High Density Wireless Design

Wireless planning can be one of two categories: Capacity or Coverage. Deciding which of the categories your design falls into is as simple as understanding the wireless network's primary function. As we have mentioned in previous articles, you need to understand what business and user applications are being used and the extend the applications and services are being used in the wireless network.


Planning for Wireless Capacity: this is considered the more challenging category because you're planning a wireless deployment for high bandwidth utilization. I refer to this as more challenging because the planning calculations are based on estimates gathered during the survey process that can change at any time. Capacity goes beyond the number of users connecting to the wireless network. It looks into the number of devices each user has, and most importantly, the applications the users will be using. Applications have minimum bandwidth requirements to function correctly, for instance, the bandwidth requirements for ssh and much lower than what smb or ftp requires.


The following chart from the FCC site gives you a general idea of bandwidth application requirements. Although it is not an exact calculation, it provides a pretty good idea of application bandwidth requirements under normal circumstances. The original chart and page are found following this link https://www.fcc.gov/consumers/guides/broadband-speed-guide


Now that you have the application information throughput at hand, you need to determine the number of users connecting to any given access point; this may be easier in fixed environments where a maximum amount of users is already predetermined. Let's say like in classroom or lecture hall. Or it may be more challenging in places where users move around, like a concert or business conference.

For the sake of this example, we're going to use a college campus as an example; let's say that the main applications are General web browsing and email ( 1mpbs), streaming online radio and VoIP (.5 mbps each), and social media (1mbps). That gives us an estimated 3mpbs per user. We have 55 students per lecture hall, so 3mpbs * 55 = 155 mpbs. The 155 mpbs is the required throughput for that specific location.

So far, so go. But it doesn't stop there. The next step is to think about the access points supporting the uses; some AP marketing material tells you how many devices the AP is good for, take it with a grain of salt; that is just a recommendation. It is recommended to have between 25-30 clients per access point; other studies call for 25-30 clients per radio with a max of 50-60 clients per access point. The recommendation is good, although it just that, a suggestion. In our example, one access point can potentially provide adequate WiFi coverage to the 55 students in the lecture hall.

Capacity planning does not end with the bandwidth\user calculation. Until this point, we have done most of the planning work; you still need to take into account the band and channel width of each band. We recommend starting with the 20 MHz channel width so you have can have more channels at your disposal. Even when allocating the proper band and channels, it's very difficult to steer the applications' behavior to ensure our bandwidth estimation stays within the calculations.


Support Wireless Capacity design with Application control. A supporting feature of enterprise-grade wireless solutions is application control. It gives the option of prioritizing, denying, or throttle traffic based on your rules. Also known as Layer 7 firewall, application control allows the administrator to perform many application access functions, including creating applications access rules that can guarantee a minimum amount of bandwidth for certain apps, prioritize traffic, deny traffic, or throttle down the maximum bandwidth it can use at any given time. Application control is an essential part of the wireless deployment, especially wireless capacity planning. It can offer another layer of control to keep our calculations as close as possible to what is delivered.

The network does not end at the access point. Keep in mind that all the wireless capacity planning is part of the network infrastructure; estimating bandwidth utilization, client connections, and access point amount and location is one piece of the puzzle. Access points are going to connect to an edge switch somewhere; depending on the size of the wireless network, you need to do a similar type of calculation at the edge switch, core switch, and the router\firewall. If your clients and access points both support 802.11ax you may need to also look at the cabling infrastructure to ensure it's capable of supporting the new standard for you to take advantage of it truly.


Planning for capacity WiFi network deployments takes time; one needs to pay attention to details and variables to develop a design capable of delivering the desired results. We also need to look at the whole network infrastructure on which the WiFi network relies to make sure no bottlenecks are throttling the connection anywhere. We are WiFi experts who understand wireless, network, and information security technology and bring together and experience and technical expertise to deploy highly effective smart wireless solutions. If you'd like to learn more about our WiFi services and solutions, contact us at info@jdtechsolutions.net | 888-580-4450 | www.jdtechsolutions.net


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