MRECW Students E- Learning Point Computer Security Student (CSS)

AODV simulation for a Sensor network 802.15.4

           The reason to write this topic is many people asked me how to simulate sensor networks.
Obviously, authors of 802.15.4/Zigbee protocol developers on NS2 have given a sample examples. But, these examples do not run correctly, and give some kind of unknown error (at least I don’t know what errors mean).
Therefore, I have decided to test AODV using 802.15.4 MAC/PHY. Thus, if my tests work, I hope you can test your own routing protocols using this source code.

Alright, the TCL file is fairly simple. I briefly explain what means what. We first set simulation environment. We are going to deploy 500 nodes, in 1000×500 sqm area, simulation time is 500 seconds. And we are using 802.15.4 MAC/PHY and interface queue is 100. We also set simulator and files to trace the simulation.

1	# Generated by Topology Generator for Network Simulator

2	set val(chan)          Channel/WirelessChannel      ;# channel type

3	set val(prop)          Propagation/TwoRayGround     ;# radio-propagation model

4	set val(netif)         Phy/WirelessPhy/802_15_4     ;# network interface type

5	set val(mac)           Mac/802_15_4                 ;# MAC type

6	set val(ifq)           Queue/DropTail/PriQueue      ;# interface queue type

7	set val(ll)            LL                           ;# link layer type

8	set val(ant)           Antenna/OmniAntenna          ;# antenna model

9	set val(ifqlen)        100                  ;# max packet in ifq

10	set val(nn)            500              ;# number of mobilenodes

11	set val(rp)            AODV             ;# protocol tye

12	set val(x)             1000             ;# X dimension of topography

13	set val(y)             500              ;# Y dimension of topography

14	set val(stop)          500              ;# simulation period

15	set val(energymodel)   EnergyModel          ;# Energy Model

16	set val(initialenergy) 100              ;# value

17

18	set ns              [new Simulator]

19	set tracefd         [open trace-aodv-802-15-4.tr w]

20	set namtrace        [open nam-aodv-802-15-4.nam w]

21

22	$ns trace-all $tracefd

23	$ns namtrace-all-wireless $namtrace $val(x) $val(y)

Let’s set radio transmission range to 40 meters, but this does not mean exactly 40 meters. The code below filters packet with receiving signal strength above “40 meters”.

1	set dist(5m)  7.69113e-06

2	set dist(9m)  2.37381e-06

3	set dist(10m) 1.92278e-06

4	set dist(11m) 1.58908e-06

5	set dist(12m) 1.33527e-06

6	set dist(13m) 1.13774e-06

7	set dist(14m) 9.81011e-07

8	set dist(15m) 8.54570e-07

9	set dist(16m) 7.51087e-07

10	set dist(20m) 4.80696e-07

11	set dist(25m) 3.07645e-07

12	set dist(30m) 2.13643e-07

13	set dist(35m) 1.56962e-07

14	set dist(40m) 1.20174e-07

15	Phy/WirelessPhy set CSThresh_ $dist(40m)

16	Phy/WirelessPhy set RXThresh_ $dist(40m)

And lets set topography as flat, deploy nodes randomly in an area of 1000 x 500 sqm.

1	# set up topography object

2	set topo       [new Topography]

3	$topo load_flatgrid $val(x) $val(y)

4

5	create-god $val(nn)

6

7	# configure the nodes

8	$ns node-config -adhocRouting $val(rp)

9	-llType $val(ll)

10	-macType $val(mac)

11	-ifqType $val(ifq)

12	-ifqLen $val(ifqlen)

13	-antType $val(ant)

14	-propType $val(prop)

15	-phyType $val(netif)

16	-channel [new $val(chan)]

17	-topoInstance $topo

18	-agentTrace ON

19	-routerTrace ON

20	-macTrace  OFF

21	-movementTrace OFF

22	-energyModel $val(energymodel)

23	-initialEnergy $val(initialenergy)

24	-rxPower 35.28e-3

25	-txPower 31.32e-3

26	-idlePower 712e-6

27	-sleepPower 144e-9

28

29	#-IncomingErrProc MultistateErrorProc

30	#-OutgoingErrProc MultistateErrorProc

31

32	for {set i 0} {$i < $val(nn) } { incr i } {

33	set mnode_($i) [$ns node]

34

}

35

36	for {set i 1} {$i < $val(nn) } { incr i } {

37	$mnode_($i) set X_ [ expr {$val(x) * rand()} ]

38	$mnode_($i) set Y_ [ expr {$val(y) * rand()} ]

39	$mnode_($i) set Z_ 0

40

}

And we are goig to deploy sink node in the center of area, i.e. at [500, 250].

1	# Position of Sink

2	$mnode_(0) set X_ [ expr {$val(x)/2} ]

3	$mnode_(0) set Y_ [ expr {$val(y)/2} ]

4	$mnode_(0) set Z_ 0.0

5

$mnode_(0) label "Sink"

The code below is useful how big the nodes are going to be shown in NAM (network animator), thus it does not have meaning in real simulation.

1	for {set i 0} {$i < $val(nn)} { incr i } {

2	$ns initial_node_pos $mnode_($i) 10

3

}

Finally, we have deployed nodes, and remained important thing is establish connection. We are going to use UDP protocol with CBR (constant bit rate, interval (interval_) is set to 2 seconds)

1	#Setup a UDP connection

2	set udp [new Agent/UDP]

3	$ns attach-agent $mnode_(10) $udp

4

5	set sink [new Agent/Null]

6	$ns attach-agent $mnode_(0) $sink

7

8	$ns connect $udp $sink

9	$udp set fid_ 2

10

11	#Setup a CBR over UDP connection

12	set cbr [new Application/Traffic/CBR]

13	$cbr attach-agent $udp

14	$cbr set type_ CBR

15	$cbr set packet_size_ 50

16	$cbr set rate_ 0.1Mb

17	$cbr set interval_ 2

18	#$cbr set random_ false

19

20	$ns at 5.0 "$cbr start"

21	$ns at [expr $val(stop) - 5] "$cbr stop"

22

23	# Telling nodes when the simulation ends

24	for {set i 0} {$i < $val(nn) } { incr i } {

25	$ns at $val(stop) "$mnode_($i) reset;"

26

}

27

28	# ending nam and the simulation

29	$ns at $val(stop) "$ns nam-end-wireless $val(stop)"

30	$ns at $val(stop) "stop"

31	$ns at [expr $val(stop) + 0.01] "puts "end simulation"; $ns halt"

32	proc stop {} {

33	global ns tracefd namtrace

34	$ns flush-trace

35	close $tracefd

36	close $namtrace

37

}

38

39

$ns run

We have finished writing sample AODV TCL script, we can run it

1	ns aodv_802_15_4.tcl

Download whole source code here : aodv_802_15_4.tcl . If you find any problem with that, leave comment here. If you want to test your own routing protocol simply change $val(rp) AODV with your own.