A Receiver for IEEE 802.15.4-based High-speed Mobile IoT Communication Systems

Currently, frequency shift keying (FSK) standardized in IEEE 802.15.4 is adopted in smart metering systems as a transmission scheme for the Internet of things (IoT). On the other hand, there are increasing demands for higher data rates, long-distance transmission, and mobile communication for further expansion of IoT applications. Orthogonal frequency division multiplexing (OFDM) standardized in IEEE 802.15.4 attracts attention as a transmission scheme to adaptively realize these demands. However, in our previous study, mobile communication with the required packet error rate (PER) was achieved at moving speeds of only up to 40 km/h in an urban environment because the receiving scheme could not follow fading fluctuations in the time domain during high-speed movement. To improve the PER performance in higher-speed mobile IoT communication systems, we propose a novel channel estimation method for IEEE 802.15.4 OFDM that improves the refresh rate of channel estimates by copying estimates of neighboring subcarriers. Computer simulation results show that the proposed method combined with the maximal ratio combining achieves the required PER even at 200 km/h in the urban environment.