Adaptive 802.15.4 backoff procedure to survive coexistence with 802.11 in extreme conditions
Eugène David Ngangue Ndih, Soumaya Cherkaoui · 2016
With the increasing deployment of smart devices for the Internet of Things (IoT) using 802.15.4 in spaces where 802.11 devices are already deployed, wireless channels are getting densely populated in the 2.4 GHz ISM band, especially when nodes operate in saturation conditions. In addition to the fact that 802.15.4 and 802.11 use different CSMA/CA protocols with considerable different backoff durations, 802.15.4 is designed for ultra-low power, low rate WPAN while 802.11 is designed for higher power and high data rate WLAN. In this paper, we aim to tackle the resulting issues due to this asymmetric coexistence. Especially we propose a simple but efficient backoff mechanism for 802.15.4 in which the backoff duration is adaptively chosen, when WiFi transmissions are detected during the clear channel assessment. Through extensive simulations, we demonstrate the efficiency of the proposed adaptive backoff mechanism and the considerable improvements of the 802.15.4 performance even in case of erroneous decision regarding the type of packet detected during the clear channel assessment.