linklayermodel.java

tinyos-2.x.rar

        outVar.nodePosX[i] = (i%nodesX) * cellLength + rand.nextDouble()*cellLength;
        outVar.nodePosY[i] = (i/nodesX) * cellLength + rand.nextDouble()*cellLength;
        wrongPlacement = true;
        while ( wrongPlacement ) {
          for (j = 0; j < i; j = j+1) {
            Xdist = outVar.nodePosX[i] - outVar.nodePosX[j];
            Ydist = outVar.nodePosY[i] - outVar.nodePosY[j];
            // distance between a given pair of nodes
            dist = Math.pow((Xdist*Xdist + Ydist*Ydist), 0.5);
            if (dist < inVar.d0) {
              outVar.nodePosX[i] = (i%nodesX) * cellLength + rand.nextDouble()*cellLength;
              outVar.nodePosY[i] = (i/nodesX) * cellLength + rand.nextDouble()*cellLength;
              wrongPlacement = true;
              break;
            }
          }
          if ( j == i ) {
            wrongPlacement = false;
          }
        }
      }
      break;
    case 3: // RANDOM
      if ( (inVar.Xterr <= 0) | (inVar.Yterr <= 0) ) {
        System.out.println("\nError: values of TERRAIN_DIMENSIONS must be positive");
        System.exit(1);
      }
      cellLength = Math.sqrt ( inVar.area / inVar.numNodes );   
      if ( cellLength < (inVar.d0*1.4) ) {
        System.out.println ("\nError: on RANDOM topology, density is too high, increase physical terrain");
        System.exit(1);
      }
      for (i = 0; i < inVar.numNodes; i = i+1) {
        outVar.nodePosX[i] = rand.nextDouble() * inVar.Xterr;
        outVar.nodePosY[i] = rand.nextDouble() * inVar.Yterr;
        wrongPlacement = true;
        while ( wrongPlacement ) {
          for (j = 0; j < i; j = j+1) {
            Xdist = outVar.nodePosX[i] - outVar.nodePosX[j];
            Ydist = outVar.nodePosY[i] - outVar.nodePosY[j];
            // distance between a given pair of nodes
            dist = Math.pow((Xdist*Xdist + Ydist*Ydist), 0.5);
            if (dist < inVar.d0) {
              outVar.nodePosX[i] = rand.nextDouble() * inVar.Xterr;
              outVar.nodePosY[i] = rand.nextDouble() * inVar.Yterr;
              wrongPlacement = true;
              break;
            }
          }
          if ( j == i ) {
            wrongPlacement = false;
          }
        }
      }
      break;
    case 4: // FILE (user-defined topology)
      readTopologyFile(inVar.topFile, outVar);
      correctTopology (inVar, outVar);
      break;
    default:
      System.out.println("\nError: topology is not correct, please check TOPOLOGY in the configuration file");
      System.exit(1);
    }

    return true;
  }


  /**
   * Checks that user-defined topology does not have inter-node distances less than D0 meter, 
   * where D0 is the reference distance in the channel model (specified in configuration file)
   *
   * @param inVar class that stores input parameters from configuration file
   * @param outVar class that stores link gains, noise floors and x/y coordinates
   * @return true if x/y coordinates provided by user satisfy the condition that no internode distance is lesss than D0
   */

  protected static boolean correctTopology ( InputVariables  inVar, 
                                             OutputVariables outVar )
  {
    Random rand = new Random();
    int i, j;
    double Xdist, Ydist, dist, avgDecay;

    for (i = 0; i < inVar.numNodes; i = i+1) {
      for (j = i+1; j < inVar.numNodes; j = j+1 ) {
        Xdist = outVar.nodePosX[i] - outVar.nodePosX[j];
        Ydist = outVar.nodePosY[i] - outVar.nodePosY[j];
        // distance between a given pair of nodes
        dist = Math.pow((Xdist*Xdist + Ydist*Ydist), 0.5);
        if (dist < inVar.d0) {
          System.out.println("\nError: file " + inVar.topFile + " contains inter-node distances less than one.");
          System.exit(1);
        }
      }
    }
    return true;
  }


  /**
   * Obtains output power and noise floor for all nodes in the network
   *
   * @param inVar class that contains radio parameters
   * @param outVar class that stores output powers and noise floors
   * @return true if all output powers and noise floors were obtained correctly
   */

  protected static boolean obtainRadioPtPn ( InputVariables  inVar, 
                                             OutputVariables outVar )
  {
    Random rand = new Random();
    int i, j;
    double t11, t12, t21, t22;
    double rn1, rn2;

    t11 = 0;
    t12 = 0;
    t21 = 0;
    t22 = 0;

    if ( (inVar.s11 == 0) && (inVar.s22 == 0) ) { // symmetric links do nothing
    }
    else if ( (inVar.s11 == 0) && (inVar.s22 != 0) ) { // both S11 and S22 must be 0 for symmetric links
      System.out.println("\nError: symmetric links require both, S11 and S22 to be 0, not only S11.");
      System.exit(1);
    }
    else {
      if ( (inVar.s12 != inVar.s21) ) { // check that S is symmetric
        System.out.println("\nError: S12 and S21 must have the same value.");
        System.exit(1);
      }
      if ( Math.abs(inVar.s12) > Math.sqrt(inVar.s11*inVar.s22) ) { // check that correlation is within [-1,1]
        System.out.println("\nError: S12 (and S21) must be less than sqrt(S11xS22).");
        System.exit(1);
      }
      t11 = Math.sqrt(inVar.s11);
      t12 = inVar.s12/Math.sqrt(inVar.s11);
      t21 = 0;
      t22 = Math.sqrt( (inVar.s11*inVar.s22 - Math.pow( inVar.s12, 2)) / inVar.s11 );
    }

    for (i = 0; i < inVar.numNodes; i = i+1) {
      rn1 = rand.nextGaussian();
      rn2 = rand.nextGaussian();
      outVar.noisefloor[i]  = inVar.pn + t11 * rn1;
      outVar.outputpowervar[i] = t12 * rn1 + t22 * rn2;
    }
    return true;
  }


  /**
   * Obtains gain for all links in the network. The link gain between nodes A and B 
   * is defined as the output power of A minus the pathloss between A and B.
   *
   * @param inVar class that contains channel parameters from configuration file
   * @param outVar class that stores link gains
   * @return true if all link gains were obtained correctly
   */

  protected static boolean obtainLinkGain ( InputVariables  inVar, 
                                            OutputVariables outVar )
  {
    Random rand = new Random();
    int i, j;
    double Xdist, Ydist, dist, pathloss;

    for (i = 0; i < inVar.numNodes; i = i+1) {
      for (j = i+1; j < inVar.numNodes; j = j+1 ) {
        Xdist = outVar.nodePosX[i] - outVar.nodePosX[j];
        Ydist = outVar.nodePosY[i] - outVar.nodePosY[j];
        // distance between a given pair of nodes
        dist = Math.pow((Xdist*Xdist + Ydist*Ydist), 0.5);
        // mean decay dependent on distance
        pathloss = - inVar.pld0 - 10*inVar.n*(Math.log(dist/inVar.d0)/Math.log(10.0)) + ( rand.nextGaussian()*inVar.sigma );
        // assymetric links are given by running two different
        // R.V.s for each unidirectional link (output power variance).
        outVar.linkGain[i][j] = outVar.outputpowervar[i] + pathloss;
        outVar.linkGain[j][i] = outVar.outputpowervar[j] + pathloss;
  
      }
    }
    return true;

  }


  /**
   * Provides link gain and noise floor in file linkgain.out, and the
   * X/Y coordinates in file topology.out.
   *
   * @param inVar class that contains input parameters from configuration file
   * @param outVar class that stores link gains, noise floors and x/y coordinates
   * @return true if files linkgain.out and topology.out were printed correctly
   */

  protected static boolean printFile( InputVariables  inVar, 
                                      OutputVariables outVar )
  {

    int i, j;

    DecimalFormat posFormat = new DecimalFormat("##0.00");

    /*
     * Output file for xy coordinates.
     */

    try{
      FileOutputStream fout =  new FileOutputStream("topology.out");
      try {
        PrintStream myOutput = new PrintStream(fout);
        for (i = 0; i < inVar.numNodes; i = i+1) {
          myOutput.print( i + "\t" + posFormat.format(outVar.nodePosX[i]) + "\t"+ posFormat.format(outVar.nodePosY[i]) + "\n");
        }
      }
      catch (Exception e) {
        System.out.println("\nError : Failed to open a print stream to the linkgain file" + e);
      }

    }
    catch (Exception e) {
      System.out.println("\nError : Failed to open the link gain file linkgains.out:" + e);
    }

   
    /*
     * Output file for link gains.
     */
    try{
      FileOutputStream fout =  new FileOutputStream("linkgain.out");
      try {
        PrintStream myOutput = new PrintStream(fout);
        for (i = 0; i < inVar.numNodes; i = i+1) {
          for (j = (i+1); j < inVar.numNodes; j = j+1 ) {
            if ( i != j) {
              myOutput.print( "gain\t" + i + "\t" + j + "\t" + posFormat.format(outVar.linkGain[i][j]) + "\n");
              myOutput.print( "gain\t" + j + "\t" + i + "\t" + posFormat.format(outVar.linkGain[j][i]) + "\n");
            }
          }
        }
        for (i = 0; i < inVar.numNodes; i = i+1) {
          myOutput.print( "noise\t" + i + "\t" + posFormat.format(outVar.noisefloor[i]) + "\t" + posFormat.format(inVar.wgn) + "\n");
        }
      }
      catch (Exception e) {
        System.out.println("\nError : Failed to open a print stream to the linkgain file" + e);
      }

    }
    catch (Exception e) {
      System.out.println("\nError : Failed to open the link gain file linkgains.out:" + e);
    }

    return true;
  }

  /**
   * Obtains nodes coordinates for user-defined topology.
   *  
   * @param inputTopoFile topology file provided by user
   * @param outVar class that contains variables to store x/y coordinates of nodes
   * @return true if x/y coordinates of user-defined topology file were read correctly.
   */

  protected static boolean readTopologyFile ( String inputTopoFile,
                                              OutputVariables outVar )
  {

    String thisLine;
    StringTokenizer st;
    int counter = 0;

    try {
      FileInputStream fin =  new FileInputStream(inputTopoFile);
      try {
        BufferedReader myInput = new BufferedReader(new InputStreamReader(fin));

        try {

          while ((thisLine = myInput.readLine()) != null) {

            if ( !thisLine.equals("")  && !thisLine.startsWith("%") && 
                 !thisLine.startsWith(" ") ) {
              st = new StringTokenizer(thisLine, " \t");
              int node = Integer.parseInt(st.nextToken());
              double x = Double.valueOf(st.nextToken()).doubleValue();
              double y = Double.valueOf(st.nextToken()).doubleValue();
              outVar.nodePosX[node] = x;
              outVar.nodePosY[node] = y;
              counter++;
            }
          }
        } // end try
        catch (Exception e) {
          System.out.println("Error4: " + e);
          System.exit(1);
        }

      } // end try
      catch (Exception e) {
        System.out.println("Error5: " + e);
        System.exit(1);
      }

    } // end try
    catch (Exception e) {
      System.out.println("Error: Failed to Open TOPOLOGY_FILE " + inputTopoFile + e);
      System.exit(1);
    }

    return true;
  }


  /**
   * Obtains number of nodes in network when user defines the topology.
   *
   * @param inputTopoFile topology file provided by user
   * @param inVar class that contains variable for number of nodes
   * @return true if number of nodes from user-defined topology file were obtained correctly
   */

  protected static boolean obtainNumNodes ( String inputTopoFile,
                                            InputVariables inVar )
  {

    String thisLine;
    StringTokenizer st;
    int counter = 0;

    try {
      FileInputStream fin =  new FileInputStream(inputTopoFile);
      try {
        BufferedReader myInput = new BufferedReader(new InputStreamReader(fin));

        try {

          while ((thisLine = myInput.readLine()) != null) {

            if ( !thisLine.equals("")  && !thisLine.startsWith("%") && 
                 !thisLine.startsWith(" ") ) {
              counter++;
            }
          }
          inVar.numNodes = counter; 

        } // end try
        catch (Exception e) {
          System.out.println("Error4: " + e);
          System.exit(1);
        }

      } // end try
      catch (Exception e) {
        System.out.println("Error5: " + e);
        System.exit(1);
      }

    } // end try
    catch (Exception e) {
      System.out.println("Error: Failed to Open TOPOLOGY_FILE " + inputTopoFile + e);
      System.exit(1);
    }

    return true;
  }

  private static void usage() {
    System.err.println("usage: net.tinyos.sim.LinkLayerModel <config file>");
  }
}