WiFi HaLow for Long-Range and Low-Power Internet of Things: System on Chip Development and Performance Evaluation
Il-Gu Lee, Duk Bai Kim, Jeongki Choi, Hyungu Park, Sok-Kyu Lee, Juphil Cho, Heejung Yu
Abstract
For Internet of Things (IoT) applications in the sub-1 GHz unlicensed band, the IEEE 802.11ah technology, also called WiFi HaLow, has been standardized. To achieve long-range and low-power features of IoT networks, the physical (PHY) and medium access control (MAC) layer functions in the previous WiFi standards are amended in the IEEE 802.11ah standard. In this article, the PHY and MAC technologies in IEEE 802.11ah are investigated, and the technical features are described by comparing it with other IoT systems. Additionally, a system on chip, which integrates a digital baseband, RF transceiver, analog-to-digital converter /digital-to-analog converter, processor, and memory with the external connection interface, is implemented. To verify the feasibility of long-range and low-power WiFi for IoT services, field tests in both indoor and outdoor environments are conducted. The power-save mode operation and power consumption are presented. Through various field tests and measured data, the feasibility of WiFi HaLow is verified as a long-range, high-throughput, and low-power IoT solution.