Wednesday, April 3, 2013

IEEE Std 802.11ac Deployment in Japan

IEEE Std 802.11ac Deployment in Japan

Japan Marketers Offer IEEE Std 802.11ac-ready Gears

I constantly monitored how the Japanese government might respond new IEEE Std 802.11ac-draft technology (“802.11ac"). Unsurprisingly, Japan Ministry of Internal Affair and Communications (MIC) formally announced their endorsement of ac-ready products on March 27, 2013.  Day after MIC’s announcement, three retail players immediately posted their ac-ready products such as
  • Buffalo, Airstation Series WZR-1750DHP
  • NEC-AT, Aterm Series WG1800HP
  • IO-Data, WN-AC1600DGR 
Beyond retail players, we also anticipated enterprise Wi-Fi equipment providers will supply their ac-ready gears into Japanese market in the late summer. 

Allowed 802.11ac Channels in Japan

The inserted table illustrates MIC’s plan for new 802.11ac channel in Japan. 

The second and third rows show current 5.x GHz 802.11n channels allowed in Japan (802.11a/n). The channels are available in either 20 MHz (HT20) or 40 MHz (HT40) crossing W52 (UNII-1), W53 (UNII-2), and W56 (UNII-2e) bands. In the second row, each of the blue segments represents 20 MHz. A newer channel is introduced after each jump. Same concept is applies to 40 MHz channel (HT40) in the third row.  
The forth to ninth row shows newly added 5.x GHz 802.11ac channels allowed in Japan. Those new 802.11ac channel are available in 80 MHz (VHT80), 160 MHz (contiguous VHT80+80), or 80+80 MHz (non-contiguous VHT80+80), crossing W52, W53 and W56 bands. 

Chart 1. Japan 802.11ac Channel Mapping

Some niche equipment providers adopt specific approaches to prevent two radios transmitting packets at the same time (such as Meru Networks' Virtual Cell). Thus, use can then enjoy widest 160-MHz channel with less interference issue. Except of the extreme case as Meru's approach, a non-contiguous 80+80 MHz channels (VHT 80+80) becomes very helpful. The channel settings is occupying 160-MHz channel, but transmitting in two separated 80-MHz segments instead. 

In Japan, government only allows four combinations for 80+80 MHz comparing to US which has a total of thirteen different combinations.

Dynamic Frequency Selection (DFS) in Japan

In the previous blog, we discussed the disadvantages for fewer available 802.11ac channels. To increase non-overlapping channels and create nature RF barrier, equipment providers will force to use channels within W53 & W56, while MIC requires Dynamic Frequency Selection (DFS) approvals. DFS mechanism is used to detect either military or weather radar signals, and force an access point to switch non-interfered channels.

In MIC DFS approval criteria, there are different sets of requirements for Wi-Fi access point with either antenna terminals (attached antenna externally) or with integral antennas. Equipment vendors also need to complete either two (2) radar signal detection in W53 band, or eight (8) radar signal detection in W56 bands. Or perhaps complete both. Your choice.
The following URL link is MIC DFS testing specification in 5 GHz. MIC provides clear guideline how such tests shall be performed. 

802.11ac Deployment Environment in Japan

Another tricky part is whether users can apply 802.11ac in the outdoor environment in Japan. The answer is positive. The following chart is showing the allowed deployment in either indoor or outdoor environments
Chart 2. Deployment Environment & 802.11ac Channel Matrix

The opinions and assertions expressed herein are solely those of author & are not constructed as official or as view of MIC Japan.

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