Industry Canada new 5GHz band regulations

Last year, I have written a blog post entitled "5GHz Band Channel Availability in Canada" explaining what 5GHz channels were available in Canada. This was based on a document from Industry Canada named "RSS-210 - Licence-exempt Radio Apparatus (All Frequency Bands): Category I Equipment" Annex 9 - Local Area Network Devices. If you go visit the Industry Canada's website today, you will see that this annex is no longer applicable and has been replaced in May 2015:

So, in this article, it is time for me to update the information provided in my previous blog post and keep things up to date!

The new document covers the new radio standards specifications for the Wi-Fi equipment operating in all the 5GHz frequency bands:
 - UNII1 (5150-5250MHz)
 - UNII2 (5250-5350MHz)
 - UNII2-Extended (5470-5600MHz and 5650-5725MHz)
 - UNII3 (5725-5850MHz)

Here are the updated radio standards specifications:

As you can see, nothing much changed from the last standards. Basically, the channel availability and the output powers were kept unchanged. 
So what has changed? According to me, two important regulations were added. They are detailed below.

TCP Implementation (UNII2 & UNII2-Extended)

Transmitter Power Control or TPC is a feature that enables a Wi-Fi device to dynamically switch between several transmission power levels in the transmission process. This is mainly used to reduce interference if another device is transmitting on the same frequency.
For Wi-Fi devices operating the UNII2 and UNII2-Extended, Industry Canada states that "devices with a maximum e.i.r.p. greater than 500mW shall implement TPC in order to have the capability to operate at least 6dB below the maximum permitted e.i.r.p. of 1W". This information can be important to keep in mind while designing a WLAN.

Higher e.i.r.p. allowed for Point-to-Point devices (UNII3 & ISM)

Concerning the UNII3 & ISM bands (5725-5850MHz), the conducted output power shall not exceed 1W. If directional antennas are used with a gain greater than 6dBi, the maximum conducted output power shall be reduced  by the amount in dB that the directional gain of the antenna exceeds 6dBi. So basically the maximum e.i.r.p. will never exceed 4W and if the gain of the antenna is greater than 6dBi, the output power will be adjusted accordingly.
However the standards stats that "fixed point-to-point devices operating in this band may employ transmitting antennas with directional gain greater than 6dBi without any corresponding reduction in transmitter conducted power".

Here is an example to explain this regulation:

So, on the left part of the drawing, we are using an antenna gain of 9dBi; which is 3dBi greater than 6dBi. If we were to use the maximum conducted power possible (i.e. 1W), the total e.i.r.p. would be: 30dBm (1W) + 9dBi = 39dBm (8W). 8W is over the maximum allowed (4W). So in order to stay under the regulations, we need to lower the conducted power by the number of the antenna gain dB greater than 6 (in our case 9-6 = 3dB). So the new conducted power would be: 30dBm (1W) - 3dB = 27dBm (500mW).
If we use a conducted power of 500mW we will have the following e.i.r.p.: 27dBm (500mW) + 9dBi = 36dBm (4W). This complies with the regulations!

On the right part of the drawing, we are setting up a point-to-point bridge link with an antenna gain of 13dBi; which is also greater than 6dBi. Even though the e.i.r.p. exceed 4W, we are still allowed to use a maximum conducted power of 1W.

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If you are installing Wi-Fi on the 5GHz band in Canada, I would invite you to read the full official document from Industry Canada named "RSS-247 Digital Transmission Systems (DTSs), Frequency Hopping Systems (FHSs) and Licence-Exempt Local Area Network (LE-LAN) Devices". The section #6 details the regulations concerning Wi-Fi devices.

I hope this information will be useful for some of you.

Written by François Vergès