1. 2/4/2019May 2008
November 2007
doc.: IEEE /2752r1
Efficient Error Control Using Network Coding for Multicast Transmission
Date:
Authors:
J.-K. Kevin Rhee, et. al, KAIST
Peter Ecclesine, Cisco Systems

2. Contents Overview of Network Coding Issues for Network Coding
2/4/2019May 2008
doc.: IEEE /0529r0
Contents
Overview of Network Coding
Issues for Network Coding
Our Proposal
System Block Diagram
Example of Network Coding Error Control Frame
Conclusion
J.-K. Kevin Rhee, et. al, KAIST
Peter Ecclesine, Cisco Systems

3. Overview of Network Coding
2/4/2019May 2008
doc.: IEEE /0529r0
Overview of Network Coding
Problems of existing error control scheme in
It involves error control frame storming.
Multicast Error Rate (# of Receiving station X Unicast error rate)
MER = 1, if # of Receiving station X Unicast error rate > 1
MER = # of Receiving station X Unicast error rate
If MER = 1, it required more than 100% of overhead.
How network coding benefits to multicast error control
Network coding requires 3 times less overhead
comparing with the existing error control scheme.
J.-K. Kevin Rhee, et. al, KAIST
Peter Ecclesine, Cisco Systems

4. Issues for Network Coding
2/4/2019May 2008
doc.: IEEE /0529r0
Issues for Network Coding
Handling variable length of frames
The size of error control frames coined by XOR operations are same as the largest frames among a set.
The way notifying receiving nodes of actual payload size of a missing frame is required.
XOR payload design concept
We should clarify which information should be XORed and which information should not.
J.-K. Kevin Rhee, et. al, KAIST
Peter Ecclesine, Cisco Systems

5. Our Proposal = Handling variable length of frames
-50-
Our Proposal
Handling variable length of frames
Padding a special ending bit sequence at the end of payload.
• Actual data payload is retrieved by matching ending bit sequence.
Payload
EoS
Frame 1
Frame 2
Payload
EoS
Padding(0x0000….)
Frame 3
Payload
EoS
Padding(0x0000….) =
XORed Payload
Error control frame
J.-K. Kevin Rhee, et. al, KAIST

6. Our Proposal = Handling variable length of frames Retrieve -60-
XORed Payload
Error control frame
Payload
EoS
Frame 1
Frame 3
Payload
EoS
Padding(0x0000….) =
Retrieved frame
Payload
EoS
Padding(0x0000….)
Payload of Frame 2
J.-K. Kevin Rhee, et. al, KAIST

7. Our Proposal = Handling variable length of frames
-70-
Our Proposal
Handling variable length of frames
Introducing a length field XORing.
• Actual data payload is retrieved by matching ending bit sequence.
• This scheme does not require
Length
Payload
Frame 1
Frame 2
Length
Payload
Padding(0x0000….)
Frame 3
Length
Payload
Padding(0x0000….) =
XORed
Length
XORed Payload
Error control frame
J.-K. Kevin Rhee, et. al, KAIST

8. Our Proposal = Handling variable length of frames Retrieve -80- XORed
XORed Payload
Error control frame
Length
Payload
Frame 1
Frame 3
Length
Payload
Padding(0x0000….) =
Length
Payload
Padding(0x0000….)
Retrieved frame
Payload of Frame 2
J.-K. Kevin Rhee, et. al, KAIST

9. System Block Diagram System Blocks -90-
J.-K. Kevin Rhee, et. al, KAIST

10. Example of Network Coding Error Control Frame
-100-
Example of Network Coding Error Control Frame
Block ACK Network Coding Error Control Frame.
It takes Block ACK Control Path.
In BAR Control field, we define an additional type field distinguishing error control frames from others.
Start Seq and End Seq fields notify receiving stations of encoded frames.
Maximum size of XOR frame body is 2425 (2423 bytes-Data + 2 bytes-Length Filed or EoS)
Frame control
Duration/ ID DA SA
BAR
Control
Start Seq
End Seq
XOR
Frame Body
FCS
Type (4bits) 0x1
Reserved (8bits)
TID (4bits)
XORed Length (2octets)
XORed Frame Body (2423octets)
XORed Frame Body
(0-2423octets)
Ending Sequence / Padding
J.-K. Kevin Rhee, et. al, KAIST

11. -110-
Conclusion
We propose two ways of supporting variable length of frames for network coding.
Introducing a Length Field
Padding EoS bit sequence at the end of payload.
Both scheme can allow receiving stations to retrieve actual data payload out of XORed payload.
We also proposed system block diagram for network coding multicast error control and example format of error control frame compliant with Block ACK.
J.-K. Kevin Rhee, et. al, KAIST

12. Thank You! 2/4/2019May 2008 doc.: IEEE 802.11-08/0529r0
J.-K. Kevin Rhee, et. al, KAIST
Peter Ecclesine, Cisco Systems