Communications network having adaptive network link optimization using wireless terrain awareness and method for use therein

• US 6,115,580 A
• Filed: 09/08/1998
• Issued: 09/05/2000
• Est. Priority Date: 09/08/1998
• Status: Expired due to Term

• Current Assignee: CDC Propriete Intellectuelle
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Beaudry, Bennett, Chuprun, Jeffrey Scott, Tarver, Byron, Bergstrom, Chad S.
• Primary Examiner(s): Kuntz, Curtis A.
• Assistant Examiner(s): Ramakrishnaiah, Melur
• Application Number:
  US09/150,196
• Time in Patent Office: 728 Days
• Field of Search: 455/456, 455/445, 455/446, 455/449, 455/435, 455/525, 455/1, 455/62, 455/67.1, 455/67.7, 340/825.02
• US Class Current: 455/1
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 4/021 Services related to particular areas, e.g. point of interest [POI] services, venue services or geofences
• CPC Class Codes: H04W 40/20 based on geographic position or location
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A communications network (10) having a plurality of wireless nodes (12-28) distributed within a region of interest makes routing decisions based on terrain information for the region of interest. A link quality determination unit (54) determines the quality of individual node-to-node links within the network (10), based on the location of the nodes (12-28) and the terrain about the nodes (12-28). A path selection unit 58 then determines an optimal path through the network 10 based on the link quality information. In one embodiment, communications corridors (102) are defined as preferred subpaths within a network for use in connecting remote nodes.

Claims

1. A communications network, comprising:

a plurality of wireless communications nodes dispersed geographically within a first region, each of said plurality of said wireless communications nodes including a geolocation device configured to determine a current location;

a node location table operative to store said current location of each of said plurality of wireless communications nodes;

a terrain awareness table operative to store terrain information for said first region, said terrain information including elevation information of surface points within said first region;

a path selection unit configured to select a substantially optimal communications path through said plurality of wireless communications nodes, said substantially optimal communications path selected by said path selection unit based at least in part on said terrain information and said current location of each of said plurality of wireless communication nodes.

2. The communications network, as claimed in claim 1, wherein said path selection unit is configured to estimate a pathloss between said plurality of wireless communications nodes based at least in part on said current location information and said terrain information.

3. The communications network, as claimed in claim 2, wherein said path selection unit includes a processor that is programmed to implement a Longley-Rice pathloss model that is modified to use terrain information in estimating said pathloss between said plurality of wireless communications nodes.

4. The communications network, as claimed in claim 2, said communications network further comprising:

a node velocity communication unit configured to receive said current location of each of said plurality of wireless communications nodes stored in said node location table and use said current location of each of said plurality of wireless communications nodes to determine velocity values for said plurality of wireless communications nodes; and

a communications corridor determination unit configured to define a plurality of communications corridors within said plurality of wireless communications nodes based on said velocity values and said path loss, each of said plurality of communications corridors including a subset of said plurality of wireless communications nodes and representing a preferred subpath for use in connecting nodes in said communications network.

5. The communications network, as claimed in claim 4, wherein:

each communications corridor includes at least two wireless communications nodes, wherein each of said at least two wireless communications nodes can communicate with each other of said at least two wireless communications nodes via a direct wireless communications link, wherein each direct wireless communications link has a pathloss below a predetermined threshold value.

6. The communications network, as claimed in claim 4, wherein:

each of said plurality of communications corridors includes at least one shared node that is shared with another of said plurality of communications corridors, wherein communications between communications corridors take place through shared nodes.

7. The communications network, as claimed in claim 4, wherein:

said plurality of wireless communications nodes includes at least one mobile node; and

said communications corridor determination unit includes means for adaptively changing said plurality of communications corridors based on movement of said at least one mobile node within said first region.

8. The communications network, as claimed in claim 7, wherein:

said at least one mobile node includes an alarm for alerting a user of said at least one mobile node of an impending loss of network link integrity based on a predicted future position of said at least one mobile node.

9. The communications network, as claimed in claim 1, said communications network further comprising a wireless transceiver for receiving said terrain information from a satellite.

10. The communications network, as claimed in claim 1, said communications network further comprising a wireless transceiver for receiving said terrain information from an airborne platform.

11. The communications network, as claimed in claim 1, said communications network further comprising a wireless transceiver for receiving said terrain information from a ground based transmitter.

12. The communications network, as claimed in claim 1, wherein:

said terrain information includes digital terrain elevation data (DTED).

13. The communications network, as claimed in claim 1, wherein:

said terrain information includes at least one of the following;

soil information, climate information, and foliage information.

14. The communications network, as claimed in claim 1, wherein:

said terrain information includes classification information for said first region.

15. The communications network, as claimed in claim 14, wherein:

said classification information includes at least one of the following designations;

urban, desert, sea, jungle, forest, and mountain.

16. The communications network, as claimed in claim 1, wherein:

said plurality of wireless communications nodes includes at least one mobile node; and

said communications network further comprises means for calculating a velocity of said at least one mobile node, wherein said path selection unit uses said velocity of said at least one mobile node to determine said substantially optimal communications path.

17. The communications network, as claimed in claim 16, wherein:

said path selection unit includes means for predicting a future position of said at least one mobile node based on a current position of said at least one mobile node, said velocity of said at least one mobile node and said terrain information, wherein said path selection unit uses said future position to determine said substantially optimal communications path.

18. The communications network, as claimed in claim 1, wherein:

at least one of said plurality of wireless communications nodes includes means for tracking locations of other wireless communications nodes in the plurality of wireless communications nodes.

19. The communications network, as claimed in claim 1, wherein:

said terrain awareness table and said path selection unit are both located within one of said plurality of wireless communications nodes.

20. The communications network, as claimed in claim 1, wherein:

said plurality of wireless communications nodes are configured in a centralized architecture having at least one base station node.

21. The communications network, as claimed in claim 1, wherein:

said plurality of wireless communications nodes are configured in a distributed architecture without centralized control.

22. The communications network, as claimed in claim 1, wherein:

said plurality of wireless communications nodes includes at least one node within an airborne vehicle.

23. The communications network, as claimed in claim 22, wherein:

said airborne vehicle establishes a communications corridor to a second plurality of wireless communications nodes remote from said first plurality of wireless communications nodes.

24. The communications network, as claimed in claim 1, wherein:

said plurality of wireless communications nodes includes at least one wired terrestrial link to a third plurality of wireless communications nodes.

25. The communications network, as claimed in claim 1, said communications network further comprising a jammer table for tracking known jamming sources in said first region, wherein said path selection unit uses said jammer table to determine said substantially optimal communications path.

32. The wireless communications node, as claimed in claim 6, wherein:

said CCDU includes means for selecting a modulation type to be used within said at least one communications corridor, wherein said modulation type is selected to enhance corridor connectivity in diverse terrain conditions.

33. The wireless communications node, as claimed in claim 32, wherein:

said modulation type is selected from a group including at least;

frequency hopping modulation, direct sequence modulation, and adaptive rate modulation.

26. A wireless communications node for use in a communications network having a plurality of wireless communications nodes arranged within a first geographic region, at least some of said plurality of wireless communications nodes being mobile, said wireless communications node comprising:

a wireless transceiver for communicating with at least one other of the plurality of wireless communications nodes;

a geolocation device for determining a current location of said wireless communications node;

a terrain awareness table for use in collecting terrain information for said first geographic region, said terrain information including at least elevation information for surface points within said first geographic region;

a node location table for use in collecting current location information for nodes in said plurality of wireless communications nodes; and

a communications corridor determination unit (CCDU) for use in establishing at least one communications corridor within said first geographic region based on said terrain information and said current location information, said at least one communications corridor including a subset of the plurality of wireless communications nodes and representing a preferred subpath through the network for use in providing a communications connection between nodes in the network.

27. The wireless communications node, as claimed in claim 26, further comprising:

a pathloss estimation unit, coupled to said terrain awareness table and said node location table, for estimating pathloss information for selected node pairs in said plurality of wireless communications nodes based on said terrain information and said current location information, said CCDU using said pathloss information to establish said at least one communications corridor.

28. The wireless communications node, as claimed in claim 26, further comprising:

a communications corridor link table (CCLT) for tracking a plurality of communications corridors in the communications network; and

a path selection unit, coupled to said CCLT, for selecting at least one of said plurality of communications corridors to provide an optimal communications connection between a first and second wireless communications node.

29. The wireless communications node, as claimed in claim 28, wherein:

said path selection unit selects a concatenation of successive communications corridors between said first wireless communications node and said second wireless communications node.

30. The wireless communications node, as claimed in claim 26, wherein:

said CCDU adaptively adjusts said at least one communications corridor based on changing node locations.

31. The wireless communications node, as claimed in claim 26, wherein:

said CCDU adaptively adjusts said at least one communications corridor based on changing terrain conditions.

34. The wireless communications node, as claimed in claim 26, wherein:

said CCDU includes means for selecting an anti-jamming countermeasure to be used in said at least one communications corridor, wherein said anti-jamming countermeasure is selected to enhance corridor connectivity.

35. The wireless communications node, as claimed in claim 26, wherein:

said CCDU includes means for selecting a frequency range of operation to be used by said at least one communications corridor, wherein said frequency range of operation is selected to enhance corridor connectivity in diverse terrain conditions.

36. The wireless communications node, as claimed in claim 26, wherein:

said CCDU includes means for setting a signal power level in said at least one communications corridor, based on said pathloss information estimated by said pathloss estimation unit.

37. In a communications network having a plurality of wireless communications nodes arranged within a first geographic region, at least some of said plurality of wireless communications nodes being mobile, a method for determining an optimal communications path between a first wireless communications node and a second wireless communications node in said plurality of wireless communications nodes, said method comprising the steps of:

obtaining terrain information for said first geographic region, said terrain information including at least elevation information for surface points within said first geographic region;

acquiring location information for each of said plurality of wireless communications nodes;

calculating pathloss information for selected pairs of wireless communications nodes in said plurality of wireless communications nodes using said terrain information and said location information, said pathloss information relating to an expected attenuation for a signal propagating between first and second nodes in each selected pair;

defining a plurality of communications corridors in said first geographic region based on said pathloss information, wherein each of said plurality of communications corridors includes a subset of said plurality of wireless communications nodes; and

selecting at least one of said plurality of communications corridors to provide the optimal communications path between the first wireless communications node and the second wireless communications node.

38. The method, as claimed in claim 37, wherein:

said step of selecting includes choosing a concatenation of successive communications corridors between the first wireless communications node and the second wireless communications node.

39. The method, as claimed in claim 37, wherein:

said step of defining includes finding a first communications corridor consisting of a first group of wireless communications nodes, wherein each node in said first group is capable of communicating with each other node in said first group via a direct wireless link having a pathloss less than a predetermined threshold value.

40. The method, as claimed in claim 37, wherein:

said step of defining is adaptive to changing terrain information and changing location information.

41. The method, as claimed in claim 37, wherein:

said step of obtaining includes receiving digital terrain elevation data (DTED) from a satellite.