1. QoS aware Load Balancing
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QoS aware Load Balancing
Authors:
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Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

2. Month Year
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Abstract
In this presentation we proposed an Access Category Station Count element considering inactive load to enable load balancing and QoS effectiveness in accordance with REQ2030 in TGv.
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

3. Motivation Call blocking probability QoS-aware Load balancing
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Motivation
Call blocking probability
- Defined as the probability that a successful call connection will not be achieved
- Dependent on the number of both active and inactive voice stations
- An important QoS metric to evaluate the voice quality but yet to be addressed in standard
QoS-aware Load balancing
- Achieved by gathering the load information in respective APs
- Not only the active load status but also the potentially inactive load should be considered.
- Different types of traffic has different access priority, i.e. EDCA in 11e, hence the load information specifying different access category or user priority is required.
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

4. Effects from Inactive Voice terminals
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Effects from Inactive Voice terminals
In large office area, many voice terminals are associated with one AP. Only parts of them are evolved in an active call connection.
How many calls are expected, i.e., changing from inactive to active, during an ongoing call, is one aspect of the VoIP QoS. It is determined by the total number of associated VoIP STAs rather than the active ongoing VoIP STAs
E.g. given 100 associated VoIP STAs, call arrival rate 2 calls/hour, average calling time 5 min.  in the BSS,
- Inter-call arrival time = 60/2/100 = 0.3 min = 18 second
- During one call, there is 5/0.3 = 16 new call requests, which may causes degraded voice quality.
- The AP with less associated rather than active voice STAs is referred.
The number of inactive voice stations is quite important for load balancing, which is not yet available in current standard.
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

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AP Selection Scenario
In large office area, many voice terminals are associated with one AP, and initiates call connection randomly.
Some voice terminals are active, i.e. is envolved in a call, while others are in stand-by and is inactive.
AP1:
5 active VoIP STAs
100 inactive VoIP STAs
4 BE STAs
AP2:
5 active VoIP STAs
200 inactive VoIP STAs
4 BE STAs
Who shall I access?
AP1
Associated with AP1
AP2
Associated with AP2
MT3
MT1
Inactive
Active
Even with the same active load status, AP1 should be selected due to less potential blocking probability.
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

6. Current load information
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Current load information
Current load information in only includes QoS-aware load balancing based on existing active load. e.g.,
1) QBSS Load:
- Station Count: (active & inactive) & no QoS differentiation
- Channel Utilization: active & no QoS differentiation
- Available Admission Capacity: active & no QoS differentiation.
2) BSS Available Admission Capacity: active & QoS differentiation
3) BSS AC Access Delay: active & QoS differentiation
 There is no load information which specifies the QoS-aware & “both active and inactive” in standard.
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

7. Proposed Solution AC Station Count element
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Proposed Solution
AC Station Count element
- included in beacon, probe response messages and STA statistics report IE to notify the STAs for better AP selection
- included in neighbor report IE for inter-AP load balancing
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

8. Beacon Frame Jan. 2007 Table 8—Beacon frame body Order Information
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Beacon Frame
Add two new elements in table 8:
Table 8—Beacon frame body
Order
Information
Notes 30
AC Station Count
The AC Station Count element shall be present in a QoS AP where dot11RadioMeasurementEnabled is true.
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

9. Probe Response Frame Jan. 2007 Table 15—Probe Response frame body
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Probe Response Frame
Add two new elements in table 15:
Table 15—Probe Response frame body
Order
Information
Notes 29
AC Station Count
The AC Station Count element shall be present in a QoS AP where dot11RadioMeasurementEnabled is true.
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

10. STA Statistics Report IE (1)
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STA Statistics Report IE (1)
Change the order 10 in table 31b as follows:
Table 31b－ Group Identity for a STA Statistics Report (continued)
Group Identity Requested
Statistics Returned 10
dot11BSSAverageAccessDelay Group (only available at an AP):
dot11STAStatisticsAPAverageAccessDelay (INTEGER),
dot11STAStatisticsAverageAccessDelayBestEffort (INTEGER),
dot11STAStatisticsAverageAccessDelayBackGround (INTEGER),
dot11STAStatisticsAverageAccessDelayVideo (INTEGER),
dot11STAStatisticsAverageAccessDelayVoice (INTEGER),
dot11STAStatisticsACStationCount (INTEGER),
11－255
None
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

11. STA Statistics Report IE (2)
Change Figure 85k as follows:
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STA Statistics Report IE (2)
Change the order 10 in table 31b as follows:
dot11STA StatisticsAP AverageAccess Delay
dot11STA Statistics AverageAccess DelayBestEffort
dot11STA Statistics AverageAccess DelayBackGround
dot11STA Statistics AverageAccess DelayVideo
dot11STA Statistics AverageAccess DelayVoice
dot11STA Statistics ACStation Count 1
3-11
Octets:
Figure 85k---Measurement Report field format for dot11BSSAverageAccessDelay Group
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

12. Neighbor Report IE Jan. 2007 Table 43B—Optional Extensions
Change Figure 85k as follows:
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Neighbor Report IE
Change the table 43B in v Draft 0.05 as follows:
Table 43B—Optional Extensions
Sub-Element ID
Name
Reserved 1
TSF Information 2
Roaming Candidate Preference 3
QBSS Available Admission Capacity 4
AC Station Count
4 5-10 11
QBSS Load
12-255
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

13. Access Category Station Count
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Access Category Station Count
Element ID
Length
Station Count Bitmask
Station Count List
Octets: 1
2 x (total number of non-zero bits in Station Count Bitmask)
Figure X1--- AC Station Count element format
Definition:
- The Station Count Bitmask field indicates the AC values that have Station Count specified in the following Station Count List.
- The Station Count List comprises a sequence of Station Count fields corresponding respectively to the non-zero bits in the Station Count Bitmask field.
- The Station Count field specifies the number of STAs that are currently associated with this QBSS for the corresponding AC traffic.
Table 44a－ Station Count Bitmask Definition
Bit (s)
Station Count Reported
AC 0 (VO) 1
AC 1 (VI) 2
AC 2 (BE) 3
AC 3 (BK)
4-7
Reserved
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

14. Procedures and Usage Scenarios (1)
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Procedures and Usage Scenarios (1)
Passive scanning:
Active scanning: AP
STAx AP
STAx
Probe Request
Beacon (AC1 STA Count)
Probe Response (AC1 STA Count )
STA considers the QoS-specified network load, and selects target BSS consi- dering the potential load.
STA considers the QoS-specified network load, and selects target BSS consi- dering the potential load.
(Re)Association Request
(Re)Association Request
(Re)Association Response
(Re)Association Response
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

15. Procedures and Usage Scenarios (2)
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Procedures and Usage Scenarios (2)
STA Statistics Request/Report:
STAx AP
Measurement Request (STA Statistics Request IE)
Measurement Report (STA Statistics Report IE ( AC Station Count)
STA considers the QoS-specified network load, and selects target BSS consi- dering the potential load.
Roaming Management Request
Roaming Management Response
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

16. Procedures and Usage Scenarios (3)
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Procedures and Usage Scenarios (3)
Neighbor Request/Report:
AP2
AP1
Neighbor Report Request ( Neighbor Report IE )
Neighbor Report Response ( Neighbor Report IE (AC STA Count) )
Inter-AP load balancing is enabled considering the potential load
Disassociation
(Re)Association Request
(Re)Association Response
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

17. Collection of AC Station Count
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Collection of AC Station Count
The AC Station Count can be collected by AP via many ways.
One example way is to use the traffic generation information in association/reassociation request frame proposed by v-traffic-generation-information-proactive-load-management.ppt
- The traffic generation IE denotes the AC that a terminal is to support.
- AP extracts the AC and count the terminal to the AC station count accordingly.
- If the traffic flag indicates “voice” terminal, then the AC1 STA count, i.e. VO STA Count increments 1.
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

18. Summary and Recommendation
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Summary and Recommendation
The proposed AC Station Count enables the QoS-aware load balancing considering both active and inactive load status.
Part of subfields corresponding to specific AC is allowed for the frame efficiency.
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company

19. Thanks & Questions Jan. 2007 Month Year doc.: IEEE 802.11-yy/xxxxr0
Lei Du, DoCoMo Beijing Labs
John Doe, Some Company