1. Mesh Media Access Coordination Ad Hoc Group Report Out
July 2004
doc.: IEEE /1077r0
Sept 2004
Mesh Media Access Coordination Ad Hoc Group Report Out
L. Lily Yang (Intel Corp.)
Lily Yang
Lily Yang

2. Ad Hoc Group Activities since Portland meeting
July 2004
doc.: IEEE /1077r0
Sept 2004
Ad Hoc Group Activities since Portland meeting
One face to face meeting at Portland,
Decided to first focus on a list of issues in MAC
Set up a WiKi page for the group:
One teleconference call,
Clarified the scope of the ad hoc group: Mesh Media Access Coordination Function
Changed the group name
Worked on the issue list
More discussion over s on the issue list
Outcome of the group: #968r05
Lily Yang
Lily Yang

3. Mesh Point Reference Architecture
Sept 2004
Mesh Point Reference Architecture
Configuration/ Management
Internetworking
Interfaces
IEEE802.11s Amendment
.11s Mesh Network Measurement
Layer 2 Mesh Routing and Forwarding
.11s Mesh Security
Mesh Media Access Coordination Function
IEEE MAC
IEEE802.11　PHY
IEEE a/b/g/j/n
*[1] slide#3
Lily Yang

4. Purpose of #968 (Issue List)
Sept 2004
Purpose of #968 (Issue List)
Informational: provide suggestions on what are the technical challenges the 11s proposal might want to address for Mesh Media Coordination Function
NOT a requirement document
FLAT list of issues:
No significance to the order
No prioritization done to the list yet
Up to TGs to decide
What is the minimum requirements
What is out of scope
What is optional
Lily Yang

5. Two Operational Phases
Sept 2004
Two Operational Phases
Mesh Discovery and Mesh Link Establishment (Section 3 in #968)
Mesh Discovery: mesh beacon?
Link Establishment:
Mesh authentication?
Mesh association?
Normal Operational Phase (Section 4 in #968)
Mesh Media Access Coordination Function is in action
Lily Yang

6. List of Issues in Mesh Media Access Coordination Function
Sept 2004
List of Issues in Mesh Media Access Coordination Function
11 Issues documented in 968
Most are needed due to the “mesh” nature
Missing or inadequate in current 11/11e MAC
Opportunities presented by mesh
Lily Yang

7. Issue #4.1 Hidden Terminal Problem
Sept 2004
Issue #4.1 Hidden Terminal Problem
hidden nodes:
nodes in I(R)
but not S(T) T R H
S(T):
Sensing
range of T
I(R):
Interference
range of R
Lily Yang

8. Issue #4.1 Performance Impact
July 2004
doc.: IEEE /1077r0
Sept 2004
Issue #4.1 Performance Impact
STA1
STA2
STA3
STA4
Case (a)
Case (c)
STA1
STA2
STA3
STA4
Case (b)
Case (b)
Case (d)
Case (a)
Case (c)
Case (d)
Lily Yang
Lily Yang

9. Issue #4.2 Exposed Terminal Problem
Sept 2004
Issue #4.2 Exposed Terminal Problem E T R
hidden nodes:
nodes in S(T)
but not in I(R)
S(T):
Sensing
range of T
I(R):
Interference
range of R
Lily Yang

10. Issue #3 Flow Control from source to destination
Sept 2004
Issue #3 Flow Control from source to destination
11 DCF: packet-based fairness
11e EDCA (TXOP): time-based fairness
Fixed slow client problem for BSS
Improve BSS network throughput
But may introduce problem for multi-hop path with multi-rate
11 mb/s
2 mb/s
Lily Yang

11. Issue #4.3 Another Flow Control Example
Sept 2004
Issue #4.3 Another Flow Control Example
Individual flow throughput (b/s) N0 N4 N1 N2 N3
Flow 1
Flow 2
Load (mb/s)
Lily Yang

12. Lack of Flow Control: Example (cont.)
Sept 2004
Lack of Flow Control: Example (cont.)
Actual Scheduling Result when load=700kb/s
e2e throughput
674k
449k
355k
235k
Congested nodes
238k
347k
450k
697k
Rx: k k k k 235k
Tx: k k k k k
Wasted TX
Ideal Scheduling, when the network is overloaded
430k
430k
430k
430k
430k
430k
430k
430k
e2e
throughput
Rx: k k k 860k 860k
Tx: k k k 860k 430k
Lily Yang

13. Issue #4.4 Mesh Load Balance
Sept 2004
Issue #4.4 Mesh Load Balance
Lily Yang

14. Issue #4.5 Multi-hop Scheduling
Sept 2004
Issue #4.5 Multi-hop Scheduling
Lily Yang

15. Issue #4.6 Distributed Admission Control
Sept 2004
Issue #4.6 Distributed Admission Control
11s Admission Control
11e Admission Control
Mesh AP
STA
Lily Yang

16. Issue #4.7 Distributed QoS Management
Sept 2004
Issue #4.7 Distributed QoS Management
Mesh AP
STA
Lily Yang

17. Issue #4.8 Mixture of BSS Traffic and Forwarding Traffic
Sept 2004
Issue #4.8 Mixture of BSS Traffic and Forwarding Traffic
Relay traffic
Mesh AP
STA N4 N0 N1 N2 N3
BSS traffic
When Mesh Point co-located with AP on one RF interface:
How to coordinate the relay traffic for mesh point and the BSS traffic for AP?
Lily Yang

18. Issue #4.9 Scalability Different usage models: Variable:
Sept 2004
Issue #4.9 Scalability
Different usage models:
Small home
Medium size office
Large campus and community network
Variable:
Network size
Node density
Fixed EDCA parameters?
Lily Yang

19. Issue #10 Channelization
Sept 2004
Issue #10 Channelization A
A->B: channel n
C->D: channel m D C B
Lily Yang

20. Issue #11 Multiple Radios
Sept 2004
Issue #11 Multiple Radios
Mesh AP
Mesh Point
BSS traffic
To/from
Stations
Forwarding
Traffic from/to
Other Mesh Points
Using multi-radio
to implement
channelization
Lily Yang

21. Sept 2004
Summary
A list of issues should be paid attention to when making proposals to 11s
Open Questions:
Is this useful to TGs?
Anything here that must be addressed by 11s as hard (minimum) requirements?
How do we intend to measure the Mesh Media Access Coordination Function performance of the proposals?
Should we derive some simulation scenarios from this list so that different aspect of the performance can be evaluated?
Lily Yang

22. July 2004
doc.: IEEE /1077r0
Sept 2004
References
[1] s-suggested-major-functional-components s.ppt
[2] s-issues-for-mesh-media-access-coordination-component-in-11s.doc
Lily Yang
Lily Yang