IEEE 802.11j


IEEE 802.11j is a wireless networking standard, also known as “Japan’s Amendment,” adopted in 2004 to accommodate the Japanese regulatory requirements for wireless local area networks (WLANs). It extends the IEEE 802.11 WLAN standards to operate in the 4.9-5 GHz frequency range, which was previously unavailable in Japan. This amendment allows for improved communication and reduced interference for wireless devices in the Japanese market.


The phonetics of the keyword “IEEE 802.11j” can be spoken as: “I – triple E, eight zero two point one one jay”.

Key Takeaways

  1. IEEE 802.11j is a wireless networking standard that was developed to address the regulatory requirements for indoor/outdoor WLAN systems in Japan, improving compatibility and coexistence with existing systems.
  2. It introduces enhancements to the 802.11 standard, such as support for additional frequency bands (4.9 GHz and 5 GHz) and dynamic frequency selection (DFS) to avoid interference with radar systems and other devices using the same frequency range.
  3. By adapting to Japanese regulations, the 802.11j amendment helps manufacturers design wireless devices that can operate seamlessly in Japan’s wireless environment, promoting global WLAN interoperability and allowing users to benefit from wireless connectivity both indoors and outdoors.


The technology term IEEE 802.11j is important because it represents an amendment to the widely used IEEE 802.11 standard, specifically targeting the Japanese market.

This amendment, also known as Wi-Fi J, focuses on improving the wireless local area networking (WLAN) technology by introducing enhancements for indoor and outdoor operations in the 4.9 GHz to 5 GHz frequency bands.

This allows for better performance, broader wireless connectivity, and more efficient utilization of available frequency spectrum within Japan’s unique regulatory requirements.

The adoption of IEEE 802.11j has played a crucial role in expanding the global interoperability and promoting the integration of advanced wireless technology within the Japanese telecommunication infrastructure.


IEEE 802.11j is a wireless networking standard developed to address the specific requirements and regulations of the Japanese market, thus facilitating the global harmonization of wireless communication systems. The primary purpose of IEEE 802.11j is to enable the operation of Wireless Local Area Networks (WLANs) in the 4.9 GHz and 5 GHz frequency bands, which are designated for indoor and outdoor wireless communication in Japan.

By utilizing these frequency bands, the standard provides Japanese users access to broader wireless communication capabilities, increased data transmission rates, and improved network performance. Notably, IEEE 802.11j is an amendment to the IEEE 802.11 standard which encompasses a family of specifications for WLAN technology.

To achieve this harmonization and facilitate efficient wireless communication, IEEE 802.11j incorporates features like Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC). DFS ensures the protection of radar systems that share the same frequency bands, by automatically detecting the presence of nearby radar systems and switching to an available frequency. TPC, on the other hand, allows the regulation of transmit power levels to reduce the potential for interference with other communication systems and improve overall wireless network performance.

These features make 802.11j invaluable for applications such as broadband wireless access, public safety, telemedicine, and the Internet of Things (IoT) in Japan.

Examples of IEEE 802.11j

IEEE11j is an amendment to the IEEE11 standard for wireless local area networks (WLAN), specifically designed for Japanese regulatory requirements and efficient use of radio frequencies. Here are three real-world examples of its implementation:

Public Wi-Fi Access Points: Public spaces such as airports, train stations, coffee shops, and shopping malls in Japan may use the IEEE11j technology to provide reliable and efficient Wi-Fi access to their visitors. This ensures the public Wi-Fi hotspots follow Japanese regulations while utilizing the available frequency bands effectively.Corporate or University Campuses: Large educational institutions and corporate offices in Japan may implement the IEEE

11j standard for their campus-wide WLAN networks, ensuring seamless wireless connectivity for all their devices. This helps keep the connectivity secure and enables better management of wireless networks in compliance with local regulations.Home Networks: In Japan, individuals may use Wi-Fi routers that work on the11j standard for their home networks. Utilizing the

9 GHz and 5 GHz frequency bands, this technology provides better radio frequency management, ensuring minimal interference from other electronic devices or neighboring Wi-Fi networks.

FAQ: IEEE 802.11j

Q1: What is IEEE 802.11j?

A1: IEEE 802.11j is an amendment to the IEEE 802.11 Wi-Fi standard which defines enhancements and clarifications related to radio frequency spectrum usage in Japan. It helps expand the use of Wi-Fi technology in Japan and provides better compatibility with country-specific regulations.

Q2: How does IEEE 802.11j differ from other Wi-Fi standards?

A2: IEEE 802.11j focuses on Japan-specific spectrum regulations and introduces provisions for spectrum sharing, channel selection, power limits, and other operational aspects in order to adapt to the unique requirements of Japan’s radio frequency environment.

Q3: What are the benefits of IEEE 802.11j?

A3: IEEE 802.11j enables Wi-Fi devices to operate more effectively in Japan by complying with local spectrum regulations. This improves performance and reduces interference with other wireless communication systems within Japan.

Q4: Are there any drawbacks to IEEE 802.11j?

A4: The main drawback of IEEE 802.11j is its limited geographical relevance, as it specifically targets the Japanese market. However, devices implementing IEEE 802.11j can also implement other Wi-Fi standards, so this is not a significant issue for devices supporting multiple standards.

Q5: How to check if my device supports IEEE 802.11j?

A5: You can find information about the supported Wi-Fi standards on the device’s technical specifications, user manual, or product web page. It may also be shown as “11j” in more comprehensive Wi-Fi standard designations, such as 802.11a/b/g/j/n/ac.

Related Technology Terms

  • Radio Frequency Band Extension
  • Japan’s Wireless LAN
  • 4.9 GHz to 5.0 GHz Frequency Range
  • Wireless Mesh Networking
  • TELEC Regulations

Sources for More Information


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