Table 1 Simulation parameters[18]

Frequency of macro cell

2 GHz

Frequency of small cell

5 GHz

Path loss model of macro cell PL_C

Hata

Path loss model of small cell PL_U

M.2135

Transmit power of macro cell P_t,C

43 dBm

Transmit power of small cell P_t,U

33 dBm

Radius of macro cell R_C

1 km

Radius of small cell R_U

0.25 km

Overlapping area distance of macro cells a_C

0.2 km

Overlapping area distance of small cells a_U

0.05 km

Distance between base station and rail D

30 m

C-plane SER threshold th_C

10⁻⁶

U-plane SER threshold th_U

10⁻²

α(th_C)

10⁻⁴

Correlation distance d_cor

100 m [19]

Modulation scheme of U-plane

16QAM

Standard variance of C-plane shadowing σ_C

6 dB

Standard variance of U-plane shadowing σ_U

8 dB