path: root/Wireless_Communications_and_Networking_by_V._Garg/ch21.ipynb

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 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "heading",
     "level": 1,
     "metadata": {},
     "source": [
      "Chapter 21: Wireless Local Area Networks"
     ]
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 21.1, Page 727"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import math\n",
      "import sympy\n",
      "from sympy import * \n",
      "\n",
      "#Variable declaration\n",
      "Fl=902; #lower limit frequency MHz\n",
      "Fh=928; #higher limit frequency in MHz\n",
      "Rt=0.5; #symbol transmission rate in Mega symbols per sec\n",
      "S=16; #No of symbols\n",
      "BER=10**-5;#Bir error rate\n",
      "SG=2.6;#sector gain\n",
      "B=0.5; #Interference factor\n",
      "a=0.9; #power control efficiency\n",
      "\n",
      "#Calculations&Results\n",
      "BW=Fh-Fl;\n",
      "Rb=Rt*math.log(S,2);\n",
      "Gp=BW/Rb;\n",
      "x = symbols('x')\n",
      "y = solve(0.5*(1-erf(sqrt(x)))-10**-5,x)\n",
      "M=Gp/y[0] * 1/(1+B) * SG * a;\n",
      "print 'Number of users that can be supported by the WLAN are %d'%M\n",
      "eff=Rb*int(M)/BW;\n",
      "print 'The bandwidth efficiency is %.2f bps/Hz'%eff"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Number of users that can be supported by the WLAN are 2\n",
        "The bandwidth efficiency is 0.15 bps/Hz\n"
       ]
      }
     ],
     "prompt_number": 1
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 21.2, Page 733"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Variable declaration\n",
      "Stepsize=200.; #in Hz\n",
      "Chipsmin=20.;#length of linear feedback shift register \n",
      "Datarate=1.2*10**3;  #bps\n",
      "\n",
      "#Calculations\n",
      "No_of_tones=2**Chipsmin;\n",
      "Bss=No_of_tones*Stepsize;\n",
      "Chiprate=Datarate*Chipsmin;\n",
      "Gp=Bss/Datarate;#processing gain\n",
      "Symbolrate=Datarate/3;  #8-ary FSK is used\n",
      "Chips_symbol=Chiprate/Symbolrate;\n",
      "\n",
      "#Results\n",
      "print 'The Hopping Bandwidth is %.3f MHz'%(Bss/10**6);\n",
      "print 'The chiprate is %d kchip/sec'%(Chiprate/10**3);\n",
      "print 'Chips per symbol are %d'%(Chips_symbol);\n",
      "print 'The processing gain is %.1f'%Gp"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "The Hopping Bandwidth is 209.715 MHz\n",
        "The chiprate is 24 kchip/sec\n",
        "Chips per symbol are 60\n",
        "The processing gain is 174762.7\n"
       ]
      }
     ],
     "prompt_number": 2
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 21.3, Page 734"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Variable declaration\n",
      "InfoSc=48.;#Information subcarriers\n",
      "SyncSc=4.;#synchronization subcarriers\n",
      "ReservedSc=12.;#Reserved subcarriers\n",
      "Symrate=250.;  #ksps(kilosymbols per second)\n",
      "BW=20.;  #/in MHz\n",
      "Grdt=800.; #Guard time in nsec\n",
      "\n",
      "#Calculations\n",
      "TotalSc=InfoSc+SyncSc+ReservedSc;#Total subcarriers\n",
      "BW_Sch=BW*10**6/TotalSc;#BW of subchannel\n",
      "Mod_eff=Symrate*10**3/(BW_Sch);#Modulation efficiency\n",
      "User_txrate=InfoSc*Symrate*10**3;\n",
      "User_bitsymbol=4;  #16-QPSK is used\n",
      "User_DR=36; #Mbps\n",
      "Sym_Dur=1./(Symrate*10**3);\n",
      "TimeUti=Sym_Dur/(Sym_Dur+(Grdt/10**9));\n",
      "\n",
      "#Results\n",
      "print 'The bandwidth of subchannel is %.1f kHz'%(BW_Sch/10**3);\n",
      "print 'Modulation efficiency is %.1f symbols/sec/Hz'%Mod_eff\n",
      "print 'User symbol rate is %d Msps'%(User_txrate/10**6);\n",
      "print 'Time Utilization efficiency is %.2f'%TimeUti"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "The bandwidth of subchannel is 312.5 kHz\n",
        "Modulation efficiency is 0.8 symbols/sec/Hz\n",
        "User symbol rate is 12 Msps\n",
        "Time Utilization efficiency is 0.83\n"
       ]
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 21.4, Page 735"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import math\n",
      "\n",
      "#Variable declaration\n",
      "Eb_No=10;  #in dB\n",
      "Noise=-120; #in dBm\n",
      "Pt=20; #in mwatt\n",
      "R=1; #Data rate in Mbps\n",
      "CHBW=0.5; #BW in MHz\n",
      "A=37.7;  #path loss at the \ufb01rst meter in dB\n",
      "Y=3.3; #path loss exponent\n",
      "Lf=19; #function relating power loss with number of \ufb02oors n        (in dB)\n",
      "Ls=10;  # lognormally distributed random variable representing the shadow effect in dB \n",
      "\n",
      "#Calculations\n",
      "S2Nreqd=Eb_No*R/CHBW;\n",
      "Rx_sensi=Noise+S2Nreqd;\n",
      "Lp=10*math.log10(20)-Rx_sensi;\n",
      "#Lp=A+10Ylod(d)+Lf+Ls;therefore\n",
      "d=10**((Lp-A-Lf-Ls)/(10*Y));\n",
      "\n",
      "#Result\n",
      "print 'The coverage of AP is %.1f metres'%d;"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "The coverage of AP is 25.3 metres\n"
       ]
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 21.5, Page 758"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Variable declaration\n",
      "R=3./4;#code rate of convolution encoder\n",
      "M1=9.; #payload transmission rate in Mbps for mode 1\n",
      "M2=36.; #payload transmission rate in Mbps for mode 2\n",
      "\n",
      "#Calculations&Results\n",
      "D1=M1*10**6/48;#user data  rate in kbps for mode 1 \n",
      "D2=M2*10**6/48;#user data rate in kbps for mode 2 \n",
      "#Refering to Table 21.11\n",
      "print 'Data transmission rate per carrier with 3/4 convolution encoder are %.1f Kbps and %d Kbps'%(D1/10**3,D2/10**3);\n",
      "C1=D1/R;\n",
      "C2=D2/R;\n",
      "print 'Carrier transmission rate with R=3/4 convolutional encoder are %d Kbps and %d Kbps'%(C1/10**3,C2/10**3);\n",
      "print 'Carrier symbol rate with R=3/4 convolutional encoder are %d ksps and %d Ksps'%(C1/10**3,C2/4/10**3);  #Mode1 as BPSK and MOde2 as 16-QAM"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Data transmission rate per carrier with 3/4 convolution encoder are 187.5 Kbps and 750 Kbps\n",
        "Carrier transmission rate with R=3/4 convolutional encoder are 250 Kbps and 1000 Kbps\n",
        "Carrier symbol rate with R=3/4 convolutional encoder are 250 ksps and 250 Ksps\n"
       ]
      }
     ],
     "prompt_number": 6
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 21.6, Page 759"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import math\n",
      "\n",
      "#Variable declaration\n",
      "R=3./4; #code rate for convolution encoder\n",
      "\n",
      "#Calculations\n",
      "#64-QAM modulation is used\n",
      "Sc=250; #Carrier symbol rate(ksps) from Exa 21.5\n",
      "Bits_sym=math.log(64,2); #64-QAM is used\n",
      "User_R=Bits_sym*Sc*10**3*R*48;\n",
      "\n",
      "#Result\n",
      "print 'The user data rate is %d Mbps'%(User_R/10**6);"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "The user data rate is 54 Mbps\n"
       ]
      }
     ],
     "prompt_number": 7
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 21.7, Page 762"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Variable declaration\n",
      "D=1000.*8;  #packet size in bits\n",
      "R=2.*10**6;  #transmission rate in bps\n",
      "L=3.; #msec(Dwell time)\n",
      "H=0.625; #msec(Duration of BT packet)\n",
      "\n",
      "#Calculations\n",
      "Tw=10**3*D/R;   #the packet duration of IEEE 802.11 in msec\n",
      "H_L=1.;\n",
      "G=(H_L)*L-Tw-H;\n",
      "Gm=abs(G);\n",
      "PER_FH=1-((1-Gm/L)*(78./79)**(H_L)+Gm/L*(78./79)**((H_L)-G/Gm));\n",
      "PER_DS=1-((1-Gm/L)*(57./79)**(H_L)+Gm/L*(57./79)**((H_L)-G/Gm));\n",
      "\n",
      "#Results\n",
      "print 'The PER for FH packet and PER for DS packet are %d percent & %.2f percent respectively'%(round(PER_FH*100),PER_DS*100);\n",
      "print \"The collision probability with 802.11 DS is much higher than with 802.11 FH.\""
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "The PER for FH packet and PER for DS packet are 2 percent & 38.73 percent respectively\n",
        "The collision probability with 802.11 DS is much higher than with 802.11 FH.\n"
       ]
      }
     ],
     "prompt_number": 8
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 21.8, Page 765"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import math\n",
      "\n",
      "#Variable declaration\n",
      "d=10; # distance between AP and IEEE 802.11 device in metres\n",
      "Y=4; #path loss exponent\n",
      "PBt=20;  #the transmitted power by the BT in dBm\n",
      "PAp=40;  #the transmitted power by the AP in dBm\n",
      "Pe=10**-5;#acceptable error probability\n",
      "\n",
      "#Calculations\n",
      "#Pe=0.5*e**(-0.5*Eb/No)\n",
      "SIR=math.log(Pe/0.5)/(-0.5);# signal-to-interference ratio \n",
      "rmax=d*(SIR*PBt/PAp)**(1./Y);# range of interference between Bluetooth and 802.11 device \n",
      "\n",
      "#Results\n",
      "print 'Minimum SIR is %.2f dB = %.1f'%(10*math.log10(SIR),SIR);\n",
      "print 'Maximum coverage range is  %.2f metres'%rmax;"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Minimum SIR is 13.35 dB = 21.6\n",
        "Maximum coverage range is  18.14 metres\n"
       ]
      }
     ],
     "prompt_number": 9
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 21.9, Page 765"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Variable declaration\n",
      "SIRmin=21.6; #From eg 21.8 i.e(13.36 dB)\n",
      "d=10; #distance between AP and IEEE 802.11 device in m\n",
      "PMs=40; # transmitted power of the IEEE 802.11 device in dBm\n",
      "PBt=20; #the transmitted power by the BT in dBm\n",
      "Y=4 ; #path loss exponent\n",
      "\n",
      "#Calculations\n",
      "rmax=d*(SIRmin*PMs/PBt)**(1./Y);\n",
      "\n",
      "#Result\n",
      "print 'Maximum coverage range is %.1f metres'%rmax"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Maximum coverage range is 25.6 metres\n"
       ]
      }
     ],
     "prompt_number": 10
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 21.10, Page 765"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import math\n",
      "\n",
      "#Variable declaration\n",
      "Gp=11;#processing gain(given)\n",
      "#Defining variables from Exa 21.8 & 21.9\n",
      "PBt=20; #  transmitted power by the BT in dBm\n",
      "PMs=40;  # transmitted power of the IEEE 802.11 device in dBm\n",
      "PAp=40;  # transmitted power by the AP in dBm\n",
      "d=10;  # distance between AP and IEEE 802.11 device in m\n",
      "Y=4;  #path loss exponent\n",
      "Pe=10**-5;#Error probability\n",
      "\n",
      "#Calculations&Results\n",
      "#Pe=0.5*e**(-0.5*Eb/No)\n",
      "SIR=math.log(Pe/0.5)/(-0.5);\n",
      "r1max=d*(SIR*PBt/(PAp*Gp))**(1./Y);# range of interference between Bluetooth and 802.11 device \n",
      "print 'Maximum coverage range for IEEE 802.11 DS is  %.2f metres'%r1max\n",
      "r2max=d*(SIR*PMs/(PBt*Gp))**(1./Y);\n",
      "print 'Maximum coverage range for IEEE 802.11 FH is %.2f metres'%r2max;\n",
      "print \"Thus, the interference ranges are smaller for the IEEE 802.11 DS device than the IEEE 802.11 FH device.\""
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Maximum coverage range for IEEE 802.11 DS is  9.96 metres\n",
        "Maximum coverage range for IEEE 802.11 FH is 14.08 metres\n",
        "Thus, the interference ranges are smaller for the IEEE 802.11 DS device than the IEEE 802.11 FH device.\n"
       ]
      }
     ],
     "prompt_number": 11
    }
   ],
   "metadata": {}
  }
 ]
}