1. Submission doc.: IEEE 11-14/0381r0 March 2014 Filip Mestanov, Ericsson ABSlide 1 Stadium scenario for HEW Date: 2014-03-19 Authors:

2. Submission doc.: IEEE 11-14/0381r0 March 2014 Filip Mestanov, Ericsson ABSlide 2 Abstract Modern sport arenas and stadiums provide a variety of services that enrich spectators’ experience with additional channels for observation and entertainment. 802.11 WLAN plays a key role in these deployments. E.g. through WLAN connected smartphones spectators can review important game events in slow motion or from different angles. Serving these high numbers of spectators requires extremely dense BSS deployments that are technologically unique and challenging. This is an initial proposal for modeling of a stadium scenario with dense BSS deployments and high user density.

3. Submission doc.: IEEE 11-14/0381r0March 2014 Filip Mestanov, Ericsson ABSlide 3 Contents The Stadium challenge Stadium deployments Model proposal Summary

4. Submission doc.: IEEE 11-14/0381r0March 2014 Filip Mestanov, Ericsson ABSlide 4 The Stadium challenge Several hundreds of APs concentrated in small area  High number of overheard APs 50,000 – 100,000 potential users  Very high interference levels and a raised noise floor One AP typically covers 150-200 seats. Traffic demands are in the order of 30-70 GB/hour during an event Currently, traffic profile is more heavy on UL than DL (~80/20 UL/DL), but likely to change in the future with the adoption of new applications [1] RF planning very important

5. Submission doc.: IEEE 11-14/0381r0March 2014 Filip Mestanov, Ericsson ABSlide 5 Stadium deployments Stadium WLAN deployments are typically very well planned Directional antennas are used to increase isolation between the large number of BSSs Antennas may point from the pitch and upwards, or towards the pitch There will typically be 3-4 rings of BSSs covering the arena bowl seating areas Each such ring will typically have an AP-AP distance of 10-30 m.

6. Submission doc.: IEEE 11-14/0381r0March 2014 Filip Mestanov, Ericsson ABSlide 6 Stadium deployments From internal measurement studies of Ericsson’s WLAN deployments we learned: Case study 1: For 2.4 GHz Only ~10% of the samples are without any detected neighbor cell/AP. About 50% of the samples has 3 interfering APs detected. Up to a total of 11 APs are detected simultaneously for some spots at pitch. For 5 GHz Things become slightly better at 5GHz and ~35-38 % of the samples are clear from neighbor interference, but there are spots with up to 5 neighbor APs detected. Case study 2: 2.4 GHz: Typically 11 other APs overheard by an AP. 5 GHz: Typically 5 other APs overheard by an AP. 20 – 80 associated STAs / AP (AP with 2.4 & 5 GHz)

7. Submission doc.: IEEE 11-14/0381r0 Stadium deployments Example of a “typical” deployment: “3-ring deployment” AP-AP distance in the same ring ~12 m. AP-AP distance between the rings 10-25 m. Antenna beamwidths 20x20 – 40x40deg. Note: colors do not indicate channel allocation! March 2014 Filip Mestanov, Ericsson ABSlide 7

8. Submission doc.: IEEE 11-14/0381r0March 2014 Filip Mestanov, Ericsson ABSlide 8 Stadium deployments Example RSSI prediction of stadium 2.4 GHz WLAN deployment 97.7% > -65 dBm

9. Submission doc.: IEEE 11-14/0381r0March 2014 Filip Mestanov, Ericsson ABSlide 9 Stadium deployments Example RSSI prediction of stadium 2.4 GHz WLAN deployment

10. Submission doc.: IEEE 11-14/0381r0 Consider a section of the seating gallery of size 12x18 m. One seat = 1x1.5 m.  12 x 12 = 144 seats If 25% connect  36 STAs If 50% connect  72 STAs This section is covered from the back by an AP with directional antenna. Row 1 Row 2. Row 12 18 m. 12 m. Model proposal wrapped strip, 2D

11. Submission doc.: IEEE 11-14/0381r0 Now consider an area of 9x3 such sections (108x54 m.). From-above view (example with 3 channel reuse): Model proposal wrapped strip, 2D Pitch

12. Submission doc.: IEEE 11-14/0381r0March 2014 Filip Mestanov, Ericsson ABSlide 12 Wrapping By using wrap-around at the left and right edges there will be no edge-effects. All STAs and APs will see interference from all directions. All APs and STAs are wrapped Example: Wrapping of the signal from an edge AP, the signal falling outside the left edge will be copied to the right edge.

13. Submission doc.: IEEE 11-14/0381r0 Possibly a 3D extension may be considered, where the different sections of the arena seating are overlapping each other, and the interference is only hitting a part of the section below. Model proposal wrapped strip, 3D Pitch

14. Submission doc.: IEEE 11-14/0381r0 Summary: Model proposal wrapped strip, 2D Simulation area is a strip of dimensions 108x54 m., subdivided into 9x3 sections of 12x18 m., each section containing 144 tentative STA positions and one AP. The strip is wrapped at the left and right edges. If 3D effects need to be captured, the strip can be split in three narrow strips, which are tilted towards the pitch and partly overlapping. Directional AP antennas: HPBW: TBD deg. Max gain: TBD dBi Tilt: TBD deg. AP-AP distance: 12 m. left-right, 18 m. towards pitch. AP-AP distance, same channel for reuse 3 (2.4 GHz): 36m. left-right 2 subscriber fraction cases proposed: Low: 25% of the seats connect  36 STAs/AP, 972 in system. High: 50% of the seats connect  72 STAs/AP, 1944 in system. Note: Traffic load generated per associated STA may still vary within the cases

15. Submission doc.: IEEE 11-14/0381r0 References [1] 11-14-0301-00-0hew-multicast-considerations-for-hew, Eisuke Sakai, Sony Corporation

16. Submission doc.: IEEE 11-14/0381r0 Across the pitch interference (1) The model assumes antennas pointing towards the pitch, antennas pointing away is actually better, since it eliminates across-the-pitch interference, might however be hard to realize in real life installations. However, with heavy down tilt the across-the-pitch interference from APs can be minimized. However, STA-STA interference will still occur across the pitch. Depending on if this needs to be considered, two strips may have to be simulated. March 2014 Filip Mestanov, Ericsson ABSlide 16

17. Submission doc.: IEEE 11-14/0381r0 Across the pitch interference (2) To capture across-the-pitch interference two parallel strips can be simulated, separated by a pitch-width of 80 m. March 2014 Filip Mestanov, Ericsson ABSlide 17 Wrap