It is predicated that the Internet of Things (IoT) brings together a massive number of devices connected to implement applications such as smart cities. Therefore, efficiency in allocating limited resources to a huge number of devices becomes a critical challenge. In many IoT applications, e.g. smart infrastructure monitoring, the amount of data generated by each device can be relatively small even though the number of connected devices are large. This feature of IoT enables the potential of massive connectivity and low-power wide-area (LPWA) networks have been proposed as a promising solution for such types of IoT applications [1]–[2][3]. Compared with traditional wireless techniques, LPWA techniques aim to offer a trade-off between power consumption, coverage, and data rates to address the more diverse needs of IoT applications. To achieve long range transmission with low energy consumption, LPWA technologies can normally operate with low data rates, which makes them more suitable for delay-tolerant applications with small amounts of data.