University:
College
Course:
College Computer Science
Academic year:

2023
Views:

27

Pages:

3
Author:

20se02ce032

20se02ce032 Nemish Lathiya Computer Network Assignment-9 (1) Write a program to implement CDMA (Code Division Multiple Access). Code: public class JavaApplication9 { private int[][] wtable; private int[][] copy; private int[] channel_sequence; public void setUp(int[] data, int num_stations) { wtable = new int[num_stations][num_stations]; copy = new int[num_stations][num_stations]; buildWalshTable(num_stations, 0, num_stations - 1, 0, num_stations - 1, false); showWalshTable(num_stations); for (int i = 0; i < num_stations; i++) { for (int j = 0; j < num_stations; j++) { copy[i][j] = wtable[i][j]; wtable[i][j] *= data[i]; } } channel_sequence = new int[num_stations]; for (int i = 0; i < num_stations; i++) { for (int j = 0; j < num_stations; j++) { channel_sequence[i] += wtable[j][i]; } } } public void listenTo(int sourceStation, int num_stations) { int innerProduct = 0; SECE3011 | Computer Networks 1 20se02ce032 Nemish Lathiya for (int i = 0; i < num_stations; i++) { innerProduct += copy[sourceStation][i] * channel_sequence[i]; } System.out.println("The data received is: " + (innerProduct / num_stations)); } public int buildWalshTable(int len, int i1, int i2, int j1, int j2, boolean isBar) { if (len == 2) { if (!isBar) { wtable[i1][j1] = 1; wtable[i1][j2] = 1; wtable[i2][j1] = 1; wtable[i2][j2] = -1; } else { wtable[i1][j1] = -1; wtable[i1][j2] = -1; wtable[i2][j1] = -1; wtable[i2][j2] = +1; } return 0; } int midi = (i1 + i2) / 2; int midj = (j1 + j2) / 2; buildWalshTable(len / 2, i1, midi, j1, midj, isBar); buildWalshTable(len / 2, i1, midi, midj + 1, j2, isBar); buildWalshTable(len / 2, midi + 1, i2, j1, midj, isBar); buildWalshTable(len / 2, midi + 1, i2, midj + 1, j2, !isBar); return 0; } public void showWalshTable(int num_stations) { SECE3011 | Computer Networks 2 Computer Network 20se02ce032 Nemish Lathiya System.out.print("\n"); for (int i = 0; i < num_stations; i++) { for (int j = 0; j < num_stations; j++) { System.out.print(wtable[i][j] + " "); } System.out.print("\n"); } System.out.print("\n"); } public static void main(String[] args) { int num_stations = 4; int[] data = new int[num_stations]; data[0] = -1; data[1] = -1; data[2] = 0; data[3] = 1; JavaApplication9 channel; channel = new JavaApplication9(); channel.setUp(data, num_stations); int sourceStation = 3; channel.listenTo(sourceStation, num_stations); } } Output: 1 1 1 1 1 -1 1 -1 1 1 -1 -1 1 -1 -1 1 The data received is: 1 SECE3011 | Computer Networks 3 Computer Network