How to Implement Network Co Channel Interference in NS2

To implement the Co-channel interference (CCI) happens when numerous transmitters use the similar frequency channel, leading to signal interference and reduced the performance within wireless networks. In the simulation NS2, we can replicate Co-channel interference by modeling how overlapping transmissions from various nodes are impacts the packet reception and the signal-to-noise ratio (SNR).Stay in touch with us to get best project implementation guidance.

However NS2 does not natively support the thorough physical layer interference models that we can mimic the impacts of co-channel interference by modifying the packet reception probability, signal strength, and interference from other nodes transmitting on the similar channel. Given below is a brief process how we can execute the Co-channel interference (CCI) in NS2:

Step-by-Step Implementation:

  1. Understanding Co-Channel Interference
  • Co-channel interference is triggered by two or more devices transmitting on the similar frequency that leads to interference and minimise signal quality.
  • Signal-to-Interference-plus-Noise Ratio (SINR) is a significant metric, which quantifies the effects of the interference. The lower the SINR, the higher the probability of packet loss or errors.
  • To mimic CCI, we modify the packet error rates, the signal strength, interference levels, and depends on the number of nodes transmitting on the similar channel.
  1. Approach to Simulate Co-Channel Interference in NS2
  • Interference Detection: Identify while several nodes are transferring on the similar channel at the same time.
  • SINR Calculation: Calculate the Signal-to-Interference-plus-Noise Ratio (SINR) to replicate the impacts of the co-channel interference on packet reception.
  • Packet Error Modeling: Fine-tune the packet error rate (PER) rely on the SINR that lower SINR values lead to higher packet error probabilities.
  1. Steps to Implement Co-Channel Interference in NS2

Step 1: Modify the Physical Layer to Incorporate Co-Channel Interference

  1. Open the Physical Layer Script (wireless-phy.tcl):
    • In the simulation environment NS2, the physical layer manages the signal propagation and reception. We will be changed physical layer to find the co-channel interference and alter the packet reception process depends on the SINR.
  2. Define Interference and Noise Parameters:
    • Configure parameters to model interference and background noise, with the signal strength of the transmitting nodes.

# Define interference and noise parameters

set Phy/WirelessPhy/interference_threshold 0.1  ;# Threshold for considering interference (in watts)

set Phy/WirelessPhy/noise_floor 0.01  ;# Background noise level (in watts)

  1. SINR Calculation:
    • Execute a function, which assess the SINR according to the signal strength of the required transmission and the interference from other nodes.

# Function to calculate SINR (Signal-to-Interference-plus-Noise Ratio)

proc calc_sinr {signal_strength interference_strength noise_floor} {

set sinr [expr $signal_strength / ($interference_strength + $noise_floor)]

return $sinr

}

  1. Packet Reception Based on SINR:
    • In the physical layer , adjust the packet reception process to verify the SINR before deciding whether to accept or drop the packet.

proc Phy/WirelessPhy::recv {packet} {

# Get the size of the incoming packet

set packet_size [$packet size]

# Get the signal strength of the received packet

set signal_strength [$self getSignalStrength]

# Calculate interference from other nodes transmitting on the same channel

set interference_strength [$self calcInterferenceStrength]

# Calculate the SINR based on signal, interference, and noise levels

set noise_floor [Phy/WirelessPhy set noise_floor]

set sinr [calc_sinr $signal_strength $interference_strength $noise_floor]

# Check if the SINR is above a certain threshold for successful reception

if {$sinr < 10} {

# If SINR is too low, drop the packet due to co-channel interference

drop $packet

return

}

# If SINR is acceptable, forward the packet to the upper layers

$self up-target $packet

}

# Function to calculate interference strength from other transmitters

proc Phy/WirelessPhy::calcInterferenceStrength {} {

set interference_strength 0.0

# Calculate the interference from all other nodes transmitting on the same channel

foreach node $::transmitting_nodes {

set node_signal_strength [$node getSignalStrength]

set interference_strength [expr $interference_strength + $node_signal_strength]

}

return $interference_strength

}

Step 2: Track Transmitting Nodes on the Same Channel

We require to trace that nodes are transferring on the similar channel and we can use those data to compute the interference triggered by simultaneous transmissions.

# List of nodes currently transmitting

set transmitting_nodes {}

# Function to add a node to the transmitting list

proc Phy/WirelessPhy::addTransmittingNode {node} {

global transmitting_nodes

lappend transmitting_nodes $node

}

# Function to remove a node from the transmitting list after transmission

proc Phy/WirelessPhy::removeTransmittingNode {node} {

global transmitting_nodes

set transmitting_nodes [lsearch -exact $transmitting_nodes $node]

set transmitting_nodes [lreplace $transmitting_nodes 0 0]

}

Step 3: Define a TCL Script to Simulate Co-Channel Interference

Here, we will make a TCL script to configure a wireless network and replicate numerous nodes are transmitting on the similar channel, triggering co-channel interference.

# Create a simulator instance

set ns [new Simulator]

# Create trace and nam files for output

set tracefile [open cci.tr w]

set namfile [open cci.nam w]

$ns trace-all $tracefile

$ns namtrace-all $namfile

# Define network topology

set topo [new Topography]

$topo load_flatgrid 1000 1000  ;# Simulation area: 1000×1000 meters

# Create the General Operations Director (GOD)

set god_ [create-god 10]  ;# 10 nodes in the network

# Define physical layer and interference parameters

set Phy/WirelessPhy/interference_threshold 0.1

set Phy/WirelessPhy/noise_floor 0.01

# Define node parameters

set opt(chan)       Channel/WirelessChannel

set opt(prop)       Propagation/TwoRayGround

set opt(netif)      Phy/WirelessPhy

set opt(mac)        Mac/802_11

set opt(ifq)        Queue/DropTail/PriQueue

set opt(ll)         LL

set opt(ant)        Antenna/OmniAntenna

set opt(x)          1000

set opt(y)          1000

# Set number of nodes

set opt(nn) 10  ;# Number of nodes

# Create nodes and set initial positions

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

set node_($i) [$ns node]

$node_($i) random-motion 1  ;# Enable random motion for nodes

}

# Set up traffic generation with co-channel interference

proc start_traffic {} {

global ns node_ opt

# Create UDP agents and attach them to nodes

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

set udp_($i) [new Agent/UDP]

set null_($i) [new Agent/Null]

$ns attach-agent $node_($i) $udp_($i)

$ns attach-agent $node_($i) $null_($i)

# Generate CBR traffic

set cbr_($i) [new Application/Traffic/CBR]

$cbr_($i) set packetSize_ 512

$cbr_($i) set interval_ 0.1

$cbr_($i) attach-agent $udp_($i)

# Connect UDP agents for communication between nodes

$ns connect $udp_($i) $null_($i)

# Add the node to the transmitting list when it starts transmitting

$ns at 1.0 “$node_($i) addTransmittingNode $node_($i)”

$ns at 2.0 “$node_($i) removeTransmittingNode $node_($i)”

}

}

# Start traffic at 1.0 second

$ns at 1.0 “start_traffic”

# Run the simulation

$ns at 100.0 “finish”

# End simulation procedure

proc finish {} {

global ns tracefile namfile

close $tracefile

close $namfile

$ns halt

}

# Run the simulation

$ns run

  1. Explanation of the Script
  • Interference Detection: The script traces the nodes, which are transferring on the similar channel and estimates the aggregated interference they cause.
  • SINR Calculation: The SINR is calculated rely on the signal strength, interference from other transmitters, and background noise.
  • Packet Reception: If the SINR is very low because of the interference, the packet is dropped; else, this is passed to the upper layers.
  • Traffic Generation: Constant Bit Rate (CBR) traffic is produced among the nodes are using the UDP agents, and co-channel interference is mimicked by permitting several nodes to transmit at the similar time.
  1. Running the Simulation
  • We can save and changed the wireless-phy.tcl file and the TCL script (cci.tcl).
  • Then we run the simulation using the below command:

ns cci.tcl

  1. Analysing Results
  • Estimate the trace file (cci.tr) to monitor how co-channel interference impacts packet delivery, after running the simulation.
  • We can assess the parameters like the packet delivery ratio, throughput, and SINR to learn the effect of the interference.
  1. Further Enhancements
  • Adaptive Channel Selection: Execute the mechanisms in which nodes are actively switch channels to prevent the interference during the SINR drops below a particular threshold.
  • Interference Mitigation Techniques: Test with interference mitigation strategies such as power control, beamforming, or frequency hopping to minimise the effect of co-channel interference.
  • Advanced SINR Models: Integrate more realistic physical-layer models with multi-path fading, shadowing, and path loss, to enhance the exactness of SINR calculations.

We were provide the details on how to start the implementation, define tcl script and examine the outcomes for the execution of Network Co channel interference in the Network simulation called ns2 including examples with codes.