Dear Arafat Habib

see these codes

Example Script for Simulation Configuration

1. Configuration of PHY and channel

// *************************************** PHY and Channel ***************************************** //

YansWifiPhyHelper wifiPhy = YansWifiPhyHelper::Default ();

// set it to zero; otherwise, gain will be added

wifiPhy.Set ("RxGain", DoubleValue (0));

wifiPhy.Set ("CcaMode1Threshold", DoubleValue (0.0));

// ns-3 supports RadioTap and Prism tracing extensions for 802.11b

wifiPhy.SetPcapDataLinkType (YansWifiPhyHelper::DLT_IEEE802_11_RADIO);

YansWifiChannelHelper wifiChannel;

wifiChannel.SetPropagationDelay ("ns3::ConstantSpeedPropagationDelayModel");

wifiChannel.AddPropagationLoss ("ns3::LogDistancePropagationLossModel");

wifiPhy.SetChannel (wifiChannel.Create ());

// ************************************************************************************************* //

2. Configuration of MAC

// **************************************** MAC **************************************************** //

// Add a non-QoS upper mac, and disable rate control

NqosWifiMacHelper wifiMac = NqosWifiMacHelper::Default ();

wifi.SetRemoteStationManager ("ns3::ConstantRateWifiManager",

"DataMode",StringValue (phyMode),

"ControlMode",StringValue (phyMode));

// Set it to adhoc mode

wifiMac.SetType ("ns3::AdhocWifiMac");

// ************************************************************************************************* //

3. Configuration of NetDevice

// ***************************************** Net Devices ******************************************* //

NetDeviceContainer devices = wifi.Install (wifiPhy, wifiMac, c.Get (0), 5);

devices.Add (wifi.Install (wifiPhy, wifiMac, c.Get(3), 1));

// This will disable these sending devices from detecting a signal

// so that they do not backoff

wifiPhy.Set ("EnergyDetectionThreshold", DoubleValue (0.0) );

wifiPhy.Set ("TxGain", DoubleValue (offset + Prss) );

devices.Add (wifi.Install (wifiPhy, wifiMac, c.Get (1), 5));

wifiPhy.Set ("TxGain", DoubleValue (offset + Irss) );

devices.Add (wifi.Install (wifiPhy, wifiMac, c.Get (2), 1));

// ************************************************************************************************* //

4. Configuration of Network Topology

// **************************************** Mobility *********************************************** //

// Note that with FixedRssLossModel, the positions below are not

// used for received signal strength.

MobilityHelper mobility;

Ptr positionAlloc = CreateObject ();

positionAlloc->Add (Vector (0.0, 0.0, 0.0));

positionAlloc->Add (Vector (distanceToRx, 0.0, 0.0));

positionAlloc->Add (Vector (0, -distanceToRx, 0.0));

positionAlloc->Add(Vector (distanceToRx, -distanceToRx, 0.0));

mobility.SetPositionAllocator (positionAlloc);

mobility.SetMobilityModel ("ns3::ConstantPositionMobilityModel");

mobility.Install (c);

// ************************************************************************************************* //

Best Regards

Thanks a lot sir for your answer. You are so kind.

Hi you can take a look in this link good luck

http://slogix.in/cognitive-radio-networks-source-code