?自由空间损失

...r and receiver are moving relative to one another  慢/快衰落(slow/fast fading) :12 2.2.1 自由空间损失(Free space loss)  P(t): 信号入(发)功率, P(r): 信号出(收)功率, 其比值的10 log 10 为其dB值。