Free space optical terminal with ad hoc network back-up and associated methods

• US 6,842,439 B2
• Filed: 06/17/2002
• Issued: 01/11/2005
• Est. Priority Date: 06/17/2002
• Status: Active Grant

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Zeitfuss, Michael P.
• Primary Examiner(s): Olms, Douglas
• Assistant Examiner(s): NGUYEN, VAN KIM T
• Application Number:
  US10/173,481
• Publication Number:
  US 20030231584A1
• Time in Patent Office: 939 Days
• Field of Search: 370/254, 370/256, 370/257, 370/258, 370/338, 370/328, 370/349, 370351-359, 370/395.21, 370/277, 370/400, 398/118, 398/123, 398/124, 398/115, 398/116
• US Class Current: 370/328
• CPC Class Codes: H04B 10/1125 using a single common optical path
• CPC Class Codes: H04B 7/18504 Aircraft used as relay or high altitude atmospheric platform
• CPC Class Codes: H04B 7/18506 Communications with or from aircraft, i.e. aeronautical mobile service
• CPC Class Codes: H04W 24/04 Arrangements for maintaining operational condition
• CPC Class Codes: H04W 76/22 Manipulation of transport tunnels
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 88/10 adapted for operation in multiple networks, e.g. multi-mode access points
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

A communication system includes a pair free space optical (FSO) terminals. The FSO terminals switch from a first operating mode to a second operating mode wherein the traffic is carried by an ad hoc network. The switching may be based upon a quality of service (QoS) parameter being exceeded. The first operating mode may be the primary operating mode, and the second operating mode may be the back-up operating mode.

Claims

1. A communications system comprising:

a pair of free space optical (FSO) communications terminals positioned in spaced apart relation to define a dedicated, point-to-point FSO communications link therebetween for carrying communications traffic in a first operating mode; and

a mobile ad hoc network comprising a plurality of spaced apart ad hoc network nodes and a plurality of wireless communication links for connecting the ad hoc network nodes together;

each FSO communications terminal comprising a controller for switching from the first operating mode to a second operating mode wherein the communications traffic is carried by said mobile ad hoc network.

2. A communications system according to claim 1 wherein said controller comprises a quality of service (QoS) monitor for determining at least one QoS parameter for the dedicated, point-to-point FSO communications link.

3. A communications system according to claim 2 wherein said controller further comprises a traffic switcher cooperating with said QoS monitor for switching from the first operating mode to the second operating mode based upon the at least one QoS parameter.

4. A communications system according to claim 3 wherein said controller switches from the second operating mode to the first operating mode based upon the at least one QoS parameter.

5. A communications system according to claim 2 wherein the at least one QoS parameter comprises a bit error rate.

6. A communications system according to claim 1 said mobile ad hoc network also carries other communications traffic.

7. A communications system according to claim 1 wherein the first operating mode defines a primary operating mode;

and wherein the second operating mode defines a back-up operating mode.

8. A communications system according to claim 1 wherein each FSO communications terminal further comprises a respective ad hoc network node of said ad hoc network connected to said controller.

9. A communications system according to claim 1 wherein each ad hoc network node comprises a radio frequency (RF) communications device to wirelessly and bi-directionally communicate with other ad hoc network nodes, and an ad hoc network node controller to route communications via the RF communications device.

10. A communications system according to claim 1 wherein said pair of FSO communications terminals operate at a higher communications traffic capacity than said mobile ad hoc network.

11. A communications system according to claim 1 wherein said pair of FSO communications terminals operate at a data rate in a range of greater than about 1 Mbps.

12. A communications system according to claim 1 wherein each FSO communications terminal further comprises a laser transmitter and a laser receiver connected to said controller.

13. A communications system according to claim 12 wherein said laser transmitter operates at about a 1550 nm wavelength.

14. A communications system according to claim 1 wherein said FSO communications terminals transmit wavelength division multilevel signals therebetween via the FSO communications link.

16. A communications system according to claim 14 wherein the at least one QoS parameter comprises a bit error rate.

17. A communications system according to claim 14 said mobile ad hoc network also carries other communications traffic.

18. A communications system according to claim 14 wherein said ad hoc network comprises a plurality of spaced apart ad hoc network nodes and a plurality of wireless communication links for connecting the ad hoc network nodes together.

19. A communications system according to claim 17 wherein each FSO communications terminal further comprises a respective ad hoc network node of said ad hoc network connected to said controller.

20. A communications system according to claim 17 wherein each ad hoc network node comprises a radio frequency (RF) communications device to wirelessly and bi-directionally communicate with other ad hoc network nodes, and an ad hoc network node controller to route communications via the RF communications device.

21. A communications system according to claim 14 wherein each FSO communications terminal further comprises a laser transmitter and a laser receiver connected to said controller.

22. A communications system according to claim 14 wherein said pair of FSO communications terminals operate at a higher communications traffic capacity than said mobile ad hoc network.

24. An FSO communications terminal according to claim 22 wherein said controller comprises a quality of service (QoS) monitor for determining at least one QoS parameter for the dedicated, point-to-point FSO communications link.

26. An FSO communications terminal according to claim 24 wherein said controller switches from the second operating mode to the first operating mode based upon the at least one QoS parameter.

28. An FSO communications terminal according to claim 22 wherein the first operating mode defines a primary operating mode;

and wherein the second operating mode defines a back-up operating mode.

29. An FSO communications terminal according to claim 22 wherein said ad hoc network node comprises a radio frequency (RF) communications device to wirelessly and bi-directionally communicate with other ad hoc network nodes, and an ad hoc network node controller to route communications via the RF communications device.

30. An FSO communications terminal according to claim 22 wherein FSO transceiver operates at a higher communications traffic capacity than said ad hoc network node.

32. A method according to claim 30 further comprising determining at least one QoS parameter for the dedicated, point-to-point FSO communications link.

34. A method according to claim 32 further comprising switching from the second operating mode to the first operating mode based upon the at least one QoS parameter.

36. A method according to claim 30 wherein mobile ad hoc network also carries other communications traffic.

37. A method according to claim 30 wherein the first operating mode defines a primary operating mode;

and wherein the second operating mode defines a back-up operating mode.

38. A method according to claim 30 wherein said pair of FSO communications terminals operate at a higher communications traffic capacity than said mobile ad hoc network.

15. A communications system comprising:

a pair of free space optical (FSO) communications terminals positioned in spaced apart relation to define a dedicated, point-to-point FSO communications link therebetween for carrying communications traffic in a primary operating mode; and

a mobile ad hoc network;

each FSO communications terminal comprising a controller comprising a quality of service (QoS) monitor and a traffic switcher cooperating therewith for switching between the primary operating mode and a back-up operating mode wherein the communications traffic is carried by said mobile ad hoc network based upon at least one QoS parameter.

23. A free space optical (FSO) communications terminal for communicating with a remote FSO communications terminal, the FSO communications terminal comprising:

an FSO transceiver for defining a dedicated, point-to-point FSO communications link with the remote FSO terminal for carrying communications traffic therebetween in a first operating mode;

an ad hoc network node for an ad hoc network comprising a plurality of spaced apart ad hoc network nodes and a plurality of wireless communication links for connecting the ad hoc network nodes together; and

a controller for switching from the first operating mode to a second operating mode wherein the communications traffic is carried by the ad hoc network node.

25. An FSO communications terminal according to claim 23 wherein said controller further comprises a traffic switcher cooperating with said QoS monitor for switching from the first operating mode to the second operating mode based upon the at least one QoS parameter.

27. An FSO communications terminal according to claim 23 wherein the at least one QoS parameter comprises a bit error rate.

31. A method of carrying communications traffic comprising:

positioning a pair of free space optical (FSO) communications terminals in spaced apart relation to define a dedicated, point-to-point FSO communications link therebetween for carrying the communications traffic in a first operating mode;

providing a mobile ad hoc network comprising a plurality of spaced apart ad hoc network nodes and a plurality of wireless communication links for connecting the ad hoc network nodes together; and

switching from the first operating mode to a second operating mode wherein the communications traffic is carried by the mobile ad hoc network.

33. A method according to claim 31 wherein switching comprises switching based upon the at least one QoS parameter.

35. A method according to claim 31 wherein the at least one QoS parameter comprises a bit error rate.