Algorithm 1 Heuristic for efficient drone placement.

1: Inputs: $N,M,{\gamma }^{max},{\gamma }^{min},\beta ,\mathbf{R},d^{max}$ 2: Initialization: $\forall n\in \{1,\cdots ,N\},m\in \{1,\cdots ,M\}$ 3:${\mathbf{Y}}_{nm}\leftarrow 0$, ${\mathbf{x}}_m\leftarrow 0$, ${\mathbf{c}}_m\leftarrow 0$, ${\mathbf{t}}_n\leftarrow 0$ 4: ${\mathbf{W}}_{nm}\leftarrow \left\{\begin{array}{cc}1,\hfill & \mathrm{if}{\mathbf{R}}_{nm}<d^{max}\hfill \\ 0,\hfill & \mathrm{otherwise}\hfill \end{array}\right.$ 5: Step I: Allocation to users with single connection option 6: ${\mathbf{t}}_n\leftarrow {\sum }_{n=1}^N{\mathbf{W}}_{n,m^{\prime }},\forall m^{\prime }\in \{1,\cdots ,M\}$ 7: for $i\in \{1,\cdots ,N\}$ do 8: if ${\mathbf{t}}_i==1$ then 9:  $\mathbf{k}\leftarrow find({\mathbf{W}}_{i,:}==1)$ 10:  ${\mathbf{Y}}_{i,k}\leftarrow 1,{\mathbf{x}}_k\leftarrow 1,{\mathbf{c}}_k\leftarrow {\mathbf{c}}_k+1$ 11: end if 12: end for 13: Step II: Allocation of users with connections options to multiple drones 14: for $i\in \{1,\cdots ,N\}$ do 15: if ${\mathbf{t}}_i>1$ then 16:  $flag\leftarrow 0$ 17:  $\mathbf{k}\leftarrow find({\mathbf{W}}_{i,:}==1),\mathbf{j}\leftarrow find(\mathbf{x}==1)$ 18:  $[\mathbf{I},\lambda ]\leftarrow sort\left(\mathbf{c}\right)$ 19:  for $j=1:len\left(\mathbf{I}\right)$ do 20:   ${\mathbf{a}}_j\leftarrow \left\{\begin{array}{cc}1,\hfill & \mathrm{if}{\mathbf{I}}_j\in \mathbf{k}\hfill \\ 0,\hfill & \mathrm{otherwise}\hfill \end{array}\right.$ 21:  end for 22:  if ${\sum }_{j=1}^{len\left(\mathbf{a}\right)}{\mathbf{a}}_j>0$ then 23:   ${\mathbf{I}}^{\prime }\leftarrow find(\mathbf{a}==1)$ 24:   for $q\leftarrow 1:len\left({\mathbf{I}}^{\prime }\right)$ do 25:    $s\leftarrow {\mathbf{I}}_q^{\prime }$ 26:    if ${\mathbf{c}}_{{\mathbf{I}}_s}<{\gamma }^{max}$ then 27:     ${\mathbf{Y}}_{i,{\mathbf{I}}_s}\leftarrow 1,{\mathbf{x}}_{{\mathbf{I}}_s}\leftarrow 1,{\mathbf{c}}_{{\mathbf{I}}_s}\leftarrow {\mathbf{c}}_{{\mathbf{I}}_s}+1$ 28:     $flag\leftarrow 1$ 29:     break 30:    end if 31:   end for 32:   if $flag==0$ then 33:    $\mathbf{k}\leftarrow \mathbf{k}\setminus \mathbf{I}$ 34:    if $\mathbf{k}==\varnothing$ then 35:     ${\mathbf{W}}_{(i,:)}\leftarrow 0$ 36:     $flag\leftarrow 1$ 37:    end if 38:   end if 39:  end if 40:  if $flag==0$ then 41:   ${\mathbf{Y}}_{i,{\mathbf{k}}_1}\leftarrow 1,{\mathbf{x}}_{{\mathbf{k}}_1}\leftarrow 1,{\mathbf{c}}_{{\mathbf{k}}_1}\leftarrow {\mathbf{c}}_{{\mathbf{k}}_1}+1$

42:  end if 43: end if 44: end for 45: Step III: Check for under utilized drones 46: $\mathbf{\nabla }\leftarrow find(((\mathbf{c}<{\gamma }^{min})·\mathbf{x})==1)$ 47: ${\mathbf{Y}}_{:,\mathbf{\nabla }}\leftarrow 0,{\mathbf{x}}_{\mathbf{\nabla }}\leftarrow 0,{\mathbf{c}}_{\mathbf{\nabla }}\leftarrow 0$ 48: $\mathbf{p}\leftarrow {\sum }_{i=1}^N{\mathbf{Y}}_{i,:}$ 49: ${\mathbf{u}}^{\prime }\leftarrow find(\mathbf{p}==0)$ 50: $b\leftarrow round(\beta ·N)$ 51: $t\leftarrow {\sum }_{i=1}^N{\sum }_{j=1}^M{\mathbf{Y}}_{i,j}$ 52: for $i\leftarrow 1:len\left({\mathbf{u}}^{\prime }\right)$ do 53: if $t<b$ then 54: $flag\leftarrow 0$ 55:  $[\mathbf{I},\lambda ]\leftarrow sort\left(\mathbf{c}\right)$ 56:  for $j\leftarrow 1:M$ do 57:   if $flag==0$ then 58:    if ${\mathbf{c}}_{{\lambda }_j}<{\gamma }^{max}\mathbf{and}{\mathbf{W}}_{{\mathbf{u}}_i^{\prime },{\lambda }_j}==1$ then 59:     ${\mathbf{Y}}_{{\mathbf{u}}_i^{\prime },{\lambda }_j}\leftarrow 1,{\mathbf{x}}_{{\lambda }_j}\leftarrow 1,{\mathbf{c}}_{{\lambda }_j}\leftarrow {\mathbf{c}}_{{\lambda }_j}+1$ 60:     $flag\leftarrow 1$ 61:     $t\leftarrow {\sum }_{ii=1}^N{\sum }_{jj=1}^M{\mathbf{Y}}_{ii,jj}$ 62:    end if 63:   end if 64:  end for 65: end if 66: end for 67: Step IV: Connect all unconnected users 68: $t\leftarrow {\sum }_{i=1}^N{\sum }_{j=1}^M{\mathbf{Y}}_{i,j}$ 69: $\mathbf{p}\leftarrow {\sum }_{i=1}^N{\mathbf{Y}}_{i,:}$ 70: ${\mathbf{u}}^{\prime }\leftarrow find(\mathbf{p}==0)$ 71: for $i\leftarrow 1:len\left({\mathbf{u}}^{\prime }\right)$ do 72: if $t<b$ then 73:  $\mathbf{r}\leftarrow {\mathbf{R}}_{(i,:)}$ 74:  $flag\leftarrow 0$ 75:  $\mathbf{k}\leftarrow {\mathbf{W}}_{{\mathbf{u}}_i^{\prime },:}$ 76:  for $j\leftarrow 1:len(\mathbf{k}$) do 77:   if $flag==0$ then 78:    $[l^v,l^i]\leftarrow min\left(\mathbf{r}\right)$ 79:    ${\mathbf{r}}_{l^i}\leftarrow inf$ 80:    $[l^v,l^i]\leftarrow min\left(\mathbf{r}\right)$ 81:    if ${\mathbf{W}}_{{\mathbf{u}}_i^{\prime },l^i}>0$ then 82:     ${\mathbf{Y}}_{{\mathbf{u}}_i^{\prime },l^i}\leftarrow 1,{\mathbf{x}}_{l^i}\leftarrow 1,{\mathbf{c}}_{l^i}\leftarrow {\mathbf{c}}_{l^i}+1$ 83:    end if 84:   end if 85:  end for 86: end if 87: end for 88: Step V: Remove all under-utilized drones 89: ${\mathbf{d}}^u\leftarrow find((\mathbf{c}<{\gamma }^{min})·\mathbf{x}==1)$ 90: ${\mathbf{Y}}_{:,{\mathbf{d}}^u}\leftarrow 0,{\mathbf{x}}_{{\mathbf{d}}^u}\leftarrow 0,{\mathbf{c}}_{{\mathbf{d}}^u}\leftarrow 0$ 91: $t\leftarrow {\sum }_{i=1}^N{\sum }_{j=1}^M{\mathbf{Y}}_{i,j}$ 92: Outputs: $\mathbf{Y},\mathbf{x}$