The picture was extracted from http://www.ccs-labs.org/teaching/c2x-2012s/01-intro.pdf.

Seminar at GRC – 12 December 2012(12/12/12)

Simulating IEEE 802.11 in VANETs(using OMNeT++ and SUMO)

Ali Baladorbalador@gmail.com

Last modification: 18 December 2012

2

Outline

● Pre-Simulation (SUMO)

– SUMO setup

● Simulation (OMNeT++)

– NED file(s)

– Ini file(s)

– Running simulation

● Post simulation&initial results

3

Pre-Simulation step(SUMO setup)

1.Extracting the map from www.OpenStreetMap.org (*.osm)

Extracted from [8]: Tutorial for Simulating VANET and ITS (using OMNeT++ and SUMO), MJ (Thinus) Booysen, july 2012.

4

Pre-Simulation(SUMO setup)

2. Creating road network file (convert *.osm to net.xml with netconvertor)

netconvert --osm rc.osm

3. Generating random trips for road network file (randomTrips.py)

./randomTrips.py -n net.net.xml -l -e 600 -o trips.trips.xml

4. Convert the trips to routes and traffic flows (duarouter)

duarouter -n net.net.xml –t trips.trips.xml -o routes.rou.xml --ignore-errors

5

Pre-Simulation(SUMO setup)

Creating config file (sumo.cfg)

6

Pre-Simulation(SUMO setup)

● Creating obstacles (extract them from osm file by polyconvert)

polyconvert --net-file net.net.xml --osm-files map.osm -o map.poly.xml

● If the city doesn't include the building layout, it must be drawn with the JOSM (Java Open Street Map editor) tool.

● Referring to obstacles in config file.

<additional-files value="map.poly.xml"/>

7

SUMO overview

● Several configuration files needed:

– .ned.xml

– .edg.xml

– .net.xml

– .poly.xml

– .rou.xml

– .sumo.cfg

● Begin, end time

● Simulation time step

netconvert

Refers to / Usespolyconvert

8

Car mobility and road networks

● I'm using the pre-defined files that were prepared by GRC group.

● Moscow

● Milan

9

Simulation step

● Modeling approach in OMNeT++

– Simple vs. compound modules

– Messages (can contain arbitrary data)

– Gates (input/output)

– Connections (within a compound module or between one submodule and compound module)

– self-messages

Extracted from [1]: OMNET++ User Manual: http://whale.hit.bme.hu/omnetpp/.

10

Simulation step

● Simulation components:

– Behavior

● C++ code

– INETMANET package

– Structure

● NED file

– Runtime parameters

● Omnetpp.ini

11

Simulation step

● Simulation components:

– Behavior

● C++ code

– INETMANET package

– Structure

● NED file

– Runtime parameters

● Omnetpp.ini

12

Simulation step

● Preparing NED file for car:module Car

{

parameters:

string routingProtocol @enum("AODVUU","DYMOUM","DYMO",

"DSRUU","OLSR","OLSR_ETX","DSDV_2","Batman") = default("");

gates:

...

submodules:

app: UDPBasicBurst

mobility: TraCIMobility

udp: UDP

networkLayer: NetworkLayer

wlan: Ieee80211Nic {

manetrouting: <routingProtocol> like ImanetRouting

if routingProtocol != ""

connections allowunconnected:

...

}

Module Type

Module Interface

13

Simulation step(continue)

● Preparing NED file for network scenario:

module Highway

{

submodules:

channelControl: ChannelControl {

parameters:

@display("p=256,128");

}

manager: TraCIScenarioManagerLaunchd {

parameters:

@display("p=512,128");

}

}

● Channel control

– determines which nodes are within communication or interference distance

● TraCIScenarioManagerLaunchd

– control creation and movement of nodes

14

Simulation step(continue)

● Modifications in order to add obstacles and using VACaMobil

import inet.world.VACaMobil.VACaMobil;

...

import inet.world.obstacles.ObstacleControl;

import inet.world.annotations.AnnotationManager;

module Highway

{

submodules:

...

manager: VACaMobil {

@display("p=430,35");

}

obstacles: ObstacleControl {

@display("p=282,108");

}

annotations: AnnotationManager {

@display("p=144,108");

}

}

15

Simulation step

● Simulation components:

– Behavior

● C++ code

– INETMANET package

– Structure

● NED file

– Runtime parameters

● Omnetpp.ini

16

Simulation step(continue)

● Preparing ini file:

[General]

network = scenario

sim-time-limit = 3000s

#########################################

**.constraintAreaMinX = 0m

**.constraintAreaMinY = 0m

**.constraintAreaMinZ = 0m

**.constraintAreaMaxX = 10699m

**.constraintAreaMaxY = 7131m

**.constraintAreaMaxZ = 0m

#########################################

# channel physical parameters

*.channelControl.carrierFrequency = 2.4GHz

*.channelControl.pMax = 2.0mW

*.channelControl.sat = -110dBm

*.channelControl.alpha = 2

*.channelControl.numChannels = 1

17

Simulation step(continue)

# udp apps

**.host[*].app.destAddresses = moduleListByPath("**.host[*]")

**.app.localPort = 1234

**.app.destPort = 1234

**.app.messageLength = 512B # Bytes

**.app.sendInterval = 0.25s + uniform(-0.001s,0.001s,0)

**.app.burstDuration = 0s

**.app.sleepDuration = 0s

**.app.chooseDestAddrMode = "perSend"

**.app.delayLimit =20s

**.app.startTime = simTime()+1s

#################################

# nic settings

**.wlan.bitrate = 54Mbps

**.wlan.opMode = "a"

**.wlan.mgmt.frameCapacity = 10

**.wlan.mgmtType = "Ieee80211MgmtAdhoc"

**.wlan.mac.address = "auto"

**.wlan.mac.maxQueueSize = 14

**.wlan.mac.rtsThresholdBytes = 2346B

**.wlan.mac.retryLimit = 7

**.wlan.mac.cwMinData = ${7, 15, 31}

**.wlan.mac.cwMaxData = 1023

**.wlan.mac.cwMinBroadcast = 15

**.wlan.mac.slotTime = 13us #

1. How can we select random connection (destination)?

● In application layer, the destination address must be set to

● “random_name(host)” or

● “moduleListByPath("**.host[*]")”

that is causes one node will be chosen randomly among the network nodes.

2. How can we run the simulation several times with different parameter values?

● In order to do this, we can assign different values to each parameter in ini file with ${ }.

● Notice that the number of simulation must be mentioned in “run configuration window” (config name and run number). Also, this activity cannot run in command line.

18

Simulation step (last step)

● SUMO and OMNeT++● SUMO generates car mobility and

road network● OMNeT++ generates car

configuration details● How can we connect these two parts to have a VANET simulation?

● VEINS

● Veins connects the SUMO and OMNET++, it means every car in sumo are defined as a node in OMNET++, veins do this and also make mobility of nodes in OMNE++.● Veins uses a TCP connection and Python scripts to enable SUMO to act as a mobility model in OMNeT++.● sumo-launchd listening for event from omnet++ and if need any change in SUMO, it is done in XML format.

● OMNeT++ must be configured to look for mobility module

● back to ini file:# TraCIScenarioManagerLaunchd*.manager.updateInterval = 1s*.manager.host = "localhost"*.manager.port = 9999*.manager.moduleType = "inet.examples.traci_launchd.Car"*.manager.moduleName = "host"...*.manager.launchConfig = xmldoc("sumo-launchd.launch.xml")

● Python set up to wait for Veins (module in OMNeT++)sumo-launchd.py -p 9999 -vv -c/c/user/src/sumo/bin/sumo.exe

19

Simulation step

● Modifications in order to add obstacles and using VACaMobil

**.meanNumberOfCars = 50

**.carHysteresisValue = 0

#########################################

# annotations

*.annotations.draw = true

#########################################

# obstacles

*.obstacles.obstacles = xmldoc("map.poly.xml")

20

Running simulation

● OMNeT++ can be run under different user interfaces such as:

– Tkenv: graphical user interface

– Cmdenv: command line user interface

Graphical user interface (Tkenv)

21

Post simulation

● Result file formats– Output vector

● Capture behavior over time.

● Contain several output vectors, each being a named series of (timestamp, value) pairs.

vector 470 scenario.host[15].udp sentPk:vector(packetBytes) ETV

1 117 5.005082890525 512

1 165 5.25059449109 512

1 194 5.501521816618 512

– Scalar result

● Contain summary statistics: number of packets sent, number of packet drops, average end-to-end delay of received packets, peak throughput.

● Every scalar generates one line in the output file like:

scalar scenario.host[186].udp passedUpPk:count 95

scalar scenario.host[186].udp rcvdPk:count 95

scalar scenario.host[186].udp rcvdPk:sum(packetBytes) 49400

scalar scenario.host[186].udp sentPk:count 2136

scalar scenario.host[186].udp sentPk:sum(packetBytes) 1110720

22

Post simulation&Initial results

5 10 15 20 25 30 35

0

20000

40000

60000

80000

100000

120000

Average Number of Collision

CWmin

Ave

rag

e N

um

be

r o

f C

ollis

ion

5 10 15 20 25 30 35

23000

24000

25000

26000

27000

28000

29000

Throughput

CWmin

Th

rou

gh

pu

t

23

24

Next steps

1. Simulating vehicular ad hoc networks with obstacles and generated car mobility by VACaMobil. [it's done/18.12.2012]

2. Creating a script file to extract and draw final graphs automatically.

3. Reading the IEEE 802.11 implementation to know how it behaves.

1.How can I implement my previous works in omnet++.

4. Reading paper about MAC layer implementation(especially IEEE 802.11p), broadcast communication, and contention window adaptation. [in parallel with step 3]

5. Evaluate performance of my previous protocol(IEEE 802.11 based MAC protocol) in vehicular ad hoc networks.

1.Idea: Adapting contention window based on local density estimation

2.Try to find a way to change the way of collision detection (channel monitoring) in my previous works.

3.Compare with other IEEE 802.11-based protocols and also IEEE 802.11p.

6. Reading about IEEE 802.11p and it's implementation in OMNeT. [in parallel with 4 and 5]

25

Broadcast communication in vehicular ad hoc networks

● IEEE 802.11 DCF

– RTS/CTS handshaking

– ACK packets

● They cause collision

● Due to lack of capability of collision detection

– CWmin does not increase

– It shows the necessity of adapting CWmin based on network density.

26

Research questions

● How can IEEE 802.11-based protocols support broadcast services?

– How have previous works detected collisions in MAC layer? (for broadcast communication)

– Which one is suitable for broadcast communications, contention or contention-free mechanisms?

27

References

1. OMNET++ User Manual: http://whale.hit.bme.hu/omnetpp/.

2. TicToc tutorial: http://www.omnetpp.org/doc/omnetpp/tictoc-tutorial.

3. IDE user guide: http://omnetpp.org/doc/omnetpp/userguide/index.html.

4. OMNeT++ 4.x Wiki page: http://www.omnetpp.org/pmwiki/index.php?n=Main.Omnetpp4.

5. Contributors: Open street map. www.openstreetmap.org. Accessed 11 November 2012

6. Omnet++ (home site). http://www.omnetpp.org/. Accessed 11 November 2012

7. SUMO Simulation of Urban MObility (home page). http://sumo.sourceforge.net/. Accessed 11 November 2012

8. Tutorial for Simulating VANET and ITS (using OMNeT++ and SUMO), MJ (Thinus) Booysen, july 2012.

9. SUMO overview, University of Innsbruck.

10. OMNeT++ tutorial. http://www.ccs-labs.org/teaching/nwsim-2012w/02-omnetpp.pdf.

28

I have read these papers

● Broadcast communication in vehicular ad hoc network safety applications.

– Simulation-based performance evaluation of enhanced broadcast schemes for IEEE 802.11-based vehicular networks.

● Physical layer simulations of IEEE 802.11a for vehicle-to-vehicle communications.

29

I am going to read these papers

● Enhancements of IEEE 802.11p protocol for access control on a VANET control channel.

– Network status detection-based dynamic adaptation of contention window in IEEE 802.11p.

– A collision alleviation scheme for IEEE 802.11p VANETs.