Think about it this way: if someone told you to go build a house, would you start by loading up on 2x4s? No. You would first ask a lot of questions — how big of a house are we building, are there any lot restrictions, what style of house is preferred, etc. In building a Wi-Fi network, you also want to ask questions first and document a full list of requirements. This will save you from missteps and headaches down the line.
Requirements can be broken down into two main categories: 1) business requirements, and 2) RF requirements.
Identifying business requirements for how a network will be used makes it easy to translate business needs into the specific inputs for your design software.
- What are the different types of clients that will need to connect to your network?
- How many of those clients need concurrent access?
- What is the least capable, most important device for your business?
- What are the expectations of the network beyond “We need good Wi-Fi”?
The answers to these questions will help you translate the business needs into Wi-Fi design requirements for Coverage, Capacity and the Least Capable, Most Important Device.
One of the most fundamental Wi-Fi design considerations is coverage planning. Primary coverage is all about area and optimizing the distance around your wireless transmitters to ensure there is sufficient signal strength for Wi-Fi-enabled devices to connect. Layering in effective secondary coverage ensures you have the right amount of overlap to ease device roaming and provide redundancy for your business-critical Wi-Fi needs.
Poor design can result in either too many APs (which can increase your overall hardware and installation costs and can cause CoChannel Contention / Interference) or too few APs (which will not provide the necessary coverage requirements and result in coverage gaps). Wi-Fi design tools like Ekahau Pro provide a clear idea of coverage and signal strength allowing you to modify AP locations and configurations on the fly and visualize exactly how those modifications can impact coverage in the environment.
Wi-Fi design tools like Ekahau Pro provide a clear idea of coverage and signal strength allowing you to modify AP locations and configurations on the fly and visualize exactly how those modifications can impact coverage in the environment.
Capacity planning goes a step beyond coverage and takes into account the different types and number of devices and applications that will connect to the network. Wireless network capacity is a measurement of the amount of traffic supported concurrently on a wireless network based on the bandwidth being consumed.
Poorly planned capacity requirements can be devastating for users. Slow speeds and intermittent connectivity drops can be the result of not identifying proper requirements for usage. It can also be a symptom of growing pains as more users are added and new devices become introduced over time without adjusting for the increased capacity demand.
Capacity needs can also vary for different areas of a site, depending on your use case. Let’s take hotels, for example. The guest rooms, lobby, outdoor pool, and conference center may each have unique capacity requirements — and Wi-Fi design software like Ekahau Pro makes it easy to design different capacity areas for the unique needs of each area.
Capacity planning is a delicate balance between adding enough APs and minimizing channel interference.
3. Designing for the Least Capable, Most Important Device
While reviewing the various types of devices that will be connecting to your network, it’s key to identify which devices are the most critical, and which of those devices is the least technologically advanced — these are known as the Least Capable, Most Important devices (LCMID).
Believe it or not, designing Wi-Fi for the latest devices to hit the market is usually quite straightforward, it’s identifying the one device that if it were to suddenly go offline would grind business to a halt — that’s the tricky part.
Here are some of the usual suspects for your network’s LCMID:
- A 10-year-old warehouse scanner used 12 hours per day to scan barcodes for inventory management
- The point-of-sale registers used to facilitate retail transactions
- Your CEO’s laptop (simply refuses to get a new one)
For these types of devices, you need to research the manufacturer’s posted specifications to ensure they will perform reliably on the network. Your predictive design is only as good as the inputs you define, and determining your LCMID is critical for the design of your Wi‑Fi network.
The physical environment plays a big role in how a network performs. Turn to the site floor plan and walk the site to gather information to help you identify the radio frequency (RF) behavior in your environment.
How high are ceilings in the coverage area? Is there sufficient access to mount access points? What are the walls made of? How noisy are the neighboring networks? The answers to these questions will help you translate environmental factors into RF requirements for Obstacles in the Physical Environment, Wall Material Attenuation, and RF Spectrum Activity.
4. Obstacles in the Physical Environmental and Where to Install APs
High ceilings, exposed metal ductwork, inventory fluctuations, living atriums, and modern art installations may not be documented in a simple building floor plan, but obstacles like these should be taken into account with your Wi-Fi requirements.
Floor plans only tell part of a story. Whenever possible, you should walk the site and gather information to help you identify the RF behavior in your environment.
Doing a pre-design floor walk survey will help you get the correct information to plug into your predictive design software. Make sure you document any potential concerns for RF: exposed ceilings with ductwork, columns, signage, large pieces of furniture, areas off limits, etc. These walk-throughs may also illuminate previously unconsidered limitations to wireless infrastructure placement — where you are unable to place APs, or where you are unable to run cables.
5. Wall Material and Attenuation Testing
The size, shape, and types of wall materials in your network’s environment all need to be accounted for when designing for WiFi. That’s because the environment’s physical characteristics impact RF coverage.
Every wall attenuates Wi-Fi signals. That means the RF strength gets partially or fully absorbed by the material. Drywall typically reduces the signal strength by 3dB. Large concrete pillars can stop a Wi-Fi signal in its tracks! Understanding the different materials in your environment and their attenuation values is key for designing a great wireless network.
Using a world-class diagnostic and measurement device like the Ekahau Sidekick will give you the exact RF measurements needed for your design. By validating wall types, you’ll either confirm your predictive design is correct or you’ll have a chance to adjust based on the empirical data you’ve collected.
6. RF Spectrum Activity
Your Wi-Fi network lives in a world of electromagnetic spectrum. Understanding the spectrum activity around you leads you toward an effective channel plan for your project. Here are some things to consider:
- Channel Contention: Access points, whether on your neighbor’s network or your own, need to be spaced properly with proper channel plans or risk suffering channel contention.
- Non-Wi-Fi Interference: Things like microwaves, Bluetooth devices, spy cameras, and motion sensors can all interfere with your Wi-Fi network’s ability to send and receive data. Issues caused by Wi-Fi interference can range from an intermittent connectivity loss to reduced data transfer and network speeds to a reduction in signal strength.
- DFS Checks and Radar Activity: Depending on the frequencies being used, radar equipment may interfere with Wi-Fi network data transmission and vice-versa. Radar can impact the performance of your Wi-Fi network by limiting the amount of 5 GHz channels you can use, or it can cause a decline in performance if your APs are constantly changing channels to avoid DFS events.
- Channel Widths: The wider the channel, the higher the potential throughput. Depending on the current RF environment and density of Wi-Fi radios, you’ll be able to determine the preferred channel width for your project. Always use the widest channel width you can without causing excessive channel contention issues.
Translating Requirements into a Wireless Network Design
A great Wi-Fi network starts with a great design, and a great design starts with accurate Wi-Fi requirements. By asking the right questions and identifying the six requirements presented in this guide, you’ll be able to develop a predictive design perfectly tuned to your business needs. Here is a quick breakdown of how the business requirements translate to design software inputs:
- Coverage: APs placed and coverage visualized on a scaled floor plan with accurate walls
- Capacity: Usage and device profiles identified listing applications and client models in use
- Least Capable, Most Important Device: Device profile created for the LCMID
- Obstacles in the Physical Environment: Ceiling heights set & deployment notes cited to account for obstacles
- Wall Material Attenuation: Appropriate wall types used throughout the floor plan including custom created wall types
- RF Spectrum Activity: A channel plan that reduces co-channel interference and optimizes client performance
Now that you have learned the best practices of wireless network design, you are on your way to making better decisions while building your Wi-Fi network.
This article was featured in the Ekahau Blog, Wi-Fi Design Best Practices [2022 Guide], here we visit the importance of defining network requirements when designing a high-performing Wi-Fi network. All too often, networks fail to meet requirements due to an incomplete discovery process.