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Introduction to Wireless simulations

Learn to simulate wireless networks with traffic and mobility files generation, simulation execution, trace formats, and Nam visualization. Explore detailed instructions and resources for efficient wireless simulations.

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Introduction to Wireless simulations

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  1. Introduction to Wireless simulations Shao-Cheng Wang

  2. 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

  3. Traffic file • cbrgen.tcl (~/ns/indep-util/cmu-trace) • ns cbrgen.tcl [-type cbr|tcp] [-nn nodes] [-seed seed] [-mc connections] [-rate rate]

  4. Traffic file (cont’d) > 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"

  5. Mobility file • ./setdest [-n num_of_nodes] [-p pausetime] [-s maxspeed] [-t simtime] \ [-x maxx] [-y maxy] > [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

  6. 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

  7. 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)

  8. Wireless simulation – cont’d • 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)

  9. $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

  10. for {set i 0} {$i < $val(nn) } {incr i} { • set node_($i) [$ns_ node ] • $node_($i) random-motion 0 ;# disable random motion } • source $val(cp) • source $val(trfile) for {set i 0} {$i < $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

  11. 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

  12. 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 >> "temp.c"; } } } exec awk $awkCode cwnd.tr • Detailed trace format : ~/ns/cmu-trace.cc

  13. Trace • s 0.000011740 _0_ RTR --- 0 ZRP 84 [0 0 0 0] ------- [0:255 -1:255 1 0] [0x1 0 [0 0] 2.000000] (HELLO) -1 sprintf(wrk_ + offset, "[0x%x %d [%d %d] %f] (%s) %d", rp->rp_type, rp->rp_hop_count, rp->rp_dst, rp->rp_dst_seqno, rp->rp_lifetime, rp->rp_type == ZRPTYPE_RREP ? "REPLY IERP" : (rp->rp_type == ZRPTYPE_UREP ? "UNSOLICITED REPLY IERP" : "HELLO"),ih->daddr());

  14. 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

  15. 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.html • Contributed Modules : http://nsnam.isi.edu/nsnam/index.php/Contributed_Code

  16. Backup Slides

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

  18. Portrait of A Mobile Node Classifier: Forwarding Agent: Protocol Entity Node Entry LL: Link layer object IFQ: Interface queue MAC: Mac object PHY: Net interface 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

  19. 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

  20. 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

  21. Wireless Channel • Duplicate packets to all mobile nodes attached to the channel except the sender • It is the receiver’s responsibility to decide if it will accept the packet • Collision is handled at individual receiver • O(N2) messages  grid keeper

  22. Grid-keeper: An Optimization

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