Persistent mesh for isolated mobile and temporal networking

• US 8,520,691 B2
• Filed: 01/29/2010
• Issued: 08/27/2013
• Est. Priority Date: 05/08/2003
• Status: Active Grant

• Current Assignee: Dynamic MESH Networks Incorporated
• Original Assignee: Mesh Dynamics Incorporated
• Inventors: daCosta, Francis, Dayanandan, Sriram
• Primary Examiner(s): Rinehart, Mark
• Assistant Examiner(s): Cheng, Peter
• Application Number:
  US12/696,947
• Publication Number:
  US 20100177703A1
• Time in Patent Office: 1,306 Days
• Field of Search: 370254- 6, 370/328, 370/338, 370/408
• US Class Current: 370/408
• CPC Class Codes: H04L 12/2858 Access network architectures
• CPC Class Codes: H04L 12/46 Interconnection of networks
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04W 40/24 Connectivity information management, e.g. connectivity discovery or connectivity update
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 40/248 Connectivity information update
• CPC Class Codes: H04W 40/32 for defining a routing cluster membership
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals
• CPC Class Codes: H04W 84/005 Moving wireless networks
• CPC Class Codes: H04W 84/02 Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
• CPC Class Codes: H04W 84/10 Small scale networks; Flat hierarchical networks
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements
• CPC Class Codes: H04W 84/22 with access to wired networks
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user
• CPC Class Codes: H04W 92/04 Interfaces between hierarchically different network devices
• CPC Class Codes: H04W 92/045 between access point and backbone network device

Abstract

A structured wireless mesh network is disclosed where a tree-like connection topology is formed. In one embodiment, each node has separate uplink and downlink radios operating on different channels. When a cluster of such nodes becomes isolated as in the case of a mobile mesh application, a node in the cluster according to this invention acts as a root node thus enabling the tree structure to persist, even in isolation. Example methods of joining sub networks are disclosed that guide the joining of mesh networks and channel management. Nodes that may operate in isolation also support a distributed DHCP capability such that IP addresses are assigned to clients even when a connection to a central DHCP server is unavailable.

Claims

1. A structured mesh network capable of isolated operation, comprising:

at least two structured mesh nodes;

wherein each structured mesh node comprises at least a connectivity logic;

an uplink radio operating on an uplink frequency and a downlink radio operating on a distinct downlink frequency;

wherein the connectivity logic determines whether each structured mesh node connects with an external network or another node using its uplink radio and client devices or other mesh nodes connect to each node using each node'"'"'s downlink radio;

wherein the structured mesh network functions in two configurations selected depending on whether a connection to an external network is present;

in the first connected configuration the structured mesh network includes at least one structured mesh node'"'"'s uplink radio comprising a connection to an external network; and

in the second isolated configuration none of the structured mesh nodes'"'"' uplink radio comprises a connection to an external network, and one of the structured mesh nodes acts as an isolated network root of the isolated configuration and all remaining nodes connect to the isolated network root node as isolated root children nodes forming a tree configuration;

wherein clients of nodes of the structured network in a second isolated configuration retain full connectivity within the structured network during the isolated configuration and wherein said client connectivity is uninterrupted during any transition from the isolated configuration to the first connected configuration;

wherein distinct downlink frequencies are used by nodes for communication with one or more nodes lower on the tree configuration.

2. The structured mesh network of claim 1 wherein the connectivity logic contained by the nodes realigns connections between the nodes upon loss of an external connection to form the isolated configuration.

3. The structured mesh network of claim 2 wherein the connectivity logic contained by the nodes designates the node which in the first configuration connected to the external network as the isolated configuration root node.

4. The structured mesh network of claim 2 wherein the connectivity logic contained by the nodes designates the node which in the first configuration passed the most traffic as the isolated configuration root node.

5. The structured mesh network of claim 2 wherein the connectivity logic contained by the nodes selects the isolated configuration root node such that the resulting network'"'"'s traffic traverses a minimal number of nodes.

6. The structured mesh network of claim 2 wherein the connectivity logic contained by the nodes selects the isolated configuration root node such that the isolated configuration root node is the most proximate to an external network connection point.

7. The structured mesh network of claim 2 wherein the connectivity logic contained by the nodes selects the isolated configuration root node such that the resulting network'"'"'s throughput is maximized.

8. The structured mesh network of claim 2 wherein the connectivity logic contained by the nodes selects the isolated configuration root node such that the resulting network'"'"'s latency is minimized.

9. The structured mesh network of claim 1 wherein the connectivity logic contained by the nodes realigns connections between the nodes upon detection of an external network connection to form the connected configuration.

10. The structured mesh network of claim 9 wherein solely the isolated network root node logic searches for the external network connection and establishes the external network connection.

11. The structured mesh network of claim 10 wherein the previously unused uplink radio of the isolated network root node is used to connect to the external network.

12. The structured mesh network of claim 1 wherein a first mesh network in the isolated configuration comprises an isolated root node and one or more isolated children nodes and a second mesh network in the isolated configuration comprises and isolated root node and at least one or more isolated children nodes and at least one child node of the first network establishes communication with a child node of the second network, thereby triggering a realignment due to joining in both networks.

13. The structured mesh network of claim 12 wherein as part of the realignment due to joining one of the isolated root nodes becomes an isolated network child node wherein the isolated root node of the smaller of the two networks becomes the child node.

14. The structured mesh network of claim 12 wherein as part of the realignment due to joining one of the isolated root nodes becomes an isolated network child node wherein the selection of the new isolated root node is made on the basis of physical position and direction of travel of the two networks.

15. The structured mesh network of claim 1 wherein a first mesh network in the isolated configuration comprises an isolated root node and one or more isolated children nodes and a second mesh network in the isolated configuration comprises an isolated root node and at least one or more isolated children nodes and the root node of the first network establishes communication with a child node of the second network, thereby the root node of the first network becomes a child node of the second network.

16. The structured mesh network of claim 15 wherein the unused uplink radio on the root node of the first network is used to connect to the child node of the second network.

17. The structured mesh network of claim 16 wherein solely the root node of the first network is able to connect to a child of the second network.

18. The structured mesh network of claim 1 wherein each network node further comprises a DHCP server used to assign addresses to client devices communicating with the node using the node'"'"'s downlink radio.

19. The structured mesh network of claim 18 wherein the DHCP server within each node assigns IP addresses to client devices containing one or more random numbers within the IP addresses.

20. A multi-part mesh network comprising:

a first mesh network and a second mesh network wherein each mesh network comprises;

a) at least two structured mesh nodes;

wherein each structured mesh node comprises at least a connectivity logic;

an uplink radio operating on an uplink frequency and a distinct downlink radio operating on a downlink frequency;

wherein the connectivity logic determines whether each structured mesh node connects with an external network or another node using its uplink radio and client devices or other mesh nodes connect to each node using each node'"'"'s downlink radio;

wherein the structured mesh network functions in two configurations selected depending on whether a connection to an external network is present;

b) in the first connected configuration the structured mesh network includes at least one structured mesh node'"'"'s uplink radio comprises a connection to an external network; and

c) in the second isolated configuration none of the structured mesh nodes'"'"' uplink radio comprises a connection to an external network, and one of the structured mesh nodes acts as an isolated network root of the isolated configuration and all remaining nodes'"'"' connect to the isolated network root node as isolated root children nodes forming a tree configuration;

wherein a first set of frequencies, the first network frequencies, is used by the first network for communications between the nodes of the first network;

a second set of frequencies, the common frequencies, is used for communications between the two networks; and

a third set of frequencies, the second network frequencies, is used for communications between the nodes of the second network;

wherein each network is in the isolated configuration; and

wherein initially no communication between the first network and the second network is occurring;

wherein clients of nodes of each network in the multi-part mesh network in the isolated configuration retain full connectivity within the network and wherein distinct downlink frequencies are used by nodes for communication with one or more nodes lower on the tree configuration.

21. The multi-part mesh network of claim 20 wherein the first set of frequencies and the third set of frequencies are mutually exclusive.

22. The multi-part mesh network of claim 20 wherein upon establishment of new communication between a child node of the first network and a child node of the second network the isolated root node of either the first network or the second network becomes the root node of a resulting multi-part network.

23. The multi-part mesh network of claim 22 wherein the connectivity logic of the root node of the root of the first network and the connectivity logic of the root of the second network select of the root node of the resulting multi-part network pursuant to a policy directive.

24. The multi-part mesh network of claim 23 wherein the policy directive is based on the relative sizes of each network.

25. The multi-part mesh network of claim 23 wherein the policy directive comprises a weighing of the direction of travel of each network and the position of each network.

26. The multi-part mesh network of claim 23 wherein the policy directive comprises minimizing the latency of the resulting multi-part mesh network or maximizing the throughput of the multi-part network.

27. The multi-part mesh network of claim 20 wherein upon establishment of new communication between the root node of the first network and a child node of the second network the isolated root node of the first network becomes a child node of the second network.

28. The multi-part mesh network of claim 27 wherein the unused uplink of the first network root node is used to communicate with the child node of the second network.

29. The multi-part mesh network of claim 28 wherein solely the root node of the first network may connect to a node of the second network.

30. The multi-part mesh network of claim 20 wherein each network comprises one or more leaf nodes wherein leaf nodes are child nodes to which no other node communicates with using the leaf node'"'"'s downlink radio, and the leaf nodes only attempt to connect using the common frequencies.

31. The multi-part mesh network of claim 20 wherein the uplink radios of the root nodes of each network attempt to connect solely using the common frequencies.

32. The structured mesh network of claim 20 wherein each network node further comprises a DHCP server used to assign addresses to client devices communicating with the node using the node'"'"'s downlink radio.

33. The structured mesh network of claim 32 wherein the DHCP server within each node assigns IP addresses to client devices containing one or more random numbers within the IP addresses.

34. The structured mesh network of claim 33 wherein said uplink and downlink frequencies are the same frequency.

35. A structured mesh network capable of isolated operation, comprising:

at least two structured mesh nodes;

wherein each structured mesh node comprises at least a connectivity logic and a radio operating on an uplink frequency and a distinct downlink frequency;

wherein the connectivity logic determines whether each structured mesh node connects with an external network or another node on the uplink frequency and client devices or other mesh nodes connect to each node on the downlink frequency;

wherein the connectivity logic in each node contains a distributed routing table;

wherein the structured mesh network functions in two configurations selected depending on whether a connection to an external network is present;

in the first connected configuration the structured mesh network includes at least one structured mesh node'"'"'s uplink connection comprising a connection to an external network; and

in the second isolated configuration none of the structured mesh nodes'"'"' uplink connections comprises a connection to an external network, and one of the structured mesh nodes acts as an isolated network root of the isolated configuration and all remaining nodes connect to the isolated network root node as isolated root children and descendant nodes forming a tree configuration;

wherein clients of the at least two structured mesh nodes in a second isolated configuration retain full connectivity within the structured network during the isolated configuration and wherein said client connectivity is uninterrupted during any transition from the isolated configuration to the first connected configuration;

wherein distinct downlink frequencies are used by nodes for communication with one or more nodes lower on the tree configuration.