Experimental Study Towards Efficient Interference Avoidance Using Wi-Fi 6 OFDMA on SDR

Interference is an important problem that influences the performance of wireless communication systems in crowded environments. In this work, we experimentally examine interference avoidance using Orthogonal Frequency Division Multiple Access (OFDMA) as defined in IEEE 802.11ax (Wi-Fi 6). The concept involves leaving a portion of the available subcarriers, specifically a designated Resource Unit (RU), unused in the presence of interference-referred to as RU puncturing. This enables concurrent transmission with narrowband technologies while mitigating the effects of interference. We use openwifi, an open-source Field-Programmable Gate Array (FPGA)-based Wi-Fi transceiver on Software-Defined Radio (SDR), extended with Wi-Fi 6 compliant OFDMA feature to exploit this mechanism. We show by simulations and experiments that our method operates effectively when using two SDR devices. However, achieving end-to-end system-level improvement is challenging when connecting to a Commercial Off-The-Shelf (COTS) Wi-Fi 6 device. For efficient interference avoidance it is important to effectively schedule punctured transmissions to make most use of the gained spectral efficiency.