FSPL_model.m

%% function for calculate free-space path loss

% calculate_FSPL Computes the Free Space Path Loss (FSPL) in dB
function [FSPL] = FSPL_model(signal_fq, d)

    % parameters
    c = 3e8;    % speed of light 3*10^8 m/s
    lambda = physconst('lightspeed')/signal_fq; % lambda = c/f
    
    % (MATLAB model 1)Free Space Path Loss (FSPL) calculation in dB
    % FSPL = fspl(d,lambda);

    % (Paper formula)theoretical free-space path loss given by following formula
    % fc = center frequency (MHz) 
    % d = distance in (km)
    % FSPL = 32.45 + 20*log10(signal_fq) + 20*log10(d);

    % fc = center frequency (GHz) 
    % d = distance in (km)
    FSPL = 92.45 + 20*log10(signal_fq) + 20*log10(d);

    % (Paper formula)free-space path loss
    % fc = caarier frequency
    % d = slant range
    % FSPL = 10*log10((4*pi*d*fc)/c)^2;

end