A Survey on Evolved LoRa-Based Communication Technologies for Emerging Internet of Things Applications

Abstract

The concept of Internet of Things (IoT) greatly extends the coverage area that human being is able to perceive, access, and even control. By connecting various “Things” to the Internet, the IoT makes it possible to measure and manage the physical world as needed. As one of the most widely adopted Low Power Wide Area network technologies, the Long-Range-Radio (LoRa) has the features of long range, low power, and robustness, and thus plays an important role in building IoT applications where IoT objects are connected to the internet at affordable costs. Since the development of LoRa, many IoT applications have adopted LoRa and achieved success in the market. Currently, IoT technologies keep evolving towards different fields, giving rise to multifarious IoT applications including industrial IoT, smart city IoT, healthcare IoT, and direct-to-satellite IoT. In the meantime, LoRa also keeps developing and finding its position in various IoT applications either as a main or complementary player. The objective of this survey is to (1) provide a fundamental understanding of the LoRa technology; (2) explore research activities studying LoRa based communication systems for new IoT applications; and (3) demonstrate how the LoRa technology works together with other technologies to deliver better IoT services to end users. Due to its requirement for massive and large-scale sensor deployment, it is common for smart city IoT to adopt the LoRa technique. Although LoRa has long range communication capability, it has relatively low data rate which affects overall system performance about network capacity, deployment density and power consumption. In [54], authors studied the radio coverage issue of LoRa networks and concluded that (1) it is possible to achieve an 100% packet delivery ratio up to 4 km range and 99% for over 4.8 km under certain conditions. In this case, a LoRaWAN gateway is installed at the height of 30 m above ground, and (2) an empirical path loss model is proposed to determine LoRa link budget at frequency bands of 868 MHz and 433 MHz.