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As usual in a ns-2 wireless simulation, to simulate a wireless sensor network (WSN) with the Mannasim Framewor, the first step is to create a simulation scenario, its topography and a trace file. Itīs also necessary to create the general operations director (god) object.
set ns_ [new Simulator] ;# simulation object set traceFile [open trace.tr w] ;# trace file $ns_ trace-all $traceFile ;# attach trace to simulation $ns_ use-newtrace ;# use new trace format set topo [new Topography] ;# simulation topology $topo load_flatgrid $val(x) $val(y) ;# flat topology create-god $val(nn) ;# god
Antenna and physical layer configurations should be set too. Ns-2 OmniAntena and WirelessPhy objects provides a good abstraction to WSN simulation. The box bellow shows an omminidirectional antenna 1.5 meters above the ground and a Lucent Radio physical layer.
# Unity gain, omni-directional antennas set up the antenas to be # centered in the node and 1.5 meters above it Antenna/OmniAntenna set X_ 0 Antenna/OmniAntenna set Y_ 0 Antenna/OmniAntenna set Z_ 1.5 Antenna/OmniAntenna set Gt_ 1.0 Antenna/OmniAntenna set Gr_ 1.0 # Initialize the SharedMedia interface with parameters to make # it work like the 914MHz Lucent WaveLAN DSSS radio interface Phy/WirelessPhy set CPThresh_ 10.0 Phy/WirelessPhy set CSThresh_ 1.559e-11 Phy/WirelessPhy set RXThresh_ 3.652e-10 Phy/WirelessPhy set Rb_ 2*1e6 Phy/WirelessPhy set Pt_ 0.2818 Phy/WirelessPhy set freq_ 914e+6 Phy/WirelessPhy set L_ 1.0
The next step is to adjust a bunch of parameters placed in the "val" vector, a de facto standard in ns-2 simulation scripts. Parameters included in this vector are, for example, simulation start and stop times, routing protocol used, number of nodes in the network, etc. See the box bellow.
set val(chan) Channel/WirelessChannel ;# channel type set val(prop) Propagation/TwoRayGround ;# radio-propagation model set val(netif) Phy/WirelessPhy ;# network interface type set val(mac) Mac/802_11 ;# MAC type set val(ifq) Queue/DropTail/PriQueue ;# interface queye type set val(ll) LL ;# link layer type set val(ant) Antenna/OmniAntenna ;# antenna model set val(ifqlen) 200 ;# max packet in ifq set val(rp) AODV ;# routing protocol set val(x) 30.0 ;# scenario X dimension set val(y) 30.0 ;# scenario Y dimension set val(start) 5.0 ;# simulation start time set val(stop) 3605.0 ;# simulation stop time set val(energy) 10.0 ;# initial energy (joules) set val(rx) 0.024 ;# reception energy set val(tx) 0.045 ;# transmission energy set val(idle) 0.000 ;# idle energy set val(nn) 22 ;# total number of nodes
All these settings creates the ground for a WSN simulation. The Mannasim Framework on the other hand provides standardized structures for common sensor, cluster heads and access point nodes. It also contains a battery data generators and processing modules.
In the following pages it's going to be shown how the user creates access points, cluster heads and common nodes.
