Regarding the title of the question, to my understanding, Channel Inversion means that "The transmitter adapts its power to maintain constant SIR at the receiver."
It is a technique used for adaptive power control.
However, I am not sure if my understanding is correct.
"The transmitter adapts its power to maintain constant SIR at the receiver."
When only one transmitter is involved, that might seem like a pointless thing to do.
When multiple different transmitters, perhaps at very different distances, are involved, it means that each transmitter arrives at the single receiver at the same power level, which optimises their signal to mutual interference ratio. Without this control, the nearest transmitter may swamp the weaker signals from the other more distant transmitters.
