1. doc.: IEEE 802.11-11/0337r0 Submission Mar 2011 Dwight Smith, Motorola MobilitySlide 1 Discussion – Issues with Access at Portals Date: 2011-03-14 Authors: Dwight SmithMotorola Mobility 5300 Westport Parkway Fort Worth, TX 76177 +1 682-514-4861dwight.smith@motorola.com

2. doc.: IEEE 802.11-11/0337r0 Submission Mar 2011 Dwight Smith, Motorola MobilitySlide 2 Abstract A portal is a location that gets many requests for associations from devices that are mostly transient and will not be keeping their association at that location. The rate of incident of association request may be near continuous or periodic but the peek levels will be problematic in the current environment. This presentation presents some of the issues seen by portals and how they are problematic in seeking Fast Initial Link Setups for those devices passing through.

3. doc.: IEEE 802.11-11/0337r0 Submission Mar 2011 Dwight Smith, Motorola MobilitySlide 3 Examples of Portals Sports Arena – the entrance gates of many sports venues will be the first AP of an ESS that a STA may encounter. Many people would be arriving for a game or match and they would be directed through these entrances. Following their entry (ticket/security) the people and their STAs would move toward concessions/seats and away from the entrance. Transportation gateway – Airport gates and bus/train platforms see large numbers of people with STAs when the vehicle arrives and opens its door(s). Such people tend to move on – to other gates or to the exits. Transit paths – many subways (and other similar locations) see much passing traffic (as with people switching from one train line to another). Unless there are concessions along the way, most people will pass through and not stop for long session periods.

4. doc.: IEEE 802.11-11/0337r0 Submission Mar 2011 Dwight Smith, Motorola MobilitySlide 4 This problem is getting worse Smartphones are increasingly replacing normal phones. These devices are Wi-Fi compatible and more likely to operate in an 'always-connected' mode where they will look to get connected where they find a usable Wi-Fi connection. –Smartphone usage is different than laptops – the expectation is that they operate like phones and are used all the time HotSpot 2.0 efforts are likely going to add loads to the Link Setup operation: –Move from free/open links to secured/authenticated links –Service discovery (some based on 11u GAS data queries) will involve larger beacons and/or more probes/resp queries Richer media – there is more streamed media content available and as users are consuming this type of data they will be more aware of the 'link outages' they experience compared to the web browsing experience

5. doc.: IEEE 802.11-11/0337r0 Submission Mar 2011 Dwight Smith, Motorola MobilitySlide 5 Some Difficulties that Arise - 1 Competitive Association Requests – when a train door opens devices will see beacons and start trying to associate/authenticate – increasing loads and possibly increasing rates of congestion/backoff retries –This gets worse as STAs get more aggressive with their connection management (always-on feature) –If 11ai improves the scan interval it feeds this issue as well With people and their devices moving through the portal, can we maintain a comparable rate of 'handoff' with devices reassociating at other APs in ESS? –Can the support of Fast BSS Transition (11r) be addressed in the initial link or down stream?

6. doc.: IEEE 802.11-11/0337r0 Submission Mar 2011 Dwight Smith, Motorola MobilitySlide 6 Some Difficulties that Arise - 2 Short duration of potential association at initial AP – one of the characteristics of portals is that people tend to move away (get off train, go to seats). Consequently, the AP may have issues: –Association/Authentication activities may not complete while STA in reach of AP – could have heavy level of traffic for device that do not complete Setup –Limited number of AIDs – if a quick association is made (and AID assigned) and device moves on the AP needs to get control of the AID value quickly (but user speed may keep reassoc from happening) Note that as the range of AIDs increases, the TIM field in Beacon could get large due to the spacing of the AID numbers involved)

7. doc.: IEEE 802.11-11/0337r0 Submission Mar 2011 Dwight Smith, Motorola MobilitySlide 7 Discussion and Review Are the issues from discussion sufficiently covered in the current use cases? –Do we need to add/expand use case(s) to help focus issues? Have we considered impact of other efficiencies? –11u – GAS service discovery –11r – Prep for BSS transition in setup Does association with 'first AP' matter – for Fast Initial Link? –If AP load is too high to support 'data'? –If STA is not expected to actually stay in area?