But the noises, the attenuation and the multipath propagation inhering in the powerline make it very difficult to realize such kind of communication system.
但是电力线信道上存在的各种噪声、衰减和多径传播等问题，这些都大大提高了通信的难度。
2
Model parameters have the important effects on three-dimensional distinct element code (3dec) modeling of the stress wave propagation and attenuation in jointed rock masses as well as other codes.