Ascertaining presence in wireless networks

• US 8,699,381 B2
• Filed: 09/14/2012
• Issued: 04/15/2014
• Est. Priority Date: 01/28/2009
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Koop, Lamonte Peter, Payne, Edward Allen
• Primary Examiner(s): Phillips, Hassan
• Assistant Examiner(s): CATTUNGAL, AJAY P
• Application Number:
  US13/620,309
• Publication Number:
  US 20130070676A1
• Time in Patent Office: 578 Days
• Field of Search: 370/228, 370/229, 370/252, 370/254, 370/310, 370/312, 370/315, 370/338, 370/329, 370/400, 709227-230, 709/238, 709/242, 709/202
• US Class Current: 370/254
• CPC Class Codes: H04L 45/122 by minimising distances, e.g. by selecting a route with minimum of number of hops
• CPC Class Codes: H04L 45/124 using a combination of metrics
• CPC Class Codes: H04L 45/20 Hop count for routing purposes, e.g. TTL
• CPC Class Codes: H04L 45/54 Organization of routing tables
• 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

Abstract

One of many aspects of the invention relates to an ad hoc network in which inbound messages are communicated from an originating node to a gateway node via a plurality of intermediate nodes. In this respect, a method performed by an intermediate node in communicating the inbound message to the gateway node includes: maintaining a routing table; and using the routing table, selecting a node for use as the next hop by determining whether a maximum number of allowable hops for an inbound message is exceeded by using such node, and comparing a preference of using such node to preferences of using other known nodes by which the maximum number of allowable hops would not be exceeded. Another aspect includes sending a “leave” message when an intermediate node leaves the ad hoc network, whereby the intermediate node is removed from similar routing tables maintained by other intermediate nodes.

Claims

1. In an ad hoc network in which inbound messages are communicated from an originating node to a gateway node via a plurality of intermediate nodes, a method performed by an intermediate node in communicating an inbound message to a gateway node, comprising the steps of:

maintaining, at a first node of the plurality of intermediate nodes, a routing table including a set of known intermediate nodes for use as a next hop towards a gateway node, the routing table comprising, for each known intermediate node, fields including,

a next hop address, representing a unique address of the respective intermediate node,

a next hop hopcount, representing a hop count to a gateway node, and

a next hop qualifier, representing a preference for using the respective known intermediate node as a next hop towards a gateway node relative to other nodes that may be used as a next hop towards a gateway node;

receiving, at the first node, an inbound message for communication to a gateway node;

selecting, at the first node, a node for use as the next hop towards a gateway node for communicating the inbound message to a gateway node by,

determining, for two or more known intermediate nodes maintained in the routing table, whether a sum of the next hop hopcount maintained in the routing table for the respective known intermediate node and a current hopcount of the inbound message exceeds a maximum number of allowable hops for the inbound message, and

comparing next hop qualifiers maintained in the routing table for two or more known intermediate nodes for which the maximum number of allowable hops for an inbound message is not exceeded;

communicating, by the first node, the inbound message to the node identified by the next hop address for which the next hop qualifier is determined to be preferred based on said comparison;

receiving, at the first node, an acknowledgment from the known intermediate node the inbound message was communicated to; and

updating, at the first node based at least partially on information contained in the received acknowledgment, the next hop qualifier maintained in the routing table for the known intermediate node the acknowledgment was received from.

2. The method of claim 1, wherein the gateway node maintains pathways among the nodes based on the messages received from each of the other nodes.

3. The method of claim 1, wherein the next hop qualifier is determined, at least in part, based on transmission failure counts of the node to which the next hop qualifier pertains.

4. The method of claim 1, wherein the next hop qualifier is determined, at least in part, based on signal strength of the node to which the next hop qualifier pertains.

5. The method of claim 1, wherein the next hop qualifier represents both efficiency and success probability associated with using the node to which the next hop qualifier pertains as the next hop towards the gateway node for communicating the inbound message.

6. The method of claim 1, wherein an intermediate node does not maintain a routing table of entire pathways from the originating node to the gateway node.

7. The method of claim 1, further comprising transmitting a message for receipt by each hop address in the table when the intermediate node leaves the ad hoc network.

8. The method of claim 1, further comprising transmitting a leaving message for receipt by nodes corresponding to each next hop address in the table when the intermediate node leaves the ad hoc network.

9. The method of claim 1, wherein the ad hoc network comprises a class-based network.

10. The method of claim 9, wherein the set of one or more rows is associated with a first class, and wherein a second set of one or more rows is associated with a second class.

11. In an ad hoc network in which inbound messages are communicated from an originating node to a gateway node via a plurality of intermediate nodes, a method performed by an intermediate node in communicating an inbound message to a gateway node, comprising the steps of:

maintaining, at a first node of the plurality of intermediate nodes, a routing table including a set of known intermediate nodes for use as a next hop towards a gateway node, the routing table comprising, for each known intermediate node, fields including,

a next hop address, representing a unique address of the respective intermediate node,

a next hop hopcount, representing a hop count to a gateway node, and

a next hop qualifier, representing a preference for using the respective known intermediate node as a next hop towards a gateway node relative to other nodes that may be used as a next hop towards a gateway node;

receiving, at the first node, an inbound message for communication to a gateway node;

selecting, at the first node, a node for use as the next hop towards a gateway node for communicating the inbound message to a gateway node by,

determining, for two or more known intermediate nodes maintained in the routing table, whether a sum of the next hop hopcount maintained in the routing table for the respective known intermediate node and a current hopcount of the inbound message exceeds a maximum number of allowable hops for the inbound message, and

comparing next hop qualifiers maintained in the routing table for two or more known intermediate nodes for which the maximum number of allowable hops for an inbound message is not exceeded; and

communicating, by the first node, the inbound message to the node identified by the next hop address for which the next hop qualifier is determined to be preferred based on said comparison.

12. The method of claim 11, wherein the gateway node maintains pathways among the nodes based on the messages received from each of the other nodes.

13. The method of claim 11, wherein the next hop qualifier is determined, at least in part, based on transmission failure counts of the node to which the next hop qualifier pertains.

14. The method of claim 11, wherein the next hop qualifier is determined, at least in part, based on signal strength of the node to which the next hop qualifier pertains.

15. The method of claim 11, wherein the next hop qualifier represents both efficiency and success probability associated with using the node to which the next hop qualifier pertains as the next hop towards the gateway node for communicating the inbound message.

16. The method of claim 11, wherein an intermediate node does not maintain a routing table of entire pathways from the originating node to the gateway node.

17. The method of claim 11, further comprising transmitting a message for receipt by each hop address in the table when the intermediate node leaves the ad hoc network.

18. The method of claim 11, wherein the ad hoc network comprises a class-based network.

19. The method of claim 18, wherein the set of one or more rows is associated with a first class, and wherein a second set of one or more rows is associated with a second class.

20. In an ad hoc network in which inbound messages are communicated from an originating node to a gateway node via a plurality of intermediate nodes, a method performed by an intermediate node in communicating the inbound message to the gateway node, comprising the steps of:

maintaining a routing table including a set of one or more rows, wherein each row of the set comprises fields including,

a next hop address, representing a unique address of a node,

a next hop hopcount, representing a hop count to the gateway, and

a next hop qualifier, representing a preference to using a node as a next hop towards a gateway node relative to other nodes that may be used as a next hop towards a gateway node,

all fields of the row pertaining to a known intermediate node for use as a next hop towards the gateway node;

selecting a node for use as the next hop towards the gateway node for communicating the inbound message to the gateway node by,

determining whether a sum of the next hop hopcount from a row and a current hopcount of the inbound message exceeds a maximum number of allowable hops for an inbound message, and

comparing a next hop qualifier of a row to a next hop qualifier of another row, wherein, for both rows, the maximum number of allowable hops for an inbound message is not exceeded; and

wherein the ad hoc network comprises a class-based network; and

wherein each row of the routing table is associated with a class.