How to Implement Bluetooth Topology in NS2

To implement the Bluetooth topology in Network Simulator 2 (ns2) encompasses to simulate Bluetooth communication by modeling its features include piconets, scatternets and the master-slave relationship. We have to replicate the Bluetooth activities using custom parameters like short-range wireless interaction, minimal data rates and particular traffic structures because ns2 doesn’t have an in-built Bluetooth module. For best implementation support you can stay in touch with ns2project.com for best guidance.

Below is a step-by-step guide on how to simulate a simple Bluetooth-like topology using NS2.

Steps to Implement Bluetooth Topology in NS2

  1. Set Up NS2

Make certain that NS2 is installed. If it’s not installed, you can install it by giving the below command on Ubuntu/Linux:

sudo apt-get update

sudo apt-get install ns2

  1. Simulate Bluetooth Topology in NS2

In a Bluetooth topology:

  • A piconet consists of one master and up to seven slave devices.
  • A scatternet is created by connecting several piconets through shared devices acting as bridges.

Example TCL Script for Bluetooth Topology Simulation

The following script replicates a basic Bluetooth piconet with one master and three slave devices. It uses a wireless channel with functionalities alike to Bluetooth containing low transmission power, short range, and low data rates.

# Define the simulator

set ns [new Simulator]

# Open trace files

set tracefile [open bluetooth_out.tr w]

set namfile [open bluetooth_out.nam w]

$ns trace-all $tracefile

$ns namtrace-all-wireless $namfile 500 500

# Define the topography object

set topo [new Topography]

$topo load_flatgrid 500 500

# Create a wireless channel to simulate Bluetooth communication

set chan_1_ [new Channel/WirelessChannel]

# Define radio propagation model, physical and MAC layers for Bluetooth-like behavior

Phy/WirelessPhy set CPThresh_ 10.0

Phy/WirelessPhy set CSThresh_ 1.0e-10

Phy/WirelessPhy set RXThresh_ 1.0e-10

Phy/WirelessPhy set Rb_ 1Mb  ;# Bluetooth operates at 1 Mbps

Phy/WirelessPhy set Pt_ 0.001 ;# Low power transmission typical in Bluetooth (1mW)

Phy/WirelessPhy set freq_ 2.4e9 ;# Bluetooth operates in the 2.4 GHz ISM band

# Configure Bluetooth-like nodes with AODV routing

$ns node-config -adhocRouting AODV \

-llType LL \

-macType Mac/802_11 \

-ifqType Queue/DropTail/PriQueue \

-ifqLen 50 \

-antType Antenna/OmniAntenna \

-propType Propagation/TwoRayGround \

-phyType Phy/WirelessPhy \

-channelType $chan_1_ \

-topoInstance $topo \

-agentTrace ON \

-routerTrace ON \

-macTrace ON

# Create nodes for the piconet (1 master, 3 slaves)

set master [$ns node] ;# Master node

set slave_1 [$ns node] ;# Slave node 1

set slave_2 [$ns node] ;# Slave node 2

set slave_3 [$ns node] ;# Slave node 3

# Position the nodes to simulate a piconet

$master set X_ 200.0

$master set Y_ 250.0

$master set Z_ 0.0

$slave_1 set X_ 150.0

$slave_1 set Y_ 250.0

$slave_1 set Z_ 0.0

$slave_2 set X_ 250.0

$slave_2 set Y_ 250.0

$slave_2 set Z_ 0.0

$slave_3 set X_ 200.0

$slave_3 set Y_ 300.0

$slave_3 set Z_ 0.0

# Define a static piconet (Bluetooth topology is typically static)

# Bluetooth devices do not move frequently

# Setup traffic flow (CBR over UDP) from master to slave_1 and slave_2

set udp_master_slave1 [new Agent/UDP]

set null_slave1 [new Agent/Null]

$ns attach-agent $master $udp_master_slave1

$ns attach-agent $slave_1 $null_slave1

$ns connect $udp_master_slave1 $null_slave1

set udp_master_slave2 [new Agent/UDP]

set null_slave2 [new Agent/Null]

$ns attach-agent $master $udp_master_slave2

$ns attach-agent $slave_2 $null_slave2

$ns connect $udp_master_slave2 $null_slave2

# Create CBR (Constant Bit Rate) traffic between master and slaves

set cbr_master_slave1 [new Application/Traffic/CBR]

$cbr_master_slave1 set packetSize_ 128

$cbr_master_slave1 set interval_ 0.05

$cbr_master_slave1 attach-agent $udp_master_slave1

set cbr_master_slave2 [new Application/Traffic/CBR]

$cbr_master_slave2 set packetSize_ 128

$cbr_master_slave2 set interval_ 0.05

$cbr_master_slave2 attach-agent $udp_master_slave2

# Start traffic at time 1.0 second

$ns at 1.0 “$cbr_master_slave1 start”

$ns at 1.0 “$cbr_master_slave2 start”

# Schedule simulation end

$ns at 10.0 “finish”

# Finish procedure to close the simulation and generate output

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exec nam bluetooth_out.nam &

exit 0

}

# Run the simulation

$ns run

Explanation of the Script:

  1. Bluetooth-like Channel and Node Configuration:
    • The script creates a wireless channel using $chan_1_, and the physical layer is configured to replicate Bluetooth characteristics (low power, low data rate, and operation in the 2.4 GHz frequency band).
  2. Piconet Setup:
    • Four nodes are built to mimic a Bluetooth piconet, where one node (master) behaves like the master, and three nodes (slave_1, slave_2, slave_3) act as slaves.
    • These nodes are placed close to one another to indicate the short-range nature of Bluetooth communication.
  3. Traffic Flows:
    • Two UDP agents are developed to imitate traffic from the master to two slave devices (slave_1 and slave_2).
    • CBR (Constant Bit Rate) applications configure packets amongst the master and the slaves at regular breaks, signifying typical Bluetooth communication.
  4. Trace and NAM Visualization:
    • The script generates trace files (bluetooth_out.tr) and a NAM file (bluetooth_out.nam), which can be visualized using NAM (Network Animator).
  1. Run the Simulation

Save the script like bluetooth_topology.tcl and execute it in NS2:

ns bluetooth_topology.tcl

Use NAM to view the network, execute:

nam bluetooth_out.nam

Customization:

  1. Adding More Slaves:
    • Stating extra nodes and including them to the master to include more slave nodes to the piconet. A Bluetooth piconet can have up to seven slaves.
  2. Scatternet Simulation:
    • Simulate a Scatternet by designing extra piconets and link them through common bridge nodes that behave like slaves in one piconet and masters in another.
  3. Mobility:
    • Bluetooth devices generally work in static or low-mobility environments, yet you can simulate movement using setdest commands for each node to launch mobility.
  4. Routing Protocols:
    • In a usual Bluetooth topology, nodes interact directly with the master, so routing protocols like AODV or DSR may not be essential. Though, if you want to mimic multi-hop communication in scatternets, routing protocols can be useful.

We have comprehensively elaborated the given demonstration including snippet codes for the better understanding of the implementation and customization of the Bluetooth topology which were executed in the Network Simulator 2 tool. If needed, we will deliver any additional information regarding this topology.