| LP-WAN is required in environments where power supply is difficult
| Representative examples include LoRa, Sigfox, NB-IoT, and Wi-SUN.
| Wi-SUN in use in Korea Electric Power Corporation AMI construction project

Since 2013, Korea Electric Power Corporation has been carrying out a project to build Advanced Metering Infrastructure (AMI) for approximately 23 million households nationwide.

This project, which is underway to install approximately 2 million households per year and aims to be completed by 2022, was made possible because IoT technology, which connects all things to the Internet, has matured.

According to Park Bae-young, Senior Researcher at I&C Technology, on Wi-SUN protocol and utilization trends, various wireless communication technologies are being announced as the IoT market expands.

For devices with relatively high data transmission rates, such as Wi-Fi or LTE, it is mainly used in IoT gateways that require continuous power supply. On the other hand, in environments where power supply is difficult or battery replacement is difficult, wireless communication technology with wide communication coverage and low power characteristics is required.

Representative LP-WAN (Low Power-Wide Area Network) technologies with these characteristics include LoRa, Sigfox, NB-IoT, and Wi-SUN.

Among them, Wi-SUN is a physical layer technology standardized as 802.15.4g, and was limited to a wireless PAN area with narrow coverage. However, the output of the 900MHz (917~923.5MHz) band was increased from the existing 10mW to a maximum of 200mW, and as the coverage expanded to the WAN area, it became possible to utilize it in various fields.

Wi-SUN technology is being used along with power line communication (ISO/IEC12139-1) technology in the AMI construction project of Korea Electric Power Corporation mentioned above.


Wi-SUN Utilization Trends
The Wi-SUN Alliance (Wireless Smart Utility Network Alliance) was founded in 2012 when the IEEE802.15.4-2011 standard was completed. The Alliance is engaged in the global certification and deployment of Wi-SUN, which has interoperability based on the IEEE 802.15.4g standard, utilizing open global standards.

ECHONET (Energy Conservation and HOmecare NETwork) Lite is a data exchange profile for smart electric power meters in Japan. It applies IEEE802.15.4g/e as a PHY, MAC-based protocol, and defines the communication technology for smart electric power meters in the American region as a FAN (Field Area Network) profile, and has completed the development of technical specifications and test standards.

Wi-SUN modems must be able to communicate at a distance of at least 100 meters based on line of sight and must support 200mW output as specified in Article 30 of the Radio Equipment Rules.

Currently, Wi-SUN is mainly constructed and operated in areas where power lines are buried underground and normal power line communication is difficult, or in rural areas.

In addition, the UGS Convergence Research Group under ETRI is using Wi-SUN FSK PHY-based IoT-based wireless communication network to monitor the status of underground facilities and underground space conditions in real time and detect and predict abnormal signs in advance.We have completed the development of a wireless communication chip technology combined with LECIM MAC.


Wide Wi-SUN Operation Area
The IEEE802.15.4 WPAN standard technology has been mainly used for applications that utilize low-speed, low-power devices in narrow coverage areas, such as home networking and wearable devices.

IEEE802.15.4 SUN PHY technology can be used in various IoT fields by expanding the HAN (Home Area Network) area to the NAN (Neighbor Area Network) area.

By using an unlicensed band, there is no need to pay separate frequency usage fees, it is advantageous for IPv6 application, and it supports frame lengths of up to 2,047 bytes in the physical layer, which sets it apart from LPWANs such as LoRa and SigFox.

The SUN PHY layer includes the FSK method, which is simple and economical to implement in transmitters and receivers, the OFDM method, which enables improved reliability and high-speed transmission, and the OQPSK method, which enables data transmission at various transmission rates in the form of DSSS/MDSSS.

There are HAN and FAN according to the latest Wi-SUN standard.

Wi-SUN HAN is a communication standard between next-generation smart meters and home energy management systems (HEMS). There is also an Enhanced HAN that has functions to cope with devices such as relay functions and power-saving modes for energy power such as battery-operated devices.

Wi-SUN FAN is for smart metering, smart grid and infrastructure management that realizes wiring automation, intelligent transportation systems, smart lighting, etc. It mainly transmits data obtained from sensors, meters, and monitors installed outdoors to the cloud, and sensors, meters, and monitors can be controlled from the cloud as needed.

Wi-SUN technology is expected to compete and coexist with LPWAN technologies that have low-power characteristics and enable long-distance communication, such as LoRa, Sigfox, and NB-IoT, in a wider range of areas, such as smart grids, smart factories, and smart cities.