1. doc.: IEEE 802.11-09/0161r1 Submission doc.: IEEE 802.11-09/1031r0 Measurement results for OBSS in home network scenarios Date: 2009-9-22 September 2009 K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT) Slide 1 Authors:

2. doc.: IEEE 802.11-09/0161r1 Submission doc.: IEEE 802.11-09/1031r0 September 2009 K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT) Slide 2 Abstract OBSS issue is important in TGac because frequency channel shortage is expected [1, 2]. In Ref [3], the OBSS effect in apartment model is discussed using empirical path-loss formula in TGn channel model. In this document, we show the measurement results of OBSS effect in a typical Japanese apartment. From the measurement results, we confirm that it is important to consider OBSS effect in home network scenarios for 11ac system design.

3. doc.: IEEE 802.11-09/0161r1 Submission doc.: IEEE 802.11-09/1031r0 September 2009 K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT) Slide 3 1 2 3 4 5 6 7 Measurement place 3.0 m 7.3 m

4. doc.: IEEE 802.11-09/0161r1 Submission doc.: IEEE 802.11-09/1031r0 September 2009 K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT) Slide 4 AP Number of antennas = 8, Linear array (Spacing 0.5λ) STA Number of antennas = 4, Linear array (Spacing 0.5λ) S * Layout of each room in the measurement place 2 S3S4 S1 S2 1 S5 7.3 m 3.0 m Measurement

5. doc.: IEEE 802.11-09/0161r1 Submission doc.: IEEE 802.11-09/1031r0 September 2009 K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT) Slide 5 Measurement equipment TCP-IP Down-conv. AGC A/D Up-conv. MT TCP-IP Channel estimator Rx (AP) : 8 element h = 2.12 m Tx (STA) : 4 element h = 2.12/0.9, 0.75 m Preamble generator D/A Up-conv. D/A Up-conv. D/A AGC A/D Down-conv. AGC A/D AGC A/D 4x8 MIMO channel measurement was carried out for SDMA evaluation. Long preamble signal is continuously transmitted. Interference between two APs or AP/STA is assumed in this measurement. LNA HPA

6. doc.: IEEE 802.11-09/0161r1 Submission doc.: IEEE 802.11-09/1031r0 September 2009 K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT) Slide 6 Image of interference from OBSS APSTAAP STA (desired) (OBSS) (my room)(other person’s room) Measured path

7. doc.: IEEE 802.11-09/0161r1 Submission doc.: IEEE 802.11-09/1031r0 September 2009 K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT) Slide 7 Measurement parameters Frequency 4.85 GHz Bandwidth 40 MHz (20MHz x 2) Signal OFDM signal Number of FFT 128 Number of subcarrier 96 (Legacy.11a mode) Antenna height 2.12 m (Rx side) 0.75m (Tx side)

8. doc.: IEEE 802.11-09/0161r1 Submission doc.: IEEE 802.11-09/1031r0 September 2009 K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT) Slide 8 Results on Interference power ~ Horizontal neighborhood rooms~ AP (Case 1) AP height = 2.12 m height = 0.9 m (Case 2) [dBm] (Case 1) (Case 2) 3m -74.46-68.28-63.52-56.89-50.18 -78.61-69.98-65.73-55.57-41.39 3m -76.54-69.18-64.63-56.23-45.79 Averaged.

9. doc.: IEEE 802.11-09/0161r1 Submission doc.: IEEE 802.11-09/1031r0 Relative Received Power [dB] -22 -32 -42 -52 -62 -72 -82 -92 TGn Model [3] Measurement Result Measurement result agrees with the path-loss model in TGn [3]. Indoor propagation loss formula (11n) *, F in MHz, d in feet For d<16.5ft Lp = – 38 + 20 log F + 20 log d + Wall/Floor loss (Free Space formula) For d>16.5ft Lp = – 38 + 20 log F + 20 log 16.5 + 35 log (d/16.5) + Wall/Floor Loss September 2009 Slide 9 K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT)

10. doc.: IEEE 802.11-09/0161r1 Submission doc.: IEEE 802.11-09/1031r0 September 2009 K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT) Slide 10 Summary When considering the interference betweens rooms on horizontal direction, interference seems to be almost same with the TGn model.[3] Hence, the model in TGn seems to be reasonable in the evaluation of OBSS in the apartment. As well as described in [3], this result shows the influence on the interference by OBSSs is serious problem in apartment. TGac should consider and establish some scenarios to evaluate the influence of OBSS interference.

11. doc.: IEEE 802.11-09/0161r1 Submission doc.: IEEE 802.11-09/1031r0 September 2009 K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT) Slide 11 References [1] Yuichi Morioka, “Two Levels of OBSS Control in.11ac,” Doc. IEEE802.11-09/0833r0. [2] Brian Hart et al., “Enterprise Simulation Scenario,” Doc. IEEE802.11-09/0816r2. [3] Graham Smith, “Overlapping BSS Analysis of Channel Requirements,” Doc. IEEE802.11-08/1470-02-00aa.