802.11ax – better known as Wi-Fi 6, is the latest Wi-Fi specification standard capable of delivering greater performance and capacity, enhanced security, more range, and increased efficiencies unrivalled by the Wi-Fi generations that came before it. The latest standard is still yet to be ratified, but this hasn’t stopped vendors from releasing hardware that conforms to the specifications outlined in the draft state of the proposal.
If your Wi-Fi infrastructure is due for a refresh, you may have already had, or are currently in discussions with vendors and/or resellers about making the leap toward a Wi-Fi 6 capable network. While there are certainly pros and cons of implementing cutting edge technologies, the most important decision you will make while planning your Wi-Fi refresh is whether you decide to engage a specialist to help you design your new network.
What a bad, or lack of design could mean to your business
The functions of a Wi-Fi network and the services it supports vary greatly between industries, but one thing is common across them all – a failing or poor performing Wi-Fi network due to a bad, or lack of design can be detrimental to the success of your business. It doesn’t matter what hardware vendor you choose, what the hardware’s advertised specifications are, or how much money you spend on hardware, the performance of your network is bound to the strict laws of physics and Radio Frequency science, and client device capabilities. A great understanding of this and designing accordingly is key to squeezing out every ounce of performance from your shiny new Wi-Fi 6 hardware.
Here are just a few industry-specific risks in running a poor performing Wi-Fi network:
Retail
- Inaccurate wayfinding services – results in a poor customer experience and potentially lost revenue.
- Unavailable stock checking and inventory systems – stock take must be completed manually resulting in inefficient use of staff time.
- Complementary Wi-Fi outages – business may lose its appeal to customers who may prefer shopping at a competitor store, resulting in lost revenue.
Manufacturing & Warehousing
- Inaccurate or loss of asset tracking services – results in manual stock tracking, loss of shipping information and/or analytical data. This could lead to a delay in the shipping of products out to customers.
- Wi-Fi network unavailable on manufacturing systems – resulting in a delay in/or completely halting production with large scale revenue loss.
Education
- Interruptions to online exams – students may have to re-sit the exam when service is available or go back to paper exam format leading to student dissatisfaction.
- Interruption to classroom learning – results in a poor learning experience and delay in student education.
- Loss of security camera footage – the inability to track incidents and provide a safe environment for staff and students.
Healthcare
- Dropouts or complete loss of voice services – Doctors and staff can no longer report potentially lifesaving information to colleagues throughout the facility resulting in a degraded quality of patient care.
- Outage for medical diagnostic machines – resulting in the manual delivery of patient information, delaying patient care.
- Inaccurate or loss of asset tracking services – staff may struggle to find lifesaving medical equipment, putting the lives of patients at risk.
Key factors determining design decisions
Business Requirements
Long before we get into the nitty-gritty technical details of network design, it is critical that we start by addressing the business requirements that are driving the network upgrade with key stakeholders. In fact, a good Wi-Fi engineer will start to gather information
Business requirements are generally gathered in meetings before potential hardware and software options have been discussed. Common examples of business requirements include:
- Increase in productivity by allowing staff to access network services and applications via their own personal hand-held devices.
- Provide Real-Time Location System (RTLS) for the tracking of moving assets.
- Provide
complementary internet access to be more appealing to customers. - Increase in performance to meet the demands of new real-time streaming applications.
- Require a
cloud managed and monitoring solution for fast resolution of incidents.
Network Service Requirements
Once we have determined business requirements, we must then determine how the wireless network will be used. Some examples include:
- Corporate Data
- Guest Internet
- BYOD
- Voice Services
- Location Services
- Sensor Network
- Security and Access Control Network
Location and voice services, for example, have a completely different set of requirements over data services. BYOD and untrusted guest devices will require different levels of security and access than managed corporate devices.
Application Requirements
We then need to understand what applications will be used on the wireless network and what their minimum requirements are. While the delivery of some application data can handle network delay or retransmissions, others require the network to support a baseline level of performance for them to operate efficiently. Some critical metrics include:
- Minimum required throughput
- Maximum latency, jitter and packet loss
- Minimum Receive Signal Strength (RSSI) from Access Points (APs)
Client Density Requirements
What is the maximum number of users expected to access each area at any given time? This, along with the application requirements, will determine the density of APs to be installed in each area.
Client Device Support
We also need to determine the client device types that the Wi-Fi network will support. Every device and its supported capabilities and protocols will vary greatly between devices models, operating systems versions, chipset models and firmware versions. Knowing the limitations and capabilities of your client devices allows us to design a network that plays nicely with the devices, and it also sets expectations around what is realistic in terms of performance. Some of the key client capabilities affecting design decisions include:
- Maximum throughput
- Radio Frequency Channel Support
- Radio Transmit Power
- Fast roaming capabilities
- Security methods and protocols
Wired Network Infrastructure
Are we upgrading the wired network or are we to make use of the existing wired infrastructure? The wired network must be capable of supporting the requirements and demands of the Wi-Fi network. Some things to consider are:
- Power Over Ethernet (PoE) capabilities
- Switch port speeds
- Switch interconnect/uplink speeds
- Length of cable runs from Access Points to communications cabinets
Critical Design Decisions
Once the information gathering process is complete, it is then time to start piecing it all together and make decisions on the design.
Architectural Model
There are many different architectural models in the world of Wi-Fi and each has its advantages and disadvantages. Some solutions provide a great level of convenience and ease of management but might fall short when it comes to scaling beyond the current project scope. Other solutions will allow you to grow indefinitely but may require a full-time wireless engineer to support it.
Access Point and Antenna Selection
This is where we determine the appropriate AP models and antenna selection (if using models with external antenna options). If there are high-density requirements in some locations it may be best to add additional APs with directional antennas to shape and focus the RF energy in particular directions. This allows for smaller high capacity cells, while also minimising interference caused by introducing more APs.
Access Point Transmit Power Levels
AP transmit power is directly proportional to the range of a transmitted signal. Theoretical data rates are directly proportional to the clients achieved signal-to-noise (SNR) ratio. SNR is the difference between the measured signal and the measured background noise.
So, why would we not just turn up our APs to maximum transmit power and receive the highest possible data rate? Well, consider an access point transmitting at is maximum power setting. It’s like two people having a conversation across a field where only one person has a megaphone. While the client can hear the AP at long distances, the AP can’t necessarily hear the client so the client repeats itself until the message is heard. The client may be able to download data, however it may struggle to upload data.
This is why it is necessary to match your transmit power to that of the lowest performing device in the network. The result is less retries, less interference from devices operating in the same frequency, and less chance of ‘sticky’ clients unwilling to roam between APs.
Access Point Channel Selection
Every AP will transmit its signal on a particular channel per radio. In the 2.4GHz band we only have three non-overlapping channels. At the time of writing, there are 22 channels available for use in the 5GHz band in Australia. For the most part, the channels you choose to enable on your AP radios is largely determined by client support. The more channels we can enable and allocate to APs, the less likely two APs within the vicinity of one another will need to transmit on the same channel, reducing co-channel interference. An AP transmitting on a channel that a client does not support will introduce coverage holes for that client.
We may also decide to completely disable the 2.4GHz band or disable 2.4GHz radios on a subset of APs to allow for a much cleaner signals between the AP and client.
Access Point Locations
Now this is where it starts to get fun – determining where APs should be mounted, their orientation and specific radio configuration by way of site surveys. Decisions made during the site survey process using all of the detail gathered in the previous phases. There are three types of site surveys that can be performed during the design phase and which surveys should be performed depends on a number of factors. The types of surveys used in the design phase are:
- Predictive surveys – utilising predictive modelling desktop software.
- Pre-deployment surveys – validating the AP signal coverage previously estimated by the predictive survey software in order to increase confidence in the number of APs proposed and their mounting locations.
- Post-deployment surveys – validating the performance of the network once it has been deployed and optimised. Tweaking and optimising, if necessary.
Hire a Wi-Fi Design Expert Now!
While this is just a taste of the Wi-Fi design process, hopefully, I have convinced you the importance of budgeting for a design on your next Wi-Fi upgrade. No matter where you are located or what your budget is, there is a Wi-Fi Engineer just dying to come out and design your network!