OCSMA/CA: A MAC protocol to support OFDMA in wireless LAN

Orthogonal Carrier Sense Multiple Access with Collision Avoidance (OCSMA/CA), a novel Medium Access Control (MAC) protocol to support Orthogonal Frequency Division Multiple Access (OFDMA) in Wireless LAN (WLAN), is presented in this paper. In OCSMA/CA, subcarrier state information is transmitted with Request-To-Send (RTS) and Clear-To-Send (CTS) packets before data transmission, so adaptive subcarrier allocation can be performed based on a proposed Virtual Subcarrier Sense (VSS) mechanism. In this scheme, each node has a standard Network Allocation Vector (NAV) and an additional Subcarrier Allocation Vector (SAV). Simulation results show that OCSMA/CA can support OFDMA effectively and can significantly increase the network throughput.