Feeling a little overwhelmed by the prospect of designing and implementing a wireless network? It’s understandable, because there’s a lot to think about and lot of people to please.
Your first step to designing a good network should be to invest in a professional Wi-Fi design tool that’s up to the job. However, there are several things you need to consider before you even start adding access points to your floorplan. We take a look at few essential design considerations.
Coverage
The layout of your store is important because on a very basic level you will probably have a distinction between front-of-house, where customers are located, and back-of-house, which is purely for warehousing and other facilities. Depending on the application, the available wireless SSIDs are often different in these areas; for instance, you generally don’t want to provide guest access in the back-of house areas.
Capacity
Making sure your network can support the bandwidth requirements placed upon it by clients is key, otherwise in peak hours your network will crumble under the strain. Especially in areas like cafés or restaurants where customers will gather and dwell for longer periods.
Most design tools help you calculate your capacity requirements by entering the types and number of devices you want to support. By default, this will evenly space the devices across the coverage area, but you can draw high capacity zones which use a different set of requirements.
Setting capacity requirements within Ekahau Site Survey v9.2.6.
Firstly, add in your corporately owned Wi-Fi devices. If you have Wi-Fi analytics from the existing network you can use them as a good guide for customer device mix and numbers. If not a good rule of thumb is to assume each staff member and customer will have a smartphone and 25% will also have a tablet (or potentially laptop).
Always account for device growth over time, otherwise your network may not be able to cope with future demand.
Neighbouring Networks
Most stores are on a high street, in a shopping centre, or on a retail park, so you will almost certainly be surrounded by wireless networks from other businesses. These networks will be causing interference with your own, so it’s worthwhile conducting a pre-deployment wireless site survey to get a clear picture of the RF environment. This will help you create a channel plan that minimises co-channel interference with neighbouring networks. In some cases, you may need to collaborate with the owners of neighbouring networks to create a harmonious co-existence by asking them to adjust their power settings or channel plan.
Integration and Infrastructure
The user’s experience of the wireless network is only as good as the wired infrastructure that supports it. If each terminal, or display screen has a wired Ethernet port, it is important to scope out the correct quantity access switch ports and the required PoE budget, remember that most enterprise access points may require 802.3at to operate with all features and full power, and to ensure that the backhaul is not a bottleneck in the flow of traffic you may be looking at multi-gig uplinks to the core. The bandwidth coming into the property will generally also need to be scaled up based on the additional number of customers.
Budget
The desired functionality of the network may exceed the funds available to implement it. That said, budget can often help you focus on critical requirements vs. those that are just nice to have. Make sure you pick an AP that actually suits the deployment, rather than your favourite model from your preferred vendor. Selecting an expensive access point with extra features that won’t get used is a bad design decision.
AP Aesthetics
Especially in high-end retail environments where a lot of time and money has been spent on the interior décor people won’t want to see antennas because it makes the access point more noticeable. This means you will likely need to select an AP with internal antennas. Most APs with plastic enclosures can be safely painted (with non-metallic paint) and have their LEDs disabled, which makes them even more discrete. Please remember that doing this may invalidate any warranty from the wireless vendor, sometimes a vinyl wrap can be used instead which can then be removed prior to returning a failed AP.
Modern access points like the Arista C-100 with internal antennas look rather handsome.
AP Placement
The golden rule of AP placement is simple; put your APs where your clients are. I’m sure in some cases, you will be asked to hide the access points entirely, such as inside access panels or above the ceiling. When doing this it’s important to remember that doing so is likely to incur additional attenuation or reflection which will affect the functionality and performance of the AP. Whenever possible resist this move and explain that for the same reason you wouldn’t put a sprinkler above the ceiling, you shouldn’t put an AP up their either.
When it comes to installing APs in stock rooms, warehouses, or distribution centres aesthetics shouldn’t be a problem. However high ceilings and metal racking create new placement challenges to contend with. You need to find a balance between placing the AP high enough it won’t get damaged by forklifts and other equipment, but not too high that your clients on the ground get poor signal strength. Apply common sense to where and how you place APs, for example keep them away from metal pipes and beams…
Don’t site APs in places like this. Image courtesy of bad-fi.com.
Mounting Restrictions
There might be certain places where you don’t have wiring infrastructure and installing such wiring would be prohibitively expensive. Make sure you know where these ‘no-go’ places are, so you can design the network accordingly.
Client Authentication and Security
In retail, the WLAN will almost certainly be used for guest access via an unencrypted SSID and controlled by means of a captive portal. Customers generally have relatively modern client devices, although devices like low-end tablets and smartphones may be 2.4 GHz only, so expect to support both 2.4GHz and 5GHz.
Bandwidth and application control may be required for the guest network, for example you don’t want to be liable for illegal activity (e.g. bit torrent downloads), or find that the wireless network is being used to download large OS updates as these will affect the user experience for all users.
The guest wireless should probably be marked as lower priority than your business critical networks, for example if you are using a tablet based ordering system you don’t want to find that its operation is being effected by guests watching HD video.
From and operations perspective there will be other network devices, including security and surveillance cameras, barcode scanners, access control systems, point-of-sale terminals, and IoT devices. Some of these, especially IoT devices, will be 2.4GHz only. Use band-steering to push any compatible clients onto 5GHz to reduce congestion on the 2.4GHz band.
Some applications will need to have a dedicated VLAN and a dedicated SSID as well. These will need WPA2 security to prevent access by customers, but if they do not support WPA2 Enterprise (i.e., authentication via a RADIUS server), you will need to rely upon WPA2 Personal security with a dedicated passphrase.
Monitoring and Control
An often-overlooked part of wireless network design is post-deployment monitoring. Whilst WLAN access points collect some data, they often don’t collect enough in order to accurately diagnose Wi-Fi performance issues. And without the data, there is little hope for long-term Wi-Fi assurance.
Handheld troubleshooting tools are excellent at tackling persistent issues, but they aren’t really suited for intermittent problems that impact workflows and the customer experience.
This is why a wireless performance monitoring solution is worth considering. They provide a comprehensive system for continually monitoring the wireless experience from the client’s point of view, proactively identifying issues so you can remediate them before they adversely impact your business.
