Toward a MAC Protocol Overcoming Hidden Stations Issue in IEEE 802.11ax Unidirectional Full Duplex Radio Communications

The Full Duplex (FD) radio technology has been spotlighted as one of the key technologies in the future generation of High Efficiency WLANs (Wireless Local Area Networks). Indeed, it has the advantage of doubling the throughput of the Half Duplex radio (HD) through the adoption of SIC (Self-Interference Cancellation) antennas. By means of said antennas, simultaneous transmissions and receptions are therefore possible at the same time on the same radio frequencies. The Full Duplex radio communications are classified into two types: Bidirectional Full Duplex (BFD) and Unidirectional Full Duplex (UFD). In case of UFD communications, the Access Point (AP) shall not accept any Up-Link (UL) traffic from any wireless station, as this traffic could interfere with Down-Link (DL) traffic. Thus, UFD communications are only possible when the station that has UL traffic is hidden to the other station that has traffic to receive from AP. The main goal of this paper is extending the operation rules of the exiting 02-MAC (OFDMA Two symbol coordination Medium Access Control) protocol, thereby enabling the AP to select between candidate hidden stations which could participate in an UFD communication without interference. The obtained simulations results demonstrate that the proposal provides better performances in terms of throughput and overhead.