Algorithm 2 2D UFBS placement process through the k-medoids algorithm

1:input: The set of coordinates of all GMTs $U=\{u_1,u_2,\cdots ,u_N\}$, and the number of UFBSs Y 2:$ϵ={10}^{-6}$ 3:t = 0 4:Initialize Y medoid points $C^t=\left\{p_1^m,p_2^m,...,p_{\mathsf{Y}}^m\right\}\subseteq U$, randomly 5:$S_k$ = $\varnothing ,{\forall }_k=1,2,\cdots ,\mathsf{Y}$. 6:for$i\leftarrow 1$ to N do 7:    $k^{\ast }=\underset{k=1\cdots \mathsf{Y}}{argmin}\parallel u_i-C_k^t\parallel$ 8:    $S_{k^{\ast }}=S_{k^{\ast }}\cup \left\{u_i\right\}$ 9:end for 10:$A^t={\sum }_{k=1}^{\mathsf{Y}}{\sum }_{u_l\in S_k}{\parallel u_i-C_k^t\parallel }^2$ 11:repeat 12:    for $k\leftarrow 1$ to $\mathsf{Y}$ do 13:        for $i\leftarrow 1$ to N do 14:           if $u_i\notin C^t$ then 15:               Swap the role of $C_k^t$ with $u_i$ 16:               Repeat steps 6 to 9 17:               $B={\sum }_{k=1}^{\mathsf{Y}}{\sum }_{u_l\in S_k}{\parallel u_i-C_k^t\parallel }^2$ 18:               if $B<A^{\left[t\right]}$ then 19:                   t = t +1 20:                   $C_k^t$ = $u_i$ 21:                   $A^t=B$ 22:               end if 23:           end if 24:        end for 25:    end for 26:until $C^t-C^{t-1}\le ϵ$ 27:output: A set of centroid points that the $\mathsf{Y}$ UFBSs will be deployed $C^t$.