bsmt in vanet

8/6/2019 Bsmt in Vanet

1/27

11

Broadcast Storm Mitigation Techniques InBroadcast Storm Mitigation Techniques InVehicular Ad Hoc NetworkVehicular Ad Hoc Network

Author:Author:

N. Wisitpongphan and O.K. Tonguz, Carnegie Mellon UniversityN. Wisitpongphan and O.K. Tonguz, Carnegie Mellon University

J.S. Parikh, P. Mudalige, P. Bai, and V. Sadekar, General Motors CorporationJ.S. Parikh, P. Mudalige, P. Bai, and V. Sadekar, General Motors Corporation

Presented by:Presented by:

Yu Danlei Ajou UniversityYu Danlei Ajou University


2/27

2

Motivation:Motivation:

Broadcast is being used to discover nearbyBroadcast is being used to discover nearby

neighbors or propagate useful traffic informationneighbors or propagate useful traffic information inin

VANETVANET

High level of contention and collisionsHigh level of contention and collisions at the linkat the linklayer due to an excessive number of broadcastlayer due to an excessive number of broadcast

packets.packets.


3/27

3

Introduction:Introduction:

Differences between VANETs and MANETsDifferences between VANETs and MANETs

mobilitymobility

dimensional onedimensional one--dimensional linedimensional line

a stripa stripbroadcast transmissionbroadcast transmission

ThreeThree broadcast suppression techniques:broadcast suppression techniques:weighted pweighted p--persistencepersistence

slotted 1slotted 1--persistencepersistence

slotted pslotted p--persistencepersistence


4/27

4

Organization:Organization:

Background on VANETs and related researchBackground on VANETs and related research

Quantify the impact of the broadcast storm problem inQuantify the impact of the broadcast storm problem in

VANETs and discussionVANETs and discussion

Three broadcast mitigation algorithms, and explain the modelThree broadcast mitigation algorithms, and explain the model

and assumptionsand assumptions

The performance of three broadcast techniquesThe performance of three broadcast techniques


5/27

5

Background and Related Work 1.1Background and Related Work 1.1

VANET:VANET:PriorityPriority--based broadcast scheme [3]based broadcast scheme [3]

RoleRole--based multicast protocol [4]based multicast protocol [4]

802.11802.11--based multihop broadcast (UMB) protocol[5]based multihop broadcast (UMB) protocol[5]

MANET:MANET:

DDistributed gossipistributed gossip--based routing [8]based routing [8]ThresholdThreshold--based techniques [9] based techniques [9]

SenderSender--based multipoint relay ( MPR) technque[11]based multipoint relay ( MPR) technque[11]

Tackle broadcast storm problem by hardware[12.13]Tackle broadcast storm problem by hardware[12.13]


6/27

6


VANET:VANET:

[3][3] Broadcast Reception Rates and Effects of Priority Access inBroadcast Reception Rates and Effects of Priority Access in

802.11802.11--Based Vehicular Ad Hoc NetworksBased Vehicular Ad Hoc Networks

M. TorrentM. Torrent-- Moreno, D.Jiang, and H.HartenstenMoreno, D.Jiang, and H.Hartensten

The scheme gives higher priority to nodes that need to transmitThe scheme gives higher priority to nodes that need to transmit

timetime--critical messages. It cancritical messages. It can indirectlyindirectly mitigate the severitymitigate the severityof the storm by allowing nodes with higher priority to accessof the storm by allowing nodes with higher priority to accessthe channel as quickly as possible.the channel as quickly as possible.


7/27

7


VANET:VANET:

[[44]] RoleRole--Based Multicast in highly Mobile but Sparsely Connected Ad HocBased Multicast in highly Mobile but Sparsely Connected Ad HocNetworksNetworks

L. Briesemeister and G. HommelL. Briesemeister and G. Hommel

A roleA role--based multicast protocol that suppressed broadcast redundancy bybased multicast protocol that suppressed broadcast redundancy byassigning shorter waiting time prior to rebroadcasting to more distantassigning shorter waiting time prior to rebroadcasting to more distantreceivers.receivers.

Disadvantages: a sparsely connected or fragmented network where theDisadvantages: a sparsely connected or fragmented network where thebroadcast storm is not a main problembroadcast storm is not a main problem


8/27

8


VANET:VANET:

[[55]] Urban MultiUrban Multi--Hop Broadcast Protocol for InterHop Broadcast Protocol for Inter--VehicleVehicle

Communication SystemsCommunication Systems

G. Korkmaz et al.,G. Korkmaz et al.,

An efficient 802.11An efficient 802.11--based urban multihop broadcast protocol.based urban multihop broadcast protocol.

Its designed to suppress broadcast redundancy by onlyIts designed to suppress broadcast redundancy by onlyallowing the furthest vehicle from the transmitter toallowing the furthest vehicle from the transmitter to

rebroadcast the packet.rebroadcast the packet.


9/27

9


Sum up:Sum up:

Our approach aims to reduce the load submitted from theOur approach aims to reduce the load submitted from the

network layer to the data link layer by combining thenetwork layer to the data link layer by combining the

probabilistic broadcast technique with timerprobabilistic broadcast technique with timer--basedbasedsuppression.suppression.

This article is on a well connected network, in this work weThis article is on a well connected network, in this work we

only consider the broadcast storm problem on major highways.only consider the broadcast storm problem on major highways.


10/27

10

Ongoing Research and Previous workOngoing Research and Previous work 1.21.2

Carnegie Mellon University:Carnegie Mellon University:1)1) GrooveNet disseminate messages to within a prespecified boundedGrooveNet disseminate messages to within a prespecified boundedregion with minimal handshaking and state sharing informationregion with minimal handshaking and state sharing information

2)2) GrooveSim simulator operates in five different modes:GrooveSim simulator operates in five different modes:

DriveDrive modemodeSimulationSimulation modemode

PlaybackPlayback modemode

Hybrid simulationHybrid simulation modemode

Test generationTest generation modemode

Disadvantage:Disadvantage:

Although GrooveNet allows only relevant vehicles to receive andAlthough GrooveNet allows only relevant vehicles to receive andrebroadcast the packets, the current version of the protocol does not have arebroadcast the packets, the current version of the protocol does not have amechanism for preventing the broadcast storm problem from happening.mechanism for preventing the broadcast storm problem from happening.


11/27

11

The Broadcast Storm In MANETs and VANETsThe Broadcast Storm In MANETs and VANETs

2.12.1

MANET:MANET:1.1.RREQ (a route request)RREQ (a route request)2.2.Expanding Ring SearchExpanding Ring Search (a node can cache each routing(a node can cache each routing

entry for a longer time and canentry for a longer time and canalso reply on behalf of thealso reply on behalf of the

destination.)destination.) VANET: RSU (roadside unit) VANET: RSU (roadside unit)


12/27

12

FourFour--Lane Traffic Case StudyLane Traffic Case Study 2.22.2

Different densityDifferent density

Total delay can be negligibleTotal delay can be negligible

Dramatic packet loss ratioDramatic packet loss ratio


13/27

13

Broadcast Suppression Techniques 3Broadcast Suppression Techniques 3

DistanceDistance--Based Broadcasting:Based Broadcasting:

weighted pweighted p--persistencepersistenceslotted 1slotted 1--persistencepersistence

slotted pslotted p--persistencepersistence

ReceivedReceived--SignalSignal--StrengthStrength Based Schemes:Based Schemes:


14/27

14

WWeighted peighted p--persistencepersistence BroadcastingBroadcasting

Rule 3.1.1Rule 3.1.1

Upon receiving a packet from node i, node j checks the packet ID andUpon receiving a packet from node i, node j checks the packet ID andrebroadcast with probability prebroadcast with probability pijij if it receives the packet for the first time;if it receives the packet for the first time;otherwise it discards the packetotherwise it discards the packet

farther node gets higher probabilityfarther node gets higher probability


15/27

15

SlotSlottedted 11--persistencepersistence BroadcastingBroadcasting


a node checks the packet ID and rebroadcasts with probability 1 at thea node checks the packet ID and rebroadcasts with probability 1 at theassigned time slot Tsij if receive the packet for the first time and hasassigned time slot Tsij if receive the packet for the first time and has

not received any duplicates before its assigned time slot; otherwise,not received any duplicates before its assigned time slot; otherwise,discards.discards.

A shorter waiting time will be assigned to the nodesA shorter waiting time will be assigned to the nodes

located in the farthest region.located in the farthest region.


16/27

16

SlotSlotted pted p--PPersistenceersistence BroadcastingBroadcasting


PrePre--determined probability pdetermined probability p

The performance of this scheme depends on theThe performance of this scheme depends on thevalue of pvalue of p


17/27

17

ReceivedReceived--SignalSignal--StrengthStrength--BasedBased

Schemes 3.2Schemes 3.2

RRS is used where GPS signals may not be received.RRS is used where GPS signals may not be received.

Nodes obtain the RSS of the broadcast packet receivedNodes obtain the RSS of the broadcast packet receivedfrom the DSRC device driver and determine whether or notfrom the DSRC device driver and determine whether or notto rebroadcast the packetto rebroadcast the packet

To get a closer estimate of the relative distance to theTo get a closer estimate of the relative distance to thetransmitter, each vehicle should periodically probe itstransmitter, each vehicle should periodically probe itsneighbors in order to keep track of the time averaged RSS.neighbors in order to keep track of the time averaged RSS.


18/27

18

Performance AnalysisPerformance Analysis 44

SingleSingle--Lane Network:Lane Network:

1) Link Load1) Link Load

2) PacketPenetration Rate2) PacketPenetration Rate

Multilane Network:Multilane Network:


19/27

19

LinkLink lload 4.1.1oad 4.1.1

The link load measuresThe link load measuresthe amount of broadcastthe amount of broadcasttraffic received at eachtraffic received at eachnode over a unit timenode over a unit time

It depends on the numberIt depends on the numberof retransmitting nodesof retransmitting nodes

The smaller p, the betterThe smaller p, the betterperformance in terms ofperformance in terms of

linklink lloadoad The linkThe link lload is reducedoad is reduced

dramatically when thedramatically when theslotted scheme isslotted scheme isemployedemployed


20/27

20

Packet penetration rate 4.1.2Packet penetration rate 4.1.2

Measured from a singleMeasured from a single--lane network with randomlane network with randomtraffic distributiontraffic distribution

Fast packet penetrationFast packet penetrationrate means goodrate means goodtransmission in emergencytransmission in emergencysystemsystem

Slotted 1Slotted 1--persistencepersistence

performs poorly in sparsperforms poorly in sparsnetworknetwork


21/27

21

There is almost no benefit in using the reforwardingThere is almost no benefit in using the reforwardingprobability in light traffic conditionprobability in light traffic condition

At higher traffic density the reforwarding probability shouldAt higher traffic density the reforwarding probability shouldbe set to at least 0.5 in the persistence case and 0.8 in thebe set to at least 0.5 in the persistence case and 0.8 in theslotted pslotted p--persistence case in order to achieve at least 80persistence case in order to achieve at least 80

percent of the maximum performancepercent of the maximum performance


22/27

22

Multilane Network 4.2Multilane Network 4.2

Multilane network is simply a collection ofMultilane network is simply a collection of

multiple singlemultiple single--lane networkslane networksNN--fold and nfold and n--lane with a factor n or 1/nlane with a factor n or 1/n


23/27

23

Packet Loss Ratio And Delay AnalysisPacket Loss Ratio And Delay AnalysisAnd DiscussionAnd Discussion 4.34.3

Communication Model and BroadcastCommunication Model and BroadcastProtocol ImplementationProtocol Implementation ::

1) OPNET using IEEE 802.11a with 10 MHz bandwidth1) OPNET using IEEE 802.11a with 10 MHz bandwidth

2) range is approx. 1km2) range is approx. 1km

3) assume that3) assume that =WAIT_TIME.=WAIT_TIME.

Simulation Results:Simulation Results:Packet Loss RatioPacket Loss Ratio

LatencyLatency


24/27

24

Packet Loss RatioPacket Loss Ratio

Four densitiesFour densities

Among the threeAmong the threeschemes proposed,schemes proposed,slotted pslotted p--persistencepersistenceyields the bestyields the bestperformance while theperformance while theworst scheme isworst scheme isweighted pweighted p--persistencepersistence


25/27

25

LatencyLatency

Slotted pSlotted p--persistence introduces the longest propagationpersistence introduces the longest propagationdelaydelay

Traffic density doesnt have much impact on the number ofTraffic density doesnt have much impact on the number ofhops chosen by the routing protocolhops chosen by the routing protocol


26/27

26

Conclusion:Conclusion:

Routing protocols should be designed to address theRouting protocols should be designed to address thebroadcast storm problem to avoid unnecessary loss ofbroadcast storm problem to avoid unnecessary loss ofimportant safety related packets during a broadcast storm.important safety related packets during a broadcast storm.

The proposed slotted 1The proposed slotted 1--persistence and slotted ppersistence and slotted p--persistence schemes can reduce broadcast redundancy andpersistence schemes can reduce broadcast redundancy andpacket loss ratio by up to 70 percent while still offeringpacket loss ratio by up to 70 percent while still offeringacceptable endacceptable end--toto--end delay for most multihop VANETend delay for most multihop VANETapplication.application.

No fixed infrastructure in VANET. Further research mayNo fixed infrastructure in VANET. Further research maylocated in fixed ones for other application.located in fixed ones for other application.


27/27

27

If you have any question,If you have any question,

slowly and loudlyslowly and loudly !!

bsmt in vanet

Documents