Area throughput enhancement of OFDM-based wireless LAN in OBSS environment by physical header modification and adaptive array antenna

To improve the area throughput of OFDM-based IEEE 802.11 wireless LAN systems in an OBSS environment, this paper proposes a new overlay transmission protocol which does not require any signal/frame exchange prior to DATA frame transmission. The proposed protocol introduces a new field which containing a portion of the BSSID to which the destination node belongs in order to indicate who must listen this frame without decoding the succeeding MAC frame. This protocol can reduce the deferring time for new frame transmission and increase the transmission chances of each node with a small overhead, whereas it causes interference toward existing communications. To suppress such interference, we employ a pre-FFT type MMSE adaptive array antenna (AAA) to suppress sporadic interference at the receiver´s side. The average area throughput of a system based on IEEE 802.11g ERP-OFDM in an OBSS environment is evaluated through PHY/MAC cross-layer computer simulations assuming an AWGN channel. Simulation results shows that the area throughput improvement of about 60% can be achieved at an offered load of 24Mbytes/s by employing our proposed protocol and AAA.