Keyholes in MIMO-OFDM: Train-to-Wayside Communications in Railway Tunnels

Table 3

Keyhole probabilities (%) for VV, VH, HV, and HH polarization setups for both antenna separations considered ( and ).

Antenna distance/polarization	VV	HV	VH	HH	Average
	0.58%	1.20%	0.85%	0.58%	0.80%
	0.34%	0.94%	0.66%	0.48%	0.60%