Sub-1 GHz Frequency Band Wireless Coexistence for the Internet of Things

Motivated by the explosion of the Internet of Things (IoT), we examined Sub-1 GHz (frequencies below 1 GHz) band wireless technologies that are essential to enable various IoT applications. IEEE 802.15.4g and IEEE 802.11ah are two wireless technologies developed for outdoor IoT applications such as smart utility, smart city and infrastructure monitoring, for which both technologies operate in Sub-1 GHz Bands. Our coexistence simulation of IEEE 802.15.4g and IEEE 802.11ah using standard defined coexistence mechanisms shows serious interference problems due to fundamental protocol differences and channel access parameter differences. Accordingly, we proposed IEEE 802.19.3 Task Group formation to lead the standard development of IEEE 802.15.4g and IEEE 802.11ah coexistence in the Sub-1 GHz band. In addition to our coexistence methods contributed to IEEE 802.19.3 standard, we propose a novel Active Carrier Sense based CSMA/CA mechanism for IEEE 802.15.4g to reduce CSMA/CA failure packet discard under interference from IEEE 802.11ah traffic, and to keep interoperability with conventional IEEE 802.15.4g CSMA/CA mechanism. Our proposed coexistence techniques can improve fair spectrum sharing between IEEE 802.15.4g and IEEE 802.11ah networks for IoT applications.