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How to Calculate Network Carrier to Interference Ratio in omnet++

To calculate the Carrier-to-Interference Ratio (CIR) in OMNeT++ requires a computing the strength of the desired signal (carrier) relative to the sum of the strengths of interfering signals. In wireless communication systems, CIR is a key metric because it affects the quality and reliability of the communication link. Below, we provided the step-by-step approach:

Steps to Calculate Carrier-to-Interference Ratio (CIR) in OMNeT++:

  1. Set Up the Wireless Network Model:
    • In OMNeT++, with the help of INET we have to state the wireless network topology as well as nodes like access points, base stations, or mobile devices, and configure the wireless channel model.
  2. Configure the Channel Model:
    • We have use to channel model which is responsible for both the carrier signal and interference from other transmitters.. In OMNeT++, especially with the INET framework, we can simulate wireless communication by using modules like Ieee80211Radio and RadioMedium.
  3. Measure the Received Signal Strength (Carrier Signal):
    • Use radio module which is linked in the node to access the received signal strength (RSS) of the carrier. This value signifies the power of the desired signal.
  4. Measure the Interference Power:
    • The interference power is the sum of the power of all unsolicited signals received by the node. These are signals from other transmitters that are not planned for the node in question.
  5. Calculate CIR:
    • The CIR is estimated as the ratio of the power of the carrier signal to the interference power: CIR=PcarrierPinterference\text{CIR} = \frac{P_{\text{carrier}}}{P_{\text{interference}}}CIR=Pinterference​Pcarrier​​
    • This value can also be expressed in decibels (dB) using: CIR (dB)=10×log⁡10(PcarrierPinterference)\text{CIR (dB)} = 10 \times \log_{10}\left(\frac{P_{\text{carrier}}}{P_{\text{interference}}}\right)CIR (dB)=10×log10​(Pinterference​Pcarrier​​)

Example Implementation: CIR Calculation

Here’s an sample of how to calculate CIR in OMNeT++ using the INET framework:

#include <omnetpp.h>

#include “inet/physicallayer/contract/packetlevel/IRadio.h”

#include “inet/physicallayer/contract/packetlevel/IRadioMedium.h”

using namespace omnetpp;

using namespace inet;

using namespace inet::physicallayer;

class CIRModule : public cSimpleModule {

private:

IRadio *radio;                      // Pointer to the radio module

IRadioMedium *radioMedium;          // Pointer to the radio medium module

simsignal_t cirSignal;              // Signal to record CIR

protected:

virtual void initialize() override {

// Find the radio and radio medium modules

radio = check_and_cast<IRadio *>(getParentModule()->getSubmodule(“radio”));

radioMedium = check_and_cast<IRadioMedium *>(getModuleByPath(“radioMedium”));

// Register the CIR signal

cirSignal = registerSignal(“cirSignal”);

// Schedule the first CIR calculation

scheduleAt(simTime() + par(“calculationInterval”).doubleValue(), new cMessage(“calculateCIR”));

}

virtual void handleMessage(cMessage *msg) override {

if (strcmp(msg->getName(), “calculateCIR”) == 0) {

// Access the received signal power (in Watts)

W receivedPower = radio->getReceptionPower(radio->getLastTransmittedSignal());

// Calculate the total interference power

W interferencePower = radioMedium->getTotalInterference(radio->getLastTransmittedSignal());

// Calculate the CIR

double cir = receivedPower.get() / interferencePower.get();

double cirDb = 10 * log10(cir);

// Emit the CIR signal

emit(cirSignal, cirDb);

EV << “Carrier-to-Interference Ratio (CIR): ” << cirDb << ” dB\n”;

// Schedule the next CIR calculation

scheduleAt(simTime() + par(“calculationInterval”).doubleValue(), msg);

} else {

delete msg;

}

}

};

Define_Module(CIRModule);

Explanation:

  • CIRModule:
    • radio: To manage the signal transmission and reception, we use a pointer to the radio module.
    • radioMedium: A pointer to the radio medium module handles the wireless channel and measures interference.
    • cirSignal: Registers a signal to radiate the calculated CIR for logging or analysis.
  • initialize() Function:
    • Trace the radio and radio medium modules and lists the first calculation of CIR.
  • handleMessage() Function:
    • calculateCIR: Recovers the power of the received carrier signal and the total interference power. It then computes the CIR and emits it as a signal.
    • The next computation will be scheduled once the CIR is logged for analysis.
  1. Run the Simulation:
  • Compile and run the OMNeT++ project. The simulation will occasionally determine and log the CIR values for the wireless links.
  1. Analyze and Interpret Results:
  • The CIR values offer visions into the quality of the wireless communication link. Higher CIR values specify better link quality, as the desired signal is stronger relative to the interference.

Additional Considerations:

  • Dynamic Conditions: Due to the user mobility, CIR can differ in the course of time, changes in interference, and varying network load. Make sure the simulation detects these dynamics.
  • Environmental Effects: Consider the impact of obstacles, fading, and shadowing, that can stimulus both the carrier and interference signals.
  • Interference Sources: The precision of the CIR computation based on accurately accounting for all sources of interference in the network.

In this computation, we successfully learned to calculate the Carrier-to-Interference Ratio (CIR) in OMNeT++ and make sure to consider the provided few points before computing. If needed, we will offer additional details about it.

We will help you with your project! Please provide us with the details of your project parameters so we can assist you in calculating the Network Carrier to Interference Ratio using the OMNeT++ tool. If you’re looking for project ideas or comparison analyses, we can definitely offer that as well!

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