Retransmission scheme for communication systems
View Patent ↗One embodiment relates to a method of communicating data between a transmitter and a receiver of a communication system. In this method, a payload data stream is received from a network interface layer. The payload data stream includes data units eligible for retransmission and data units non-eligible for retransmission. These data units are grouped into containers, where a container is associated with a container identifier that distinguishes the container from other containers. The containers are grouped into data transmission units, where a data transmission unit includes at least one container along with redundancy information that facilitates error detection for that data transmission unit. The data transmission units are transmitted to the receiver as a transmission data stream. Other methods and systems are also disclosed.
1. A method of communicating data between a transmitter and a receiver of a communication system, comprising:
receiving a payload data stream comprising data units eligible for retransmission (EL) and data units non-eligible for retransmission (NEL);
grouping the data units into a container stream comprising a series of containers, where an original container is associated with a container identifier that distinguishes the original container from other containers and where the original container includes one or more data units eligible for retransmission and one or more data units non-eligible for retransmission;
incorporating the container stream into a transmission data stream transmitted to a receiver;
receiving a retransmission request from the receiver, the retransmission request specifying the original container in the transmission data stream which was received having corrupted data or which was not received at the receiver; and
generating a retransmission container in response to the retransmission request, the retransmission container having a payload section including both the data units eligible for retransmission in the original container as well as at least one new data unit not previously transmitted in the original container.
2. The method of claim 1 , where data units non-eligible for retransmission in the original container are not included in the retransmission container.
3. The method of claim 2 , where the retransmission container and the original container are equal in length, and where a position of new data in the retransmission container corresponds to a position of the data units non-eligible for retransmission in the original container.
4. The method of claim 1 , further comprising:
fragmenting a data unit into at least two fragments prior to grouping the data units into the container stream.
5. The method of claim 4 , where a single fragment is split between at least two containers and where the single fragment is associated with a header specifying how a boundary of the single fragment aligns with respect to the at least two containers.
6. The method of claim 1 , where the payload data stream is received at a network interface layer that is a data link layer or a physical layer of a network stack.
7. The method of claim 1 , where each data unit includes only a single complete Ethernet packet, only a single complete Asynchronous Transfer Mode (ATM) cell, or a single complete Ethernet fragment.
8. The method of claim 1 , where containers are grouped so that each container has an approximately constant number of data units.
9. The method of claim 8 , where the approximately constant number of data units for each container can be changed dynamically using a reconfiguration protocol.
10. The method of claim 1 , where containers are grouped so that data units eligible for retransmission are packed into a container having a container length up to some maximum number of data units, and where data units non-eligible for retransmission are packed into separate containers from the data units eligible for retransmission.
11. A transmitter, comprising:
a network interface layer adapted to receive a payload data stream;
a container controller adapted to group data units of the payload data stream into containers, where an original container includes one or more data units eligible for retransmission and one or more data units non-eligible for retransmission;
a data transmission controller adapted to group the containers into data transmission units, where a data transmission unit includes the original container;
a transmission controller that mixes un-transmitted data transmission units with data transmission units to be retransmitted, thereby generating a transmission data stream suitable for transmission over a transmission medium; and
a retransmission controller adapted to analyze a retransmission request and determine which eligible data units stored in the retransmission buffer are to be re-transmitted over the transmission medium, and further configured to pack both a data unit eligible for retransmission from the original container and a new data unit not previously transmitted into a payload section of a retransmission container for transmission over the transmission medium.
12. The transmitter of claim 11 , where a data transmission unit includes redundancy information that facilitates error detection for the data transmission unit.
13. The transmitter of claim 11 , where the container controller is adapted to append a container header to each container, the container header comprising:
a retransmission eligibility field; and
a container identifier that distinguishes the containers from one another.
14. The transmitter of claim 11 , further comprising:
a fragment controller adapted to fragment a data unit into at least two fragments, where a fragment is associated with a fragment header that is different from that of other fragments.
15. The transmitter of claim 14 , where the fragment header comprises:
a fragment sequence identifier; and
an end_of_fragment (EF) field that indicates how a fragment boundary associated with the fragment relates to a container boundary of a container in which the fragment at least partially resides.
16. The transmitter of claim 11 , further comprising:
a retransmission buffer adapted to store eligible data units from the transmission data stream after the eligible data units are transmitted.
17. The transmitter of claim 11 , where the retransmission controller uses a table-lookup to correlate a container identification number obtained from the retransmission request with the eligible data units stored in the retransmission buffer.
18. The transmitter of claim 16 , where the retransmission buffer is adapted to store embedded overhead channel data associated with eligible data units of a container.
19. A communication system, comprising:
a transmitter adapted to transmit data transmission units over a transmission medium, the data transmission units including one or more containers associated with respective container identifiers, and the containers including data units eligible for retransmission and data units non-eligible for retransmission;
a receiver adapted to receive the data transmission units and transmit a retransmission request that specifies uncorrectable data received in at least one of the containers;
where the transmitter further comprises:
a retransmission controller adapted to generate a retransmission container in response to the retransmission request, where the retransmission container includes at least one previously transmitted data unit eligible for retransmission from a container along with new data instead of at least one previously transmitted data unit non-eligible for retransmission from the container.
20. The communication system of claim 19 , where the retransmission request includes a container identifier that corresponds to a container associated with the uncorrectable data.
21. The communication system of claim 20 , where the retransmission request includes upstream payload data piggybacked onto the container identifier.
22. The communication system of claim 20 , where the transmitter and receiver synchronously update a count value representative of the container identifier.
23. A method, comprising:
packing a data unit eligible for retransmission and a data unit non-eligible for retransmission into a payload section of an original container;
providing a header section for the original container and transmitting the original container and header section to a receiver;
after the original container has been transmitted, receiving a request for retransmission of the original container from the receiver;
packing the data unit eligible for retransmission and a new data unit into a payload section of a retransmission container; and
providing a retransmission header section for the retransmission container and transmitting the retransmission container and retransmission header section to the receiver in response to the request for retransmission.