Communication Systems
Matlab code:
% Introduction:
% The Goal of this Code is to make an estimate of the number of Relays
%necessary to achieve a reliable communication channel between the earth
%and the HD imaging Satellite Probe. The last link would
%be a relay orbiting around the earth and Transmitting the information
%Variables
YL=9460730472580.8e03;
c=3e+08;
F=27e+09;
%BW=0.05e+03;
BW=20;
Eb_N0=10^0.2;%reliable channel with Turbo Codes BER 10^-6
k=1.3807e-23;
T=6;% open Space between relays
T2=150;
Pt_dB=30;% Power of transmission 10kW(?)
%R=50;%rate bit of the link
R=0.02e+03;
V = 100e6; % m/s velocity of probe
f_Dop = V*F/c;
Ant_rad=7;% meters
nu=0.9%efficiency
G_dB = 10*log10(nu*4*pi*(pi*Ant_rad^2)*(F^2/c^2));%gain of the antenna
Phi_theta=32000/10^(G_dB/10);%3dB angular aperture in degree
Gr_db = G_dB; Gt_db = G_dB;
SNR=Eb_N0*R/BW;
SNR_dB=10*log10(SNR)% The required SNR for Reliable Channel with Trubo Code
%Noise Power
N_dB=10*log10(k*BW*T)
%this part estimates the maximum Range for a reliable
% Channel implementing Turbo Code
r=10^((Pt_dB+Gr_db+Gt_db-10*log10((4*pi)^2*F^2/c^2)- N_dB - SNR_dB)/20);
% light Years....
r_YL=r/YL
%value of the main lobe aperture at next reciever
Aperture=sqrt(Phi)*pi/180*r% in meters
% Required number of Relays
N_relay=10.5/r_YL
%This second part is aimed to validate the Choice of different rates and
%values
CNR_dB=Pt_dB+Gr_db+Gt_db -10*log10((4*pi)^2*F^2/c^2)...
- 20*log10(10.5*YL/N_relay)- N_dB
CNR=10^(CNR_dB/10);
%Maximum Channel Capacity for each connection
MAX_C=BW*log2(1+CNR)
% Required CNR for R<C reliable Channel and BER 10^-6
%Imaging
%Using LORRI Telescope and CDD process Please Refer Documentation for
%specifcations
resolution=1024*1024%pixels
%Visible Colors
size_bits=24% 24 bits per Pixel
Image_size=resolution*size_bits/3% using zip compression of 1/3
Transmission_Time_Image=Image_size/R/3600/24 %in Days
%Part 2 We were able to find the limits of a
%reliable communication link, in this part will use the previous results
%and a number of Relay of 5 to estimate The transmitted power needed in
%order to save energy
N_Designed_Relays=13
CNR_dB_link_relay=Pt_dB+Gr_db+Gt_db -10*log10((4*pi)^2*F^2/c^2) - ...
20*log10(10.5*YL/N_Designed_Relays)- N_dB
Pt_dB_per_Relay=-(Gr_db+Gt_db-10*log10((4*pi)^2*F^2/c^2)- N_dB - SNR_dB)...
+20*log10(10.5*YL/N_Designed_Relays)