The Ministry of Internal Affairs and Communications (MIC) of Japan amends WLAN system regulations to support IEEE 802.11ax, revise DFS radar detection, and allow use of channel 144.

Considering the current increased traffic of the mobile communications in Japan, it is necessary for Japan to improve the efficiency of Wireless LAN (WLAN) connections. In order to expand of the WLAN system, Japan will amend the technical regulations of the WLAN system to support IEEE 802.11ax.

This amendment affects wireless LAN (WLAN) systems (2.4/5.2/5.3/5.6GHz band).

Objectives of the Amendment:

1. to allow the WLAN system to support IEEE 802.11ax
2. to allow the WLAN system to use channel 144
3. to revise the Dynamic Frequency Selection (DFS) radar detection mechanism employed in the WLAN system operating in the 5.25-5.35 GHz band

Proposed Changes:

• Occupied Band Width (OBW): 40 MHz WLAN systems operating in 2400MHz to 2483.5MHz should have OBW of 40 MHz.
• Spectrum Mask:
  • OBW is 18MHz to 20MHz: Average powers within the ± 10MHz regions of 20MHz and 40MHz separations from the carrier frequency are respectively 25dB and 40dB less than the average power of the carrier frequency.
  • OBW is 20MHz to 40MHz: Average powers within the ± 20MHz regions of 40MHz and 80MHz separations from the carrier frequency are respectively 25dB and 40dB less than the average power of the carrier frequency.
  • OBW is 40MHz to 80MHz: Average power within the ± 40MHz region of 80MHz separation from the carrier frequency are 25dB less than the average power of the carrier frequency.
• Unwanted Emission Levels (unlicensed 5.2/5.3GHz WLAN system):
  • OBW is 18MHz to 20MHz, for applied frequency region 5250MHz – 5250.2MHz: the allowable unwanted emission level is 10^{1-(8/3)(f-9.75)} mW/MHz.
  • OBW is 18MHz to 20MHz, for applied frequency region 5249.8MHz - 5250MHz: the allowable unwanted emission level is 10^{1-(8/3)(f-9.75)} mW/MHz.
• Unwanted Emission Levels (registered 5.2GHz High-power WLAN system):
  • OBW is 18MHz to 20MHz, for applied frequency region 5250MHz – 5250.2MHz: the allowable unwanted emission level is 10^{1+log(5)-(8/3)(f-9.75)} mW/MHz.

The tentatively proposed date of entry into force of this notice is June or July of 2019