Free space path loss
L = fspl(R,lambda)
returns
the free space path loss in decibels for a waveform with wavelength L
= fspl(R
,lambda
)lambda
propagated
over a distance of R
meters. The minimum value
of L
is zero, indicating no path loss.

realvalued 1byM or Mby1 vector Propagation distance of signal. Units are in meters. 

realvalued 1byN or Nby1 vector The wavelength is the speed of propagation divided by the signal frequency. Wavelength units are meters. 

Path loss in decibels. MbyN nonnegative
matrix. A value of zero signifies no path loss. When 
Calculate free space path loss in decibels incurred by a 10gigahertz wave over a distance of 10 kilometers.
lambda = physconst('LightSpeed')/10e9;
R = 10e3;
L = fspl(R,lambda);
[1] Proakis, J. Digital Communications. New York: McGrawHill, 2001.