Coexistence of Wi-Fi and IoT Communications in WLANs

As most Internet-of-Things (IoT) devices are powered by small-sized batteries and expected to operate for many years without battery replacement, energy-efficient wireless IoT communication has been considered as a crucial component of the future network infrastructure. In this article, we propose a practical design (termed WiFi-IoT) to add energy-efficient IoT communication capability into WLANs. WiFi-IoT features two innovative techniques: 1) an asymmetric physical (PHY) design and 2) a transparent coexistence scheme. The asymmetric PHY allows an access point (AP) to communicate with multiple IoT devices at a much low sampling rate (250 ksps), thereby significantly reducing the power consumption for the IoT devices. The transparent coexistence scheme enables a multiantenna AP to serve Wi-Fi and IoT devices simultaneously, leading to an efficient utilization of spectrum. We have built a prototype of WiFi-IoT on a USRP2 wireless testbed and evaluated its performance in real-world wireless environments. The experimental results show that a two-antenna AP can simultaneously serve one broadband Wi-Fi device and 24 narrowband IoT devices on the same spectrum.