1. doc.: IEEE 802.11-09/0161r1 Submission Doc.:IEEE 802.11-09/0537r0 May 11th, 2009 Slide 1 Measured Doppler Frequency in Indoor Office Environment Date: 2009-05-11 Authors: doc.:IEEE 802.11-09/0537r0

2. doc.: IEEE 802.11-09/0161r1 Submission Doc.:IEEE 802.11-09/0537r0 Purpose of this measurement Although there is a model for Doppler frequency in IEEE802.11n, we could not find other reliable papers for Doppler frequency effect in indoor environment. Since SDMA performance may be vulnerable to the channel variation compared to single user MIMO, Doppler frequency should be carefully considered in IEEE802.11ac. We conducted measurements to show actual Doppler frequency effects in a typical office room. The followings are the measured two scenarios. (1) Influence of fluorescent light: Measured environment is shown in page5-6 (2) Comparison between LOS and NLOS environment: Measured environment is shown in page7-8.

3. doc.: IEEE 802.11-09/0161r1 Submission Doc.:IEEE 802.11-09/0537r0 Measurement equipment 10MHz L.O. Signal Generator Transmitter site Wireless Communication Analyzer (Base band real-time spectrum analyzer) Receiver site LNA Sleeve antenna (Omni-directional) Sleeve antenna (Omni-directional)

4. doc.: IEEE 802.11-09/0161r1 Submission Doc.:IEEE 802.11-09/0537r0 Measurement parameter Frequency 4.85GHz Signal CW Transmit power 0 dBm Number of FFT 1024 Frequency span 100 Hz Antenna height (Mes.1) 1.7m (Tx), 0.7m (Rx) Antenna height (Mes.2) 2.7m (Tx), 0.7m (Rx)

5. doc.: IEEE 802.11-09/0161r1 Submission Doc.:IEEE 802.11-09/0537r0 Measurement place (A) In this measurement, the receive antenna is located at the position B. Influence of fluorescent light is evaluated.

6. doc.: IEEE 802.11-09/0161r1 Submission Doc.:IEEE 802.11-09/0537r0 Photo of measurement place (A) Transmit antenna Receive antenna There is no people between the transmit and receive antennas.

7. doc.: IEEE 802.11-09/0161r1 Submission Doc.:IEEE 802.11-09/0537r0 Measurement place (B) 女子更衣室 男子更衣室 書庫 / 倉庫ｽﾍﾟｰｽ 円卓 P P ＋専用 FAX 脇机 + 書庫 書庫 COPY P P FAX 冷・ﾚﾝｼﾞ TV ﾄﾞｱ たな ﾄﾞｱ 紙置場 LAN スペース ﾄﾞｱ 富士山側 Tx2 Rx1 Window LOS NLOS LOS (Line of sight) and NLOS (Non LOS) are assumed.

8. doc.: IEEE 802.11-09/0161r1 Submission Doc.:IEEE 802.11-09/0537r0 Photo of measurement place (B) Tx2(1.2m)-Rx1(0.75m) Transmit antenna Spectrum analyzer 0.7m 2.7m Receive antenna Sometime, people walk between the transmitter and receiver.

9. doc.: IEEE 802.11-09/0161r1 Submission Doc.:IEEE 802.11-09/0537r0 In our measurement, the measured Doppler frequency was not affected by the fluorescent condition, i.e. light was on or off. As can be seen in the slide, the bell shape curve fits to the measured Doppler frequency while fd is around 0.10Hz but not 1Hz Influence of fluorescent light ON OFF 1Hz 0.1Hz

10. doc.: IEEE 802.11-09/0161r1 Submission Doc.:IEEE 802.11-09/0537r0 In the channel model of IEEE802.11n, 0 Hz component was removed from the measured Doppler frequency not to include the direct path component. However, we found that 0 Hz component still existed even in the LOS environment. fd was around 0.05~0.2 Hz so the Doppler frequency in a typical office may be lower than that in IEEE802.11n channel model. Comparison between LOS and NLOS NLOS fd=0.05Hz LOS fd=0.05Hz

11. doc.: IEEE 802.11-09/0161r1 Submission Doc.:IEEE 802.11-09/0537r0 CDF of Measured Doppler Frequency The measured Doppler frequency are around 0.1Hz and Doppler frequency variation is small in each measurement. 1 st mes. 2 nd mes. 3 rd mes. 4 th mes Interval of the measurement: 10 minutes Time duration for each measurement: 30 seconds

12. doc.: IEEE 802.11-09/0161r1 Submission Doc.:IEEE 802.11-09/0537r0 Conclusion Dependency on the fluorescent condition was not observed in our measurement. The estimated fd from the measured data was around 0.05~0.2Hz which was much lower than that of IEEE802.11n channel model. Ignoring 0 Hz component may not be a reasonable way to evaluate fd because high level of 0Hz component was observed even in NLOS environment. Doppler frequency variation is small in infoor office environment.