Interferential Packet Detection Scheme for a Solution to Overlapping BSS Issues in IEEE 802.11 WLANs

In this manuscript, an interferential packet detection scheme in IEEE 802.11 WLANs is proposed. If another basic service set (BSS) is overlapping domestic BSS, some stations (STAs) may suffer from interference from a hidden terminal in overlapping BSS (OBSS). One of the best ways to avoid this undesirable situation is channel switching after detecting OBSS. However there are some difficulties to recognize existence of OBSS. One difficulty is that STAs in domestic BSS can´t receive frames from OBSS correctly and can´t check BSSID of frames if traffic in domestic BSS is heavy and if transmission rates of frames from OBSS are higher. Another difficulty is that if the cell radius of domestic BSS is smaller than that of OBSS, some STAs in OBSS may transmit frames asynchronously and interfere with transmissions in domestic BSS. If interference causes frame error, domestic STA can´t distinguish interference from degradation of channel condition. This paper proposes a method whereby STAs can detect interferential packet even while STAs receive frames from domestic BSS. If STAs detect interference, channel switching is performed dynamically. The probability of detecting interferential packets is evaluated by computer simulation, and the results confirm the effectiveness of the proposed method