# US 2010/0246445 A1 · Method for Maintaining Links in a Mobile Ad Hoc Network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0246445 A1 - Document ID: US20100246445A1 - Status: Published application - Kind: A1 - Application number: 12/730,864 - Filed: 2010-03-24 - Published: 2010-09-30 - Earliest claimed: 2009-03-30 - Assignees: The Boeing Company - Inventors: David Scarlatti; Roberto Molina; Nicolas Peña Ortiz; Anibal Ollero; Carlos Montes Relanzon - Web page: https://patentgrep.com/patent/US20100246445A1 ## CPC - H04B 7/18508: {with satellite system used as relay, i.e. aeronautical mobile satellite service} - H04B 7/18506: {Communications with or from aircraft, i.e. aeronautical mobile service} - H04B 7/18584: {Arrangements for data networking, i.e. for data packet routing, for congestion control (data switching networks H04L12/00)} - H04L 45/123: {Evaluation of link metrics (techniques for monitoring network metrics H04L43/08)} - H04L 45/28: using route fault recovery - H04W 40/248: {Connectivity information update} - H04W 40/20: based on geographic position or location - H04W 84/06: Airborne or Satellite Networks (space-based or airborne stations H04B7/185) - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract The present disclosure relates to mobile ad hoc networks, and to ad hoc networks using aircraft in particular. A method of maintaining data links to and from a source node in an ad hoc mobile network is provided. The network comprises nodes including neighbour nodes corresponding to nodes within range for direct communication with the source node. The neighbour nodes comprise active neighbour nodes and inactive neighbour nodes, the active neighbour nodes being connected to the source node via respective active data links and the inactive neighbour nodes having respective inactive data links to the source node. One or more lost neighbour nodes are identified and revised configurations of data links are considered that account for the change in neighbour nodes. A new configuration is selected based at least partly on the cost of sending messages from the source node using the revised configurations. ## Claims ### Claim 1 A method of maintaining data links to and from a source node in an ad hoc mobile network, wherein the network comprises nodes including neighbour nodes corresponding to nodes within range for direct communication with the source node, the neighbour nodes comprising active neighbour nodes and inactive neighbour nodes, the active neighbour nodes being connected to the source node via respective active data links and the inactive neighbour nodes having respective inactive data links to the source node, the active and inactive data links forming an existing configuration of data links, the method comprising: (1) identifying one or more lost neighbour nodes corresponding to neighbour nodes of the existing configuration that have moved out of range for direct communication with the source node and/or are about to move out of range for direct communication; (2) determining revised configurations of data links in which any active links to lost neighbour nodes are considered inactive and, for at least one revised configuration, an inactive link is considered active and/or a further active link is considered inactive; (3) determining an overall configuration value for each revised configuration based at least partly on the cost of sending messages from the source node using the revised configuration of data links; (4) selecting a new configuration of data links from the revised configurations according to the overall configuration values determined; and (5) forming the new configuration of data links by breaking data links with neighbour nodes that are active on the existing configuration list but inactive on the new configuration list, and forming data links with any neighbour nodes that are inactive on the existing configuration list and active on the new configuration list. ### Claim 2 (depends on 1) The method of claim 1, further comprising identifying new neighbour nodes that have moved into range for direct communication with the source node or are about to move into range for direct communication, and wherein step (2) includes determining at least one revised configuration in which an active link to a new neighbour node is considered. ### Claim 3 (depends on 1) The method of claim 1, wherein step (2) comprises determining a revised configuration in which any active data links to lost neighbour nodes are considered inactive and no further links are changed from active to inactive or vice versa, and a further revised configuration is determined for each inactive link in which that inactive link is considered active and any active data links to lost neighbour nodes are considered inactive. ### Claim 4 (depends on 1) The method of claim 1, wherein step (2) comprises determining at least one revised configuration in which two or more inactive links are considered to be active. ### Claim 5 (depends on 1) The method of claim 1, wherein step (3) comprises determining the best cost of sending messages from the source node to their respective destination nodes, and attributing points to the overall configuration value in accordance with the best costs. ### Claim 6 (depends on 5) The method of claim 5, wherein step (3) comprises attributing points to the overall configuration value by considering the messages sent by the source node during a prior period. ### Claim 7 (depends on 1) The method of claim 1, wherein if a message cannot be sent from the source node because a required neighbour node is an inactive neighbour node, the method further comprises: (i) determining revised configurations of data links in which an inactive link is considered active and/or an active link is considered inactive; (ii) determining an overall configuration value for each revised configuration based at least partly on the cost of sending messages from the source node using the revised configuration of data links; (iii) selecting a new configuration of data links from the revised configurations according to the overall configuration values determined; and (iv) forming the new configuration of data links by breaking data links with neighbour nodes that are active on the existing configuration list but inactive on the new configuration list, and forming data links with any neighbour nodes that are inactive on the existing configuration list and active on the new configuration list. ### Claim 8 (depends on 7) The method of claim 7, wherein step (i) comprises determining a revised configuration of data links in which the inactive link to the required neighbour node is considered active. ### Claim 9 (depends on 1) The method of claim 1, wherein if a message cannot be sent from the source node because a required neighbour node is an inactive neighbour node, the method further comprises: (a) putting the message into a queue and increasing a queue score; (b) determining when the queue score exceeds a threshold, and when the threshold is exceeded; (c) determining revised configurations of data links in which an inactive link is considered active and/or an active link is considered inactive; (d) determining an overall configuration value for each revised configuration based at least partly on the cost of sending messages from the source node using the revised configuration of data links; (e) selecting a new configuration of data links from the revised configurations according to the overall configuration values determined; and (f) forming the new configuration of data links by breaking data links with neighbour nodes that are active on the existing configuration list but inactive on the new configuration list, and forming data links with any neighbour nodes that are inactive on the existing configuration list and active on the new configuration list. ### Claim 10 (depends on 9) The method of claim 9, further comprising determining whether any of the messages currently stored in the queue may be sent as a required inactive neighbour node is now an active neighbour node according to the new configuration, and sending any such queued messages, and decreasing the queue score whenever a queued message is sent. ### Claim 11 (depends on 1) The method of claim 1, wherein each neighbour node has an associated neighbour node score, the method further comprising assigning points to neighbour node scores according to the traffic that neighbour node sees. ### Claim 12 (depends on 11) The method of claim 11, wherein if a neighbour node score falls below a threshold, the method further comprises: (A) determining revised configurations of data links in which an inactive link is considered active and/or an active link is considered inactive; (B) determining an overall configuration value for each revised configuration based at least partly on the cost of sending messages from the source node using the revised configuration of data links; (C) selecting a new configuration of data links from the revised configurations according to the overall configuration values determined; and (D) forming the new configuration of data links by breaking data links with neighbour nodes that are active on the existing configuration list but inactive on the new configuration list, and forming data links with any neighbour nodes that are inactive on the existing configuration list and active on the new configuration list. ### Claim 13 (depends on 11) The method of claim 11, further comprising assigning points to the neighbour node scores for each message sent according to the cost of sending that message through that neighbour node.