1. Multi-packet FEC Date: 2007-11-13 Authors: November 2007 November 2007
doc.: IEEE /2847r0
November 2007
Multi-packet FEC
Date:
Authors:
Alex Ashley, NDS Ltd
Alex Ashley, NDS Ltd

2. November 2007
doc.: IEEE /2847r0
November 2007
Abstract
This presentation describes an example of an end-to-end flow of video content in which a forward error correction code is applied.
Alex Ashley, NDS Ltd
Alex Ashley, NDS Ltd

3. Example IPTV Deployment
November 2007
Example IPTV Deployment
Content flows from VOD servers to the home via the core network.
This flow has to provide end-to-end QoS.
VOD Servers
Retransmissions outside the home disabled, to avoid overloading network.
DSLAM
Core Network
DSL Modem
Alex Ashley, NDS Ltd

4. November 2007
Multi-packet FEC
A side-channel is added at the VOD server, which provides ‘n’ error correction data packets
Ptotal = Pdata + Pprotection
Receiver can create perfect picture with loss of any ‘n’ packets
Alex Ashley, NDS Ltd

5. November 2007
Multi-packet FEC &
Over , all unicast traffic gets re-transmitted until positive ACK received
Or MIB defined retry limit reached
If an application level FEC is already in place, could be more intelligent in its retries
A STA could reduce its retries if it had knowledge of higher level recovery technique
Alex Ashley, NDS Ltd

6. November 2007
References
Alex Ashley, NDS Ltd