Method for automatic signal routing in ad hoc networks

• US 8,089,887 B2
• Filed: 11/19/2002
• Issued: 01/03/2012
• Est. Priority Date: 11/19/2002
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Lippman, Andrew Benjamin, Reed, David P., Bletsas, Aggelos
• Primary Examiner(s): Wong, Warner
• Application Number:
  US10/299,973
• Publication Number:
  US 20040095920A1
• Time in Patent Office: 3,332 Days
• Field of Search: None
• US Class Current: 370/246
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04W 40/02 Communication route or path selection, e.g. power-based or shortest path routing
• CPC Class Codes: H04W 40/08 based on transmission power
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and system provide routing of signals through a communications network. A transmitted signal is received. The signal has an associated parameter that is monitored as the signal is received. The parameter indicates the extent to which prior retransmission of the signal has occurred. The signal is retransmitted only if its parameter satisfies at least one predetermined criterion.

Claims

1. A method for routing signals through a communications network, the method comprising:

receiving a signal at an intermediate node;

monitoring, at the intermediate node, a parameter derived from the signal domain and measured by examination of an initial portion of the received signal, the parameter being characteristic of the energetic or physical makeup of the received signal and indicating an extent of prior retransmission of the signal; and

forwarding the received signal from the intermediate node to a second node or a destination receiver only if the intermediate node is a member of a predefined communications pathway between the received signal'"'"'s origination and destination nodes and the parameter associated with the signal satisfies at least one predetermined criterion, the predetermined criterion being selected to ensure that the received signal will only be forwarded if forwarding the signal will enhance reception and decoding of the signal at the destination receiver.

2. The method of claim 1, wherein the signal is associated with one of an analog communication and a digital communication.

3. The method of claim 1, wherein the parameter comprises at least one of an amplitude, a phase, and a time delay of the signal.

4. The method of claim 1, wherein the parameter comprises a phase of the signal, and the at least one predetermined criterion comprises a predetermined maximum phase shift.

5. The method of claim 1, wherein the signal comprises a plurality of pulses each having an amplitude and a duration.

6. The method of claim 5, wherein the parameter is associated with a shape of an edge of a pulse of the plurality of pulses.

7. The method of claim 5, wherein the parameter is associated with a width of the edge.

8. The method of claim 5, further comprising causing selection of a pulse duration that is greater than a preselected maximum permissible pulse time delay.

9. The method of claim 5, wherein the step of forwarding comprises beginning retransmission of a pulse of the plurality of pulses prior to completion of receiving the pulse.

10. The method of claim 1 wherein the step of forwarding further comprises forwarding the signal with a power level sufficient only for reception of the forwarded signal by neighboring nodes within a selected range.

11. The method of claim 1, wherein receiving comprises receiving the signal from more than one location, and the step of forwarding comprises forwarding the signal to more than one location.

12. The method of claim 11, wherein each one of the locations is one of a node and a reflection site.

13. The method of claim 5, wherein the at least one predetermined criterion comprises a threshold time delay, and the parameter comprises a pulse time delay, and the step of forwarding comprises forwarding a pulse of the plurality of pulses if the pulse time delay does not exceed the threshold time delay.

14. The method of claim 5, wherein the parameter comprises a pulse time delay relative to a reference time, and the at least one predetermined criterion comprises a preselected maximum acceptable pulse time delay.

15. The method of claim 5, wherein the parameter is associated with a number of times a pulse of the plurality of pulses has been relayed.

16. The method of claim 5, wherein a pulse of the plurality of pulses arises from a combination of pulses received from a plurality of locations.

17. The method of claim 1, wherein the step of forwarding comprises forwarding the signal via a frequency that is different than a frequency of the received signal.

18. The method of claim 1 wherein the signal consists of one of a radio signal, a light signal and an electrical signal.

19. The method of claim 1, wherein the step of forwarding comprises forwarding the signal while ceasing reception of a second signal having a frequency effectively the same as a frequency of retransmission.

20. The method of claim 1, further comprising receiving a plurality of signals, and repeating the step of forwarding the signal for each of the plurality of signals.

21. The method of claim 1, wherein the signal comprises a plurality of sub-signals that each are associated with a different frequency within a band of frequencies.

22. The method of claim 1, wherein the transmitted signal is associated with at least one message.

23. A communications network node configured to implement the method of claim 1.

27. The method of claim 1, wherein the parameter comprises a duration of signal edge distortion or an abrupt pulse amplitude or phase change.

24. A system for signal routing, comprising:

a receiver for receiving a signal at an intermediate node;

at least one monitor for monitoring, at the intermediate node, a parameter derived from the signal domain and measured by examination of an initial portion of the signal, the parameter being characteristic of the energetic or physical makeup of the received signal and indicating an extent of prior retransmission; and

a transmitter for forwarding a signal from the intermediate node to a second node or a destination receiver only if the intermediate node is a member of a predefined communications pathway between the received signal'"'"'s origination and destination nodes and the parameter associated with the signal satisfies at least one predetermined criterion, the predetermined criterion being selected to ensure that the received signal will only be forwarded if forwarding the signal will enhance reception and decoding of the signal at the destination receiver.

25. The system of claim 24, wherein the receiver, the monitor and the transmitter are components of a network node.

26. The system of claim 24, further comprising a processor for comparing the parameter to the predetermined criterion.