CTS 274: 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 *