1. Video Broadcast/Multicast
December 2007
doc.: IEEE /xxxxr0
December 2007
Video Broadcast/Multicast
Date:
Authors:
Graham Smith, DSP Group
Graham Smith, DSP Group

2. December 2007
doc.: IEEE /xxxxr0
December 2007
Abstract
Outline of Video Broadcast and Multicast requirement for inclusion in the PAR5C document
Graham Smith, DSP Group
Graham Smith, DSP Group

3. Video Broadcast/Multicast Use
December 2007
Video Broadcast/Multicast Use
Main Reason – Efficient use of Bandwidth
HOME
TV Broadcast around the home to screens in Kitchen, Bathrooms, Study, bedrooms
Don’t miss a touchdown/goal when getting a beer out of the refrigerator!
Keep watching the movie, along with the family, when visiting the kitchen or bathroom.
Show a DVD around the home similar to TV. No need to pause when one family member visits another room.
Enterprise
Advertising displays, (Please add more here, not my area)
Graham Smith, DSP Group

4. Broadcast and Multicast Data
December 2007
Broadcast and Multicast Data
802.11
Broadcast and Multicast Frames known as “Group Frames”
Simplest frame exchanges because NO Acknowledgement
Broadcast data frames have broadcast address in Address 1 Field
Multicast data frames have multicast address in Address 1 Field
Group Frames are not acknowledged and cannot be fragmented
Single frame sequence, NAV set to 0
All STAs wait for DIFS and contend on each frame
QoS data frames can be used if known that ALL STAs support
Clearly not ideal for Video!!
Graham Smith, DSP Group

5. Possible Areas to Look At
December 2007
Possible Areas to Look At
Block Ack (11e)
Use of a Block Ack Frame
Acks of frames with same TID, but TX’d during multiple TXOPs may be combined into single Block Ack Frame
A-MSDU Operation (11n)
Use of A-MPDU for QoS determined by Block Ack agreement
A-MSDU is composed of MSDUs with the same TID
Maximum length defined by receiver
Graham Smith, DSP Group

6. No obvious method – Ideas?
December 2007
Areas of Work
Pure Broadcast with no Ack?
Need for FEC?
What data rate to use? How to determine the ‘worst case’ STA?
Need to aggregate packets rather than single packets, for QoS considerations?
Simple re-send, i.e. if high number of STAs, then sending every pkt 2 times is still more efficient than sending to all individually (don’t like this)
Other?
“Broadcast” with Acks?
Every STA Ack is not efficient
Use of a “NO ACK”? Within Block Ack?
Use of a selected STA to Ack? How to select the STA? Range not the only concern, contention issues vary around the network.
No obvious method – Ideas?
Graham Smith, DSP Group

7. December 2007
PAR5C
Investigate methods for efficient broadcast or multicast transmission of Video content and propose (MAC) changes to accommodate them.
Graham Smith, DSP Group