Abstract:

Sub-1 GHz (920 MHz) frequency bands for LPWAN (Low Power Wide Area Network) wireless communications systems are attracting attention from various IoT applications. Environmental and infrastructure monitoring systems, such as smart meter, ground inclinometer, and bridge sensor, are widely deployed. With LPWAN wireless communication systems on 920 MHz bands having the features of long distance, low rate and low power consumption, a huge number of IoT devices distributed in wide area can be connected to communication networks. Although these networks can be configured in a star configuration for a relatively small area, the mesh configuration has been emerging recently. IEEE 802.15.4g-FSK PHY/OFDM PHY is a typical PHY technology in mesh networks for the purpose of transferring IoT application data over a wider area. When distributing the same data such as firmware to IoT devices during network operation, improving the efficiency of distribution method becomes critical. On the one hand, using broadcast transmission, the delivery confirmation cannot be performed. On the other hand, unicast transmission is very time consuming if the number of IoT devices is large. Therefore, we proposed a new firmware distribution method with erasure code for large number of IoT devices. Our computer simulation result shows that the proposed method improves the efficiency of distribution by 1.48 times compared with conventional method and achieves higher spectrum efficiency for IEEE 802.15.4g-OFDM PHY.