Hi
seems to me that R curves goes up as x0 goes closer to zero (but not rqual to zero otherwise you get Inf values)
also all the small for loops to create the sum1, sum2,sum3 variables can be replaced with sum function directly
close all; clear all; clc;
x0_range = [0.01 0.25 0.5 1];
% System parameters
F = 10000; % Number of files
S = 100; % SBS cache capacity (set to 100)
M = 50; % Cash capacity fraction
alpha = 2; % Path loss exponent for LOS link
c = 3e8; % Light speed
fr = 1e12; % Operating frequency
B = 10e6; % System bandwidth
epsilon = 0.8; % Skewness factor
K = 0.0016; % Molecular absorption coefficient
P_M = 10^(64/10); % Transmit power MBS
P_S = 10^(30/10); % Transmit power SBS
sigma = 10^(-90/10); % Noise power
N_L = 512;
N_M = 16;
eta = 1;
x2 =30; % RIS-MBS distance
d_range = 1:1:40;
R = zeros(numel(d_range),numel(x0_range));
for k = 1:numel(x0_range)
x0 = x0_range(k);
for i = 1:length(d_range)
d = d_range(i);
x1 = d-x0; % added line
% sum1 = 0;
% for f = 1:F
% sum1 = sum1 + f^(-epsilon);
% end
f = 1:F;
sum1 = sum(f.^(-epsilon));
% sum2 = 0;
% for f = 1:M
% sum2 = sum2 + f^(-epsilon)/sum1;
% end
f = 1:M;
sum2 = sum(f.^(-epsilon))/sum1;
% sum3 = 0;
% for f = (M + 1):(M + (S - M) / eta)
% sum3 = sum3 + (f^(-epsilon)) / sum1;
% end
% sum3 = sum3 * eta;
f = (M + 1):(M + (S - M) / eta);
sum3 = eta*sum(f.^(-epsilon))/sum1;
beta = (c/(4*pi*fr))^2; % Spreading loss index
Rs = B * log2(1 + (P_S * beta * (d-x1)^(-alpha) * exp(-K * (d-x1))) / sigma);
Rm = B * log2(1 + (P_M * (N_L^2) * N_M * (beta * (d-x0)^(-alpha) * exp(-K * (d-x0))) * (beta * x2^(-alpha) * exp(-K * x2))) / sigma);
Rt = Rs * (sum2 + sum3) + Rm * (1 - (sum2 + sum3));
R(i,k) = Rt;
leg{k} = ['x0 = ' num2str(x0)];
end
end
plot(d_range, R, '^-')
legend(leg)
xlabel('SBS-RIS Distance, d')
ylabel('Achievable Rate')
