Introduction to Wireless simulations

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Introduction to Wireless simulations

• Shao-Cheng Wang

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Wireless Simulations

• Before simulation
• Generate traffic files cbrgen.tcl
• Generate mobility files setdest calcdest
• Simulation
• simple-wireless.tcl
• After simulation
• Trace formats
• Nam

• Marc Greis's tutorial http//www.isi.edu/nsnam/ns/
  tutorial/index.html

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Traffic file

• cbrgen.tcl (/ns/indep-util/cmu-trace)
• ns cbrgen.tcl -type cbrtcp -nn nodes -seed
  seed -mc connections -rate rate

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Traffic file (contd)

• gt ns cbrgen.tcl -type cbr -nn 10 -seed 1.0 -mc 8
  -rate 4.0
• 2 connecting to 3 at time 82.557023746220864
• set udp_(0) new Agent/UDP
• ns_ attach-agent node_(2) udp_(0)
• set null_(0) new Agent/Null
• ns_ attach-agent node_(3) null_(0)
• set cbr_(0) new Application/Traffic/CBR
• cbr_(0) set packetSize_ 512
• cbr_(0) set interval_ 0.25
• cbr_(0) set random_ 1
• cbr_(0) set maxpkts_ 10000
• cbr_(0) attach-agent udp_(0)
• ns_ connect udp_(0) null_(0)
• ns_ at 82.557023746220864 "cbr_(0) start"

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Mobility file

• ./setdest -n num_of_nodes -p pausetime -s
  maxspeed -t simtime \ -x maxx -y maxy gt
  outdir/movement-file
• node_(0) x,y,z
• ns_ at 2.000000000000 "node_(0) setdest
  90.441179033457 44.896095544010 1.373556960010"
• ns_ at 899.642 "god_ set-dist 23 46 2"

calcdest
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Wireless Simulations

• Before simulation
• Generate traffic files cbrgen.tcl
• Generate mobility files setdest calcdest
• Simulation
• simple-wireless.tcl
• After simulation
• Trace formats
• Nam

• Marc Greis's tutorial http//www.isi.edu/nsnam/ns/
  tutorial/index.html

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Wireless simulation

• set val(chan) Channel/WirelessChannel
  channel type
• set val(prop) Propagation/TwoRayGround
  radio-propagation model
• set val(ant) Antenna/OmniAntenna
  Antenna type
• set val(ll) LL
  Link layer type
• set val(ifq) Queue/DropTail/PriQueue
  Interface queue type
• set val(ifqlen) 50
  max packet in ifq
• set val(netif) Phy/WirelessPhy
  network interface type
• set val(mac) Mac/802_11
  MAC type
• set val(rp) DSDV
  ad-hoc routing protocol
• (optional)
• Phy/WirelessPhy set bandwidth_ 11000000
• Phy/WirelessPhy set Rb_ 11000000
• Mac/802_11 set dataRate_ 11000000
• Mac/802_11 set basicRate_ 2000000
• Agent/DSDV set min_update_periods_ 3
• (ref tcl/lan/ns-mac.tcl, tcl/mobility/dsdv.tcl)

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Wireless simulation contd

• set val(nn) 2
  number of mobilenodes
• set opt(x) 1300 X dimension of
  the topography
• set opt(y) 1300 Y dimension of
  the topography
• set val(cp) "example.scen"
• set val(trfile) "example.traffic"
• set ns_ new Simulator
• ns_ trace-all tracefd
• set topo new Topography
• wtopo load_flatgrid opt(x) opt(y)
• create-god val(nn)

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• ns_ node-config -adhocRouting val(rp) \
• -llType val(ll) \
• -macType val(mac) \
• -ifqType val(ifq) \
• -ifqLen val(ifqlen) \
• -antType val(ant) \
• -propType val(prop) \
• -phyType val(netif) \
• -topoInstance topo \
• -channelType val(chan)
  \
• -agentTrace ON \
• -routerTrace OFF \
• -macTrace OFF \
• -movementTrace OFF

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• for set i 0 i lt val(nn) incr i
• set node_(i) ns_ node
• node_(i) random-motion 0
  disable random motion
• source val(cp)
• source val(trfile)
• for set i 0 i lt val(nn) incr i
• ns_ at 150.0 "node_(i) reset"
• ns_ at 150.0001 "stop"
• ns_ at 150.0002 "puts \"NS EXITING...\" ns_
  halt"
• proc stop
• global ns_ tracefd
• close tracefd
• puts "Starting Simulation..."
• ns_ run

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Wireless Simulations

• Before simulation
• Generate traffic files cbrgen.tcl
• Generate mobility files setdest calcdest
• Simulation
• simple-wireless.tcl
• After simulation
• Trace formats
• Nam

• Marc Greis's tutorial http//www.isi.edu/nsnam/ns/
  tutorial/index.html

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After simulation trace format

• Special parameter
• Enables trace for congestion window.
• tcp trace cwnd_
• Attaches trace file handle to agent.
• set tchan_ open cwnd.tr w
• tcp attach tchan_
• set awkCode
• if (6 "cwnd_")
• print 1, 7 gtgt "temp.c"
• exec awk awkCode cwnd.tr
• Detailed trace format /ns/cmu-trace.cc

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Trace

• s 0.000011740 _0_ RTR --- 0 ZRP 84 0 0 0 0
  ------- 0255 -1255 1 0 0x1 0 0 0
  2.000000 (HELLO) -1
• sprintf(wrk_ offset, "0xx d d d f
  (s) d",
• rp-gtrp_type,
• rp-gtrp_hop_count,
• rp-gtrp_dst,
• rp-gtrp_dst_seqno,
• rp-gtrp_lifetime,
• rp-gtrp_type
  ZRPTYPE_RREP ? "REPLY IERP"
• (rp-gtrp_type
  ZRPTYPE_UREP ? "UNSOLICITED REPLY IERP"
• "HELLO"),ih-gtdaddr())
  

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Nam

• node color color sets color of node
• node shape shape sets shape of node
• node label label sets label on node
• node label-color lcolor sets color of
  label
• node label-at ldirection sets position of
  label
• node add-mark name color shape adds a
  mark to node
• node delete-mark name deletes mark from
  node

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More resources

• Doc
• ns by Example
• http//nile.wpi.edu/NS/
• NS Manual
• http//www.isi.edu/nsnam/ns/doc/index.html
• Workshop and presentations
• http//www.isi.edu/nsnam/ns/ns-tutorial/index.htm
  l
• Contributed Modules
• http//nsnam.isi.edu/nsnam/index.php/Contributed_C
  ode

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• Backup Slides

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Mobile Node Abstraction

• Location
• Coordinates (x,y,z)
• Movement
• Speed, direction, starting/ending location, time
  ...

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Portrait of A Mobile Node
port classifier
Node
protocol agent
255
routing agent
addr classifier
defaulttarget_
ARP
LL
LL
LL
IFQ
IFQ
MAC
MAC
Propagation and antenna models
PHY
PHY
MobileNode
CHANNEL
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Mobile Node Components

• Link Layer
• Same as LAN, but with a separate ARP module
• Interface queue
• Give priority to routing protocol packets
• Mac Layer
• IEEE 802.11
• RTS/CTS/DATA/ACK for all unicast packets
• DATA for all broadcast packets

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Mobile Node Components

• Network interface (PHY)
• Parameters based on Direct Sequence Spread
  Spectrum (WaveLan)
• Interface with antenna and propagation models
• Update energy transmission and reception
• Radio Propagation Model
• Friss-space attenuation(1/r2) at near distance
• Two-ray Ground (1/r4) at far distance
• Antenna
• Omni-directional, unity-gain

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Wireless Channel

• Duplicate packets to all mobile nodes attached to
  the channel except the sender
• It is the receivers responsibility to decide if
  it will accept the packet
• Collision is handled at individual receiver
• O(N2) messages ? grid keeper

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Grid-keeper An Optimization