Algorithm 4 Power Allocation Scheme for MIMO-NOMA

1:${\overline{p}}_{{\tilde{i}}_n(l)}=\frac{P_{tot}}{S}\frac{g_{{\tilde{i}}_n(l)}^{-\gamma }}{{\displaystyle \sum _{j=1}^{m_n}}{g}_{{\tilde{i}}_n(j)}^{-\gamma }},\forall n,l$. 2:Initialize $\eta$. 3:$r_0\leftarrow {\displaystyle \sum _{n=1}^S}{\displaystyle \sum _{l=1}^{m_n}}log(1+\frac{{\overline{p}}_{{\tilde{i}}_n(l)}{g}_{{\tilde{i}}_n(l)}}{1+{\displaystyle \sum _{b=1}^{l-1}}{\overline{p}}_{{\tilde{i}}_n(b)}{g}_{{\tilde{i}}_n(l)}})$. 4:i = 0. 5:repeat 6:   i = i + 1. 7:   Produce an equivalence problem of (29) as (34)–(37) based on the Taylor expansion at $\{{\overline{p}}_k,\forall k\}$. 8:   Solve the obtained convex problem to get $\{{\tilde{p}}_k,\forall k\}$. 9:   $r_i\leftarrow {\displaystyle \sum _{n=1}^S}{\displaystyle \sum _{l=1}^{m_n}}log(1+\frac{{\tilde{p}}_{{\tilde{i}}_n(l)}{g}_{{\tilde{i}}_n(l)}}{1+{\displaystyle \sum _{b=1}^{l-1}}{\tilde{p}}_{{\tilde{i}}_n(b)}{g}_{{\tilde{i}}_n(l)}})$. 10:   ${\overline{p}}_k\leftarrow {\tilde{p}}_k,\forall k$. 11:until$\left|\frac{r_i-r_{i-1}}{r_{i-1}}\right|<\eta$ 12:$p_k={\overline{p}}_k,\forall k$.