# Doopler spread and delay spread in an equation of channel freq response

Assumed the transmission system with channel impulse response is determined by the matrices $$H(\tau_l) \in C^{N_R \times N_T}$$ ( $$N_R$$ and $$N_T$$ are numbers of received and transmit antennas)

By taking the Fourier Transform (FT) of the impulse response, we get the frequency response of the channel at subcarrier $$n$$.

$$$$H(n)=\sum_{l=1}^{L} H(\tau_l) \cdot e^{i \cdot 2 \pi (f_c+\Delta f \cdot n)\tau_l},$$$$ where $$f_c$$ is the centre frequency, $$\Delta f$$ is the subcarrier bandwidth, $$n$$ is a subcarrier index, $$n=1, \ldots N$$.$$t$$ denote time, $$\tau$$ is delay. $$\tau_l$$ is the cluster delays.

How should I change the equation above if I need to check how the doppler delay is affected system?