{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter No.3 : The cellular concept system design fundamentals" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.1 Page No.61" ] }, { "cell_type": "code", "execution_count": 14, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " The number of channels available per cell for 4-cell reuse system = 165 channels\n", "\n", " One control channel and 160 voice channels would be assigned to each cell.\n", "\n", " \n", " The number of channels available per cell for 7-cell reuse system = 95 channels\n", "\n", " Each cell would have one control channel, four cells would have 90 voice channels and three cells would have 91 voice channels.\n", "\n", " \n", " The number of channels available per cell for 12-cell reuse system = 55 channels\n", "\n", " Each cell would have one control channel, eight cells would have 53 voice channels and four cells would have 54 voice channels.\n" ] } ], "source": [ "from math import ceil\n", "# To compute the number of channels available per cell for a)four-cell reuse system a)seven-cell reuse system a)12-cell reuse system\n", "\n", "# Given data\n", "B=33*10**6# # Total bandwidth allocated to particular FDD system in Hz\n", "Bc=25*10**3# # Bandwidth per channel in Hz\n", "Nc=2# # Number of simplex channels\n", "Bc=Bc*Nc# # Channel bandwidth in Hz\n", "\n", "Ntotal=B/Bc# # Total number of channels\n", "\n", "#a) To compute the number of channels available per cell for four-cell reuse system\n", "N=4# # frequency reuse factor\n", "chpercell=Ntotal/N# # number of channels available per cell for four-cell reuse system\n", "\n", "# Displaying the result in command window\n", "print \"\\n The number of channels available per cell for 4-cell reuse system = %0.0f channels\"%(chpercell)\n", "print \"\\n One control channel and 160 voice channels would be assigned to each cell.\"\n", "\n", "# b) To compute the number of channels available per cell for seven-cell reuse system\n", "N=7# # frequency reuse factor\n", "chpercell=ceil(Ntotal/N)# # number of channels available per cell for seven-cell reuse system\n", "\n", "# Answer is varrying due to round-off error\n", "\n", "# Displaying the result in command window\n", "print \"\\n \\n The number of channels available per cell for 7-cell reuse system = %0.0f channels\"%(chpercell)\n", "print \"\\n Each cell would have one control channel, four cells would have 90 voice channels and three cells would have 91 voice channels.\"\n", "\n", "# c) To compute the number of channels available per cell for 12-cell reuse system\n", "N=12# # frequency reuse factor\n", "chpercell=Ntotal/N# # number of channels available per cell for seven-cell reuse system\n", "\n", "# Displaying the result in command window\n", "print \"\\n \\n The number of channels available per cell for 12-cell reuse system = %0.0f channels\"%(chpercell)\n", "print \"\\n Each cell would have one control channel, eight cells would have 53 voice channels and four cells would have 54 voice channels.\"" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.2 Page No.72" ] }, { "cell_type": "code", "execution_count": 15, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Signal to noise ratio for n=4 with frequency reuse factor N=7 = 18.66 dB\n", "\n", " Signal to noise ratio for n=3 with frequency reuse factor N=7 = 12.05 dB\n", "\n", " Signal to noise ratio for n=3 with frequency reuse factor N=12 = 15.56 dB\n", "\n", " Since SIR is for n=3 with frequency reuse factor N=7 greater than the minimum required, so N=12 is used.\n" ] } ], "source": [ "from math import sqrt, log10\n", "from __future__ import division\n", "# To find frequency reuse factor for path loss exponent (n) a)n=4 b)n=3\n", "\n", "# Given data\n", "SIdB=15# # Signal to interference(dB)\n", "io=6# # Number of cochannel cell\n", "\n", "# For n=4\n", "n1=4# # Path loss exponent\n", "N1=7# # First consideration: frequency reuse factor N=7\n", "DR1=sqrt(3*N1)# # Co-channel reuse ratio\n", "si1=(1/io)*(DR1)**n1# # Signal to interference\n", "sidB1=10*log10(si1)# # Signal to interference(dB)\n", "\n", "# For n=3\n", "n2=3# # Path loss exmponent\n", "si=(1/io)*(DR1)**n2# # Signal to interference for first consideration: frequency reuse factor N=7\n", "sidB=10*log10(si)# # Signal to interference(dB)\n", "\n", "N2=12# # second consideration : frequency reuse factor N=12 since sidB