Direct transmission protection in IEEE 802.11 networks

In this paper, we discuss some problems related to direct transmissions between QSTAs in an infrastructure 802.11 WLAN with a legacy access point (AP). In the infrastructure mode, collisions of data frames caused by hidden terminals interference can be avoided by the RTS/CTS exchange anticipating the data frames, if and only if all data communications between stations are performed via the AP. The interference problem is solved because all terminals are within the transmission range (TX range) of the AP. However, the RTS/CTS exchange is not enough to protect direct transmissions between QSTAs. In this paper, we analyze the state-of-the-art direct transmissions protection approaches, show their limitations, propose and simulate our own protection schemes.