【课程学习】Wireless Communications
Goldsmith A. Wireless communications[M]. Cambridge university press, 2005.
Wireless Communications 无线通信课程
文章目录
- 2-Path Loss, Shadowing, and Multipath
- 2.4-Two-Ray Multipath Model
- 时延扩展 delay spread P33
- 3-Statistical Multipath Channel Models
- 3.3-Wideband Fading Model
- 3.3.3-Coherence Bandwidth
2-Path Loss, Shadowing, and Multipath
2.4-Two-Ray Multipath Model
时延扩展 delay spread P33
OFDM中CP长度需要大于信道的最大时延扩展，这样才有效避免ISI。
本质就是由于不同长度路径带来的时间差
The delay spread of the two-ray model equals the difference between the delay of the LOS ray and that of the reflected ray: (d1 − d0)/c.
3-Statistical Multipath Channel Models
3.3-Wideband Fading Model
3.3.3-Coherence Bandwidth
相干带宽（coherence bandwidth）pp99
c ( τ , t ) = ∑ i = 0 N ( t ) − 1 α i ( t ) e − j ϕ i ( t ) δ ( τ − τ i ( t ) ) c(\tau,t)=\sum_{i=0}^{N(t)-1}\alpha_i(t)e^{-j\phi_i(t)}\delta(\tau-\tau_i(t)) c(τ,t)=i=0∑N(t)−1αi(t)e−jϕi(t)δ(τ−τi(t))