Practical Analysis of IEEE 802.11n 2.4 GHz Communication Quality in the Context of IoT Devices Operating in an Area Shared with Modern Wi-Fi 6 and Wi-Fi 7 Networks

This article presents an experimental evaluation of the data-transmission performance of an IoT device communicating with an MQTT broker over a local IEEE 802.11n Wi-Fi network in the 2.4 GHz band, coexisting with modern Wi-Fi networks based on the IEEE 802.11ax (Wi-Fi 6) and IEEE 802.11be (Wi-Fi 7) standards. The effect of sharing the radio medium on the communication quality parameters of the IoT device, such as end-to-end delay, jitter, the packet delivery ratio (PDR), and application throughput (goodput), was assessed. Unlike previous work, which focuses primarily on PHY/MAC metrics or on simulation-based analysis, this study targets the application layer (MQTT) from the perspective of a legacy IoT end-device. The results presented and discussed herein show that the presence of 802.11ax and 802.11be networks in the 2.4 GHz band can significantly degrade the temporal parameters of MQTT transmissions performed by IoT devices operating in the older 802.11n standard. The greatest impact is observed in jitter and in the extreme delay values (for instance, in the worst-case coexistence scenario—with simultaneous Wi-Fi 6 and Wi-Fi 7 interference, the P95 delay increased from 38 to 869 ms), whereas the PDR remains relatively high because retransmissions compensate for packet losses at the expense of delay.