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Designing Wi-Fi for Lecture Halls

Designing Wi-Fi for university lecture halls can be challenging. From dealing with BYOD, high density, aesthetics, and more.. How do you tackle it? What should you consider? And what will the results be?

There are many challenges to consider such as high density, high capacity, BYOD, aesthetics, application usage, and more. All must be considered in the design. In our experience, it is best to communicate with multiple people – building manager, professors, etc.

If you’re looking for a partner to work with on your next Wi-Fi project. Reach out to us. Rowell & François are available for engagements from our respective companies: Packet6 or SemFio Networks.

In this episode we discuss a specific scenario where over 1000 devices associated to Wi-Fi and brought it to it’s knees. This lecture hall had a seat capacity of 498 people.

When it comes to Wi-Fi design in lecture halls, we use Ekahau for the design so we can determine capacity. After determining installation possibilities, we identify the antenna we want to use. Our preference is to use directional antennas to shape signal over areas of the lecture hall. We avoid omnidirectional antennas because of the propagation pattern. Even in a lecture hall, the signal from directional antennas will still spread over the room.

We take the seat capacity to determine how many devices we can expect to see in the lecture hall. We will want to multiply that number by the number of devices each person typically carries. For example, if the room capacity is 500 and everyone has 2 devices, then we may expect 1000 total devices.

But not everyone uses both devices simultaneously. That’s when we determine a “take rate”. How many devices we believe will be using the Wi-Fi network. Maybe out of the 1000 devices the take rate is 80%? Around 800 devices. You have to determine what that number is.

Additionally, you must consider any applications that will be used. We add all these details into Ekahau for capacity planning to find out if we will exceed capacity or not.

Listen to the episode to hear the full conversation!

Here are a few photos and screenshots for context

Here’s a look at one of the access points before optimizations were made. The screenshots were taken from Cisco Prime.

Here is the result after making a channel change and optimizing transmit power.

Additional Resources
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Rowell, CWNE #210, is a network engineer in Higher-Ed. He enjoys working with wireless networking technologies and loves to share and engage with the community. You can connect with him on Twitter, LinkedIn, and Facebook.

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  • Thanks for the link!

    As an engineering community, I think it’s probably good that we distinguish Large Public Venues (stadiums, arenas) from auditoriums and lecture halls – I think the key engineering distinction is that the latter generally doesn’t lend itself to spectrum reuse owing to the small size of the space.

    Customers often have incredibly unrealistic expectations about what is possible in such a space. At the end of the day, your available performance per client device will depend almost entirely on how many devices are in the space.

    6 GHz is going to be a huge game changer. When I wrote the blog post, the Aruba AP-635 hadn’t been announced yet,. so it was a bit tricky to try and design for an as-yet unreleased AP, for a space that was still quite some time out.

  • Thanks for a go podcast.

    I Design for lecture hall at University of Aarhus Denmark. And we use 802.11v, k and r. And band steering I think it works for os. I have place the AP on the wall a 3,5 meter high. I have talk to Jim Florwick (Cisco) about AP Groups and RF Planner. The things is only 35 AP Seen kan be calculatet. And it is not the 35 stronges just det 35 firste. So it is at god ideer to divede APs in to smaller AP groups. That makes the best Cisco RRM calulation. What is you mandatory datarate and min/max TPC level 7 to 20 ? Our AP tent to turn down power if the see to many APs. wen you have more than 200 Client is it on the dual 5G. Isn’t 200 the limit for one radio? If it works with 200 Client then you don an amazing RF job. 😉

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