Video Broadcast/Multicast December 2007 doc.: IEEE 802.11-07/xxxxr0 December 2007 Video Broadcast/Multicast Date: 2007-12-13 Authors: Graham Smith, DSP Group Graham Smith, DSP Group

December 2007 doc.: IEEE 802.11-07/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

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. Send the same signal to display and speakers Want to send the same stream to all devices as each IP packet contains a mixture of audio, video & data packets and it is complex to split these streams Enterprise Advertising displays, Town hall meetings, Webinars, training classes, Graham Smith, DSP Group

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 STAs in power save causes buffering until DTIM Clearly not ideal for Video!! Graham Smith, DSP Group

Possible Areas to Look At December 2007 Possible Areas to Look At Block Ack and A-MSDU can be used for more efficient streaming, can these features be adapted to be more applicable for Broadcast 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

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? Data rate set by Acks, need a ‘set-up’ procedure? 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, but it is used) 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

December 2007 PAR5C A protocol to enable improved reliability and rate adaptation for broadcast and multicast video traffic. Graham Smith, DSP Group