two slots after $T_{SIFS}$, the Direct transmission mode is selected instead. In this last case, the node that obtained the channel and sent the first RTS will send directly the data packet waiting at most $T_{SIFS}$ plus $2T_s$ after the CTS reception. This minor delay of two time slots is very short when compared to the overall performance benefits of the proposed scheme. Note that busy tones are used since other relay candidates might also transmit a busy tone in the same slot (e.g. nodes $N_6,N_7$), which means that at least one node can be used for ANC-OL.

Relay Prioritization
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The next question is the following: How does the system treat multiple relay candidates? From all the potential relay nodes, the one with the highest possible increase in the transmission rate should obtain the channel and be used as a relay. To solve this problem a separate round is introduced during which relays are allowed to contend for this role. Fig. \[fig:relay-prioritization\] presents how two relays contend for the relaying opportunity. We named this process *the relay contention round* and it works as follows. After the relay nodes transmit their respective busy tones, they set the value of a 