1. Audio Video Multicast Protocol
January 2007
Audio Video Multicast Protocol
Date:
Authors:
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Yongho SEOK, LG Electronics

2. January 2007
Authors (cont.)
Yongho SEOK, LG Electronics

3. Motivations IEEE 802.11e AV Multicast Protocol in IEEE 802.11e
January 2007
Motivations
IEEE e
Provides Quality of Service for AV connection
However, AC_VO and AC_VI frames have high collision probability because of the small contention window
AV Multicast Protocol in IEEE e
Difficult to provide Quality of Service because the collided frames are lost
Unfair channel access between AV multicast and AV unicast
Yongho SEOK, LG Electronics

4. Problem Definition Requirements of Audi Video Multicast (AVM)
January 2007
Problem Definition
Requirements of Audi Video Multicast (AVM)
Quality of Service provision
Fair channel access between AV connections
Compatibility with IEEE MAC
Multicast PHY rate adaptation
Yongho SEOK, LG Electronics

5. 1. Quality of Service Provision
January 2007
1. Quality of Service Provision
AVM protocol should provide a retransmission mechanism for corrupted frames
Yongho SEOK, LG Electronics

6. 2. Fairness between AV Streams
January 2007
2. Fairness between AV Streams
AVM protocol should use the binary exponential backoff mechanism
<Channel Access Mechanism between unicast and multicast connections>
Yongho SEOK, LG Electronics

7. 3. Compatibility with IEEE 802.11 MAC
January 2007
3. Compatibility with IEEE MAC
The AV multicast frame should never be changed
Legacy IEEE stations discard new frame formats such as the QDATA frame in IEEE e or A-MSDU frame in IEEE n
<IEEE e DATA Frame Format>
Yongho SEOK, LG Electronics

8. 4. Multicast Rate Adaptation
January 2007
4. Multicast Rate Adaptation
AVM protocol should provide a rate adaptation mechanism
Current MAC uses the fixed multicast PHY rate
The lowest multicast rate is the bottleneck of the WLAN performance
Yongho SEOK, LG Electronics

9. January 2007
Related Works
IEEE v TG
Just provides the simple multicast diagnostic capability
1) Multicast Diagnostic Request
2) Multicast Diagnostic Report
(Beacon Units)
3) Triggered Multicast Diagnostic Report
Yongho SEOK, LG Electronics

10. Proposed AVM Protocol Summary AVM Protocol consists of
January 2007
Proposed AVM Protocol
Summary
Proposed AVM protocol is the leader based multicast protocol
A leader station for the multicast group transmits the ACK frame whenever it correctly receives the multicast frame
AVM Protocol consists of
Leader Election Protocol
EDCA mechanism for Multicast
Yongho SEOK, LG Electronics

11. Proposed AVM Leader Election Protocol Leader Request Action frame
January 2007
Proposed AVM
Leader Election Protocol
Leader Request Action frame
Leader Response Action frame
Leader Release Action frame
Category
Action
Multicast
Address
Octets: 1 1 6
Category
Action
Multicast
Address
Status
Code
Octets: 1 1 6 1
Category
Action
Multicast
Address
Octets: 1 1 6
Yongho SEOK, LG Electronics

12. Proposed AVM Leader Election Protocol Leader Selection Algorithm
January 2007
Proposed AVM
Leader Election Protocol
Leader Selection Algorithm
It is possible to utilize IEEE v multicast diagnostic capability
But, the specific algorithm is out of scope
New Leader
Old Leader
New Leader
Old Leader
New Leader
Old Leader
(a) Leader Request Action
(b) Leader Response Action
(b) Leader Release Action
Yongho SEOK, LG Electronics

13. Proposed AVM EDCA for Multicast
January 2007
Proposed AVM
EDCA for Multicast
The multicast frame includes the correct Duration field for the NAV setting.
Leader sends ACK frame whenever it successfully receives the multicast frame
Binary Exponential Backoff
Multicast DATA
Multicast DATA
ACK
Leader
Collision
Non-leader
Unicast DATA
NAV
Yongho SEOK, LG Electronics

14. Proposed AVM Multicast Rate Adaptation
January 2007
Proposed AVM
Multicast Rate Adaptation
Multicast Diagnostic capability in v TG can provides a long-term solution for the multicast rate adaptation
Because the timescale of the multicast rate reporting is larger than the variation of the link quality
Additionally, AVM can use the rate adaptation mechanism similar to ARF, for the short-term solution
<Measurement Report field format for Multicast Diagnostic Report>
Yongho SEOK, LG Electronics

15. Summary The AV multicast applications such as IPTV are increasing
January 2007
Summary
The AV multicast applications such as IPTV are increasing
But, a current multicast protocol in IEEE wireless LAN has many issues
AVM protocol is one proposal to improve the Quality of Service of Audio/Video multicast
Yongho SEOK, LG Electronics

16. January 2007
Straw Poll #1
Is it necessary to include a AV multicast protocol in the new emerging standard ?
Yes: 14
No: 13
Yongho SEOK, LG Electronics

17. Call for interest What should be the next steps: January 2007
Yongho SEOK, LG Electronics

18. January 2007
Reference
J. Kuri and S.K. Kasera, “Reliable Multicast in Multi-access Wireless LANs,” ACM Wireless Networks, 2001.
D. Dujovne and T. Turletti, “Multicast in WLANs: An Experimental Study,” in ACM MSWiM 2006.
J. Villalon, P. Cuenca, L. Orozco-Barbosa, Y. Seok and T. Turletti, “Cross-Layer Architecture for Adaptive Video Multicast Streaming over Multirate Wireless LANs,” to appear in JSAC, 2007.
Yongho SEOK, LG Electronics

19. Video Goodput Comparison
January 2007
Video Goodput Comparison
Leader based
Legacy Multicast
Yongho SEOK, LG Electronics