Packet coding based network communication
A method for data communication between a first node and a second node over a data path includes estimating a rate at which loss events occur, where a loss event is either an unsuccessful delivery of a single packet to the second data node or an unsuccessful delivery of a plurality of consecutively transmitted packets to the second data node, and sending redundancy messages at the estimate rate at which loss events occur.
1. A method for data communication between a first node and a second node over a data path coupling the first node and the second node, the method comprising:
receiving messages at the first node from the second node, including receiving messages indicative of successful and unsuccessful delivery of the messages transmitted from the first node to the second node;
maintaining an estimate of a rate at which loss events occur over the communication path based on the messages received from the second node, including:
updating the estimate to incorporate a single loss event when one or more of the messages received from the second node indicate an unsuccessful delivery of a single packet to the second data node, and
updating the estimate to incorporate a single loss event when one or more of the messages received from the second node indicate an unsuccessful delivery of a window of transmitted packets to the second data node; and
dynamically adjusting a code rate or packet transmission rate of redundancy messages transmitted from the first node based on the estimate of the rate at which loss events occur as opposed to a rate of packet loss.
2. The method of claim 1 , wherein dynamically adjusting the code rate or packet transmission rate of redundancy messages transmitted from the first node based on the estimate of the rate at which loss events occur includes dynamically adjusting both the code rate and the packet transmission rate of redundancy messages transmitted from the first node.
3. The method of claim 1 , further comprising determining one or more redundancy messages from data messages at the first node using an error correcting code which is selected based at least in part on an estimated rate of loss events where a number of consecutive messages unsuccessfully delivered to the second data node in the window is less than a predetermined threshold.
4. The method of claim 3 , wherein the error correcting code includes a burst error correcting code.
5. The method of claim 3 , further comprising selecting the error correcting code.
6. The method of claim 5 , wherein selecting the error correcting code comprises selecting a burst error correcting code when the estimate of the rate at which loss events occur indicates loss bursts of up to a certain length in the window.
7. A communication apparatus comprising a first device having an interface for passing messages to and from a second device over a communication path coupling the first device to the second device, the first device further comprising a communication controller configured to:
receive messages at the first node from the second node, including receiving messages indicative of successful and unsuccessful delivery of the messages transmitted from the first node to the second node;
maintain an estimate of a rate at which loss events occur over the communication path based on the messages received from the second node, including:
updating the estimate to incorporate a single loss event when one or more of the messages received from the second node indicate an unsuccessful delivery of a single packet to the second data node, and
updating the estimate to incorporate a single loss event when one or more of the messages received from the second node indicate an unsuccessful delivery of a window of transmitted packets to the second data node; and
dynamically adjust a code rate or packet transmission rate of redundancy messages transmitted from the first node based on the estimate of the rate at which loss events occur as opposed to a rate of packet loss.
8. The communication apparatus of claim 7 , wherein dynamically adjusting the code rate or packet transmission rate of redundancy messages transmitted from the first node based on the estimate of the rate at which loss events occur includes dynamically adjusting both the code rate and the packet transmission rate of redundancy messages transmitted from the first node.
9. The communication apparatus of claim 7 , wherein the communication controller is further configured to determine one or more redundancy messages from data messages at the first node using an error correcting code, which is selected based at least in part on an estimated rate of loss events where a number of consecutive messages unsuccessfully delivered within the window to the second data node is less than a predetermined threshold.
10. The communication apparatus of claim 9 , wherein the error correcting code includes a burst error correcting code.
11. The communication apparatus of claim 9 , wherein the communication controller is further configured to select the error correcting code.
12. The communication apparatus of claim 11 , wherein selecting the error correcting code comprises selecting a burst error correcting code when the estimate of the rate at which loss events occur indicates loss bursts of up to a certain length in window.
13. The method of claim 5 , wherein selecting the error correcting code comprises selecting a combination of a burst error correcting code and an isolated error correcting code.
14. The method of claim 1 , wherein updating the estimate to incorporate the single loss event when one or more of the messages received from the second node indicate the unsuccessful delivery of the window of transmitted packets to the second data node comprises:
determining a number of the plurality of consecutively transmitted packets unsuccessfully delivered to the second data node; and
updating the estimate to incorporate the single loss event when the number of the plurality of consecutively transmitted packets unsuccessfully delivered to the second data node is below a threshold.
15. The method of claim 14 , further comprising updating the estimate to incorporate more than the single loss event when the number of the plurality of consecutively transmitted packets unsuccessfully delivered to the second data node is above the threshold.
16. The method of claim 15 , wherein dynamically adjusting the code rate or packet transmission rate of redundancy messages transmitted from the first node based on the estimate of the rate at which loss events occur includes dynamically adjusting both the code rate and the packet transmission rate of redundancy messages transmitted from the first node.
17. The communication apparatus of claim 11 , wherein selecting the error correcting code comprises selecting a combination of a burst error correcting code and an isolated error correcting code.
18. The communication apparatus of claim 7 , wherein updating the estimate to incorporate the single loss event when one or more of the messages received from the second node indicate the unsuccessful delivery of the window of transmitted packets to the second data node comprises:
determining a number of the plurality of consecutively transmitted packets unsuccessfully delivered to the second data node; and
updating the estimate to incorporate the single loss event when the number of the plurality of consecutively transmitted packets unsuccessfully delivered to the second data node is below a threshold.
19. The communication apparatus of claim 18 , wherein the communication controller is further configured to update the estimate to incorporate more than the single loss event when the number of the plurality of consecutively transmitted packets unsuccessfully delivered to the second data node is above the threshold.
20. The communication apparatus of claim 19 , wherein dynamically adjusting the code rate or packet transmission rate of redundancy messages transmitted from the first node based on the estimate of the rate at which loss events occur includes dynamically adjusting both the code rate and the packet transmission rate of redundancy messages transmitted from the first node.