Free-space optical mesh network

Patent metadata

Field	Value
Publication number	US-9270372-B2
Application number	US-201314069464-A
Country	US
Kind code	B2
Filing date	Nov 1, 2013
Priority date	Jun 25, 2013
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

The disclosure provides a practical system and methods for implementing an adaptive free-space optical network with a high-connectivity, dynamic mesh topology. The network can have operational characteristics similar to those of RF mobile ad-hock networks. Each node has one or more optical terminals that may utilize space-time division multiplexing, which entails rapid spatial hopping of optical beams to provide a high dynamic node degree without incurring high cost or high size, weight, and power requirements. As a consequence the network rapidly sequences through a series of topologies, during each of which connected nodes communicate. Each optical terminal may include a plurality of dedicated acquisition and tracking apertures which can be used to increase the speed at which traffic links can be switched between nodes and change the network topology. An RF overlay network may be provided to act as a control plane and be used to provide node discovery and adaptive route planning for the optical network.

First claim

What is claimed is:

1. A network comprising:
four or more nodes, each node having a plurality of optical data terminals to provide optical beam hopping capability to connect to at least two remote nodes using an optical link;
wherein each of the nodes includes:
a network node controller;
a network processor;
an RF system connected to the node controller and the network processor, establishing RF links with each of the other nodes, and monitoring spatial and temporal information of each of the other nodes; and
an optical system connected to the network node controller and including an optical bench and the optical data terminals;

wherein at least a first pair of nodes and a second pair of nodes connected in a first network topology during a first period of time, and
wherein at least a different first pair of nodes and a different second pair of nodes connected in a second network topology during a second period of time,
wherein a first data path is established among the connected nodes during the first period of time and a second data path is established among the connected nodes during a second period of time,
wherein adaptive routing and link switching are used to select the first and second network topology based upon the number of nodes in the network and based on the spatial and temporal information of the nodes in the network.

2. The network of claim 1 wherein each node is assigned a time slot to transmit data during the first period of time and each node is assigned a time slot to transmit data during the second period of time.

3. The network of claim 1 wherein each node is assigned a time slot to receive data during the first period of time and each node is assigned a time slot to receiving data during the second period of time.

4. The network of claim 1 wherein the time between the end of the first time period and the start of the second time period is 15 milliseconds or less.

5. The network of claim 1 wherein:
each node is assigned a time slot to transmit data during the first period of time;
each node is assigned a time slot to receive data during the first period of time, and the time slots to transmit data coincide with the time slots to receive data.

6. The network of claim 1 wherein the duration of the time slots can different for each network topology.

7. The network of claim 1 wherein the duration of either of the first or second periods of time is based upon a factor selected from the group consisting of:
real-time traffic demand;
environment conditions;
the status of at least one node; and
the status of at least one optical link.

8. The network of claim 1 wherein of either the first or second network topology is based upon a factor selected from the group consisting of:
real-time traffic demand;
environment conditions;
the status of at least one node; and
the status of at least one optical link.

9. The network of claim 1 wherein the optical data terminal includes an optical phased array.

10. The network of claim 1 wherein each node further includes a tracking assembly to spatially track a plurality of remote nodes and each node transmits tracking beacons to be tracked by a plurality of remote nodes.

11. The network of claim 10 wherein the tracking assembly has an attribute selected from the group consisting of:
smaller size compared to the optical data terminal;
a lower weight compared to the optical data terminal;
a lower power requirement compared to the optical data terminal; and
a lower cost compared to the optical data terminal.

12. The network of claim 1 wherein each node further includes an acquisition assembly providing capability to acquire the spatial position of a plurality of remote nodes.

13. The network of claim 12 where the acquisition assembly includes an RF antenna.

14. The network of claim 12 wherein the acquisition assembly includes an optical phased array.

15. The network of claim 12 wherein the acquisition assembly further provides capability to spatially track a plurality of remote nodes.

16. A method for transmitting data in a free-space optical network having four or more nodes, the method comprising:
establishing an RF overlay network including a first node, a second node, a third node, and a fourth node, wherein each of the nodes is connected with wireless RF links the other nodes;
each of the nodes monitoring spatial and temporal information of each of the other nodes using the wireless RF links;
selecting a first network topology to define a first data path between the first node and the second node and second data path between the third node and the fourth node;
pointing optical data beams, using the spatial and the temporal information from the RF overlay network, and connecting the first node and the second node and connecting the third node and the fourth node according to the first network topology;
transmitting data from the first node to the second node and from the third node to the fourth node during a first period of time;
using adaptive routing and link switching selecting a second network topology based upon a number of nodes in the network and locations of the nodes in the network, wherein the second network topology defines a third data path between the first node and the third node and a fourth data path between the second node and the fourth node;
pointing optical data beams, using the spatial and the temporal information from the RF overlay network, and connecting the first node and the third node and connecting the second node and the fourth node according to the second network topology; and
transmitting data from the first node to the third node and from the second node to the fourth node during a second period of time.

17. The method of claim 16 wherein the second node transmits data to the first node during the first time period.

18. The method of claim 16 wherein the time between the end of the first time period and the start of the second time period is 15 milliseconds or less.

19. The method of claim 16 wherein electronic steeling is used to point the optical data beams.

20. The method of claim 16 further comprising pointing tracking beacons from the first and second nodes.

21. The network of claim 1 wherein each of the nodes includes:
an RF system to send traffic load and link state information to one or more other nodes and to receive traffic load and link state information from one or more other nodes; and
a network processor coupled to the RF system and operable to maintain the topology of the network and to participate in the distributed calculation of primary and backup routes using traffic load and link state information received from one or more other nodes.

22. The method of claim 16 wherein using adaptive routing and link switching to select the second network topology comprises using traffic load and link state information shared via an RF overlay network.

Assignees

• Raytheon Co

Inventors

• Miniscalco William J

Classifications

• H04B7/18504

  Aircraft used as relay or high altitude atmospheric platform · CPC title

• H04B10/11

  Arrangements specific to free-space transmission, i.e. transmission through air or vacuum · CPC title

• H04B10/1141

  One-way transmission · CPC title

• H04B10/1149

  Arrangements for indoor wireless networking of information · CPC title

• H04B10/1143

  Bidirectional transmission · CPC title