In the context of Low Power Wide Area (LPWA) networks, terminals are expected to be low cost, to be able to communicate over a long distance, and to operate on battery power for many years. In order to support a wide range of LPWA applications, the next generation of LPWA technologies is expected to provide faster throughput, be more resilient, and guarantee lower levels of latency for a similar battery lifetime. These contradictory requirements, lead to consider the design of a flexible physical layer with the aim to be efficient for the identified operating modes from “low data rate, low power consumption, long range” to “high data rate”. Performance of waveform candidates is assessed in terms of PER, range and also power consumption in order to obtain the best compromise between operating modes. A new flexible waveform based on frequency domain processing is finally proposed to address the large scale of requirements of new LPWA applications. © 2018, ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.