1. doc.: IEEE 802.11-14/1443r0 SubmissionEsa Tuomaala Adapting CCA and Receiver Sensitivity Date: 2014-11-03 Authors: Slide 1 November 2014

2. doc.: IEEE 802.11-14/1443r0 Submission Background CCA/Receiver Sensitivity –Threshold governing packet reception (decode NAV and deferral) –More aggressive threshold governing pure energy detection Maximum threshold defined by the standard –Vendors are free to have more ‘sensitive’ receivers (e.g. -90dBm vs. -82 dBm) Modifying CCA has shown various levels of gain [1-6] –Uniform thresholds have shown mixed results Adaptive thresholds proposed in [7] November 2014 Esa TuomaalaSlide 2

3. doc.: IEEE 802.11-14/1443r0 Submission This Contribution Scenario 1 simulations shown with varying receiver sensitivities Demonstrating the unfairness in per-floor throughput Impact of local adaptation of thresholds (per-floor basis) November 2014 Esa TuomaalaSlide 3

4. doc.: IEEE 802.11-14/1443r0 Submission Contention Domains November 2014 Esa TuomaalaSlide 4 Relative size of contention domains affects throughput –More contention for crowded areas –Less contention in certain spots (e.g. building edges) Easily observed in the 11ax scenarios (e.g. Scenario 1) -82dBm

5. doc.: IEEE 802.11-14/1443r0 Submission In a dense deployment, not all STAs/APs experience the same conditions Multiple parameters could be adjusted to improve fairness –EDCA parameters: adjust contention window, TXOP duration, etc… –CCA/Receiver Sensitivity/Color bit: shrink deferral radius The above parameters can be optimized to improve spatial reuse while maintaining fairness November 2014 Esa TuomaalaSlide 5 Improving Fairness

6. doc.: IEEE 802.11-14/1443r0 Submission Centralized –Feasible in managed environments (e.g. corporate setting) –Can arrive at a better solution according to given metrics (e.g. 5% throughput) Distributed –Using beacons or inter-AP communication to set per BSS parameters –AP could assign parameters to all associated STAs (RAW concept) –Hybrid approach possible (centralized in-BSS, distributed inter- BSS) November 2014 Esa TuomaalaSlide 6 Adjusting Parameters

7. doc.: IEEE 802.11-14/1443r0 Submission Scenario 1 (Residential) : Setup Assumptions: –1 AP Per apartment –2 STAs per AP –Uplink only traffic (full buffer AC2) –Fading OFF –11ax Scenario 1 Pathloss formula –AP: 21dBm, STA: 15dBm Parameters: –Fixed MCS: 256QAM ¾ –RTS/CTS OFF –80 MHz Channel (single channel) –Max Number of AMPDUs: 64 November 2014 Esa TuomaalaSlide 7 Residential Scenario [8] Floor layout 10 m 3 m

8. doc.: IEEE 802.11-14/1443r0 Submission Scenario 1 (Residential) : Results Floor plots –Average throughput per apartment over a large number of drops –Each drop with random node positioning –Results displayed in Kbps CDFs: –Per floor throughput for all nodes in all drops –Clear symmetries in floors 1,5 and 2,4 as expected November 2014 Esa TuomaalaSlide 8

9. doc.: IEEE 802.11-14/1443r0 Submission Receiver sensitivity: -90dBm Floors 1,5 get much better throughput than 2-4 Significant difference in floor throughput (unfair) November 2014 Esa TuomaalaSlide 9 Default (-90dBm) floors 2-4 with worse throughput better throughput at edge

10. doc.: IEEE 802.11-14/1443r0 Submission Receiver sensitivity: -82dBm Overall throughput is improved Floors 2-4 still receive poor throughput compared to 1,5 November 2014 Esa TuomaalaSlide 10 -82 dBm worse throughput better throughput at edge

11. doc.: IEEE 802.11-14/1443r0 Submission Receiver sensitivity: -72dBm General picture improves November 2014 Esa TuomaalaSlide 11 -72 dBm

12. doc.: IEEE 802.11-14/1443r0 Submission More ‘fair’ by using per-floor thresholds No optimization done for best thresholds 5 th percentile suffers on some floors November 2014 Esa TuomaalaSlide 12 -86,-65,-62,-65,-86 dBm almost uniform throughput per floor (fair) better throughput persists

13. doc.: IEEE 802.11-14/1443r0 Submission Scenario 1 (Alternate Pathloss) Same as previous setup, only pathloss is modified: –Floor penetration loss is 10dB per floor, wall loss remains at 5dB How scenario dependent are the thresholds? –How adaptive should they be? November 2014 Esa TuomaalaSlide 13

14. doc.: IEEE 802.11-14/1443r0 Submission Receiver sensitivity: -82dBm Floor 3 has better throughput because floors 2,4 rarely transmit Very different results compared to prior pathloss model November 2014 Esa TuomaalaSlide 14 -82 dBm (alternate PL)

15. doc.: IEEE 802.11-14/1443r0 Submission Receiver sensitivity: -72dBm Some improvements, but floors 2 & 4 continue to do poorly November 2014 Esa TuomaalaSlide 15 -72 dBm (alternate PL)

16. doc.: IEEE 802.11-14/1443r0 Submission Conclusion Fundamental Unfairness –With fixed thresholds, we show that there is unfairness (based on location, interference, etc.) –The unfairness can be mitigated by intelligent selection of thresholds Results are scenario dependent –Results are sensitive to path loss parameters and scenario setup We show that adaptive configuration of CCA threshold or receiver sensitivity can help improve spatial reuse while maintaining fairness November 2014 Esa TuomaalaSlide 16

17. doc.: IEEE 802.11-14/1443r0 Submission References [1] IEEE 802.11-14/0082r0 – Improved Spatial Reuse Feasibility – Part I [2] IEEE 802.11-14/0083r0 – Improved Spatial Reuse Feasibility – Part II [3] IEEE 802.11-14/0372r2 – System Level Simulations on Increased Spatial Reuse [4] IEEE 802.11-14/846r1 – Changing CCA in the Residential Environment [5] IEEE 802.11-14/861r0 – Impact of CCA adaptation on spatial reuse in dense residential scenario [6] IEEE 802.11-14/0578r0 - Residential Scenario CCA/TPC Simulation Discussion [7] IEEE 802.11-14/1233r2 – Adaptive CCA for 11ax [8] IEEE 802.11-14/0621r4 – TGax Simulation Scenarios November 2014 Esa TuomaalaSlide 17