Agenda¾ Introduction¾ Proposed System

The System that provides the InternetConnectivity by using Ad-hoc Network¾ Overview¾ Configuration of the AdAd-hoc Network¾ Selection of Access Points¾ Selection Criterions of Access Points¾ Simulations about the Number of Hops
¾ Conclusions

inetinet-lab
postdoctoral researchers

Hideki Shimada
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Introduction¾

What is Ad-hoc Network ?
¾ No infrastructure

The spread of Internet connectivity using the cellular
phone and the wireless LAN system¾ Autonomously Constitution¾ The access speed of these devices is being improved.
¾ These devices are available in the public spaces.
¾2¾ Wireless PeerPeer-toto-Peer Communication

among mobile hosts

PeerPeer-toto-Peer (P2P) System¾ The terminals of client have been high performance.
¾ P2P system manages information more distributed than clientclientserver model.

¾ Applications¾ Military affairs¾ Lifeline at the disaster area
¾ ITS

Wireless communication ＋ P2P→ Ad-hoc Network
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1st COE Postdoctoral and Doctoral Researchers Technical PresentationPresentation

Purpose

4Overview
mobilePropose of wireless Peer-to-Peer systemusing mobile Ad-hoc network
Internet¾ Wireless multimulti-hop network is constituted inConfigure mobile
Ad-hoc network

mobilemobilemobileAccessPoint

the environment where the access points
exist.

mobile¾ An adad-hoc network is constituted between
mobile hosts.
¾ Mobile hosts that are in the area unreached theradio wave from the access point can connect tothe Internet.

mobilemobilemobilemobileAccessPoint

mobilemobilemobilemobilemobilemobilemobile

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mobile

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Configuration of a Ad-hoc NetworkAPA

Communication to the Access Point

1. Host A broadcast the packets
to neighbor hosts.

APA

1. Each hosts relays the beaconof AP.
2. Host A receives this beaconfrom neighbor hosts andacquires the information of AP.

2. Neighbor hosts send the reply
packets to host A.
3. Host A and neighbor hosts
are established connection.

3. Host A selects the AP andsends the query packets toAP.

4. Other terminals establish
connection in the same
operation.

4. Hosts intermediate this query
packet and this packet is sentto AP.

APAP
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Selection Problem of Wireless Hot Spots¾¾ Which routes is selected when two or

Which access point is appropriate?
¾ The number of hops is fewer
 There is little influence by movement of other hosts,

since there are few intermediate hosts.

more access points are detected?

¾ The intensity of radio wave is strong¾ Necessary to select the access point thatcommunicates.
¾ Selection Criterions
 The number of hops on wireless multimulti-hopnetwork
 The intensity of the radio wave The number of hosts using an access point The place located the access point As shown in the following figure, radio wave

intensity is calculated, and it uses for access point
selection.
Access Point
Left Access Point
0.8×0.6×0.8=0.384

AccessPoint
mobile0.80.6
mobile9¾¾¾¾ Simulator¾¾ Network Simulator NSNS-2(ver 2.26)

¾¾¾
¾¾¾

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0.80.8Right Access Point
0.9×0.8×0.8×0.8=0.4608
10Conditions of Simulation¾¾ The relation of the number of hops andcommunication time

mobile

1st COE Postdoctoral and Doctoral Researchers Technical Presentation
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Simulation¾ Measurement item

0.80.9mobile0.8

1st COE Postdoctoral and Doctoral Researchers Technical Presentation
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mobileField size Æ 1000m×1000m×1000m
The number of mobile nodes Æ 50
The number of static nodes Æ 2Mobile nodes move by Random Waypoint Model( within 3m/s )Simulation time Æ 100 second
Routing Protocol Æ AODV (Ad hoc OnOn-Demand DistanceVector )Transfer area of radio wave Æ 250m
Bandwidth of radio wave Æ 2Mbps
Propagation model of radio wave Æ Two Ray Ground model
CBR packet of 500 byte is transferred 4 packet / s
Antenna characteristic Æ Omni antenna

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Simulation

Simulation Result(1)2019

The number of hops
Divisions of network
Total communication time 84.888

86.777

18100
90

1680

1470

1260

Access Point X

1000m

1050
886Source NodeAccess Point Y

40304.875
3.737

42021000m

1000
Access Point X

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Access Point Y

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Simulation Result(2)Simulation Result (3)Percentage of total communication time for every number of hops

Time(s)

The relation of the number of hops andcommunication time141210864
20

94%12.7317411
10.951806

612%

4.78472242

75%

82%

4191011121314151617180%

124%

26%

512%
417%

3318%

5The number of hops
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Consideration of the Simulation¾ Simulation Result (1) (2)

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34
56789101112131415
161718
1916Conclusion¾ I have proposed the wireless peerpeer-toto-peer¾ These results are results in a certain scenario.
 If the number of hops is small, the communication time

becomes long.

system using the adad-hoc network to the accesspoint.

 However, it turns out that the number of times of thedivision of routes influences greatly.

¾ Moreover, I have proposed about the structure¾ Simulation Result (3)that selects the suitable wireless hot spot.

¾ This result shows the relation between thenumber of hops and the communication time.
 The communication time becomes long when the routeof smaller hop is selected.

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17¾ I have simulated to inquire stability of communicationroutes in terms of the number of hops.
¾ As simulation results, stability of communicationroutes is more depended on the number of divisionsof network than the number of hops.
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