5G NR

where ${\mathbf{a}}_{tx}\left({\theta }_{n,m,ZoD},{\varphi }_{n,m,AoD}\right)$ and ${\mathbf{a}}_{rx}\left({\theta }_{n,m,ZoA},{\varphi }_{n,m,AoA}\right)$ are the transmit and receive antenna array impulse response vectors, respectively, corresponding to ray $m\in \left\{1,\dots ,M\right\}$ in cluster $n\in \left\{1,\dots ,N\right\}$ given by the following expression:

$\begin{array}{l}{\mathbf{a}}_{tx}({\theta }_{n,m,ZoD},{\varphi }_{n,m,A}\end{array}$