1. doc.: IEEE 802.11-04/XXXr0 Submission May 2004 Masahiro Takagi and Tomoko Adachi, TOSHIBASlide 1 Simulation Scenarios and Comparison Criteria for Coexistence Masahiro Takagi takagi@csl.rdc.toshiba.co.jp Tomoko Adachi adachi@csl.rdc.toshiba.co.jp TOSHIBA CORPORATION

2. doc.: IEEE 802.11-04/XXXr0 Submission May 2004 Masahiro Takagi and Tomoko Adachi, TOSHIBASlide 2 What PAR says about Coexistence Additional Explanatory Notes in PAR –Table 1 “ Evaluation Metrics ” includes “ coexistence ” as an evaluation parameter. PAR (11-02-798r7) itself does not have the definition of “ coexistence ”, but draft PAR (11-02-798r6) has the following definition –The ability of one system to perform a task in a given shared environment in which other systems have an ability to perform their tasks and may or may not be using the same set of rules. It is impractical to evaluate the coexistence of HT system with all other systems. But coexistence of HT system with Legacy 802.11a/g system should be evaluated. –This should be regarded as a responsibility of 802.11 WG.

3. doc.: IEEE 802.11-04/XXXr0 Submission May 2004 Masahiro Takagi and Tomoko Adachi, TOSHIBASlide 3 Review of Simulation Scenarios and Comparison Criteria w.r.t. Coexistence (1/2) Legacy 802.11 coexistence are supposed to be evaluated by SS9 and SS11 (clause 8.1 of 11-03-802r18 “ Usage Models ” ) –Scenario 9 (Mixed-Mode BSS) 3 Legacy STAs and 3 HT STAs associate with the mixed-mode AP. –Scenario 11(Co-channel legacy BSS) Legacy BSS and HT BSS shares the same wireless medium (location and channel). Table.6 of 11-03-802r18 has the following note: –Note, the BSSs are overlapping, without any STA/AP being exactly on top of another STA/AP. –This note implies HT BSS shall not dictate legacy STA/AP ’ s media access. No comparison criterion in 11-03-803r25 refers to SS9 and SS11. –This inconsistency has been introduced during FRCC comment resolution process, since the references to SS9 and SS11 were removed from CC18, 19 and 20.

4. doc.: IEEE 802.11-04/XXXr0 Submission May 2004 Masahiro Takagi and Tomoko Adachi, TOSHIBASlide 4 Review of Simulation Scenarios and Comparison Criteria w.r.t. Coexistence (2/2) CC15 “ Sharing of medium with legacy devices ” –Scenario 17 (Point-to-Point HT Goodput Test for CC 15) HT STA associates with AP. –Scenario 18 (Point-to-Point Legacy Throughput Test for CC 15) Legacy STA associates with AP. –Scenario 19 (Point-to-Point Legacy Sharing Throughput Test for CC 15) HT STA and Legacy STA associates with AP. SS19 can be regarded as a simplified version of SS9, But one aspect of coexistence which are supposed to be evaluated by SS11 cannot be covered by these simulation scenarios. –HT AP cannot control the media access of Legacy STA in the other Legacy BSS.

5. doc.: IEEE 802.11-04/XXXr0 Submission May 2004 Masahiro Takagi and Tomoko Adachi, TOSHIBASlide 5 Simplified simulation scenario corresponding to SS11 for CC15 HT BSS part is same as SS17. Legacy BSS part is same as SS18. The distance between HT STA and 11a STA are determined so that the RSSI at 11a STA (-64.47dBm) is below the CCA threshold power (-62dBm). –(HT STA TxPower = 17dBm, Channel B) –This configuration is appropriate to evaluate protection mechanisms of HT systems. CC15 reports the goodputs of HT STA and 11a STA in this scenario respectively in addition to T1, T2, T3 and T4. HT AP 20m 10m HT STA11a STA 10m 22.368m 11a AP 20m 10m Legacy BSSHT BSS

6. doc.: IEEE 802.11-04/XXXr0 Submission May 2004 Masahiro Takagi and Tomoko Adachi, TOSHIBASlide 6 Conclusion Coexistence of HT system with legacy 802.11a/g system should be evaluated. Current comparison criteria cannot evaluate HT BSS and Legacy BSS coexistence at all. Simple simulation scenario and modification of CC15 for HT BSS and Legacy BSS coexistence evaluation is proposed. Evaluation of the coexistence should use SS11 or the proposed simulation scenario.

7. doc.: IEEE 802.11-04/XXXr0 Submission May 2004 Masahiro Takagi and Tomoko Adachi, TOSHIBASlide 7 Backup Slides

8. doc.: IEEE 802.11-04/XXXr0 Submission May 2004 Masahiro Takagi and Tomoko Adachi, TOSHIBASlide 8 IEEE802.11a CCA sensitivity 17.3.10.5 CCA sensitivity The start of a valid OFDM transmission at a receive level equal to or greater than the minimum 6 Mbit/s sensitivity (- 82 dBm) shall cause CCA to indicate busy with a probability >90% within 4 µs. If the preamble portion was missed, the receiver shall hold the carrier sense (CS) signal busy for any signal 20 dB above the minimum 6 Mbit/s sensitivity (-62 dBm).

9. doc.: IEEE 802.11-04/XXXr0 Submission May 2004 Masahiro Takagi and Tomoko Adachi, TOSHIBASlide 9 Path Loss Model Dth = 5m (Channel A,B and C) 10m (Channel D) 20m (Channel E) 30m (Channel F)