Multicast data communication method and network

• US 20060256740A1
• Filed: 05/10/2005
• Published: 11/16/2006
• Est. Priority Date: 05/10/2005
• Status: Active Grant

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Koski, Eric
• Granted Patent: US 7,586,930 B2
• Time in Patent Office: Days
• US Class Current: 370/278
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 12/1863 comprising mechanisms for improved reliability, e.g. status reports arrangements for detecting or preventing errors by carrying supervisory signal the return channel H04L1/16
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services

Abstract

The communication method and system include wirelessly transmitting a data packet from a first node to a plurality of second nodes to define a wireless multicast transmission. Each second node determines whether the data packet was received with errors and if so transmits a negative acknowledgement (NAK) to the first node in a common allocated NAK time slot for the second nodes. The first node retransmits the data packet to the second nodes based upon receiving the NAK from any second node. The method and system may include measuring propagation delay between the first node and each of the plurality of second nodes, or measuring a maximum propagation delay between the first node and the plurality of second nodes, to determine the common allocated NAK time slot.

Claims

1. A communication method comprising:

wirelessly transmitting a data packet from a first node to a plurality of second nodes defining a wireless multicast transmission;

at each second node determining whether the data packet was received with errors and if so transmitting a negative acknowledgement (NAK) to the first node in a common allocated NAK time slot for the second nodes; and

at the first node retransmitting the data packet to the second nodes based upon receiving the NAK from any second node.

2. The communication method of claim 1 wherein NAKs corresponding to a same-data packet are identical.

3. The communication method of claim 2 wherein each of the identical NAKs comprises a pseudo-noise (PN) sequence signal.

4. The communication method of claim 3 wherein the PN sequence of subsequent NAKs is different.

5. The communication method of claim 1 wherein transmitting a NAK further comprises different second nodes staggering their respective NAK transmissions so as to ensure that the respective NAKs are received by the first node within the common allocated NAK time slot but at times differing by at least one symbol period of the PN sequence signal to prevent the respective NAKs from canceling each other.

6. The communication method of claim 1 further comprising measuring propagation delay between the first node and each of the plurality of second nodes to determine the common allocated NAK time slot.

7. The communication method of claim 1 further comprising measuring a maximum propagation delay between the first node and the plurality of second nodes to determine the common allocated NAK time slot.

8. The communication method of claim 1 further comprising each second node transmitting a repeat-NAK to the first node in a common allocated repeat-NAK time slot if the second node transmitted the NAK in the common allocated NAK time slot or the second node heard a NAK from another of the plurality of second nodes in the common allocated NAK time slot.

9. The communication method of claim 1 wherein the first node and plurality of second nodes define a communication network using an automatic retransmission protocol for communicating data packets.

10. The communication method of claim 9 wherein the automatic retransmission protocol comprises an Automatic Repeat reQuest (ARQ) technique.

11. The communication method of claim 10 wherein the ARQ technique comprises a hybrid-ARQ technique including Forward Error Correction (FEC).

12. The communication method of claim 1 further comprising:

storing at least a portion of the data packet received with errors at the second node; and

when the retransmitted data packet is also received with errors by the second node, combining the stored portion with the retransmitted data packet to attempt recovery of the data packet.

13. A communication network comprising:

a plurality of wirelessly connected communication nodes including a first node and a plurality of second nodes;

the first node wirelessly transmitting a data packet to the plurality of second nodes to define a wireless multicast transmission;

each of the plurality of second nodes receiving the data packet from the first node, and determining whether the data packet was received with errors and, if so, transmitting a negative acknowledgement (NAK) to the first node in a common allocated NAK time slot among the plurality of nodes; and

the transmitter retransmitting the data packet when receiving a NAK from any second node of the plurality of nodes.

14. The communication network of claim 13 wherein NAKs corresponding to a same data packet are identical.

15. The communication network of claim 14 wherein each of the identical NAKs comprises a pseudo-noise (PN) sequence signal.

16. The communication network of claim 15 wherein the second node varies the PN sequence signal of subsequent NAKs.

17. The communication network of claim 13 wherein the first and second nodes measure propagation delay from the first node to each of the plurality of second nodes to determine the common allocated NAK time slot.

18. The communication network of claim 13 wherein the first and second nodes measure a maximum propagation delay to the plurality of second nodes to determine the common allocated NAK time slot.

19. The communication network of claim 13 wherein the second nodes stagger their respective NAK transmissions so as to ensure that the respective NAKs are received by the first node within the common allocated NAK time slot but at times differing by at least one symbol period of the PN sequence signal to prevent the respective NAKs from canceling each other.

20. The communication network of claim 13 wherein each of the second nodes transmits a repeat NAK to the first node in a common allocated repeat NAK time slot if either a NAK was transmitted in the common allocated NAK time slot or if a NAK was heard from another of the second nodes in the common allocated NAK time slot.

21. The communication network of claim 13 wherein the plurality of nodes use a NAK-only hybrid-ARQ technique including Forward Error Correction (FEC).

22. The communication network of claim 13 wherein each second node stores at least a portion of the data packet received with errors, and combines the stored portion with the retransmitted data packet to attempt recovery of the data packet when the retransmitted data packet is also received with errors.

23. A communication network comprising:

a plurality of wirelessly connected communication nodes, each node comprising

a transmitter to wirelessly transmit a data packet to second nodes of the plurality of nodes to define a wireless multicast transmission,

a receiver to receive data packets from a first node of the plurality of nodes, and

an error detection unit operating in connection with the receiver to determine whether a data packet was received with errors and, if so, operating in connection with the transmitter to transmit a negative acknowledgement (NAK) to the first node in a common allocated NAK time slot among the plurality of nodes, and

the transmitter operating in connection with the receiver to retransmit the data packet when receiving a NAK from any second node of the plurality of nodes.

24. The communication network of claim 23 wherein NAKs corresponding to a same data packet are identical.

25. The communication network of claim 24 wherein each of the identical NAKs comprises a pseudo-noise (PN) sequence signal.

26. The communication network of claim 23 wherein each node further comprises a controller to measure propagation delay to each of the plurality of second nodes to determine the common allocated NAK time slot.

27. The communication network of claim 23 wherein each node further comprises a controller to measure a maximum propagation delay to the plurality of second nodes to determine the common allocated NAK time slot.

28. The communication network of claim 23 wherein the error detection unit operating in connection with the transmitter transmits a repeat NAK to the first node in a common allocated repeat NAK time slot if either a NAK was transmitted in the common allocated NAK time slot or if a NAK was heard from another of the plurality of nodes in the common allocated NAK time slot.

29. The communication network of claim 23 wherein each node further comprises a memory to store at least a portion of the data packet received with errors;

and wherein the error detection unit operating in connection with the memory combines the stored portion with the retransmitted data packet to attempt recovery of the data packet when the retransmitted data packet is also received with errors.