부산대학교 도서관

Nowadays, the number of wireless stations (STAs) connected to a wireless local area network (WLAN) is increasing, and the quality of service (QoS) requirements of transferred data are diverse. Even in such congested situations, it is necessary to assign sufficient frame transmission opportunities to each STA and base station (BS) according to the QoS requirements of transferred data. IEEE 802.11ax introduces simultaneous transmission of multiple frames by Orthogonal Frequency Division Multiple Access (OFDMA) for efficiently accommodating many STAs in a WLAN. For backward compatibility, OFDMA transmission in IEEE 802.11ax is used in cooperation with Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) that is conventionally used in IEEE 802.11. In this paper, we propose a frame transmission method that selectively uses OFDMA transmission and CSMA/CA-based transmission, taking into account the QoS requirements of transferred data and the characteristics of the two types of transmissions.