Resource Unit (RU) based OFDMA Scheduling in IEEE 802.11ax system

Abstract

IEEE 802.11ax is a revolutionary effort to provide a improvement over current generation of 802.11 and has been approved to deliver the next-generation Wireless Local Area Network (WLAN) technologies. The medium access control protocol is the critical component to enable efficient sharing of the wireless medium whilst at the same time providing Quality of Service (QoS) to diverse applications. Orthogonal Frequency Division Multiple Access (OFDMA) is the access method adopted by IEEE 802.11ax where the subcarriers are divided into Resource Units (RUs) for scheduling. We propose a contention-based RU allocation in OFDMA based IEEE 802.11ax using an adaptation of IEEE 802.11e Enhanced Distributed Channel access (EDCA). We extend EDCA to the OFDMA system where the access point (AP) transmits Physical Protocol Data Units (PPDUs) by determining the RUs to be allocated to its associated stations (STAs). We also determine the RU limit by normalizing the RU requirements using different methods that is provided as input to the scheduling algorithm and also propose a feedback mechanism to throttle the input arrival process.