Setting up Propagation and Fading loss in LTE Systems

[Vishnu Raj]

Hello all,

I'm using the following code for setting up an LTE system with 4 cells, each cell with 2 mobile and 2 static users.

    // Create eNodeBs and UE nodes
    // Set up mobility models,
    //     Constant Mobility Model for Static users
    //     RandomWayPoint model for mobile users. Mobile users start at cell center and moves towards cell edege at 16.67 m/s

    // Setting up LTE Helper
    Ptr<LteHelper> lteHelper                = CreateObject<LteHelper>();
    Ptr<PointToPointEpcHelper> epcHelper    = CreateObject<PointToPointEpcHelper>();    // @TODO: one unknown node gets created here, PGW?
    lteHelper->SetEpcHelper( epcHelper );

    Config::SetDefault( "ns3::LteUePhy::TxPower", DoubleValue(40) );         // Transmission power in dBm
    Config::SetDefault( "ns3::LteUePhy::NoiseFigure", DoubleValue(6) );     // Default 5
    Config::SetDefault( "ns3::LteEnbPhy::TxPower", DoubleValue(24) );        // Transmission power in dBm
    Config::SetDefault( "ns3::LteEnbPhy::NoiseFigure", DoubleValue(6) );    // Default 5
    lteHelper->SetAttribute ("PathlossModel", StringValue ("ns3::FriisPropagationLossModel"));

    // Install eNode devices
    // Install UE devices
    // Do an OnOff Application from one UE to a remote node
    // Enable traces
    // Run simulation

When I do the above experiment and plot SINR from 'DlRsrpSinrStats.txt' variation with time, I get the following plot(after converting to dB):

Here User#1 and User#2 are moving away from eNodeB, User#3, User#4 are static users. The observed SINR values are very high compared to pratical cases.

Can anybody help in finding out what I'm doing wrong?

Thanks ahead,

vish

[Marco Miozzo]

Hi,

there is no plot in  the email.

Anyway, I would recommend you to use a more realistic propagation model for cellular type communication scenarios, such as: TwoRayGroundPropagationLossModel, OhBuildingsPropagationLossModel.

Best,

marco.

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[Vishnu Raj]

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[Biljana Bojović]

Could you please attach also the 'DlRsrpSinrStats.txt' file?

[Vishnu Raj]

I have modified the code to include Propagation loss + Fading as below:

    Ptr<LteHelper> lteHelper                = CreateObject<LteHelper>();
    Ptr<PointToPointEpcHelper> epcHelper    = CreateObject<PointToPointEpcHelper>();    // @TODO: one unknown node gets created here, PGW?
    lteHelper->SetEpcHelper( epcHelper );

    Config::SetDefault( "ns3::LteUePhy::TxPower", DoubleValue(24) );         // Transmission power in dBm

    Config::SetDefault( "ns3::LteUePhy::NoiseFigure", DoubleValue(6) );     // Default 5

    Config::SetDefault( "ns3::LteEnbPhy::TxPower", DoubleValue(40) );        // Transmission power in dBm

    Config::SetDefault( "ns3::LteEnbPhy::NoiseFigure", DoubleValue(6) );    // Default 5

    // lteHelper->SetAttribute ("PathlossModel", StringValue ("ns3::FriisPropagationLossModel"));

    lteHelper->SetAttribute("PathlossModel",StringValue("ns3::OkumuraHataPropagationLossModel"));
    lteHelper->SetPathlossModelAttribute("Environment", StringValue("Urban"));
    Config::SetDefault ("ns3::RadioBearerStatsCalculator::EpochDuration", TimeValue (Seconds(1.00)));


    lteHelper->SetFadingModel("ns3::TraceFadingLossModel");
    lteHelper->SetFadingModelAttribute ("TraceFilename", StringValue ("/Users/vish/developer/ns3/bake/source/ns-3-dev/scratch/Lte1CellTestbed/fading-traces/fading_trace_EVA_60kmph.fad"));
    lteHelper->SetFadingModelAttribute ("TraceLength", TimeValue (Seconds (10.0)));
    lteHelper->SetFadingModelAttribute ("SamplesNum", UintegerValue (10000));
    lteHelper->SetFadingModelAttribute ("WindowSize", TimeValue (Seconds (0.5)));
    lteHelper->SetFadingModelAttribute ("RbNum", UintegerValue (100));

Now my graphs go like below:



I'm attaching the 'DlRsrpSinrStats.txt' and my code.

Thanks,
Enter code here...
vish

Enter code here...