1. July 2006
doc.: IEEE /0975r0
July 2006
Dynamic signaling of parameter for target network behavior and operation
Date:
Authors:
Name
Company
Address
Phone
Marc Emmelmann
Technical University Berlin
Einsteinufer 25
10587 Berlin, Germany
Berthold Rathke
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Marc Emmelmann, Technical University Berlin
Marc Emmelmann, Technical University Berlin

2. July 2006
doc.: IEEE /0975r0
July 2006
Abstract
TGv works on a coherent network management interface specifying several capabilities to achieve this goal. In a heterogeneous operator or vendor environment, several vendors or operators may optimize their network for different requirement which may cause poor performance or even a collapse of the network.
Having knowledge of these different optimization goals can be used to improve network performance or even avoid the network to collapse.
This presentation is intended to start a discussion in TGv to elaborate if this further information should be distributed using protocol mechanisms.
Marc Emmelmann, Technical University Berlin
Marc Emmelmann, Technical University Berlin

3. Motivation Status Quo: Result:
July 2006
doc.: IEEE /0975r0
July 2006
Motivation
Status Quo:
Goal: complete a coherent upper layer interface for network management (.11v PAR)
objectives specify required capabilities, e.g.:
spectrum etiquette / dynamic power control (Req 2041)
dynamic channel selection (Req 2000)
but the reason for employing these mechanisms will not be standardized
Result:
Each vendor may use these management interfaces / capabilities and employ its own algorithms to for network and resource management
Different algorithms having the same aim may different in their performance and the “quality” of the result
These algorithms characterizes the maturity of each vendor’s product and should not be covered in the standard, but ...
Problem: Algorithms with different aims may hinder each other and may cause poor performance or even the collapse of the network
Marc Emmelmann, Technical University Berlin
Marc Emmelmann, Technical University Berlin

4. Example 1 -- Ordering Names
July 2006
doc.: IEEE /0975r0
July 2006
Example 1 -- Ordering Names
Sort the following names: Tim Adam John Bob Peter
Several algorithms exist to sort these name, one are more efficient, others are not, e.g.:
Vendor A applies algorithm A
Vendor B applies algorithm B
Problem: What happens if the two vendors do not agree on the sorting order (alphabetically increasing or decreasing)
Imagine if only the top three in the list get a promotion and the others are fired ... only John won’t care :-)
Adam -- Bob -- John -- Peter -- Tim
Marc Emmelmann, Technical University Berlin
Marc Emmelmann, Technical University Berlin

5. Example 2 -- Optimization of Cell Size
July 2006
doc.: IEEE /0975r0
July 2006
Example 2 -- Optimization of Cell Size
Goal: Optimize Cell Size
Employed Mechanism: Spectrum Etiquette / Dyn. Power Ctrl.
Criteria:
Vendor A tries to reduce interference
Vendor B tries to maximize network coverage
What could happen?
Marc Emmelmann, Technical University Berlin
Marc Emmelmann, Technical University Berlin

6. Min. Interference VS. Max. Coverage
July 2006
doc.: IEEE /0975r0
July 2006
Min. Interference VS. Max. Coverage
APs have adjusted cell size to minimize interference AP
AP joins and maximizes coverage area employing medium Tx power
APs detect interference and reduce cell size AP AP AP
APs further increases Tx power to ensure contineous coverage AP
APs detect interference and further reduce cell size
Is this the desired behavior? Maybe, maybe not.
But this will happen regardless of the employed algorithm at each AP.
Marc Emmelmann, Technical University Berlin
Marc Emmelmann, Technical University Berlin

7. Solution: Signaling of Optimization Criteria
July 2006
doc.: IEEE /0975r0
July 2006
Solution: Signaling of Optimization Criteria
If the optimization criteria (max. coverage or min. interference) was signaled, each AP had some idea on the possible behavior of others.
What could happen?
Vendor specific algorithm does not use this information --> nothing gained but also nothing lost (this is what we have)
Some vendors use this algorithm:
The “green” now knows that they can never reach optimal (zero) interference and may act accordingly.
The “red” now knows that others optimize for reduced interference and may change its algorithm or even the optimization criteria.
Marc Emmelmann, Technical University Berlin
Marc Emmelmann, Technical University Berlin

8. Partial use of knowledge: Adapt min. interference criteria
July 2006
doc.: IEEE /0975r0
July 2006
Partial use of knowledge: Adapt min. interference criteria
APs have adjusted cell size to minimize interference AP
AP joins and maximizes coverage area employing medium Tx power
APs detect interference but know that the source is an AP optimizing for network coverage AP AP AP
APs might accept a region of interference and a do not decrease cell size AP
Vendor-specific behavior of employed algorithm
Marc Emmelmann, Technical University Berlin
Marc Emmelmann, Technical University Berlin

9. Partial use of knowledge: Adapt max. network coverage criteria
July 2006
doc.: IEEE /0975r0
July 2006
Partial use of knowledge: Adapt max. network coverage criteria
APs have adjusted cell size to minimize interference AP
AP joins and maximizes coverage area employing medium Tx power
APs detect interference and reduce cell size AP AP AP
APs do not further increases Tx power but accept limited coverage AP
Vendor-specific behavior of employed algorithm
Marc Emmelmann, Technical University Berlin
Marc Emmelmann, Technical University Berlin

10. Agreement on Optimization Criteria
July 2006
doc.: IEEE /0975r0
July 2006
Agreement on Optimization Criteria
All APs have knowledge on the other’s behavior and may try to negotiate a common optimization criteria
They do not agree on a common criteria --> noting gained but also nothing lost
They agree either on interference reduction or coverage optimization
Marc Emmelmann, Technical University Berlin
Marc Emmelmann, Technical University Berlin

11. July 2006
doc.: IEEE /0975r0
July 2006
Conclusion
Providing only mechanisms for network management may result in unintended network behavior as different vendors might use them for different purposes employing different criteria
Distributing information on these criteria may help to deal with this problem and should be made available using 11v mechanisms
Further improvement: Mechanisms to reach an agreement on a common criteria
First steps already included in 11v draft, e.g.: providing reasons for STA transition / handover
TRANSITION EVENT LOG REPORT (Transition reason field) § v-D0.03.
Marc Emmelmann, Technical University Berlin
Marc Emmelmann, Technical University Berlin

12. Discussion Feasibility to
July 2006
doc.: IEEE /0975r0
July 2006
Discussion
Feasibility to
announce how capabilities 11v devices are used, i.e., the “aim” / optimization criteria
provide schemes to negotiate / agree on common “aim”
Possible TGv objectives that could address this issue:
Client Management Protocol (Req 1500)
Access Point Coordination (Req 2050)
Advertisement (Req 1300)
other ?
Marc Emmelmann, Technical University Berlin
Marc Emmelmann, Technical University Berlin

13. References P802.11v-D0.03 11-06/827r3 July 2006 July 2006
doc.: IEEE /0975r0
July 2006
References
P802.11v-D0.03
11-06/827r3
Marc Emmelmann, Technical University Berlin
Marc Emmelmann, Technical University Berlin