personally customizable group navigation system using cellular phones and wireless ad-hoc...
TRANSCRIPT
PERSONALLY CUSTOMIZABLE GROUP NAVIGATION SYSTEMUSING CELLULAR PHONES AND WIRELESS AD-HOC COMMUNICATION
Yoshitaka Nakamura, Guiquan Ren, Masatoshi Nakamura, Takaaki Umedu and Teruo HigashinoOsaka University, JAPAN
BackgroundBackground•Portable computing devices have been developed
•With GPS and Wireless Communication↓
•Some Navigation Services are provided•Personal Navigation•Location Searching for others•Map Search
•Few navigation service for Group has been proposed so far
•Example: Navigation for Group Tour
Problems of Group NavigationProblems of Group Navigation•This system needs route navigation and group management facilities
•Using unicast communication between the server and the terminal
•Separate download of same information is inefficient•Bandwidth congestion problem occurs when many terminal concentrates in a single base station
Our Group Navigation SystemOur Group Navigation SystemServerServer
SolutionSolution•Only a few terminals communicate with the server•Distribute information by wireless ad-hoc communication
→Traffic on the wireless Internet network can be decreased by sharing the information between terminals
ServerServer
Ad-hoc Communication
Navigation ServerNavigation Server Management Management ToolTool
LeaderLeaderMemberMember
Personal Navigation SystemPersonal Navigation SystemGroupGroup
GPS
Outline of Group NavigationOutline of Group Navigation•Servers and client softwere are implemented by JAVA•Personal Navigation Facility
•Navigation Server: Provides service on the Web•Management Tool: Customizes navigation data
•Group Management Facility•Leader: Connect to the Web by PHS or Mobile Phone•Member: Receive data via Leader by Wireless LAN
・ Comment・ Start ・ End
PathPath
・ Longitude・ Latitude・ Name ・ File・ Comment
PointPoint
・ Image
PicturePicture
・ Vector maps
MapMap
Search Engine○Route search○Create Contents○Create URL of Picture
Trim of mapSending Picture
Navigation ServerNavigation Server
SQL ServerSQL Server
Management ToolManagement Tool
Personal Navigation FacilityMobile TerminalsMobile Terminals
StartStart Turning PointTurning Point
EndEnd
Warning message
NavigationNavigation•Navigation Server provides Text, Map and Picture data to each member•Send warning message if some members come off from the navigation route
Wireless LANWireless LAN Construction of Navigation ScenarioConstruction of Navigation Scenario•Management Tool
•Construction of Scenario Mode•Users can add
•Point data( Picture, Text message and Map)•Path data( Text message and Map)•Route data( Constructed by some paths)
•Rehearsal Mode
Rehearsal ModeRehearsal Mode•Emulate the mobility of users
•Users with mobile terminals seems to be moving on the general map
•Rehearse whether to transmit information correctly
Click
Synchronizes with the Synchronizes with the place on the mapplace on the map
Management ToolManagement Tool
Variable configuration files
Variable configuration files
Rehearsal Mode of Rehearsal Mode of Management ToolManagement Tool
MapMap
Mobile Terminal EmulatorMobile Terminal Emulator
Coordinates ⇒ longitude & latitude
•User who has the mobile terminal seems to move on the map•Mobile Terminal Emulator shows the navigation of the point
Simulation ExperimentsSimulation Experiments•Examination of GPS distribution intervals
•Short: Easy to observe member's position •Long: Member’s power consumption is decreased
•Simulation of the group mobility•Leader can catch its members continuously•Warning to member away does not become too late Using Network Simulator MobiREAL (http://www.mobireal.net)
A realistic network simulator for MANET It can simulate mobility of mobile node under realistic environment
Group Management FacilityGroup Management Facility•Not to make member get lost from group
•Each member periodically scatters the packet including GPS information•Members make the leader which receive this packet as a parent•Leader observes the member-node position and maintain the group
•Several leaders cover the entire group•Member makes one of leaders as parent•Leaders exchange the member-node list with each other, and know the position of all members•When members can communicate with two or more leaders, they can select one parent who receive service by itself
Group Construction•Participation in the group (child→parent)
•Each member periodically scatters the packet including GPS information•Leader adds received GPS information of the member to the member-node list•Leader delivers its member-node list to the member•Member confirms the addition to the group by received parent’s member-node list
•Distribution interval of GPS information packet is the trade-off of the power consumption and the group maintenance
1. Generate GPS packet
3. Add node A to the neighbor-list
4. Broadcast all member-node list
A
P
C
2. Receive the packet of membersAnd refresh nodes list
ServerServer
LeaderLeaderLeaderLeader
GroupGroup
Warning Message•If members left from it’s leader’s wireless range
•Cannot receive the navigation data and announce from the leader
•The leader discovers member (e.g. node A) with the problem from GPS information then the communication situation, and sends the warning packet•If the leader cannot send warning packet to the member directly, leader send it via another member (e.g. node B) near the member
Warning Packet
LeaderLeader
Node ANode A
Node BNode B
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25 30 35 40 45 50
Time for catching node(s)
Rat
io o
f cau
ght
mem
ber(
%)
5s10s15s20s
GPS Distribution Interval•Time after member goes out of leader’s communication range, until is caught by a leader
•More than 10s, it takes much time until the warning packet reach the member•It cannot catch up with a speed away of the member when it takes 30s or more for catching
Simulation of the Group Mobility•Scenario
•Sightseeing of Kyoto city•# of leaders: 3, # of members: 200•The distance limit of wireless communication is 70m
•From the simulation results, we could confirm,•Member who starts coming off from the group can receive the warning packet•And the member can return to the group
Leaving out of wireless range
Leader’s wireless range
Receiving warning packet