LPWAN Technologies for IoT Systems: Choice Between Ultra Narrow Band and Spread Spectrum

Low Power Wide Area Network (LPWAN) is imperative for the expansion and development of IoT networks and their connectivity infrastructure. This far-reaching connectivity of low power devices that are placed virtually anywhere is evolving a new things-based business model. This things-based business model has certain requirements such as long range, extended battery life and very low end point cost. LPWAN technologies have successfully addressed these IoT requirements and are receiving wider acceptance in the IoT industry. In most LPWAN technologies, two main alternative communication techniques, Ultra Narrow Band (UNB) and Spread Spectrum (SS) are used at the physical layer. However, the greatest dilemma is the selection of the most suitable technique from UNB and SS for LPWAN. This paper addresses this selection dilemma of UNB and SS by examining some of the most critical factors responsible for the performance of LPWAN technologies such as interference, capacity, link budget and coexistence. Furthermore, it evaluates the most popular UNB-based LPWAN technologies Sigfox and Telensa, and SSbased LPWAN technologies LoRa and RPMA investigating their strengths and limitations for IoT applications.