Wireless network for sensor array

• US 9,743,370 B2
• Filed: 04/28/2015
• Issued: 08/22/2017
• Est. Priority Date: 04/28/2015
• Status: Expired due to Fees

• Current Assignee: Charles Stark Draper Laboratory Incorporated
• Original Assignee: Charles Stark Draper Laboratory Incorporated
• Inventors: Davis, Almir D., Wilmarth, Roger J., Babcock, IV, Philip S., Khan, Imran
• Primary Examiner(s): Han, Clemence
• Application Number:
  US14/697,831
• Publication Number:
  US 20160323839A1
• Time in Patent Office: 847 Days
• CPC Class Codes: H04L 41/0893 Assignment of logical groups to network elements
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 45/72 Routing based on the source address
• CPC Class Codes: H04W 40/20 based on geographic position or location
• CPC Class Codes: H04W 40/22 using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 8/08 Mobility data transfer
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A linear wireless sensor network includes network nodes having monotonically varying network node identifiers along each branch of the network. The network identifiers enable the nodes to forward network packets without use of routing tables. Low duty cycle wireless communication protocols enable network packets to be routed to all nodes of very large networks while consuming very little electrical power. Broadcast, rather than unicast, transmissions between nodes take advantage of favorable signal propagation conditions to forward messages using largest possible hops, skipping over nodes when possible, as well as automatically adapting to time- or spatially- varying conditions. A group of network packets is broadcast and forwarded by a most distant receiving node that received all packets of the group. A receiving node'"'"'s clock is automatically adjusted, based on which packet(s) of a group of packets was received. A sending node synchronizes near-by receiving nodes. Nodes are provisioned over-the-air, with built-in scheduling. Health and welfare information piggybacks on other network traffic.

Claims

1. In a wireless linear network comprising a first node, a plurality of second nodes proximate the first node and a plurality of additional nodes, all arranged along a branch, wherein each node has a node identifier and the node identifiers monotonically vary along the branch, from one end of the branch to the other end of the branch, a method for routing a plurality of packets from the first node via one of the second nodes, the plurality of packets comprising an initial packet and at least one subsequent packet, the method comprising:

the first node wirelessly sequentially broadcasting each packet of the plurality of packets, wherein each packet is broadcast exactly once and each packet contains;

a sequence number identifying the packet within the plurality of packets; and

an indication of a total number of packets in the plurality of packets;

each second node wirelessly receiving at least one packet of the plurality of packets directly from the first node and, in response, wirelessly transmitting an acknowledgement message to the first node, the acknowledgement message containing the node identifier of the second node and identifying which at least one packet was received by the second node, the plurality of second nodes thereby collectively transmitting a plurality of transmitted acknowledgement messages;

the first node receiving at least one acknowledgement message of the plurality of transmitted acknowledgement messages;

if, according to the at least one acknowledgement message received by the first node, at least one second node received all packets of the plurality of packets;

the first node selecting one second node that received all the packets, such that a difference between the node identifier of the first node and the node identifier of the selected one second node is larger than a difference between the node identifier of the first node and the node identifier of any other second node that received all the packets; and

the first node wirelessly transmitting an instruction message to the selected one second node instructing the selected one second node to forward the plurality of packets;

otherwise, within a predetermined number of make-up attempts;

the first node broadcasting a set of the plurality of packets, such that the set includes packets that were not received by at least one second node.

2. A method according to claim 1, wherein each second node wirelessly transmitting the acknowledgement message to the first node comprises each second node wirelessly transmitting the acknowledgement message to the first node during a time slot assigned to the second node.

3. A method according to claim 1, wherein each second node wirelessly transmitting the acknowledgement message to the first node comprises each second node wirelessly transmitting the acknowledgement message according to a carrier sense multiple access protocol with a collision type selected from the group consisting of collision detection and collision avoidance.

4. A method according to claim 1, wherein the set comprises a union of packets that were not received by at least two second nodes.

5. A method according to claim 1, wherein each second node comprises a clock and a wireless transceiver, the method further comprising each second node:

adjusting the second node'"'"'s clock, based on timing of receipt of the at least one packet of the plurality of packets by the second node; and

using the clock to control when to turn on the second node'"'"'s wireless receiver and when to turn off the wireless receiver.

6. A method according to claim 5 wherein, if the second node did not receive the initial packet, adjusting the clock comprises adjusting the clock such that the second node turns on its wireless receiver earlier in a cycle than previously.

7. A method according to claim 5 wherein, if the second node did not receive all packets of the plurality of packets, adjusting the clock comprises adjusting the clock such that the second node turns on its wireless receiver earlier in a cycle than previously, by an amount that depends at least in part on a number of packets not received by the second node.

8. A method according to claim 5, wherein adjusting the clock comprises adjusting the clock by an amount that depends at least in part on a number of packets not received by the second node.

9. A method according to claim 5, wherein adjusting the clock comprises adjusting the clock by an amount that depends at least in part on an amount of time the receiver was on before the initial packet was received by the second node.

10. A method according to claim 5 wherein, if the second node received the initial packet, adjusting the clock comprises adjusting the clock such that the second node turns on its wireless receiver later in a cycle than previously, by an amount that depends at least in part on an amount of time the receiver was on before the initial packet was received by the second node.