selection decision and the time slot allocation to the strongest link. If a source-relay link is the strongest link, the source transmits and the corresponding relay is selected for reception; on the other hand, if a relay-destination link is the strongest link, the corresponding relay is selected for transmission. The $\maxlink$ relay selection policy can be analytically expressed as follows: $$\begin{aligned}
R^*=\arg\max_{R_k\in \mathcal{C}}\Bigg\{   \bigcup_{R_k\in \mathcal{C}: \Psi(Q_k)\neq L}\{g_{S,R_k} \} \bigcup_{R_k\in \mathcal{C}: \Psi(Q_k)\neq 0}\{g_{R_k,D} \}   \Bigg\},\end{aligned}$$ where $R^*$ denotes the selected relay (either for transmission or reception) and the function $0\leq\Psi(Q_k)\leq L$, gives the number of data elements that are stored in buffer $Q_k$.

$\minpow$ relay selection policy {#sec:minpow}
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In this section, we present a novel relay selection policy called $\minpow$. This relay selection scheme is associated with a one-slot cooperative protocol (similar to the $\maxlink$ relay selection policy [@KRICHAR] and the one in [@IKH3] where however, IRI and power minimization are not considered), rather than two-slot protocols (as in [@IKH2]). At each time slot, the source $S$ transmits data to a selected relay (denoted by $R_r \in \mathcal{K}$) with a non-full buffer, and another relay with a non-empty buffer (denoted by $R_t\in\mathcal{T}$, $R_t \neq R_r$) transmits data to the destination 