Systems and methods for energy-conscious communication in wireless ad-hoc networks

• US 20080049620A1
• Filed: 08/24/2007
• Published: 02/28/2008
• Est. Priority Date: 08/25/2006
• Status: Active Grant

• Current Assignee: Raytheon BBN Technologies Corp. (Rtx Corporation)
• Original Assignee: BBN Technologies (Rtx Corporation)
• Inventors: Redi, Jason, Medina, Alberto, Matta, Abraham, Castineyra, Isidro, Partridge, Craig, Riga, Niky
• Granted Patent: US 7,924,728 B2
• Time in Patent Office: Days
• US Class Current: 370/236
• CPC Class Codes: G01D 21/00 Measuring or testing not otherwise provided for
• CPC Class Codes: G01D 9/005 Solid-state data loggers
• CPC Class Codes: H04J 3/0652 Synchronisation among time division multiple access [TDMA] nodes, e.g. time triggered protocol [TTP] bus network with centralized control in which slots are of a TDMA packet structure H04L12/4035
• CPC Class Codes: H04J 3/0679 by determining clock distribution path in a network
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04W 40/10 based on available power or energy
• CPC Class Codes: H04W 40/12 based on transmission quality or channel quality
• CPC Class Codes: H04W 56/003 Arrangements to increase tolerance to errors in transmission or reception timing
• CPC Class Codes: H04W 56/004 compensating for timing error of reception due to propagation delay

Abstract

The invention relates to a transport protocol and associated methods and stack architectures for improving the energy efficiency of transmitting packets through an ad hoc network. The protocol controls transmissions by taking into account per-packet energy limits, per-node loss tolerances, and/or minimum availability rates determined based on path quality measurements collected by packets traversing the network and application reliability requirements associated with various applications.

Claims

1. A method of setting at least one transmission parameter at a first node based on information transmitted from a second node in an ad hoc network, comprising:

transmitting a plurality of packets from the first node to the second node along a path;

collecting path quality measurements in each respective packet of the plurality of packets as the packets travel along the path;

aggregating the path quality measurements at the second node;

adjusting, by the second node, a feedback schedule based on the aggregated path quality measurements;

setting a transmission parameter for the first node at the second node based on the aggregated path quality measurements; and

transmitting a feedback message to the first node including the transmission parameter according to the adjusted schedule.

2. The method of claim 1, wherein according to the feedback schedule, the first node periodically transmits a feedback signal from the second node to the first node regardless of changes in the path.

3. The method of claim 1, wherein the first node adheres to a periodic feedback schedule, and wherein adjusting the feedback schedule comprises:

determining by the second node if a significant and persistent change in the connection path has occurred based on the aggregated path quality measurements;

in response to a determination that a significant and persistent change has occurred, transmitting a feedback message from the second node to the first node notifying the first node of the change before the end of a current feedback schedule period.

4. The method of claim 1, wherein the path quality measurements include an end-to-end per-packet transmission energy associated with the connection path and a minimum available rate over a plurality of links in the connection path.

5. The method of claim 3, wherein the significant and persistent change in the connection path is detected using a flip-flop filter.

6. The method of claim 1, wherein setting a transmission parameter comprises adjusting a per-packet energy budget based on an aggregated path energy expenditure included in the first signal, wherein the aggregated path energy expenditure in the first signal is determined by the second node based on the aggregated path quality measurements.

7. The method of claim 4, wherein setting a transmission parameter comprises setting a sending data rate based on a minimum available rate measured over a plurality of links in the connection path.

8. The method of claim 1, wherein the transmission parameter is initially set based at least in part on path quality measurements collected during the transmission of a connection establishment message.

9. The method of claim 1, wherein the transmission parameter is set based at least in part on a delivery reliability requirement of an application corresponding to the packet.

10. The method of claim 1, further comprising transmitting by the first node another packet based on the set transmission parameter.

11. The method of claim 1, wherein each packet collects the path quality measurements by storing data in a header portion of the packet.

12. A method of forwarding a packet, comprising:

receiving at a node a packet having a per-node loss tolerance;

forwarding the packet to the next hop node;

determining whether the packet failed to reach its destination;

in response to determining that the packet failed to reach its destination, determining whether to retransmit the packet based on the per-node loss tolerance; and

in response to determining to retransmit the packet, retransmitting the packet.

13. The method of claim 12, further comprising storing the packet in a cache of the node.

14. The method of claim 13, wherein the memory cache comprises an array of packet lists and a hash function for mapping the packet to a cache slot associated with an element of the array.

15. The method of claim 12, comprising determining that the next hop node is non-responsive, and in response, transmitting the packet to a second next hop from the node.

16. The method of claim 12, wherein the determination as to whether to retransmit the packet is further based on a per-packet energy budget.

17. A stack architecture, comprising:

a first interface between a transport layer and an application layer, wherein the first interface maps data from an application of the application layer and a packet of the transport layer; and

a second interface between the transport layer and at least one of a data link layer and a physical layer, bypassing at least one intervening stack layer, for providing the transport layer information about at least one of transmission energy requirements and link characteristics.

18. The stack architecture of claim 17, comprising a third interface, between the transport layer and the network layer, wherein the transport layer is adapted to forward the packet to a destination node using a path management module of the network layer and influence at least one transmission parameter of the packet using a forwarding module of the network layer.

19. The stack architecture of claim 17, wherein the second interface is between the transport layer and the data-link layer, wherein the transport layer is adapted to instruct the data-link layer to transmit the packet according to a number of transmission attempts computed based on a per-node loss tolerance parameter associated with the packet.

20. The stack architecture of claim 19, wherein the transport layer is further adapted to obtain, via the second interface, characteristic information regarding at least one of a link and a node from a neighbor discovery module of the data-link layer.

21. The stack architecture of claim 20, wherein the characteristic information includes path loss and a path loss rate.

22. A transport protocol of an ad-hoc network, comprising:

at least one module implemented on intermediate nodes of the network configured to;

forward received packets having a per-node loss tolerance,

limit retransmissions of the received packets failing to reach their destination according to the per-node loss tolerance of the respective packets, and

update forwarded packets to reflect an amount of energy expended by the respective intermediate node in forwarding the respective packets; and

at least one module implemented on end nodes of the network configured to;

set per-node loss tolerances for transmitted packets based on reliability requirements of an application associated with the respective transmitted packets, and

transmit path characteristic messages to other end nodes of the network indicating characteristics of paths through the network derived from data obtained from headers of packets received from the respective other end nodes.

23. The transport protocol of claim 22, wherein the path characteristic messages include a transmission sending rate for another node to use in transmitting packets to the end node transmitting the path characteristic message based on availability data aggregated in headers of packets received by the end node.

24. The transport protocol of claim 22, wherein the at least one module implemented on intermediate nodes is configured to limit retransmissions of the received packets failing to reach their destination according to per-packet energy budgets of the respective packets.

25. The transport protocol of claim 22, wherein the at least one module implemented on intermediate nodes is configured to update per-node loss tolerances of respective packets.

26. The transport protocol of claim 22, wherein the at least one module implemented on end nodes of the network is configured to set the per-node loss tolerances of respective packets based on reliability requirements of applications associated with respective packets.

27. The transport protocol of claim 22, wherein the at least one module implemented on intermediate nodes is configured to cache a received packet until receipt of the packet by a destination nodes is acknowledged, the energy budget for the packet is expended, or a cache replacement policy implemented on the intermediate node requires the packets deletion from the cache to make room for other received packets.