Table 2 User selection

Set $\mathcal{U}=\left\{m|{\sum }_{l=1}^L{\alpha }_{l,m}{B}_{l,m}<R_m^b\right\}$ which is the set of multicast groups which did not achieve the rate requirement.

2. Iteration:

While $\mathcal{U}\ne \phi$

   for each m ∈ U

1) find a user $u^{*}=\mathsf{\text{arg }}{\mathsf{\text{min}}}_{u\in {\mathcal{U}}_m^{\mathrm{mul}}}SN{R}_u$, $SN{R}_u=1/L\cdot {\sum }_{l=1}^L{P}_l{G}_{l,u}/N_0$.

2) exclude the user u* from set ${\mathcal{U}}_m^{\mathsf{\text{mul}}}$, set ${\mathcal{U}}_m^{\mathsf{\text{mul}}}={\mathcal{U}}_m^{\mathsf{\text{mul}}}-\left\{u^{*}\right\}$.

   end

   do our proposed cost-based subchannel allocation, reset $\mathcal{U}=\left\{m|{\sum }_{l=1}^L{\rho }_{l,m}{r}_{l,m}<R_m^b\right\}$.

end