infrastructureless wireless networks
DESCRIPTION
An overview of the basic algorithmic knowledge about ad-hoc and sensor networks for engineers.TRANSCRIPT
Infrastructure-lessWireless NetworksGwendal SimonDepartment of Computer ScienceInstitut Telecom2009
Literature
Books include:“Algorithms for sensor and ad hoc networks”,D. Wagner and R. Wattenhofer“Wireless sensor networks: an informationprocessing approach”, F. Zhao and L. Guibas
and journal/conferences include:ACM SigMobile (MobiHoc, SenSys, etc.)IEEE MASS and WCNCElsevier Ad-Hoc Network, Wireless Networks
2 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Motivations
Current wireless net. require an infrastructure:cellular network: interconnected base stationswifi Internet: an access point and Internet
Same flaws than centralized architectures:costscalabilityprivacydependability
3 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Motivations
Current wireless net. require an infrastructure:cellular network: interconnected base stationswifi Internet: an access point and Internet
Same flaws than centralized architectures:costscalabilityprivacydependability
3 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Motivations
Sometimes, there is no infrastructuretransient meetingdisaster areasmilitary interventionsalter-communication
Sometimes not every station hear every other stationlimited wireless transmission rangelarge-scale area
4 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Motivations
Sometimes, there is no infrastructuretransient meetingdisaster areasmilitary interventionsalter-communication
Sometimes not every station hear every other stationlimited wireless transmission rangelarge-scale area
4 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Multi-hop Wireless Networks
Nodes: portable wireless devicestransmission ranges do not cover the areadensity ensures network connectivity
Links: wireless characteristicstransmission model: local broadcastingenergy consumption: transmission is costly
Behavior: devices emit, receive and forward data
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A Taxonomy ofApplications
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Ad-Hoc vs. Sensor Networks
Ad-Hoc Networks Sensor Networksnodes powerful wifi devices tiny zigbee nodes
algorithms all-to-all routing echo to sinkmobility human or car motions failures
performance criteria quality of service energy consumption
7 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Ad-Hoc Applications
Delay-Tolerant Network (social media application)assumption: no connectivity, but high mobilityobjective: ensuring eventual message delivery
Mesh Networks (rural wireless coverage)assumption: some nodes have Internet accessobjective: maintaining path to these nodes
Vehicular Ad-Hoc Networksassumption: a particular mobility modelobjective: mostly services related to car safety
8 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Ad-Hoc Applications
Delay-Tolerant Network (social media application)assumption: no connectivity, but high mobilityobjective: ensuring eventual message delivery
Mesh Networks (rural wireless coverage)assumption: some nodes have Internet accessobjective: maintaining path to these nodes
Vehicular Ad-Hoc Networksassumption: a particular mobility modelobjective: mostly services related to car safety
8 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Ad-Hoc Applications
Delay-Tolerant Network (social media application)assumption: no connectivity, but high mobilityobjective: ensuring eventual message delivery
Mesh Networks (rural wireless coverage)assumption: some nodes have Internet accessobjective: maintaining path to these nodes
Vehicular Ad-Hoc Networksassumption: a particular mobility modelobjective: mostly services related to car safety
8 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Sensor Network Applications
Sink-Based Networks (monitoring of natural areas)assumption: one sink retrieves all sensed dataobjective: increasing life-time
Mobile Object Tracking (area surveillance)assumption: sensors know their locationobjective: determining hostile position
Multi-Sink Networks (intervention teams)assumptions: mobile sinks and fixed sensorobjectives: increasing sink coverage
9 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Sensor Network Applications
Sink-Based Networks (monitoring of natural areas)assumption: one sink retrieves all sensed dataobjective: increasing life-time
Mobile Object Tracking (area surveillance)assumption: sensors know their locationobjective: determining hostile position
Multi-Sink Networks (intervention teams)assumptions: mobile sinks and fixed sensorobjectives: increasing sink coverage
9 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Sensor Network Applications
Sink-Based Networks (monitoring of natural areas)assumption: one sink retrieves all sensed dataobjective: increasing life-time
Mobile Object Tracking (area surveillance)assumption: sensors know their locationobjective: determining hostile position
Multi-Sink Networks (intervention teams)assumptions: mobile sinks and fixed sensorobjectives: increasing sink coverage
9 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Short Introductionto Popular Models
10 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Network as a Graph
Unit-Disk Graph:
→ node position
→ circular transmission
→ boolean connections00
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11 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Network as a Graph
Unit-Disk Graph:
→ node position
→ circular transmission
→ boolean connections
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11 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Network as a Graph
Unit-Disk Graph:
→ node position
→ circular transmission
→ boolean connections
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11 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Interferences
Signal-to-noise-plus-interference (SINR) ratioPu
d(u,v)α
N +∑
w∈V \{u}Pw
d(w ,v)α≥ β
Pu: power level of sender ud(u, v): distance between u and vα: path-loss exponentN : noiseβ: minimum ratio
12 / 41 Gwendal Simon Infrastructure-less Wireless Networks
A Tour of the MostStudied Issues
13 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Broadcasting I: Stormy Effect
Broadcast:a simple basic problem :
a source emits a messageall nodes within the network eventually receive themessage
a simple and efficient solution:upon first reception of message, forward it.
Limits of flooding in wireless networks:redundant messagesinterferences
14 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Broadcasting II: Proposals
Probabilistic flooding:idea: forward the message with some probability pdrawbacks: no guarantee of deliveringrefinements: adjust p to node density
Constrained flooding:idea: only some nodes forward the messageimplementation: build the MinimumConnected Dominating Setdrawbacks: maintaining cost in dynamic systems
15 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Broadcasting II: Proposals
Probabilistic flooding:idea: forward the message with some probability pdrawbacks: no guarantee of deliveringrefinements: adjust p to node density
Constrained flooding:idea: only some nodes forward the messageimplementation: build the MinimumConnected Dominating Setdrawbacks: maintaining cost in dynamic systems
15 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Mobility Models I
Few theoretical proof, few real implementations⇒ generate realistic node motions for simulations
The simplest model: Random Waypoint1. each node picks a random position uniformly2. it travels toward this destination with a speed v3. once it reaches it, it stops during few seconds4. back to 1
16 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Mobility Models I
Few theoretical proof, few real implementations⇒ generate realistic node motions for simulations
The simplest model: Random Waypoint1. each node picks a random position uniformly2. it travels toward this destination with a speed v3. once it reaches it, it stops during few seconds4. back to 1
16 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Mobility Models II: Improvements
Basic Structural Flaws:non-uniform distribution of node location:
higher node distribution in the centeraverage speed decay:
low speed nodes spend more time to travel
Realistic Mobility Models:group movementarea popularityurban modelscommunity-based
the most realistic one : using real traces!
17 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Mobility Models II: Improvements
Basic Structural Flaws:non-uniform distribution of node location:
higher node distribution in the centeraverage speed decay:
low speed nodes spend more time to travel
Realistic Mobility Models:group movementarea popularityurban modelscommunity-basedthe most realistic one : using real traces!
17 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Localized Data Gathering
Basic idea: query data from sensors within an areatwo rounds:
query diffusionretrieve data from sensors
main objectives:minimize energy consumptionminimize the delay
A problem related with broadcasting except:only sensors from the queried area are reached:complex queries are possible (average, max, etc.)
18 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Time Synchronization I
Different time on nodes:different oscillator frequency ⇒ frequency errorabsolute difference between clocks ⇒ phase error
The need of a common clocklocalization protocolssome MAC protocolsdata fusion in sensor network
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Time Synchronization II
Broadcasting standard time via GPS system:√precision, simple implementation
× expensive devices× limited usage (outdoor environment)
Achieve a common time distributively:√(almost) no special devices required√more tolerant to the environment
× special protocols× message overhead, multi-hop delays
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A Focus onRouting Protocols
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Routing Protocols
Objective:select a path between a source and a destination
Main design challenges:unstable network topologylow-cost devices (energy, computing. . . )
Main routing mechanisms:neighbor discoveringroute setuproute maintenance
22 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Proactive routing vs. On demand routing
Proactive ReactiveSetup all-to-all on demand
Maintenance regularly during utilizationAdvantages no setup delay no unused routes
Disadvantages fixed overhead long setup delayMain examples OLSR AODV
23 / 41 Gwendal Simon Infrastructure-less Wireless Networks
AODV Route Discovery
D
S B
EA
FG
H
BroadcastingRREQ Mes-sage.Setting upreverse path.
ReplyingRREP tosource.Forward pathsetup.
24 / 41 Gwendal Simon Infrastructure-less Wireless Networks
AODV Route Discovery
D
S B
EA
FG
H
BroadcastingRREQ Mes-sage.
Setting upreverse path.
ReplyingRREP tosource.Forward pathsetup.
24 / 41 Gwendal Simon Infrastructure-less Wireless Networks
AODV Route Discovery
D
S B
EA
FG
H
BroadcastingRREQ Mes-sage.
Setting upreverse path.
ReplyingRREP tosource.Forward pathsetup.
24 / 41 Gwendal Simon Infrastructure-less Wireless Networks
AODV Route Discovery
D
S B
EA
FG
H
BroadcastingRREQ Mes-sage.
Setting upreverse path.
ReplyingRREP tosource.Forward pathsetup.
24 / 41 Gwendal Simon Infrastructure-less Wireless Networks
AODV Route Discovery
D
S B
EA
FG
H
BroadcastingRREQ Mes-sage.
Setting upreverse path.
ReplyingRREP tosource.Forward pathsetup.
24 / 41 Gwendal Simon Infrastructure-less Wireless Networks
AODV Route Discovery
D
S B
EA
FG
H
BroadcastingRREQ Mes-sage.
Setting upreverse path.
ReplyingRREP tosource.Forward pathsetup.
24 / 41 Gwendal Simon Infrastructure-less Wireless Networks
AODV Route Discovery
D
S B
EA
FG
H
BroadcastingRREQ Mes-sage.
Setting upreverse path.
ReplyingRREP tosource.Forward pathsetup.
24 / 41 Gwendal Simon Infrastructure-less Wireless Networks
AODV Route Discovery
D
S B
EA
FG
H
BroadcastingRREQ Mes-sage.Setting upreverse path.
ReplyingRREP tosource.
Forward pathsetup.
24 / 41 Gwendal Simon Infrastructure-less Wireless Networks
AODV Route Discovery
D
S B
EA
FG
H
BroadcastingRREQ Mes-sage.Setting upreverse path.
ReplyingRREP tosource.
Forward pathsetup.
24 / 41 Gwendal Simon Infrastructure-less Wireless Networks
AODV Route Maintenance
D
S B
EA
FG
H
Link breaksbetween Band D.
SendingRERR mes-sage.
Restartingroute discov-ery.New routediscovered.
25 / 41 Gwendal Simon Infrastructure-less Wireless Networks
AODV Route Maintenance
D
S B
EA
FG
H
Link breaksbetween Band D.
SendingRERR mes-sage.
Restartingroute discov-ery.New routediscovered.
25 / 41 Gwendal Simon Infrastructure-less Wireless Networks
AODV Route Maintenance
D
S B
EA
FG
H
Link breaksbetween Band D.
SendingRERR mes-sage.
Restartingroute discov-ery.
New routediscovered.
25 / 41 Gwendal Simon Infrastructure-less Wireless Networks
AODV Route Maintenance
D
S B
EA
FG
H
Link breaksbetween Band D.
SendingRERR mes-sage.
Restartingroute discov-ery.
New routediscovered.
25 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Some Tricks
Intelligent flooding (detect close destination)idea: init TTL at 1, then 2, then 3. . .idea: flood slowly and send message to stop it
Route caching (use past flooding)idea: during flood, answer for a distant nodedrawback : contradict reactive routing philosophy
Local maintenance (almost unchanged route)idea: instead of NAK s, look for d by yourselfdrawback : sometimes it does not work
26 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Some Tricks
Intelligent flooding (detect close destination)idea: init TTL at 1, then 2, then 3. . .idea: flood slowly and send message to stop it
Route caching (use past flooding)idea: during flood, answer for a distant nodedrawback : contradict reactive routing philosophy
Local maintenance (almost unchanged route)idea: instead of NAK s, look for d by yourselfdrawback : sometimes it does not work
26 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Some Tricks
Intelligent flooding (detect close destination)idea: init TTL at 1, then 2, then 3. . .idea: flood slowly and send message to stop it
Route caching (use past flooding)idea: during flood, answer for a distant nodedrawback : contradict reactive routing philosophy
Local maintenance (almost unchanged route)idea: instead of NAK s, look for d by yourselfdrawback : sometimes it does not work
26 / 41 Gwendal Simon Infrastructure-less Wireless Networks
A Proactive Routing Protocol: OLSR
Objective: make use of Multi-Point Relay (MPR)acting as super-peerseasing topology discoveryhandling most of the traffic
OLSR message types:HELLO: discover 1-hop and 2-hop neighborstopology discovery through MPR
27 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Neighbor sensing
D
S B
E A
F GH
BroadcastingHELLO Message.
Nb:{S},2hopNb:{}
Nb:{S},2hopNb:{}
Nb:{S},2hopNb:{}
Nb:{E},2hopNb:{}
Nb:{E},2hopNb:{S}
Nb:{S,E},2hopNb:{}
Nb:{E,F},2hop Nb:{}
Nb:{S,E,F},2hop Nb:{}
Nb:{F},2hop Nb:{S}
Nb:{E,F,B},2hopNb:{G,A}
Nb:{S,A,B},2hopNb:{F,G,D}
Nb:{S,B,G},2hopNb:{E,A,H}
Nb:{S,E,F,A,G},2hopNb:{D,H}
Nb:{F,B,H},2hopNb:{S,E,A,D}
Nb:{E,B,D},2hopNb:{S,F,G,H}
Nb:{A,H},2hopNb:{B,E,G}
Nb:{G,D},2hopNb:{B,F,A}
28 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Neighbor sensing
D
S B
E A
F GH
BroadcastingHELLO Message.
Nb:{S},2hopNb:{}
Nb:{S},2hopNb:{}
Nb:{S},2hopNb:{}
Nb:{E},2hopNb:{}
Nb:{E},2hopNb:{S}
Nb:{S,E},2hopNb:{}
Nb:{E,F},2hop Nb:{}
Nb:{S,E,F},2hop Nb:{}
Nb:{F},2hop Nb:{S}
Nb:{E,F,B},2hopNb:{G,A}
Nb:{S,A,B},2hopNb:{F,G,D}
Nb:{S,B,G},2hopNb:{E,A,H}
Nb:{S,E,F,A,G},2hopNb:{D,H}
Nb:{F,B,H},2hopNb:{S,E,A,D}
Nb:{E,B,D},2hopNb:{S,F,G,H}
Nb:{A,H},2hopNb:{B,E,G}
Nb:{G,D},2hopNb:{B,F,A}
28 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Neighbor sensing
D
S B
E A
F GH
BroadcastingHELLO Message.
Nb:{S},2hopNb:{}
Nb:{S},2hopNb:{}
Nb:{S},2hopNb:{}
Nb:{E},2hopNb:{}
Nb:{E},2hopNb:{S}
Nb:{S,E},2hopNb:{}
Nb:{E,F},2hop Nb:{}
Nb:{S,E,F},2hop Nb:{}
Nb:{F},2hop Nb:{S}
Nb:{E,F,B},2hopNb:{G,A}
Nb:{S,A,B},2hopNb:{F,G,D}
Nb:{S,B,G},2hopNb:{E,A,H}
Nb:{S,E,F,A,G},2hopNb:{D,H}
Nb:{F,B,H},2hopNb:{S,E,A,D}
Nb:{E,B,D},2hopNb:{S,F,G,H}
Nb:{A,H},2hopNb:{B,E,G}
Nb:{G,D},2hopNb:{B,F,A}
28 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Neighbor sensing
D
S B
E A
F GH
BroadcastingHELLO Message.
Nb:{S},2hopNb:{}
Nb:{S},2hopNb:{}
Nb:{S},2hopNb:{}
Nb:{E},2hopNb:{}
Nb:{E},2hopNb:{S}
Nb:{S,E},2hopNb:{}
Nb:{E,F},2hop Nb:{}
Nb:{S,E,F},2hop Nb:{}
Nb:{F},2hop Nb:{S}
Nb:{E,F,B},2hopNb:{G,A}
Nb:{S,A,B},2hopNb:{F,G,D}
Nb:{S,B,G},2hopNb:{E,A,H}
Nb:{S,E,F,A,G},2hopNb:{D,H}
Nb:{F,B,H},2hopNb:{S,E,A,D}
Nb:{E,B,D},2hopNb:{S,F,G,H}
Nb:{A,H},2hopNb:{B,E,G}
Nb:{G,D},2hopNb:{B,F,A}
28 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Neighbor sensing
D
S B
E A
F GH
BroadcastingHELLO Message.
Nb:{S},2hopNb:{}
Nb:{S},2hopNb:{}
Nb:{S},2hopNb:{}
Nb:{E},2hopNb:{}
Nb:{E},2hopNb:{S}
Nb:{S,E},2hopNb:{}
Nb:{E,F},2hop Nb:{}
Nb:{S,E,F},2hop Nb:{}
Nb:{F},2hop Nb:{S}
Nb:{E,F,B},2hopNb:{G,A}
Nb:{S,A,B},2hopNb:{F,G,D}
Nb:{S,B,G},2hopNb:{E,A,H}
Nb:{S,E,F,A,G},2hopNb:{D,H}
Nb:{F,B,H},2hopNb:{S,E,A,D}
Nb:{E,B,D},2hopNb:{S,F,G,H}
Nb:{A,H},2hopNb:{B,E,G}
Nb:{G,D},2hopNb:{B,F,A}
28 / 41 Gwendal Simon Infrastructure-less Wireless Networks
MPR selection
D
S B
E A
F GH
Nb:{E,F,B},2hopNb:{G,A}
Nb:{S,A,B},2hopNb:{F,G,D}
Nb:{S,B,G},2hopNb:{E,A,H}
Nb:{S,E,F,A,G},2hopNb:{D,H}
B
HELLO messageindicating B asMPR of S and Bnote S as its MPRselector.
MPR Selector:{}
MPR Selector:{}
MPR Selector:{}
MPR Selector:{S,G,E,F,A}
MPR Selector:{B,F,H}
MPR Selector:{B,E,D}
MPR Selector:{A,H}
MPR Selector:{G,D}
29 / 41 Gwendal Simon Infrastructure-less Wireless Networks
MPR selection
D
S B
E A
F GH
Nb:{E,F,B},2hopNb:{G,A}
Nb:{S,A,B},2hopNb:{F,G,D}
Nb:{S,B,G},2hopNb:{E,A,H}
Nb:{S,E,F,A,G},2hopNb:{D,H}
B
HELLO messageindicating B asMPR of S and Bnote S as its MPRselector.
MPR Selector:{}
MPR Selector:{}
MPR Selector:{}
MPR Selector:{S,G,E,F,A}
MPR Selector:{B,F,H}
MPR Selector:{B,E,D}
MPR Selector:{A,H}
MPR Selector:{G,D}
29 / 41 Gwendal Simon Infrastructure-less Wireless Networks
MPR selection
D
S B
E A
F GH
Nb:{E,F,B},2hopNb:{G,A}
Nb:{S,A,B},2hopNb:{F,G,D}
Nb:{S,B,G},2hopNb:{E,A,H}
Nb:{S,E,F,A,G},2hopNb:{D,H}
B
HELLO messageindicating B asMPR of S and Bnote S as its MPRselector.
MPR Selector:{}
MPR Selector:{}
MPR Selector:{}
MPR Selector:{S,G,E,F,A}
MPR Selector:{B,F,H}
MPR Selector:{B,E,D}
MPR Selector:{A,H}
MPR Selector:{G,D}
29 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Topology Table
Each node maintains a Topology Tablecontaining all possible destinationsnotifying a MPR to reach them
Structure of Topology Table (on S for example):Dest Addr Last Hop Seq Holding Time
G B 1 10A B 4 20D A 6 10H G 5 15. . . . . . . . . . . .
30 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Building the Topology Table
D
S B
E A
F GHMPR Selector:
{B,F,H}
BTopology Table
Des Lhop Seq HtimeF G 2 30H G 2 30
MPR Selector:{S,G,E,F,A}
MPR Selector:{G,D}S
Topology TableDes Lhop Seq HtimeF G 2 30H G 2 30B G 2 30
MPR Selector:{B,E,D}
MPR Selector:{A,H}
Broadcasting contin-ues. . .
D
B
A
GH
MPR Selector:{}
MPR Selector:{}
MPR Selector:{}
MPR Selector:{S,G,E,F,A}
MPR Selector:{B,F,H}
MPR Selector:{B,E,D}
MPR Selector:{A,H}
MPR Selector:{G,D}
31 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Building the Topology Table
D
S B
E A
F GH
MPR Selector:{B,F,H}
BTopology Table
Des Lhop Seq HtimeF G 2 30H G 2 30
MPR Selector:{S,G,E,F,A}
MPR Selector:{G,D}S
Topology TableDes Lhop Seq HtimeF G 2 30H G 2 30B G 2 30
MPR Selector:{B,E,D}
MPR Selector:{A,H}
Broadcasting contin-ues. . .
D
B
A
GH
MPR Selector:{}
MPR Selector:{}
MPR Selector:{}
MPR Selector:{S,G,E,F,A}
MPR Selector:{B,F,H}
MPR Selector:{B,E,D}
MPR Selector:{A,H}
MPR Selector:{G,D}
31 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Building the Topology Table
D
S B
E A
F GH
MPR Selector:{B,F,H}
BTopology Table
Des Lhop Seq HtimeF G 2 30H G 2 30
MPR Selector:{S,G,E,F,A}
MPR Selector:{G,D}
S
Topology TableDes Lhop Seq HtimeF G 2 30H G 2 30B G 2 30
MPR Selector:{B,E,D}
MPR Selector:{A,H}
Broadcasting contin-ues. . .
D
B
A
GH
MPR Selector:{}
MPR Selector:{}
MPR Selector:{}
MPR Selector:{S,G,E,F,A}
MPR Selector:{B,F,H}
MPR Selector:{B,E,D}
MPR Selector:{A,H}
MPR Selector:{G,D}
31 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Building the Topology Table
D
S B
E A
F GH
MPR Selector:{B,F,H}
BTopology Table
Des Lhop Seq HtimeF G 2 30H G 2 30
MPR Selector:{S,G,E,F,A}
MPR Selector:{G,D}
S
Topology TableDes Lhop Seq HtimeF G 2 30H G 2 30B G 2 30
MPR Selector:{B,E,D}
MPR Selector:{A,H}
Broadcasting contin-ues. . .
D
B
A
GH
MPR Selector:{}
MPR Selector:{}
MPR Selector:{}
MPR Selector:{S,G,E,F,A}
MPR Selector:{B,F,H}
MPR Selector:{B,E,D}
MPR Selector:{A,H}
MPR Selector:{G,D}
31 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Building the Topology Table
D
S B
E A
F GH
MPR Selector:{B,F,H}
BTopology Table
Des Lhop Seq HtimeF G 2 30H G 2 30
MPR Selector:{S,G,E,F,A}
MPR Selector:{G,D}S
Topology TableDes Lhop Seq HtimeF G 2 30H G 2 30B G 2 30
MPR Selector:{B,E,D}
MPR Selector:{A,H}
Broadcasting contin-ues. . .
D
B
A
GH
MPR Selector:{}
MPR Selector:{}
MPR Selector:{}
MPR Selector:{S,G,E,F,A}
MPR Selector:{B,F,H}
MPR Selector:{B,E,D}
MPR Selector:{A,H}
MPR Selector:{G,D}
31 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Building the Topology Table
D
S B
E A
F GH
MPR Selector:{B,F,H}
BTopology Table
Des Lhop Seq HtimeF G 2 30H G 2 30
MPR Selector:{S,G,E,F,A}
MPR Selector:{G,D}S
Topology TableDes Lhop Seq HtimeF G 2 30H G 2 30B G 2 30
MPR Selector:{B,E,D}
MPR Selector:{A,H}
Broadcasting contin-ues. . .
D
B
A
GH
MPR Selector:{}
MPR Selector:{}
MPR Selector:{}
MPR Selector:{S,G,E,F,A}
MPR Selector:{B,F,H}
MPR Selector:{B,E,D}
MPR Selector:{A,H}
MPR Selector:{G,D}
31 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Building the Routing Table
Topology Table on SDes Lhop Seq HtimeF G 2 30H G 2 30B G 2 30F B 3 30A B 3 30E B 3 30G B 3 30B A 6 30E A 6 30D A 6 30A D 7 30H D 7 30D H 8 30G H 8 30
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2H B 3D B 3
32 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Building the Routing Table
Topology Table on SDes Lhop Seq HtimeF G 2 30H G 2 30B G 2 30F B 3 30A B 3 30E B 3 30G B 3 30B A 6 30E A 6 30D A 6 30A D 7 30H D 7 30D H 8 30G H 8 30
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2H B 3D B 3
32 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Building the Routing Table
Topology Table on SDes Lhop Seq HtimeF G 2 30H G 2 30B G 2 30F B 3 30A B 3 30E B 3 30G B 3 30B A 6 30E A 6 30D A 6 30A D 7 30H D 7 30D H 8 30G H 8 30
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2H B 3D B 3
32 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Building the Routing Table
Topology Table on SDes Lhop Seq HtimeF G 2 30H G 2 30B G 2 30F B 3 30A B 3 30E B 3 30G B 3 30B A 6 30E A 6 30D A 6 30A D 7 30H D 7 30D H 8 30G H 8 30
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2H B 3D B 3
32 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Building the Routing Table
Topology Table on SDes Lhop Seq HtimeF G 2 30H G 2 30B G 2 30F B 3 30A B 3 30E B 3 30G B 3 30B A 6 30E A 6 30D A 6 30A D 7 30H D 7 30D H 8 30G H 8 30
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2H B 3D B 3
32 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Building the Routing Table
Topology Table on SDes Lhop Seq HtimeF G 2 30H G 2 30B G 2 30F B 3 30A B 3 30E B 3 30G B 3 30B A 6 30E A 6 30D A 6 30A D 7 30H D 7 30D H 8 30G H 8 30
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2H B 3D B 3
32 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Building the Routing Table
Topology Table on SDes Lhop Seq HtimeF G 2 30H G 2 30B G 2 30F B 3 30A B 3 30E B 3 30G B 3 30B A 6 30E A 6 30D A 6 30A D 7 30H D 7 30D H 8 30G H 8 30
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2
Neighbor Table on SNb:{E,F,B},2hopNb:{G,A}
Routing Table on SDes Nhop HopsE E 1F F 1B B 1A B 2G B 2H B 3D B 3
32 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Any Hybrid Approach ?
Merging advantages from both approaches:build a routing table at 4 ∼ 5 hopslaunch a reactive process if d is not
Applicative concerns:OLSR is attractive because networks often smallAODV scales well but no all-to-all routing
33 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Research Activity:Multi-Sinks QueryRange
34 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Multi-sink Multi-hop WSN
0 50 100 150 200 250 3000
50
100
150
200 Target application: “fireman application”Many sensors (small, blue) and somefiremen (large, green)
Firemen talk directly with the sensors
Gather only local information
On demand, fixed rate data gathering
Hop based query, constrained flooding
Simple to deploy and scalable
Networking assumptions:
IEEE 802.15.4 MAC layer, ZigBee tree routing
No in-network data aggregation, compression
Static sensors and sinks (may extend to mobile sinks)
35 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Multi-sink Multi-hop WSN
0 50 100 150 200 250 3000
50
100
150
200 Target application: “fireman application”Many sensors (small, blue) and somefiremen (large, green)
Firemen talk directly with the sensors
Gather only local information
On demand, fixed rate data gathering
Hop based query, constrained flooding
Simple to deploy and scalable
Networking assumptions:
IEEE 802.15.4 MAC layer, ZigBee tree routing
No in-network data aggregation, compression
Static sensors and sinks (may extend to mobile sinks)
35 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Multi-sink Multi-hop WSN
0 50 100 150 200 250 3000
50
100
150
200 Target application: “fireman application”Many sensors (small, blue) and somefiremen (large, green)
Firemen talk directly with the sensors
Gather only local information
On demand, fixed rate data gathering
Hop based query, constrained flooding
Simple to deploy and scalable
Networking assumptions:
IEEE 802.15.4 MAC layer, ZigBee tree routing
No in-network data aggregation, compression
Static sensors and sinks (may extend to mobile sinks)
35 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Multi-sink Multi-hop WSN
0 50 100 150 200 250 3000
50
100
150
200 Target application: “fireman application”Many sensors (small, blue) and somefiremen (large, green)
Firemen talk directly with the sensors
Gather only local information
On demand, fixed rate data gathering
Hop based query, constrained flooding
Simple to deploy and scalable
Networking assumptions:
IEEE 802.15.4 MAC layer, ZigBee tree routing
No in-network data aggregation, compression
Static sensors and sinks (may extend to mobile sinks)
35 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Multi-sink Multi-hop WSN
0 50 100 150 200 250 3000
50
100
150
200 Target application: “fireman application”Many sensors (small, blue) and somefiremen (large, green)
Firemen talk directly with the sensors
Gather only local information
On demand, fixed rate data gathering
Hop based query, constrained flooding
Simple to deploy and scalableNetworking assumptions:
IEEE 802.15.4 MAC layer, ZigBee tree routing
No in-network data aggregation, compression
Static sensors and sinks (may extend to mobile sinks)35 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Network Sharing Without Congestions
0 50 100 150 200 250 3000
50
100
150
200Capacity of sensors c = 5Each flow consumes r = 1Nodes within u hops generate traffic
S1
S2u1 = 5
u2 = 1
Configurations Feasible?(5, 1) yes
u1 = 4
u2 = 2
Configurations Feasible?(5, 1) yes(4, 2) no
u1 = 3
u2 = 2
Configurations Feasible?(5, 1) yes(4, 2) no(3, 2) yesu1 = 2
u2 = 3
Configurations Feasible?(5, 1) yes(4, 2) no(3, 2) yes(2, 3) yes
62 configurations
36 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Network Sharing Without Congestions
0 50 100 150 200 250 3000
50
100
150
200Capacity of sensors c = 5Each flow consumes r = 1Nodes within u hops generate traffic
S1
S2
u1 = 5
u2 = 1
Configurations Feasible?(5, 1) yes
u1 = 4
u2 = 2
Configurations Feasible?(5, 1) yes(4, 2) no
u1 = 3
u2 = 2
Configurations Feasible?(5, 1) yes(4, 2) no(3, 2) yesu1 = 2
u2 = 3
Configurations Feasible?(5, 1) yes(4, 2) no(3, 2) yes(2, 3) yes
62 configurations
36 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Network Sharing Without Congestions
0 50 100 150 200 250 3000
50
100
150
200Capacity of sensors c = 5Each flow consumes r = 1Nodes within u hops generate traffic
S1
S2
u1 = 5
u2 = 1
Configurations Feasible?(5, 1) yes
u1 = 4
u2 = 2
Configurations Feasible?(5, 1) yes(4, 2) no
u1 = 3
u2 = 2
Configurations Feasible?(5, 1) yes(4, 2) no(3, 2) yes
u1 = 2
u2 = 3
Configurations Feasible?(5, 1) yes(4, 2) no(3, 2) yes(2, 3) yes
62 configurations
36 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Network Sharing Without Congestions
0 50 100 150 200 250 3000
50
100
150
200Capacity of sensors c = 5Each flow consumes r = 1Nodes within u hops generate traffic
S1
S2
u1 = 5
u2 = 1
Configurations Feasible?(5, 1) yes
u1 = 4
u2 = 2
Configurations Feasible?(5, 1) yes(4, 2) no
u1 = 3
u2 = 2
Configurations Feasible?(5, 1) yes(4, 2) no(3, 2) yes
u1 = 2
u2 = 3
Configurations Feasible?(5, 1) yes(4, 2) no(3, 2) yes(2, 3) yes
62 configurations
36 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Network Sharing Without Congestions
0 50 100 150 200 250 3000
50
100
150
200Capacity of sensors c = 5Each flow consumes r = 1Nodes within u hops generate traffic
S1
S2
u1 = 5
u2 = 1
Configurations Feasible?(5, 1) yes
u1 = 4
u2 = 2
Configurations Feasible?(5, 1) yes(4, 2) no
u1 = 3
u2 = 2
Configurations Feasible?(5, 1) yes(4, 2) no(3, 2) yes
u1 = 2
u2 = 3
Configurations Feasible?(5, 1) yes(4, 2) no(3, 2) yes(2, 3) yes
62 configurations
36 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Which Configuration is Better?
0 50 100 150 200 250 3000
50
100
150
200Basic considerations:(4, 2): not feasible, (1, 1): inefficient
Optimality criteria:Maximum Impact Range
(5, 1): Sum up to 6Max-Min Fairness
(2, 3) = (3, 2) � (5, 1)
1
2 34
(?, ?, ?, ?)
37 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Which Configuration is Better?
0 50 100 150 200 250 3000
50
100
150
200Basic considerations:(4, 2): not feasible, (1, 1): inefficient
Optimality criteria:Maximum Impact Range
(5, 1): Sum up to 6Max-Min Fairness
(2, 3) = (3, 2) � (5, 1)
1
2 34
(?, ?, ?, ?)
37 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Problem Formulation
Multi-Dimensional Multiple Choice Knapsack Problema NP-complete problem
Toward a distributed heuristic algorithmonly local views of the networkonly local optimal solutions
38 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Problem Formulation
Multi-Dimensional Multiple Choice Knapsack Problema NP-complete problem
Toward a distributed heuristic algorithmonly local views of the networkonly local optimal solutions
38 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Protocol
0 50 100 150 200 250 3000
50
100
150
200
A 12
3
4
At each sink:enlarge requirement periodicallyreceive notification from sensorsadjust requirement if it is smaller
At each sensor:measure the trafficdetect congestionsolve the local problemnotify related sinks
39 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Conclusion
40 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Personal Thoughts
Great theoretical importance:a lot of new and scientifically exciting problemsa multi-disciplinary field (network, algorithms,computational geometry, probabilities)
Unsure applicative importance:no killer application yetcellular networks just do what we want
41 / 41 Gwendal Simon Infrastructure-less Wireless Networks
Personal Thoughts
Great theoretical importance:a lot of new and scientifically exciting problemsa multi-disciplinary field (network, algorithms,computational geometry, probabilities)
Unsure applicative importance:no killer application yetcellular networks just do what we want
41 / 41 Gwendal Simon Infrastructure-less Wireless Networks