; and
the second set of rings are intra-plane rings.

### Claim 23 (depends on 21)

The method of claim 21, further comprising:
updating routing data structures on the satellite based on the portion of the wireless network is not available; and
communicating between satellites using the updated routing data structures.

### Claim 24 (depends on 21)

The method of claim 21, wherein the method further comprises:
encapsulating the message into a layer two packet, the network switch operates as a layer two switch that sends the message encapsulated in the layer two packet toward the identified target satellite via the first set of rings and the second set of rings.

### Claim 25 (depends on 21)

The method of claim 21, wherein:
the operating the network switch on one or more satellites of the constellation of satellites orbiting the Earth to send the message toward the identified target satellite includes operating the first set of rings and the second set of rings as Resilient Packet Rings.