System and method for relaying turbo-coded piggyback messages

• US 20080144665A1
• Filed: 12/19/2006
• Published: 06/19/2008
• Est. Priority Date: 12/19/2006
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Ross, John Anderson Fergus, Hershey, John Erik, Van Stralen, Nick Andrew
• Granted Patent: US 7,885,289 B2
• Time in Patent Office: Days
• US Class Current: 370/477
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 27/3488 Multiresolution systems

Abstract

Systems and/or methods for relaying messages between nodes in a network (e.g. a wireless network) are provided. In accordance with certain exemplary embodiments, substantially simultaneous communications between nodes may be accomplished. At least one secondary turbo-coded message may be piggybacked onto a turbo-coded primary message. Messages in the network may be queued and sent from a transmitter to at least one receiver based at least in part on the signal-to-noise ratio(s) of the receiver nodes with respect to the transmitter. Thus, it may be possible to realize a network that reduces collision problems, reduces delays in communications, and/or increases throughput.

Claims

1. A method of communicating a message between nodes, the method comprising:

identifying a primary message and at least one secondary message to be communicated from a transmitter, the primary message being designated for a first receiver node and the at least one secondary message being designated for a second receiver node;

turbo-coding the primary message to form a turbo-coded primary message;

turbo-coding each secondary message to form a turbo-coded secondary message; and

,

piggybacking the at least one turbo-coded secondary message onto the turbo-coded primary message to form a turbo-coded piggybacked message in response to a signal indicating that piggybacking of the at least one turbo-coded secondary message onto the turbo-coded primary message is possible, the signal being based at least in part on a characteristic of the first receiver node and the second receiver node relative to the transmitter node.

2. The method of claim 1, further comprising:

when the signal indicates that piggybacking is possible, transmitting the turbo-coded piggybacked message; and

,

when the signal indicates that piggybacking is not possible, transmitting the turbo-coded primary message and/or the at least one turbo-coded secondary message.

3. The method of claim 1, further comprising maintaining a list storing the characteristic corresponding to each link between the nodes.

4. The method of claim 3, wherein the list is static.

5. The method of claim 3, wherein the list is maintained based on feedback between the nodes.

6. The method of claim 3, wherein the signal is further based on the list.

7. The method of claim 1, wherein the characteristic of the first receiver node is SNR relative to the transmitter node, and the characteristic of the second receiver node is SNR relative to the transmitter node.

8. The method of claim 1, wherein the step of piggybacking is further practiced by:

scaling the at least one turbo-coded secondary message by a scale factor to form a scaled message; and

,

summing the turbo-coded primary message and the scaled message.

9. The method of claim 8, further comprising determining the scale factor based at least in part on a SNR of the first receiver node relative to the transmitter node and a SNR of the second receiver node relative to the transmitter node.

10. The method of claim 1, wherein the step of identifying a primary message and at least one secondary message further comprises searching a message queue for a most-forward packet capable of piggybacking and/or being piggybacked.

11. A method of communicating a message between nodes, the method comprising:

identifying a transmitter node and at least two receiver nodes;

identifying a primary message and at least one secondary message to be transmitted from the transmitter node, each message being stored in a message queue, and each message including packets of data;

determining a next packet of the primary message to be transmitted;

turbo-coding the primary message to form a turbo-coded primary message;

turbo-coding each secondary message to form a turbo-coded secondary message;

identifying possible partner links between nodes that are capable of supporting piggybacking for the next packet; and

,

generating a full message by piggybacking a packet of each of turbo-coded secondary message onto the next packet of the turbo-coded primary message in response to a signal indicating that piggybacking is possible,

wherein the signal is based at least in part on relative signal-to-noise ratios of the at least two receiver nodes with respect to the transmitter node.

12. The method of claim 11, further comprising:

when piggybacking is possible, transmitting the full message; and

,

when piggybacking is not possible, transmitting the turbo-coded primary message and/or the at least one turbo-coded secondary message.

13. The method of claim 11, wherein the step of piggybacking a packet of each turbo-coded secondary message onto the next packet of the turbo-coded primary message further comprises:

for each turbo-coded secondary message, identifying a piggyback packet by searching the message queue for the most forward secondary packet that uses a partner link;

scaling each piggyback packet according to link signal-to-noise ratio; and

,

combining the next packet and each piggyback packet.

14. The method of claim 13, wherein the scaling is based at least in part on the signal-to-noise ratios of the receivers relative to the transmitter.

15. The method of claim 11, further comprising estimating a link signal-to-noise ratio for each link between nodes.

16. A system for relaying a message through a network of nodes comprising:

a transmitter node and at least two receiver nodes, each having a turbo-code encoder and a turbo-code decoder associated therewith, and each of the transmitter node and the at least two receiver nodes being configured to communicate at least a primary message and at least one secondary message therebetween,

wherein the primary message and the at least one secondary message are turbo-code encoded and sent from the transmitter node to the at least two receiver nodes based at least in part on a comparison of signal-to-noise ratios of the at least two receiver nodes relative to the transmitter node, and

wherein the primary message and the at least one secondary message are piggybacked based at least in part on the comparison.

17. The system of claim 16, further comprising a message queue associated with a node operable to store messages to be communicated.

18. The system of claim 17, further comprising a list of SNRs for each link between nodes in the network.

19. The system of claim 18, wherein the nodes are operable to update the list.

20. The system of claim 18, further comprising a list including comparisons for each link between nodes in the network.

21. The system of claim 16, wherein each node comprises a piggybacking mechanism, the piggybacking mechanism including:

a scaler operable to scale the at least one turbo-coded secondary message to form a scaled message; and

,

a summer operable to sum the scaled message and the turbo-coded primary message.

22. The system of claim 17, wherein the message queue is operable to output a most-forward packet capable of piggybacking and/or being piggybacked.

23. The system of claim 16, wherein the turbo-coded primary message and the at least one turbo-coded secondary message are piggybacked if the comparison indicates a substantial SNR ratio for the at least two receiver nodes relative to the transmitter node.

24. The system of claim 23, wherein the substantial SNR ratio is 100:

1.

25. A system for relaying a message through a network of nodes comprising:

means for identifying a primary message and at least one secondary message to be communicated from a transmitter, the primary message being designated for a first receiver node and the at least one secondary message being designated for a second receiver node;

means for encoding the primary message to produce an encoded primary message;

means for encoding each secondary message to produce an encoded secondary message; and

,

means for piggybacking the at least one encoded secondary message onto the encoded primary message to form a piggybacked message in response to a signal indicating that piggybacking of the at least one secondary message onto the primary message is possible, the signal being based at least in part on a characteristic of the first receiver node and the second receiver node relative to the transmitter node.

26. The system of claim 25, further comprising a transmitter configured to transmit the piggybacked message, and/or the primary message and/or the at least one secondary message.

27. A method of relaying messages over a communications network, the method comprising:

identifying a first message to be communicated by a first antenna of a transmitter node and a secondary message to be communicated by a second antenna of the transmitter node, the first antenna and the second antenna having substantially distinctive antenna apertures;

turbo-coding the first message;

turbo-coding the second message; and

,

communicating substantially non-orthogonally at substantially the same time over substantially the same channel the first message and the second message using the first antenna and the second antenna in dependence on a breakpoint difference between near and far field regions of the network.

28. The method of claim 27, further comprising:

receiving the first message and the second message by a receiver node having two antennas with distinct apertures;

scaling and separating the messages in dependence on the antenna apertures; and

,

turbo-decoding the first message and the second message.

29. A system for relaying messages over a communications network, comprising:

a transmitter node having two transmit antennas, each transmit antenna having a distinct aperture;

a receiver node having two receive antennas, each receive antenna having a distinct aperture corresponding to an antenna aperture of the transmit antennas;

wherein the transmitter node is configured to transmit substantially non-orthogonally at substantially the same time over substantially the same channel a first message using a first antenna and the second message using a second antenna in dependence on a breakpoint difference between near and far field regions of the network, and

wherein the transmitter node is further configured to turbo-code the first message and the second message.

30. The system of claim 29, wherein the receiver node is operable to receive the first message and the second message, scale and separate the messages in dependence on the receive antenna apertures, and turbo-decode the first message and the second message.

31. The system of claim 29, wherein the first transmit antenna has a signal drop-off rate of approximately 1/r² and the second transmit antenna has a signal drop-off rate of approximately 1/r³.

32. A method of relaying messages over a communications network, the method comprising:

identifying a primary message and at least one secondary message to be communicated from at least one transmitter node, the primary message being designated for one or more first receiver nodes and the at least one secondary message being designated for one or more second receiver nodes;

turbo-coding the primary message;

turbo-coding the at least one secondary message; and

,

piggybacking the at least one secondary message onto the primary message to form a substantially non-orthogonal piggybacked message such that the primary message and the at least one secondary message are capable of being transmitted at substantially the same time over substantially the same channel.

33. The method of claim 32, further comprising when a receiver node receives a message, processing the message in dependence on whether the message is a piggybacked message.

34. The method of claim 32, wherein the piggybacking is performed in dependence on predefined SNRs between the at least one transmitter node, and the one or more first receiver nodes and the one or more second receiver nodes.

35. The method of claim 32, wherein the piggybacked message includes multicast information.

36. A system for relaying messages over a communications network, comprising:

a transmitter node and at least two receiver nodes, the transmitter node and the at least two receiver nodes being configured to communicate at least a primary message and at least one secondary message therebetween;

wherein the primary message and the at least one secondary message are piggybacked to form a substantially non-orthogonal piggybacked message, such that the primary message and the at least one secondary message are capable of being transmitted at substantially the same time over substantially the same channel, and

wherein the transmitter node is further configured to turbo-code the primary message and the at least one secondary message.

37. The system of claim 36, wherein each receiver node is further operable to process a received message in dependence on whether the received message is a piggybacked message.

38. The system of claim 36, wherein the primary message and the at least one secondary message are piggybacked in dependence on predefined SNRs between the transmitter node and the at least two receiver nodes.

39. The method of claim 36, wherein the primary message is broadcast for one or more receiver nodes.

40. The method of claim 36, wherein the piggybacked message includes multicast information.

41. An encoder for use with a transmitter node to prepare a message to be relayed through a network of nodes, comprising:

a turbo-encoding module configured to turbo-code a primary message designated for at least one first receiver node and configured to turbo-code at least one secondary message designated for at least one second receiver node based at least in part on a comparison of signal-to-noise ratios of the receiver nodes relative to the transmitter node; and

,

a piggybacking module configured to generate a piggybacked message by piggybacking the at least one secondary message onto the primary message based at least in part on the comparison.

42. The encoder of claim 41, further comprising a transmitting module configured to transmit at least one of the piggybacked message, the primary message, and the at least one secondary message based at least in part on the comparison.

43. An encoder for use with a transmitter node to prepare a message to be relayed over a communications network, comprising:

a piggybacking module configured to generate a piggybacked message by piggybacking at least one secondary message designated for at least one second receiver node onto a primary message designated for at least one first receiver node, the piggybacked message being substantially non-orthogonal, such that the primary message and the at least one secondary message are capable of being transmitted at substantially the same time over substantially the same channel; and

,

a turbo-encoding module configured to turbo-code the primary message and the at least one secondary message.

44. A decoder for use with a receiver node to process a message received from a transmitter node, comprising:

a turbo-decoding module configured to turbo-decode a primary message designated for at least one first receiver node and configured to turbo-decode at least one secondary message designated for at least one second receiver node based at least in part on a comparison of signal-to-noise ratios of the receiver nodes relative to the transmitter node; and

,

a separating module configured to separate a piggybacked message based at least in part on the comparison, the piggybacked message comprising the at least one secondary message and the primary message.

45. The decoder of claim 44, wherein the turbo-decoding module further comprises a switch configured to control the turbo-decoding process.

46. A decoder for use with a receiver node to process a message relayed over a communications network, comprising:

a separating module configured to separate a substantially non-orthogonal piggybacked message by separating at least one secondary message designated for at least one second receiver node from a primary message designated for at least one first receiver node; and

,

a turbo-decoding module configured to turbo-decode the primary message and the at least one secondary message.

47. The decoder of claim 46, wherein the turbo-decoding module further comprises a switch configured to control the turbo-decoding process.