Sub-channel Based Uplink OFDMA Random Access Scheme Considering Hidden Nodes in the Next Generation Wireless LAN

In this paper, a novel sub-channel based uplink Orthogonal Frequency Domain Multiple Access (OFDMA) random access scheme is proposed. In the next generation Wireless Local Area Network (WLAN), OFDMA was adopted in order to enhance throughput performance. OFDMA can be used for both downlink and uplink. In order to utilize OFDMA for uplink, AP needs to schedule stations’ packet transmission. In order for AP to schedule stations’ uplink packet transmission, either random access scheme or pre-scheduling scheme can be utilized. Because pre-scheduling scheme requires lengthy scheduling procedure, random access scheme is preferred and used in various wireless technologies including 4 th generation wireless technology. For such purpose, IEEE 802.11ax adopted uplink OFDMA random access scheme. However, how multiple channels can be utilized or how stations transmit random access packets during random access period is not defined. In this paper, a novel sub-channel based uplink OFDMA random access scheme considering hidden nodes is proposed. Detailed Medium Access Control (MAC) header formats are presented in order to provide a complete protocol.