How to detect Multipath?

Code Visual Basic - [expand]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
% *****************************************************************
%%%%%%%%%%%% here is my code and plot %%%%%%%%%%%%%%
% *****************************************************************
%% multipath with 2 signals : Direct signal (Light Of Sight) and reflected signal
clear all; %close all
f_c             = 533e6; 
speed_of_light  = 3e8 ;                         % m/s
d               = 0.01;                         % distance between 2 rx antenna 10cm
lamda           = speed_of_light / f_c;         % wave length
k               = (2 * pi) / lamda;             % notation for electro-magnetic
w               =  2 * pi * f_c;
a               = [1 1/3];                      % attenuation
x               = [-d/2  d/2];
y               = [0  0];
alpha           = [0   pi/2];                   % turn every time by (pi/2)
tau             = [0  0.1e-6];                  % time delay
t               = 0 : (pi / 100) : (pi * 1);
N_path          = length(tau);
 
% *****************************************************************
% %%%%%%%%%%%%%%  simple calculation %%%%%%%%%%%%%
% *****************************************************************
a0      = a(1);
a1      = a(2);
x0      = x(1);
x1      = x(2);
y0      = y(1);
y1      = y(2);
tau0    = tau(1);
tau1    = tau(2);
alpha0  = alpha(1);
alpha1  = alpha(2);
 
plane0 = x0 * cos(alpha0) + y0 * sin(alpha0); % 
plane1 = x1 * cos(alpha1) + y1 * sin(alpha1); % 3.417721599179047e-18
 
complex0 = k * plane0 - w * (t - tau0);
z_Direct_signal    = a0 * exp(j*complex0);
 
complex1 = k * plane1 - w * (t - tau1);
z_Reflected_signal = a1 * exp(j*complex1);
 
z_total            = z_Direct_signal + z_Reflected_signal;
 
figure, subplot(2,2,1)
plot(real(z_Direct_signal),'r')
title('Direct Signal in Real');
subplot(2,2,2)
plot(imag(z_Direct_signal))
title('Direct Signal in Imaginary');
subplot(2,2,3)
plot(abs(z_Direct_signal));
title('Magnitude of LOS');
subplot(2,2,4)
plot(angle(z_Direct_signal));
title('Phase of LOS');
 
figure, subplot(2,2,1)
plot(real(z_Reflected_signal),'r')
title('Reflected Signal in Real');
subplot(2,2,2)
plot(imag(z_Reflected_signal))
title('Reflected Signal in Imaginary');
subplot(2,2,3)
plot(abs(z_Reflected_signal));
title('Magnitude of Reflected');
subplot(2,2,4)
plot(angle(z_Reflected_signal));
title('Phase of Reflected');
 
figure, subplot(2,2,1)
plot(real(z_total),'r')
title('total Signal in Real');
subplot(2,2,2)
plot(imag(z_Reflected_signal))
title('total Signal in Imaginary');
subplot(2,2,3)
plot(abs(z_Reflected_signal));
title('Magnitude of total');
subplot(2,2,4)
plot(angle(z_Reflected_signal));
title('Phase of total');