def get_los_path(self, dvec):
"""
Computes LOS path loss and angles
Parameters
----------
dvec : (n,3) array
Vector from cell to UAV
Returns
-------
los_pl: (n,) array
LOS path losses computed from Friis' Law
los_ang: (n,AngleFormat.nangle) = (n,4) array
LOS angles
los_dly: (n,) array
Delay of the paths computed from the speed of light
"""
# Compute free space path loss from Friis' law
dist = np.maximum(np.sqrt(np.sum(dvec**2,axis=1)), 1)
lam = 3e8/self.fc
los_pl = 20*np.log10(dist*4*np.pi/lam)
# Compute the LOS angles
r, los_aod_phi, los_aod_theta = cart_to_sph(dvec)
r, los_aoa_phi, los_aoa_theta = cart_to_sph(-dvec)
# Stack the angles
los_ang = np.stack((los_aoa_phi, los_aoa_theta,\
los_aod_phi, los_aod_theta), axis=-1)
# Compute the delay
los_dly = dist/PhyConst.light_speed
return los_pl, los_ang, los_dly
def transform_ang(self, dvec, nlos_ang, nlos_pl):
"""
Performs the transformation on the angle data
Parameters
----------
dvec : (nlink,ndim) array
Vectors from cell to UAV for each link
nlos_ang : (nlink,npaths_max,nangle) array
Angles of each path in each link.
The angles are in degrees
nlos_pl : (nlink,npaths_max) array
Path losses of each path in each link.
A value of pl_max indicates no path
Returns
-------
Xang : (nlink,nangle*npaths_max)
Tranformed angle coordinates
"""
# Compute the LOS angles
r, los_aod_phi, los_aod_theta = cart_to_sph(dvec)
r, los_aoa_phi, los_aoa_theta = cart_to_sph(-dvec)
# Get the NLOS angles
nlos_aod_phi = nlos_ang[:,:,AngleFormat.aod_phi_ind]
nlos_aod_theta = nlos_ang[:,:,AngleFormat.aod_theta_ind]
nlos_aoa_phi = nlos_ang[:,:,AngleFormat.aoa_phi_ind]
nlos_aoa_theta = nlos_ang[:,:,AngleFormat.aoa_theta_ind]
# Rotate the NLOS angles by the LOS angles to compute
# the relative angle
aod_phi_rel, aod_theta_rel = spherical_add_sub(\
nlos_aod_phi, nlos_aod_theta,\
los_aod_phi[:,None], los_aod_theta[:,None])
aoa_phi_rel, aoa_theta_rel = spherical_add_sub(\
nlos_aoa_phi, nlos_aoa_theta,\
los_aoa_phi[:,None], los_aoa_theta[:,None])
# Set the relative angle on non-existent paths to zero
I = (nlos_pl < self.pl_max-0.01)
aod_phi_rel = aod_phi_rel*I
aod_theta_rel = aod_theta_rel*I
aoa_phi_rel = aoa_phi_rel*I
aoa_theta_rel = aoa_theta_rel*I
# Stack the relative angles and scale by 180
Xang = np.hstack(\
(aoa_phi_rel/180, aoa_theta_rel/180,\
aod_phi_rel/180, aod_theta_rel/180))
return Xang
def inv_transform_ang(self, dvec, Xang):
"""
Performs the transformation on the angle data
Parameters
----------
dvec : (nlink,ndim) array
Vectors from cell to UAV for each link
Xang : (nlink,nangle*npaths_max)
Tranformed angle coordinates
Returns
-------
nlos_ang : (nlink,npaths_max,nangle) array
Angles of each path in each link.
The angles are in degrees
"""
# Compute the LOS angles
r, los_aod_phi, los_aod_theta = cart_to_sph(dvec)
r, los_aoa_phi, los_aoa_theta = cart_to_sph(-dvec)
# Get the transformed angles
npm = self.npaths_max
aoa_phi_rel = Xang[:,:npm]*180
aoa_theta_rel = Xang[:,npm:2*npm]*180
aod_phi_rel = Xang[:,2*npm:3*npm]*180
aod_theta_rel = Xang[:,3*npm:]*180
# Rotate the relative angles by the LOS angles to compute
# the original NLOS angles
nlos_aoa_phi, nlos_aoa_theta = spherical_add_sub(\
aoa_phi_rel, aoa_theta_rel,\
los_aoa_phi[:,None], los_aoa_theta[:,None], sub=False)
nlos_aod_phi, nlos_aod_theta = spherical_add_sub(\
aod_phi_rel, aod_theta_rel,\
los_aod_phi[:,None], los_aod_theta[:,None], sub=False)
# Stack the relative angles
nlink = nlos_aod_phi.shape[0]
nlos_ang = np.zeros((nlink,self.npaths_max,AngleFormat.nangle))
nlos_ang[:,:,AngleFormat.aoa_phi_ind] = nlos_aoa_phi
nlos_ang[:,:,AngleFormat.aoa_theta_ind] = nlos_aoa_theta
nlos_ang[:,:,AngleFormat.aod_phi_ind] = nlos_aod_phi
nlos_ang[:,:,AngleFormat.aod_theta_ind] = nlos_aod_theta
return nlos_ang