How to Implement Secondary Users Routing in OMNeT++

To implement secondary users routing in OMNeT++ has needs to simulating a network where secondary users (SUs) enthusiastically access the network based on available resources that usually in the aspect of Cognitive Radio Networks (CRNs) or Dynamic Spectrum Access (DSA) scenarios and the secondary users do not have licensed access to the spectrum and should use routing techniques that adjust to the presence of primary users (PUs) who have priority. The below are the procedures to implement the secondary users routing in OMNeT++:

Steps to Implement Secondary Users Routing in OMNeT++

Install OMNeT++ and INET Framework:
- Make sure that OMNeT++ and the INET framework are installed. INET delivers the essential components for wireless communication and routing protocols.
Define the Network Topology:
- Generate a network topology using a .ned file that has primary users (PUs) and secondary users (SUs). The SUs will essential to tranmit their data dynamically, considering the presence of PUs.
Implement Secondary User Behaviour:
- Improve or use existing models for secondary users that replicate their behaviour in retrieving the network and this contain sensing the presence of PUs, enthusiastically selecting channels, and routing their information via the network.
Implement Routing Protocol for Secondary Users:
- Execute or configure a routing protocol that permits the SUs to route their information while preventing interference with PUs. Common approaches have contained Opportunistic Routing, Spectrum Aware Routing, or Cognitive Routing.
Simulate Various Scenarios:
- Setup scenarios where secondary users need to route the information via the network while adjusting to the dynamic availability of channels triggered by the presence of primary users.
Configure the Simulation Environment:
- Use the .ini file to configure parameters like mobility patterns, routing protocol settings, spectrum availability, and the behaviour of primary users.
Run the Simulation and Analyse Results:
- Implement the simulation and evaluate the performance of secondary users routing. Key metrics that contain packet delivery ratio, end-to-end delay, throughput, and how well the routing protocol adjust to spectrum availability.

Example: Implementing Secondary Users Routing in OMNeT++

Define the Network Topology in a .ned File

// SecondaryUsersRoutingNetwork.ned

package networkstructure;

import inet.node.inet.WirelessHost;

network SecondaryUsersRoutingNetwork

{

parameters:

int numPUs = default(5); // Number of primary users

int numSUs = default(10); // Number of secondary users

submodules:

primaryUser[numPUs]: WirelessHost {

@display(“p=100,100”);

numApps = 1;

app[0].typename = “PrimaryUserApp”;

}

secondaryUser[numSUs]: WirelessHost {

@display(“p=300,200”);

numApps = 1;

app[0].typename = “SecondaryUserApp”;

}

connections:

// No fixed connections as routing is dynamic based on available spectrum

}

Implement Secondary User Behavior

Generate a C++ class for the secondary user application that emulates the dynamic selection of channels and transmit of information.

#include <omnetpp.h>

#include <inet/applications/base/ApplicationBase.h>

using namespace omnetpp;

using namespace inet;

class SecondaryUserApp : public ApplicationBase

{

protected:

virtual void initialize(int stage) override;

virtual void handleMessageWhenUp(cMessage *msg) override;

void senseChannelAndRoute();

public:

virtual int numInitStages() const override { return NUM_INIT_STAGES; }

};

Define_Module(SecondaryUserApp);

void SecondaryUserApp::initialize(int stage)

{

ApplicationBase::initialize(stage);

if (stage == INITSTAGE_APPLICATION_LAYER) {

// Schedule initial channel sensing and routing

scheduleAt(simTime() + uniform(1, 3), new cMessage(“senseAndRoute”));

}

void SecondaryUserApp::handleMessageWhenUp(cMessage *msg)

{

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

senseChannelAndRoute();

scheduleAt(simTime() + uniform(1, 3), msg); // Re-schedule sensing and routing

} else {

delete msg;

}

void SecondaryUserApp::senseChannelAndRoute()

{

EV << “Sensing available channels and routing data.” << endl;

// Example: Sense the environment to find available channels

bool channelAvailable = uniform(0, 1) > 0.3; // Simplified sensing logic

if (channelAvailable) {

EV << “Channel is available. Routing data.” << endl;

// Implement routing logic here based on available channels

cMessage *dataPacket = new cMessage(“DataPacket”);

send(dataPacket, “wlan$o”);

} else {

EV << “No channel available. Waiting for the next opportunity.” << endl;

}

Implement Routing Protocol for Secondary Users

We can either execute a custom routing protocol or setup an existing one such as AODV or DSR, adjusting it to account for dynamic channel availability.

Configure the Simulation in the .ini File

network = networkstructure.SecondaryUsersRoutingNetwork

sim-time-limit = 300s

# Secondary user settings

*.secondaryUser[*].wlan.mac.maxQueueSize = 1000;

*.secondaryUser[*].wlan.phy.transmitter.power = 2mW;

*.secondaryUser[*].mobility.bounds = “500m 500m”;

*.secondaryUser[*].app[0].sensingInterval = uniform(1s, 5s);

# Primary user settings

*.primaryUser[*].wlan.mac.maxQueueSize = 1000;

*.primaryUser[*].wlan.phy.transmitter.power = 10mW; # PUs generally have higher power

*.primaryUser[*].mobility.bounds = “500m 500m”;

Explanation of the Example

Network Topology (SecondaryUsersRoutingNetwork.ned):
- The network consists of primary users (PUs) and secondary users (SUs). SUs effort to route their information enthusiastically based on the availability of channels not employed by PUs.
Secondary User Behavior (SecondaryUserApp.cc):
- The SecondaryUserApp module senses the setting to identify available channels and transmits the information when a channel is available. The sensing and routing logic is occasionally summoned.
Routing Protocol:
- The routing protocol for secondary users should account for the dynamic availability of channels, adjusting the routing decisions based on sensed information.

Running the Simulation

Compile project in OMNeT++ IDE and execute the simulation.
To track how secondary users adjust to the presence of primary users that concentrate on parameters such as packet delivery ratio, delay, and how efficiently secondary users can exploit available spectrum using the OMNeT++’s tools.

Extending the Example

Advanced Sensing and Routing: Execute more sophisticated channel sensing and routing techniques that consider additional factors such as signal strength, interference, and network topology.
Dynamic Primary User Behaviour: To emulate the more complex primary user behaviour, that includes mobility, changing transmission power, and dynamic access patterns.
QoS-Aware Routing: Integrate QoS requirements into the routing protocol for secondary users; make sure that latency-sensitive traffic is prioritized when channels are available.
Energy-Efficient Routing: Execute energy-efficient routing approaches for secondary users to conserve battery life while maintaining communication reliability.
Scalability Testing: Upsurge the number of secondary users and primary users to verify how the routing protocol scales and manage the increased network density.

In the end, you can get to know more about the installation and implementation of secondary users routing in OMNeT++. We plan to deliver more information on how the secondary users routing will perform in other scenarios. We’re here to guide you through each step of setting up your Secondary Users Routing in the OMNeT++ tool. Stay in touch with us to find out more about this subject!