Antaira APX-3200 WiFi access point

Covering WiFi Gaps for Reliable Communications

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Media access is an essential component of empowering employees and workstations to achieve their fullest. Sometimes simple WiFi access can boost productivity on even simple tasks. In more extreme cases, Internet of Things (IoT) and similar massive data sampling require virtually every square foot of your facility have fast and reliable wireless communication. No matter the intended utility, if you require industrial Wi-Fi, you have to understand how to manage gaps.

Common Problems

Industrial networks tend to be vast.  Complications are as varied as the jobs that take place on these sites. Addressing every specific scenario has filled many volumes of books.  This post is a simplified look at common sources of signal loss and general ways to overcome them.

WiFi Interference Patterns

Any sufficiently large facility will require overlapping WiFi access points to prevent the emergence of dead spots. The obviousness of this problem leads to a subtler issue that is often overlooked. Overlapping radio signals create interference patterns. These patterns have naturally occurring regions of increased and decreased signal strength. In extreme cases, you can have total dead spots that are well inside of your expected coverage. If you’re just using two signal broadcasters, then you can pretty reliably predict the pattern.  But, as you add devices, the complexities compound exponentially.

There are a few ways to address WiFi interference. The most thorough is to do a site survey and mathematical analysis that will optimize device placement and eliminate these gaps. If you want to spend less money, a few best practices go a long way. First, interference patterns have natural symmetry. Asymmetric deployment can eliminate a good number of dead spots. Additionally, you can reduce the number of channels in use and adjust antennas to better control and simplify the shape of your interference patterns. This enables you to place access points that provide adjacent regions with fewer overlaps.

Signal Blocking

One of the more complicated issues in industrial wireless communications is signal blocking. Every material will have different rates of absorption, reflection, and scattering.  That makes it very difficult to predict how signals will travel through your facility. On top of that, the arrangement of walls, shelves and stored materials can create diffraction gradients that further complicate signal reliability. A few generalizations can rule out a lot of possibilities. On average, materials that absorb or block loud sounds will behave similarly with WiFi bands. This will limit how well your signal can travel through thick walls and floors. It also gives you an indication of how large apparatuses or stored materials will treat your WiFi. A warehouse full of construction supplies will tend to dampen signal while rows of metallic containers can create interesting reflection and interference.

A second form of signal blocking is easy to forget. Industrial settings often require safety measures that can completely kill WiFi. This mostly comes in the form of unintended Faraday cages. Metal meshwork can be found on heavy equipment or a number of other places.  Its design creates a conductive shield that limits or completely impedes the radio signals of your WiFi. Resolving this usually doesn’t involve adjusting your access points. Instead, try to place equipment antennas outside of the metal cages whenever possible. Generally speaking, Faraday cages can only be reliably overcome with a wired connection that crosses the cage.

Streamlining Power and Coverage

The conventional thought is that you can cover a large area with fewer devices by cranking the power up to maximum. This allows each access point to service a larger area and saves on equipment costs. This line of thinking can lead to a few traps. First, higher powered signals are more susceptible to creating unintended interference patterns. Second, high-powered signals will be seen at greater distances, but they won’t always perform quickly. This can lead to a situation where devices are seeing and connecting to an access point that is simply too far away to provide good data rates. The rule of thumb is to instead design your coverage with devices running at 50-percent power.  Then, make small adjustments that help eliminate coverage gaps without sacrificing speed or amplifying interference.

Variable Solutions

Planning and strategy are your best tools to combat the most common contributors to signal problems.  Still, no plan is completely foolproof.  Also, you’ll need to consider investing in tools that let you respond to arising problems and build towards scalability.  You can do this with relatively small investments that cater to two ideas: multi-functional tools and interchangeable ties to infrastructure lines.

Swiss Army Knives

Obviously, stockpiling a few multi-function routers or access points can go a long way.  The emphasis of these devices is on rapid deployment and minimal management.  If they can be predesigned for daisy chaining or run Power over Ethernet (PoE), all the better. It almost goes without saying, but the point is direct.  If you have temporary or rapidly changing operations that need Wi-Fi, you’ll want a handful of clients that can bring signal on demand.

Infrastructure Access

The other fundamental consideration for ad hoc Wi-Fi adjustments is the distance to the mainline infrastructure. Whether you network is built around fiber or copper (or a combination of the two), you want adjustable Wi-Fi components to direct that infrastructure as directly as possible. Multiple signal conversions and long daisy chains can quickly bottleneck data streams. For that reason, simple media converters and self-sufficient Wi-Fi hubs are the go-to devices to manage your network adaptability.

Ultimately, industrial networks require planning, study and constant upkeep. You can reasonably expect to build a central Wi-Fi network with minimal gaps and the ability to adjust on demand without investing too heavily in network analytics. But, as your facility grows to require higher precision, you can expect trial and error to give way to professional surveys and Fourier transforms. If you want to avoid total redesigns and overhauls, stick to the basics. They’ll keep you from committing to unsustainable design flaws and make it easier to grow and improve your network right alongside business needs.

Kelvin Aist

Written By

Kelvin Aist is Founder and Sales Manager at Westward Sales. He has designed and sold networking and communication solutions his entire career. He frequently blogs for Westward Sales.