number of links that are available in this mode is reduced if the relays have full or empty buffers.

Let $N_i$ denote all the possible out-going links from state $s_i$. Among them, $n_i$ links are considered through non-successive (also referred to as *single-link*[^4]) transmissions, while $N_i-n_i$ through successive transmissions. These transmissions endure for one transmission phase. Since the source and one relay will transmit simultaneously, inter-relay interference will arise and the transmission power in each hop will be adjusted, according to Section \[sec:minpow\], depending on whether or not interference cancellation took place. In what follows, we denote with superscript $ns$ the non-successive (single-link) transmissions and with $s$ the successive ones. Since we have i.i.d fading channels, single link transitions can occur with equal probability. On the other hand, due to the inter-relay interference, the successive transitions will have equal probabilities in the high SNR regime as interference cancellation is always feasible there. Thus, the probability of a single link transition from state $s_i$ to a state $s_j$ is equal to: $$\label{eq:single_tr}
p^{\rm ns}_{ij} \buildrel \Delta \over = \frac{1}{n_i}\left[ {1 - {{\left( {1 - \exp \left( { - \frac{{{2^{2{r_0}}} - 1}}{P}} \right)} \right)}^{{D_{{\rm ns}}}}}} \right] \;.$$ On the other hand, single 