Wi-Fi 5 802.11ac Wave 2 – What is it and do you need it?

Wi-Fi 5 Logo

Apologies for the hiatus on posting. I recently started a new position as a Regional Product Manager for a networking hardware manufacturer so I’ve been acclimating to a new company and culture. Now that the dust has settled, I will try to put out more content in relation to the industry I’m working in while trying to finish some AI side projects. In any case, on with the show!

Introduction to Wi-Fi 5

802.11ac Wave 2 MU-MIMO is the latest and greatest version of Wi-Fi 5 from the IEEE Standards Association. The question is, do you need it? Well it depends. But before we go into that let’s talk about the major differences between the last generation and this current generation.

Wi-Fi Speeds Comparison Chart
Wi-Fi Speeds Comparison Chart

Even though Wave 2 can support up to 8 antennas theoretically, you will only see that type of configuration in the high end market. It will be extremely expensive and directed for high density applications where cost is no issue and you need to maximize performance on each AP installed.

How many MHz does it take to setup an Access Point?

5GHz Channel Map
5GHz Channel Map

The 5GHz band has 24 non-overlapping channels when you’re using a 20MHz channel width. That’s reduced to 12 non-overlapping channels at 40MHz, then to 6 at 80MHz and then to just 2 at 160MHz. The smaller the channel width, the more flexibility you have for avoiding overcrowded channels. The larger the channel width though, the faster your aggregate speed will be. For 802.11ac Wave 2, if you’re deploying 2 APs or less and you can get away with using 160MHz then go for it! But typically, 80MHz will be the best option giving you 6 channels to play with to avoid interference from other APs.

What is MIMO?

Single Lane
Single Lane
Multiple Lanes
Multiple Lanes

MIMO or Multiple In Multiple Out was first introduced as an optional feature in 802.11n. Imagine you have a hose and you need to fill a one gallon bucket. Normally you would shoot a single stream into the bucket until it’s full. Now imagine you had four hoses and four buckets, but you still only needed to fill a total of one gallon. Because of the efficiency, it would take a shorter amount of time to fill that same amount of water. MIMO is exactly that, it does some wireless magic to combine data from multiple antennas (streams) to make data move faster.

Single User versus Multiple User

Single User vs. Multiple User
Single User vs. Multiple User

Wi-Fi in general has a mechanism where it can talk to only one client at a time. In the background, clients are lining up and taking turns transmitting/receiving data. It’s just happening so fast that you don’t necessarily feel it. Standard MIMO (typically referred to as SU-MIMO or Single User) increases that efficiency by allowing multiple data paths to that single client. MU-MIMO (Multi-User), which is supported in 802.11ac Wave 2, expands that even further by enabling the AP to talk to multiple clients at the same time, instead of just 1. Keep in mind this is only on the downlink traffic to the user and not on the uplink to the AP. Even so, this generally increases the overall efficiency of the Wi-Fi network because let’s face it, we all have multiple devices on our networks.

What’s the verdict, do I need it?

If you’re coming from 802.11n then yes, 802.11ac Wave 2 is a worthwhile upgrade. You’ll get a boost in speed up to 5x and you’ll get more efficiency from the Wi-Fi network when dealing with a larger number of concurrent clients.

If you already have 802.11ac Wave 1, I would wait. It’s not a huge performance jump from Wave 1 to Wave 2 so I wouldn’t upgrade unless your business requirements absolutely need it (i.e. expanding capacity for higher density scenarios).

Wi-Fi 6 802.11ax is also just around the corner which adds MU-MIMO for uplink as well as downlink, higher modulation with QAM-1024 and WPA3. If you have the budget and don’t mind being an early adopter, you can go for the latest and greatest. Otherwise you can wait for prices to fall a bit more as the technology matures.

I hope this article helps in your Wi-Fi networking journey. If you still need help, I recommend reaching out to a local Managed Services Provider or a Value Added Reseller that offers additional services like Site Survey Planning, AP Installation and Monitoring.

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