Impact of Wi-Fi traffic on the IEEE 802.15.4 channels occupation in indoor environments

This paper investigates the IEEE 802.15.4 channel occupation pattern under Wi-Fi IEEE802.11b traffic, to provide a better understanding of the cross-interference and the coexistence between these two standards. The overcrowding of the ISM band centered around 2.4 GHz is becoming in fact a serious challenge for the development of the next-generation networks operating in these bands (e.g., ad-hoc, low-power networks). The analysis of this paper is based on experimental measurements carried out using an IEEE 802.15.4 Wireless Sensor Network (WSN) node with Wi-Fi interference at different traffic rates. Three propagation environments are considered: an anechoic chamber, a realistic indoor environment with negligible background interference, and the same environment with high background interference. The measured data are analyzed in terms of energy probability distributions and spectrograms, to characterize the occupation of the IEEE 802.15.4 channels from a statistical and temporal perspective. Finally, the outage probability is introduced as a metric to evaluate the potential impact of Wi-Fi interference on the considered channels.