WiFi/WLAN

By default almost all WiFi access points transmit at full power (100mW on 2.4GHz). This gives maximum coverage and users see a good signal (“full bars”). However, there are good reasons to turn down the transmit power to a fraction of the maximum.

Most Wi-Fi systems have some kind of automatic setting for selecting the channel. Systems with a central controller have advanced RRM or Radio Resource Management solutions. The promise is to optimize channel selection, transmit power levels and other settings. Can you trust this automation?

I am the first Certified Wireless Network Expert in Finland. I was certified in February 2019. This article is about CWNE and how I got into this.

In Wi-Fi world you are bound to come across decibels. Yet they confuse many of us. Sound is measured in decibels, but Wi-Fi? And what about those negative numbers? How can a signal be negative?

Sounds like a simple question. However, no matter how much you search, you can’t seem to find an answer. The reason is simple, it depends…

This may sound silly, but yes, you can really improve your cell phone battery life with a small change in the access point. The change has no drawbacks and is easy to make. It has even more impact in your home Wi-Fi where your cell phone spends most of its time in sleep mode.

In most Wi-Fi systems you can disable the slowest transfer rates. This is typically done to improve efficiency since the transfers at slower rates eat up limited air time. This can backfire however with unexpected results.

Don’t use the same WiFi channel as the closest weather radar!

The regulatory bodies are now strict about DFS requirements on WiFi access points. This applies to both new devices and updates to old ones. A simple firmware update may cause a lengthy delay before the network is operable.

Quite often the most expensive part of a Wi-Fi deployment is the cabling. Cabling? Wasn’t this supposed to be wireless? Can’t we use these APs wirelessly? At least there are lots of products claiming to do so.

Roaming or switching from one access point to the next is a common source of confusion. Technically Wi-Fi roaming is the opposite of the cellular network. Wi-Fi access points are passive and the client devices choose which access point they want to use and when to switch, if they switch. What are the consequences?

The original Wi-Fi (also known as 802.11) used the 2.4GHz band. It is still the more popular band since virtually all devices support it. That makes it more crowded and it is also more prone to interference than the alternative 5GHz band.

On 5GHz WiFi there are more channels and less interference, both are important for fast wireless communications. The bandwidth can even be increased multifold by combining channels.

It is fairly easy to create a heat map of a WiFi network that shows the signal level across the coverage area. What’s the use, what’s the benefit of surveying and is it worth paying for?