1. Submission doc.: IEEE 11-13/0030r0 January 2013 Katsuo Yunoki, KDDI R&D LaboratoriesSlide 1 User Level Performance Date: 2013-01-07 Authors:

2. Submission doc.: IEEE 11-13/0030r0 January 2013 Katsuo Yunoki, KDDI R&D LaboratoriesSlide 2 Abstract This submission is: a supporting document for 11-13/0009r0 (InterDigital, etc.), indicating possible reasons of performance degradations on WLAN communication,

3. Submission doc.: IEEE 11-13/0030r0 January 2013 Katsuo Yunoki, KDDI R&D LaboratoriesSlide 3 An 11ai STA: Is mobile, Is connected with cellular network usually, Tries to associate with an 11ai AP automatically when it enters into that coverage area and Executes transitions between cellular and WLAN without user’s operation. Cellular macro cell WLAN access point Isolated WLAN area

4. Submission doc.: IEEE 11-13/0030r0 January 2013 Katsuo Yunoki, KDDI R&D LaboratoriesSlide 4 User Experience at transition from cellular to WLAN Quick transition (FILS) Slow... Fast! Cellular NWWLAN AP Quick transition (FILS) GOOD!! Unsatisfied! Cellular NW (LTE, WiMAX, etc.) WLAN AP Good quality Higher throughput Congested, Not so fast Congested!! Appropriate performance

5. Submission doc.: IEEE 11-13/0030r0January 2013 Katsuo Yunoki, KDDI R&D LaboratoriesSlide 5 User Level Performance User level performance is measured by “end- to-end performance” from STA to content server, while using WLAN communication. Major performance indicators are: Throughput Round trip delay Jitter Packet loss Possible reasons of performance degradations on each section are described on the following slides:

6. Submission doc.: IEEE 11-13/0030r0January 2013 Katsuo Yunoki, KDDI R&D LaboratoriesSlide 6 Network Diagram Example of public WLAN spot service STA AP Content servers Access Network Core GW Internet GW Service Provider Facility APC AAA DHCP The Internet (1)802.11 Link (2)Backhaul Link (3)Core network & Facilities (4)The Internet (5)Access net at another end & servers

7. Submission doc.: IEEE 11-13/0030r0January 2013 Katsuo Yunoki, KDDI R&D LaboratoriesSlide 7 Possible Reasons of Degradations (1) 802.11 Link Low signal strength, Low available PHY rate, Congestion (many terminals), Many associated terminals, Hidden terminals, Interference, etc.

8. Submission doc.: IEEE 11-13/0030r0January 2013 Katsuo Yunoki, KDDI R&D LaboratoriesSlide 8 Possible Reasons of Degradations (2) Backhaul Link Low PHY rate, Congestion (best effort), Sometimes, backhaul link is also wireless link, LTE, WiMAX, WLAN, etc. for faster deployment Larger delay than wired link etc.

9. Submission doc.: IEEE 11-13/0030r0January 2013 Katsuo Yunoki, KDDI R&D LaboratoriesSlide 9 Possible Reasons of Degradations (3) Core Network & Center Facilities (4) The Internet Not critical generally Except in case of disaster or unusual situation, etc. Sufficient bandwidth and processing power relative to 802.11 and Backhaul link

10. Submission doc.: IEEE 11-13/0030r0January 2013 Katsuo Yunoki, KDDI R&D LaboratoriesSlide 10 Possible Reasons of Degradations (5) Content Server Side Insufficient processing power in content server or access GW router Insufficient bandwidth in access network  however, these are not issues generally.

11. Submission doc.: IEEE 11-13/0030r0January 2013 Katsuo Yunoki, KDDI R&D LaboratoriesSlide 11 Summary Major reasons of user level performance degradations on WLAN communications locate on 802.11/backhaul link mainly. Indications of 802.11/backhaul link performance from an AP will prevent unhappy transition from cellular to WLAN on an user terminal. Method for notification about cellular side performance degradations should be determined by 3GPP, etc.