Blog
Field notes on complex Wi-Fi.
Wi-Fi Data Rates Are Not Negotiated
PHY data rates are not negociated between the client and the access point. For most transmissions, the device sending the frame selects a rate based on what it believes the RF link can support at that moment.
François Vergès, CWNE #1805 min read
117 posts
Most recent first
When the Wi-Fi Design Is Right but the AP Installation Is Wrong
A predictive Wi-Fi design can be completely correct and still fail after installation.
François Vergès, CWNE #1803 min read
What RTS/CTS Does Today
RTS/CTS is often taught as a solution to the hidden-node problem. That is still true, but it is only one part of what these control frames do in a modern Wi-Fi network.
François Vergès, CWNE #1806 min read
PoE for Wi-Fi Explained
PoE is one of those topics everyone assumes is solved. You plug the access point in, it powers up, the survey looks fine, and the project moves on. Then someone measures two spatial streams on a 4x4 access point, or notices that the 6 GHz radio never came up, and the investigation ends at the switch.
François Vergès, CWNE #1806 min read
Why More Transmit Power Does Not Mean Better Wi-Fi
I get this question in almost every deployment: why not just run every access point at maximum transmit power?
François Vergès, CWNE #1804 min read
MIMO Gain: The Part We Forget When We Set Transmit Power
Last week I wrote about the difference between a 2x2:2 and a 4x4:4 access point. The discussion that followed was more interesting than the article itself, as often!
François Vergès, CWNE #1807 min read
What is the difference between a 2x2:2 AP and a 4x4:4 AP?
I get this question a lot in the field.
François Vergès, CWNE #1805 min read
5150–5250 MHz: new outdoor & licensing rules
The 5150–5250 MHz band contains channels 36, 40, 44 and 48. It is one of the most used bands in Wi-Fi networks. With the new version of RSS-247 (Issue 4, July 2025), the rules around outdoor use and high power have been clarified by ISED.
François Vergès, CWNE #1804 min read
5850-5895 MHz is now Wi-Fi spectrum in Canada
The 5850–5895 MHz range was not part of Wi-Fi in Canada until recently. It was reserved for Intelligent Transportation Systems (ITS) and connected vehicle applications, and standard Wi-Fi devices had no business there. With RSS-247 Issue 4 (July 2025), ISED formally opened this 45 MHz of spectrum for Wi-Fi use.
François Vergès, CWNE #1803 min read
New 5 GHz Wi-Fi Regulations in Canada: What It Means for Wi-Fi Engineers
RSS-247 Issue 4 (July 2025) brings real changes to how Wi-Fi can be deployed in Canada. This post summarizes what you need to do, or stop doing, as a result. It is the closing post of this series and is written as a practical reference for engineers who design, deploy, or audit Wi-Fi networks in Canada.
François Vergès, CWNE #1804 min read
New DFS channels unlocked: 120, 124, 128
For years, channels 120, 124 and 128 were off-limits in Canada. They sit in the 5600–5650 MHz range, right where Environment Canada operates weather radar. Any Wi-Fi signal in that range risked interfering with radar systems used for meteorology and aviation safety. As a result, ISED simply blocked them.
François Vergès, CWNE #1803 min read
The Channel 144 & 169 Trap: When Bonded Channels Span Bands
Two channels in the 5 GHz band deserve special attention: channel 144 and channel 169. Both sit at the boundary between two sub-bands, meaning part of their spectrum falls under one set of rules and part under another. The principle that applies in both cases is simple: the most restrictive rule wins.
François Vergès, CWNE #1804 min read
Updated 5 GHz Wi-Fi Regulations in Canada (RSS-247, July 2025)
In July 2025, ISED published a new version of RSS-247. This document defines how Wi-Fi devices can operate in Canada. The changes are important and they affect how we design, deploy and operate Wi-Fi networks in the 5 GHz band.
François Vergès, CWNE #1803 min read