doc.: ieee 802.11-09/0161r1 submission doc.: ieee 802.11-09/1031r0 measurement results for obss in...
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doc.: IEEE /0161r1 Submission doc.: IEEE /1031r0 September 2009 K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT) Slide Measurement place 3.0 m 7.3 mTRANSCRIPT
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
Name Affiliations Address Phone email Kentaro Nishimori NTT Corporation Hikarino-oka
Yokosuka-shi Japan +81 46 859 8266
Tomoki Murakami NTT Corporation Hikarino-oka Yokosuka-shi Japan
+81 46 859 2057
Riichi Kudo NTT Corporation Hikarino-oka Yokosuka-shi Japan
Yasushi Takatori NTT Corporation Hikarino-oka Yokosuka-shi Japan
Yusuke Asai NTT Corporation Hikarino-oka Yokosuka-shi Japan
+81 46 859 3494
Authors:
doc.: IEEE 802.11-09/0161r1
Submission
doc.: IEEE 802.11-09/1031r0September 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.
doc.: IEEE 802.11-09/0161r1
Submission
doc.: IEEE 802.11-09/1031r0September 2009
K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT)Slide 3
12345
6
7
Measurement place
3.0 m
7.3 m
doc.: IEEE 802.11-09/0161r1
Submission
doc.: IEEE 802.11-09/1031r0September 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
2S3 S4
S1 S21S5
7.3 m
3.0 m
Measurement
doc.: IEEE 802.11-09/0161r1
Submission
doc.: IEEE 802.11-09/1031r0September 2009
K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT)Slide 5
Measurement equipment
TCP-IP
Down-conv.AGCA/D
Up-conv.
Up-conv.
MTTCP-IPChannel estimator
Rx (AP) : 8 elementh = 2.12 m
Tx (STA) : 4 elementh = 2.12/0.9, 0.75 m
Preamble generator
D/A
D/A
Up-conv. D/A
Up-conv. D/AAGCA/D Down-conv.
Down-conv.
Down-conv.
AGCA/D
AGCA/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
LNA
LNA
LNA
HPA
HPA
HPA
HPA
doc.: IEEE 802.11-09/0161r1
Submission
doc.: IEEE 802.11-09/1031r0September 2009
K.Nishimori, T. Murakami, R.Kudo, Y.Takatori, Y.Asai (NTT)Slide 6
Image of interference from OBSS
AP
STA
AP
STA
(desired)
(desired)
(OBSS)
(OBSS)
(my room)(other person’s room)
Measured path
doc.: IEEE 802.11-09/0161r1
Submission
doc.: IEEE 802.11-09/1031r0September 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)
doc.: IEEE 802.11-09/0161r1
Submission
doc.: IEEE 802.11-09/1031r0September 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]
[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 -45.79Averaged.
doc.: IEEE 802.11-09/0161r1
Submission
doc.: IEEE 802.11-09/1031r0
-70
-60
-50
-40
-30
-20
-10
0
0 5 10 15 20 25 30
Power[dBm]
ave
Rec
ieve
d Po
wer
[dB
m]
distance[m]
Rel
ativ
e R
ecei
ved
Pow
er [d
B]
-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 feetFor d<16.5ftLp = – 38 + 20 log F + 20 log d + Wall/Floor loss (Free Space formula)For d>16.5ftLp = – 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)
doc.: IEEE 802.11-09/0161r1
Submission
doc.: IEEE 802.11-09/1031r0September 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.
doc.: IEEE 802.11-09/0161r1
Submission
doc.: IEEE 802.11-09/1031r0September 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.