1. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 1 QoS aware Load Balancing Date: 2007-01-09 Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at.http:// ieee802.org/guides/bylaws/sb-bylaws.pdfstuart.kerry@philips.compatcom@ieee.org Authors:

2. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 2 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.

3. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 3 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 802.11 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 prority, i.e. EDCA in 11e, hence the load information specifying different access category or user priority is required.

4. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 4 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 activ 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 802.11 standard.

5. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 5 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. AP Selection Scenario Who shall I access? AP1 Associated with AP1 AP2 Associated with AP2 MT3 MT1 AP1: 5 active VoIP STAs 100 inactive VoIP STAs 4 BE STAs Even with the same active load status, AP1 should be selected due to less potential blocking probability. Inactive Active AP2: 5 active VoIP STAs 200 inactive VoIP STAs 4 BE STAs

6. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 6 Current load information Current load information in 802.11 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 802.11 standard.

7. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 7 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

8. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 8 Beacon Frame Table 8—Beacon frame body OrderInformationNotes 30AC Station Count The AC Station Count element shall be present in a QoS AP where dot11RadioMeasurementEnabled is true. Add two new elements in table 8:

9. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 9 Probe Response Frame Table 15—Probe Response frame body OrderInformationNotes 29AC Station Count The AC Station Count element shall be present in a QoS AP where dot11RadioMeasurementEnabled is true. Add two new elements in table 15:

10. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 10 STA Statistics Report IE (1) Change the order 10 in table 31b as follows: Group Identity Requested Statistics Returned 10dot11BSSAverageAccessDelay Group (only available at an AP): dot11STAStatisticsAPAverageAccessDelay (INTEGER), dot11STAStatisticsAverageAccessDelayBestEffort (INTEGER), dot11STAStatisticsAverageAccessDelayBackGround (INTEGER), dot11STAStatisticsAverageAccessDelayVideo (INTEGER), dot11STAStatisticsAverageAccessDelayVoice (INTEGER), dot11STAStatisticsACStationCount (INTEGER), 11 － 255 None Table 31b － Group Identity for a STA Statistics Report (continued)

11. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 11 STA Statistics Report IE (2) Change the order 10 in table 31b as follows: Change Figure 85k as follows: dot11ST A Statistics AP Average Access Delay dot11STA Statistics AverageA ccess DelayBes tEffort dot11STA Statistics AverageA ccess DelayBac kGround dot11ST A Statistics Average Access DelayVid eo dot11STA Statistics AverageA ccess DelayVoic e dot11STA Statistics ACStation Count 111113-11 Figure 85k---Measurement Report field format for dot11BSSAverageAccessDelay Group Octets:

12. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 12 Neighbor Report IE Change the table 43B in 802.11v Draft 0.05 as follows: Change Figure 85k as follows: Sub-Element IDName 0Reserved 1TSF Information 2Roaming Candidate Preference 3QBSS Available Admission Capacity 4AC Station Count 4 5-10Reserved 11QBSS Load 12-255Reserved Table 43B—Optional Extensions

13. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 13 Access Category Station Count 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. Element IDLengthStation Count Bitmask Station Count List Octets:1112 x (total number of non-zero bits in Station Count Bitmask) Table 44a － Station Count Bitmask Definition Bit (s)Station Count Reported 0 AC 0 (VO) 1AC 1 (VI) 2AC 2 (BE) 3AC 3 (BK) 4-7Reserved Figure X1--- AC Station Count element format

14. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 14 Procedures and Usage Scenarios (1) AP STAx Beacon (AC1 STA Count) (Re)Association Request STA considers the QoS- specified network load, and selects target BSS consi- dering the potential load. (Re)Association Response APSTAx Probe Request (Re)Association Request (Re)Association Response Probe Response (AC1 STA Count ) Passive scanning:Active scanning: STA considers the QoS- specified network load, and selects target BSS consi- dering the potential load.

15. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 15 Procedures and Usage Scenarios (2) AP STAx Measurement Request (STA Statistics Request IE) Measurement Report (STA Statistics Report IE ( AC Station Count) Roaming Management Response STA Statistics Request/Report: Roaming Management Request STA considers the QoS- specified network load, and selects target BSS consi- dering the potential load.

16. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 16 Procedures and Usage Scenarios (3) AP1 AP2 Neighbor Report Request ( Neighbor Report IE ) Inter-AP load balancing is enabled considering the potential load (Re)Association Response Neighbor Request/Report: Disassociation Neighbor Report Response ( Neighbor Report IE (AC STA Count) ) (Re)Association Request

17. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 17 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 Jeong’s proposal (xxxx). - 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.

18. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 18 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.

19. doc.: IEEE 802.11-06/1726r2 Submission Jan. 2007 Lei Du, DoCoMo Beijing LabsSlide 19 Thanks & Questions