Continuing the example above, if STA2 is hidden to STA1, then transmission of Packet1 from STA1 to AP would not affect the ability of STA2 to receive Packet2 from AP.
4(c) and (d), after three-way handshaking of RTS/SRTS/CTS, two stations (STA1 and STA2) and AP transmit packets simultaneously in the asymmetric dual link.
4(c) and (d) show the IBFD asymmetric dual link transmissions that occur when STA1 sends a packet to AP and AP sends a packet to another station (STA2) simultaneously.
4(c), STA1 transmits Packet1 to AP and AP forwards Packet1 to STA2 immediately in the IBFD asymmetric dual link.
Using RTS/SRTS/CTS medium access, AP knows the communication link between AP and STA2 has been reserved.
4(d), STA1 has a packet (Packet1) to transmit to AP while AP transmits another packet (Packet2) to STA2 in IBFD asymmetric dual link.