iSPP International Conference in Sendai

A Ballooned Wireless Mesh Network
for Disaster Response

Yoshitaka Shibata* and Saneatsu Arimura andNoriki Uchida***Iwate Prefectural University,**Saitama Institute of Technology
Japan
July 22, 2012

Background• East Japan Great Earthquake in March 11th in 2011 caused
sever damage over the wide area of Northern Japan.
• 5,841 persons died and 3,490 are missing due to the greattsunami• The tsunami destoryed power supply, information systems
and communication lines on the ground• It is strongly required to quickly reconstruct emergency
network- to recover from disorder- to provide urgent hotspot at evacuated places- to connect to Internet and regional intranet- to provide information services for evaluated residents

2

Background
Advantages of WLAN as disaster information network are- Robust in case of disaster and less failure- No cable disconnection,- Quickly reconstruct network and establish the emergency
information system just after occurrence of disaster- Mobile communication environment using vehicles with
WLAN to organize adhoc network
Disadvantages- Limited Communication range : Max 2~5 Km (forIEEE802.11b/g)- Signal distortion by influence buildings on the ground
Therefore, by installing WLANs to balloons and by multi-hopping
those in the sky over ground, more useful disaster information
can be realized

3Introduction of Ballooned Wireless Mesh Network 	•••

Both backbone and access networks can be established by multiple meshpints
In horizontal, backbone network can organize an adhoc network, while invertical, each mesh point can support multiple MTA access
Thus, mesh network can deploy as a temporal emergency network coveredon the disaster area by installing to balloons
MP	MP	MP	MP	MTAMP	MTA
MTA

MTA

MTA

MTAMTAInternet	MPG	Purpose
To construct wide-area wireless mesh network by combining
balloons and Wireless mesh network(BWMN) for disaster
information network :• To prototype BWMN system using conventional commerciallyavailable WLANs such as IEEE802.11b/g/j• To evaluate performance the BWMN prototype• To offer various information service applications useful whendisaster happened- WIde-area Disaster Information sharing System- Wireless IP telephone network- Ballooned wireless video surveillance network

5

BWMS as Disaster Information Network
Combination of Balloon and BWMS and multi-hopping1) In case of Disasterat mountain village2) In case of Disasterat city side

Local government

Mobile ＰＣ	

Regional Government

Mobile ＰＣ	

Mobile ＩＰ Phone

Mobile ＰＣ	 Mobile ＩＰ Phone

Disaster Area6

Prototyping Two BWMS
• Although IEEE802.11s is standardized for meshnetwork, there is no commercial product• We prototyped two BWMSs using current available
standard LANs with different antennas- Type 1: combination of IEEE802.11j + IEEE802.11b/g- Type 2: combination of IEEE802.11b + g

7Characteristics of Type 1 BWMN
１）Horizontal (Back bone network)- Standards：IEEE802.11j- Power：250mW- Data Transmission：54Mbps- Antenna：6 directions plane antenna (covered 360°）	
- Adhoc function：Automatic Network configuration with minimum
spanning tree according signal power２）Vertical (Access network)- Standards：IEEE802.11b/g- Power: 10mW
- Data Transmission: Max 54Mbps- Antenna：co-linear antenna8System Architecture
WIDIS
VoIP
Video
Application

Wireless Network

9Antenna Direction of Type 1

Horizontal Direction

70 °Vertical Direction
+5 °
-5°

10Characteristics of Type 2 BWMN
１）Horizontal (Back bone network)- Standards：IEEE802.11g- Power：10mW- Data Transmission：54Mbps- Antenna：2 directions patch antennas(covered 180°）	- Adhoc function：Automatic Network
configuration with minimum spanning treeaccording signal power２）Vertical (Access network)- Standards：IEEE802.11b/g- Power: 10mW
- Data Transmission: Max 54Mbps- Antenna：plane antenna11Ballooned Wireless Mesh Network Node

Balloon ３．５ｍ	

Balloon PartRopes

Connection rope

Wireless NodeControl rope
Fixed frame
Access nodeSupporting rope

SupportＬＡＮ cable
Power cableanchor12

Performance Evaluation of Type 1 BWMN
• Evaluation of transmission propagation characteristics• Horizontal Direction (IEEE 802.11j, 4.9GHz) andVertical Direction (IEEE 802.11b,g, 2.4GHz) withvarious parameters:- distance,- height difference,- signal power,- the No. of hoppings- antenna direction- wind influence13

Transmission Characteristics: Type 1 BWMN
Horizontal (4.９ＧＨｚ), Vertical(2.4GHz)【Base Station
RADIUS FTP/DHCP
ServerServer(L3 ｽｲｯﾁ	)(x)=50-650m(x)=50-650m

4.9GHz250mW

4.9GHz250mW①50m(1 Hop )Wireless -GW
NAP -R(GW7250)(L3 ｽｲｯﾁ	)Server⇔Throughput Test

②100m(2 Hop )Client PC(TestPC_A)

Height (h)	 
=0~40m	 

Client PC(TestPC_B)⇔Ping Test14

Result of Propagation Characteristics: Type 1 BWMN
Horizontal Direction vs. RSSI and Packet Arrival Rate
40356M bps
18M bps
24M bps
36M bps
48M bps
54M bps

Distance vs. Ave. RSSI [dB] 	 
Sending Signal Power:250mw

R S S I	 [dB ]30252015
105050

100

150

200

250300387500600

650

D istance	 (m )Distance vs.
Packet Arrival Rate [%] 	 	 Sending Signal Power:250mw
RSSI: Received Signal
Strength Indicator)

P acket	 A rrival	 R ate	 (%)

120100

6M bps18M bps
24M bps
36M bps
48M bps
54M bps

8060
40
20050

100

150200250300387

D istance	 (m )

500

600

650

15

Result of Influence of the Number of Hopping :Type 1 BWMN
9300

R esponse	 T im e	 (m s)T hroughput	 (M bit/sec)

8765432

250
200
150
100
50

100

０ホップ数0
１ ホッ２プ数1 ホッ３プ数2 ホップ数3４	

The No. of Hoppingvs.
Throughput (Mbps)

０ ホッ１プ数1 ホッ２
３プ数3	
ホップ数0プ数2 ホッThe No. of Hoppingvs.
Response Time (ms)16

Result of Influence of Shaking Access Point:
Type 1 BWMS
Throughput (Mbit/sec)

76543210NormalShaking
SenderShakingReceiverThroughput (Mbps) when Shaking

・Shaking strongly sender and receiver AP by handequivalent to 10 (m/s )17

Performance Evaluation of Type 2 BWMN
• Evaluation of transmission characteristics• Horizontal Direction (IEEE 802.11b,g, 2.4GHz) andVertical Direction (IEEE 802.11b,g, 2.4GHz) withvarious parameters:- communication distance,- height difference,- antenna direction

18

Result of Propagation Characteristics: Type 2 BWMN
Throughput for Communication
Throughput vs. Horizontal Distance for different antennas

Distance

6.0

Yagi-Patch
Yagi-Plane
Yagi-Yagi
Yagi-Co-linear	Throughput [Mbps]	

5.0
4.0
3.0
2.0
1.00.0
500

700

900
1100
1300
1500
Communication Distance [m]

1700

1900

Result of Characteristics: Type 2 BWMN
Throughput & Packet Loss Rate vs. Horizontal Distance

5.00

100
90

4.00

80

Distance	
3.50

70

3.00

60

2.50

50

2.00

40

1.50

30

1.00

20

0.50

100.00

Packet Loss Rate [%]	Throughput [Mbps]	

Throughput
Packet Loss Rate 	

45m	

4.50

00

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

Distance between balloon and relay station [m]20	Performance Evaluation of WIDIS
Evacuation
Place(Takizawa)

BWLAN

LocalGovernment(Iwate Prefectural)
University

RADIUS FTP/DHCP
ServerServerAP(L3ｽｲｯﾁ)

Mobile PC

NAP-R Wireless-GW 測定用(L3ｽｲｯﾁ) (GW7250)
Server(L3ｽｲｯﾁ)

at Iwate

Internet
JGN2APAP

DisasterServer（WIDIS)
DisasterServer（WIDIS)at sizuoka

Safety Information
Disaster Information
Lifeline information
Result:50 users could access to WIDIS
Server without performancedegradation21

Wide Area Disaster Information Sharing System

22Performance Evaluation ofThree Different Applications on BWLAN
We developed three difference disaster applications- WIde-area Disaster Information sharing System
based on Web GIS (WIDIS)- Wireless IP telephone network- Ballooned wireless omni-directiona video surveillance
System23

Performance Evaluation of Mobile IP Phone
by BWLAN
Evacuation Place

Mobile
phone

MANET

Local Government

Mobilephone

Bi-directional Mobile IP Phone Communication

・Good voice quality
・within 240 msec time delay24Performance Evaluation of Realtime Video Streaming by
BWLAN
BWLAN

Evacuation PlacePC
ClientLocal
Government
PC
ClientMobile PC
serverWireless LAN
Card(802.11n)

Wireless LAN
Card(802.11g)

Wireless LAN
Card(802.11g)

Relay Station

Wireless LAN(802.11n/b/g１１b/)

PC
Client 1Video Transmission from Disaster Area

25

Realtime Video Streaming
System over BWMN

26

27

Camera Control by Remote Operation

28

29

Result of Video Transfer Function	

Video image	  Omni-Directional 	 PTZ camera	 Size 	 

800x250	 

320x240	 

Format	 

WMV	 

WMV	 

Req. BW	 

2 Mbps	 

1 Mbps	 Frame Rate	 

10~15	 

10~15	 30

Concluding Remarks and Future Works
Conclusions
In order to realize robust wide area disaster information network,- introduced ballooned wireless mesh network- prototyped two types of BWMN using conventional standard
wireless LAN such as IEEE802.11b,g,j- Evaluated performance of throughput, packet loss rate forboth BWMSs- Also evaluated the performance of disaster applications,including Web GIS, Wireless IP Phone and Video.
- Through the performance, verified the usefulness
Future Works• Stabilization of Balloon in the sky against strong wind
• Simple operation miniaturization of Balloon with small numberof person• Introduction of autonomous disaster information network
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Autonomous Disaster Information Network	Solar	  Panel	  	Obal shped ballooned
Cognitive WBMS withdirectional antenna
・楕円型気球により風の影響を軽減	  ・フィルム型太陽光発電により自律的	  供給電源	  ・6角形アンテナと高速無線の組み合わせ	  802.11jにより水平方向にマルチホップ	  ・802.11b,gにより垂直方向にホットスポット	  ・小型軽量全方位映像カメラによる上空から	  の映像監視（地上からパン・チルト・ズーム	  操作可能）	  	Thank you for your attention

33

Quick Recovery Requirement from Failure
System functionality just after disaster is critical
SystemFunctionality %	 tytx

1	 0	 0	 This	 period	 	 must	 be	 	 shorten	 	 as	 possible	 	 Minimum
Functionality0	 0	 

Occurrence ofdisaster

TemporalrecoveryCompleterecoveryElapsed	 time	 

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Long Distance Wireless Network	

WHAN
IEEE802.
11b,g

HWAN
IEEE802.1
1n

WiMAX
IEEE802.
16e

W Access
IEEE802.
11j

SubscribedWireless

Personal
Wireless

3G
CellularPhone

1.2GHz800 MHz

Freq.

2.4GHz

2.4GHz

~5GHz

5 GHz

22~38GHz

MAX.
Speed

11,
54Mbps

300Mbps~75Mbps

54Mbps165Mbps

128Kbps

1.2Mbps

Sig.
Power

10mW

10mW

-250mW

-10 W

250mW

Max
Distance

~5Km

~5Km

10Km

30Km

4Km

20Km

10Km

LicenseNot
RequiredNot
Required

Required

Registered

RequiredNot
required

Required35