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September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 1
doc.: IEEE 802.11-08/1020r1
Submission
WLAN field trial in high speed moving environment
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Date: 2008-09-09
Name Company Address Phone email Hitoshi MORIOKA ROOT Inc. 2-1-22-307 Momochihama,
Sawara-ku, Fukuoka 814-0001 JAPAN
+81-92-832-3391 [email protected]
Hiroshi MANO ROOT Inc. 8F TOC2 Bldg. 7-21-11 Nishi-Gotanda, Shinagawa-ku, Tokyo 141-0031 JAPAN
+81-3-5719-7631 [email protected]
Authors:
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 2
doc.: IEEE 802.11-08/1020r1
Submission
Abstract
• We introduce our WLAN field trial in high speed moving environment (> 200km/h)– Packet loss measurement
– Video Transfer
• Doppler Effect Calculation
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 3
doc.: IEEE 802.11-08/1020r1
Submission
Packet loss measurement
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 4
doc.: IEEE 802.11-08/1020r1
Submission
Location• Fuji Speedway in Japan
– May, 2007
– Weather: cloudy (no rain)
– Course length: 4.5km
– Home straight length: 1.5km
– F1 GP will be held here in next month
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 5
doc.: IEEE 802.11-08/1020r1
Submission
SystemIEEE802.11gOFDM6Pseudo ad-hoc(No BSS/Association)
• Transmitter transmits UDP broadcast packet (avoid retry) in 20ms interval.• Receiver records captured packets by “tcpdump” with time stamp and all headers.• Packet length is 100, 500, 1500byte including IP header.• Each packet has sequential number as a part of payload for packet loss detection.
• Intel Celeron• Atheros WLAN• NetBSD
Transmitter
Vehicle
Receiver
Antenna RoadsideAntenna
20ms
100B 500B 1500B
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 6
doc.: IEEE 802.11-08/1020r1
Submission
AntennaVehicle Roadside
Gain: 3.5dBi Gain: 6dBi
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 7
doc.: IEEE 802.11-08/1020r1
Submission
Antenna installation in vehicle
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 8
doc.: IEEE 802.11-08/1020r1
Submission
Installation at roadside
ReceiverReceivable Area
RX1RX2
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 9
doc.: IEEE 802.11-08/1020r1
Submission
Antenna installation at roadside
View from antenna
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 10
doc.: IEEE 802.11-08/1020r1
Submission
Packet loss
• Maximum speed is approximately 280km/h.• Packet loss occurred only behind the antenna.
(-90dBm is the minimum signal strength for connection while stopping)
RX1
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 11
doc.: IEEE 802.11-08/1020r1
Submission
Video Transfer
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 12
doc.: IEEE 802.11-08/1020r1
Submission
Location
• JARI (Japan Automobile Research Institute)High Speed Test Course– Apr. 2003– Oval course with banked curve– Length: 5km
IEEE802.11b APwith MISP
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 13
doc.: IEEE 802.11-08/1020r1
Submission
System
Base RouterMobile Router
Vehicle Antenna RoadsideIEEE802.11bDS11MIS protocol
• MPEG1 encoded video is transferred from vehicle to roadside.• MIS protocol is a suitable protocol for high speed moving environment. It uses pseudo ad-hoc mode and has function like authentication, encryption… (See 05/859r0)• Mobile router supports Mobile IP for handover.
Antenna
• Hitachi SH-4• Intersil WLAN• NetBSD
PC
PC AS HA
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 14
doc.: IEEE 802.11-08/1020r1
Submission
AntennaVehicle Roadside
• Omnidirectional• Gain: 3dBi
• Omnidirectional• Gain: -1.27dBi
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 15
doc.: IEEE 802.11-08/1020r1
Submission
Antenna installation
Vehicle antenna
Roadside antenna
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 16
doc.: IEEE 802.11-08/1020r1
Submission
Video transferred from vehicle(moving in 260km/h)
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 17
doc.: IEEE 802.11-08/1020r1
Submission
Doppler Effect Calculation
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 18
doc.: IEEE 802.11-08/1020r1
Submission
Doppler Phase Shift Calculation
R360vNDBPSSHIFT =
Wave length (2.4GHz: 12.5cm)
SHIFT: Phase Shift per OFDM symbolv: Velocity (200km/h)
NDBPS: Data bits per OFDM symbol (OFDM6: 24bit/symbol, OFDM54: 216bit/symbol)R: Data rate (OFDM6: 6Mbps, OFDM54: 54Mbps)
= 0.64 [degree]
Minimum phase difference between neighbor symbolsin 64-QAM is 3.18 degree.
Symbols can be identified.
(Data rate independent. Because R=250000NDBPS)
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 19
doc.: IEEE 802.11-08/1020r1
Submission
Moving distance
R
1500*8*vd =
d: Moving distancev: Velocity (200km/h)R: Data rate (OFDM54: 54Mbps)
QAM amplitude change can be ignored.
= 1.23 [cm]
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 20
doc.: IEEE 802.11-08/1020r1
Submission
Conclusion
• IEEE802.11 PHY can be used in high speed moving environment. (> 200km/h)
• Doppler effect can be ignored.
• But….IEEE802.11 MAC has some issues in high speed moving environment especially on handover.(So we used MIS protocol instead of IEEE802.11 MAC.)
September 2008
Hitoshi MORIOKA, ROOT Inc.
Slide 21
doc.: IEEE 802.11-08/1020r1
Submission
Questions and Comments?
