Re: flat channel?# EE - 电子工程
s*o
1 楼
基本上,在无线通信中有两大类四种small-scale fading
1. Time dispersion due to "multipath delay spread"
a) flat fading
b) frequency selective fading
2. Frequency despersion due to "Doppler spread"
a) fast fading
b) slow fading
以上这两大类fading基本上是independent of one another
关于flat fading,通俗讲,就是传输信号的带宽小于信道的相干带宽,所以,信号
经过衰落信道后,在receiver处,信号的spectral characteristics依旧不变。
其对应的则是frequency selective fading,其信号的带宽大于信道的相干带宽,
所以,在RX处,接收信号在不同的频率其衰落特性也不同,即spectral characteristics
变了。
具体的,可以参考 Rappaport的"wireless com
1. Time dispersion due to "multipath delay spread"
a) flat fading
b) frequency selective fading
2. Frequency despersion due to "Doppler spread"
a) fast fading
b) slow fading
以上这两大类fading基本上是independent of one another
关于flat fading,通俗讲,就是传输信号的带宽小于信道的相干带宽,所以,信号
经过衰落信道后,在receiver处,信号的spectral characteristics依旧不变。
其对应的则是frequency selective fading,其信号的带宽大于信道的相干带宽,
所以,在RX处,接收信号在不同的频率其衰落特性也不同,即spectral characteristics
变了。
具体的,可以参考 Rappaport的"wireless com