Algorithm 2: ACO for the Placement Scheme

Input: $M$, $N$

Output: $O$, $F_{pro}$

$n_a\leftarrow 0$, $P{a}_{N_a\times n}=\varnothing$

While $n_a<N_a$

Initial $P{a}_{n_a}$

$P{a}_{N_a\times n}\leftarrow P{a}_{N_a\times n}\cup P{a}_{n_a}$

$n_a\leftarrow n_a+1$

End

While $t<N_r$

Foreach $P{a}_{n_a}(t)$ do

Create $P{a}_{n_a}(t)$ by $p_{ij}(t)$

Get $O_{ij}(t)$ &$F_{pro}(t)$

${\tau }_{j,i}\left(t\right)\leftarrow {\tau }_{j,i}(t+1)$

End

$t\leftarrow t+1$

End

Find $O_{ij}$ by ${\tau }_{j,i}$

Calculate $F_{pro}$