How to Implement Channel Interference Avoidance in OMNeT++
To implement the channel interference avoidance in OMNeT++ has encompasses mimicking a wireless network where nodes identify and prevent interference on communication channels, normally by transferring to a less congested channel or modifying transmission parameters. It is especially vital in setups like cognitive radio networks, Wi-Fi networks, and other wireless settings where several devices share the similar frequency bands. Given below is a procedure to executing channel interference avoidance in OMNeT++ with examples:
Step-by-Step Implementations:
Step 1: Set Up the OMNeT++ Environment
Make sure that OMNeT++ and the INET framework are installed and configured correctly. INET offers a range of models for wireless communication, with mechanisms for channel selection, interference modelling, and more.
Step 2: Define the Wireless Node with Channel Switching Capability
Primarily, describe a wireless node that can identify interference on its present channel and switch to other channel if crucial. This node will use the INET framework’s wireless models, which contain channel selection mechanisms.
Example Node Definition
module WirelessNodeWithInterferenceAvoidance
{
parameters:
@display(“i=block/wifilaptop”); // Icon for visualization
gates:
inout wlan; // Wireless communication gate
submodules:
wlan: <default(“Ieee80211Nic”)>; // Wireless NIC for communication
mobility: <default(“MassMobility”)>; // Mobility module for movement
connections:
wlan.radioIn <–> wlan.radioIn; // Connect the wireless gate to the NIC
}
Step 3: Implement Interference Detection and Channel Switching Logic
Execute the logic for detecting interference and switching channels. It shall encompass observing the signal-to-noise ratio (SNR) or other metrics to decide when to switch channels.
Example Interference Avoidance Logic
class WirelessNodeWithInterferenceAvoidance : public cSimpleModule
{
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
void checkInterference();
void switchChannel();
private:
int currentChannel;
double interferenceThreshold;
cMessage *interferenceCheckTimer;
};
void WirelessNodeWithInterferenceAvoidance::initialize()
{
currentChannel = par(“initialChannel”);
interferenceThreshold = par(“interferenceThreshold”);
interferenceCheckTimer = new cMessage(“interferenceCheckTimer”);
scheduleAt(simTime() + par(“checkInterval”), interferenceCheckTimer);
// Set the initial channel
getModuleByPath(“^.wlan.radio”)->par(“channelNumber”) = currentChannel;
}
void WirelessNodeWithInterferenceAvoidance::handleMessage(cMessage *msg)
{
if (msg == interferenceCheckTimer)
{
checkInterference();
scheduleAt(simTime() + par(“checkInterval”), interferenceCheckTimer);
}
else
{
// Handle other messages
delete msg;
}
}
void WirelessNodeWithInterferenceAvoidance::checkInterference()
{
// Example: Simplified check for interference based on SNR
double snr = getModuleByPath(“^.wlan.radio”)->par(“snr”);
if (snr < interferenceThreshold)
{
EV << “Interference detected, switching channel…” << endl;
switchChannel();
}
}
void WirelessNodeWithInterferenceAvoidance::switchChannel()
{
// Example: Cycle through channels 1 to 11
currentChannel = (currentChannel % 11) + 1;
getModuleByPath(“^.wlan.radio”)->par(“channelNumber”) = currentChannel;
EV << “Switched to channel ” << currentChannel << endl;
}
Step 4: Define the Network Scenario with Multiple Nodes
Generate a network scenario where numerous nodes operate on numerous channels and possibly interfere with each other. This will establish the interference avoidance mechanism.
Example Network Scenario Definition
network ChannelInterferenceNetwork
{
parameters:
int numNodes = default(5); // Number of nodes in the network
submodules:
nodes[numNodes]: WirelessNodeWithInterferenceAvoidance {
@display(“p=100,100”);
}
connections allowunconnected:
for i=0..numNodes-2 {
nodes[i].wlan <–> IdealWirelessLink <–> nodes[i+1].wlan;
}
}
Step 5: Configure the Simulation Parameters
Form the simulation parameters in the .ini file, containing the interference thresholds, initial channels, and other node-specific settings.
Example Configuration in the .ini File
[General]
network = ChannelInterferenceNetwork
sim-time-limit = 300s
# Channel and interference configuration
*.nodes[*].initialChannel = intuniform(1, 11) # Random initial channel for each node
*.nodes[*].interferenceThreshold = 10 # SNR threshold for switching channels
*.nodes[*].checkInterval = 5s # Interval for checking interference
# Wireless communication parameters
*.nodes[*].wlan.radio.transmitter.power = 20mW
*.nodes[*].wlan.radio.transmitter.datarate = 54Mbps
*.nodes[*].wlan.radio.receiver.sensitivity = -85dBm
*.nodes[*].wlan.radio.snr = uniform(5, 20) # Example SNR range
Step 6: Implement Traffic Generation
Execute the logic for creating traffic from each node to mimic network usage. It will support generate interference scenarios.
Example Traffic Generation Logic
class TrafficGenerator : public cSimpleModule
{
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
private:
cMessage *sendTimer; // Timer to trigger sending data
};
void TrafficGenerator::initialize()
{
sendTimer = new cMessage(“sendTimer”);
scheduleAt(simTime() + par(“sendInterval”), sendTimer);
}
void TrafficGenerator::handleMessage(cMessage *msg)
{
if (msg == sendTimer)
{
cMessage *packet = new cMessage(“DataPacket”);
send(packet, “out”);
scheduleAt(simTime() + par(“sendInterval”), sendTimer);
}
else
{
delete msg;
}
}
Step 7: Run the Simulation
Compile and run the simulation. Monitor how nodes detect interference and switch channels to prevent it.
Step 8: Analyse the Results
Use OMNeT++’s analysis tools to estimate the performance of the channel interference avoidance mechanism. Analyse metrics like:
- Channel Switching Frequency: How frequently nodes switch channels in response to interference.
- Network Throughput: Assess the overall throughput of the network and see if it increases after executing interference avoidance.
- Interference Levels: Observe the interference levels like SNR before and after channel switching.
Step 9: Extend the Simulation (Optional)
We can expand the simulation by:
- Implementing Dynamic Channel Selection: Instead of cycling via channels, execute a more sophisticated algorithm that chooses the smallest congested channel.
- Adding More Complex Interference Models: Mimic more realistic interference scenarios, containing co-channel interference, Doppler shifts, and multi-path fading,
- Simulating Different Network Topologies: Test with various network topologies like mesh, star to understand how interference avoidance executes in several scenarios.
- Integrating Cognitive Radio Techniques: Execute cognitive radio strategies where nodes sense the spectrum and dynamically modify their transmission parameters to prevent interference.
In this page, we focussed on how to execute the Channel interference avoidance the tool OMNeT++ that contains wireless network, traffic generation logic, and network scenario in multiple nodes. We will furnish further details about this topic as needed. Get customised implementation and thesis topics from omnet-manual.com researchers.