We’ve often heard that Wi-Fi deployment is much simpler and cheaper than cellular systems. We asked the experts at iBwave, whose in-building RF planning and design suite now handles both, what the key differences were and why it might make sense to combine them.
We spoke with Benoit Fleury, VP Product Line Management, and Scott Pereira, who leads iBwave’s new Wi-Fi initiative. The company announced a Wi-Fi only product in January, which is integrated into their latest full product suite version 7 released this month.
What are the fundamental differences between RF planning for 3G, LTE and Wi-Fi?
The key difference isn’t just the technology itself, it’s also the fact that designers are dealing with licensed and unlicensed spectrums. While mobile operators have the advantage of controlling their own spectrum, Wi-Fi in the unlicensed spectrum can be subject to a variety of additional interference sources. These include everything from microwave ovens (operating around 2.4GHz), lighting and any other Wi-Fi hotspots. A notable difference between an office and a public venue is the likelihood of rogue hotspots. That’s further complicated because in most places almost any smartphone can become a temporary Wi-Fi hotspot.
We deal with this by assuming an ambient noise level within our software’s RF plans.
From a radio perspective, frequency and channel assignment is one of the most important factors for Wi-Fi.
How does the perceived low cost of Wi-Fi equipment result in a different planning and installation approach?
There is a misconception that the cost of Wi-Fi Access Points determines the bulk of the total solution price. That’s really not the case, especially considering the longer term lifecycle of the venue, and installation work, which can cost as much as the equipment. Other factors need to be taken into account.
Installation costs include power, backhaul, cabling and technician time. Downtime during a major installation can disrupt business operations or be restricted to specific times/days. There may be hidden costs such as building lease restrictions and time spent/lost by office staff.
It’s definitely the case that you end up with an overpriced Wi-Fi solution if you don’t plan it properly.
Does it make sense to combine the cellular/Wi-Fi RF planning, or are the coverage footprints so divergent that there’s little advantage?
There are so many different variables, equipment types, building use cases etc. that it’s hard to give a generic answer. It really does depend on each situation, therefore we need to design solutions on a per site basis. It’s fair to say we might require a different number of Wi-Fi Access Points compared to the number of small cells to ensure good overall coverage.
Historically, Wi-Fi and cellular RF planning have been done as separate activities. However products are now available that combine both and we are hearing about more integrators and OEM service providers who are looking to deploy both together. So although these have been separate planning activities until now, we are seeing a trend for convergence.
Many aspects of the planning activity are common – capturing the physical building dimensions, use cases in each area, cabling etc. By using the same tool, we avoid duplication and save additional costs. It also allows consideration of where best to deploy combined small cell/Wi-Fi and where to augment with additional Wi-Fi only access points.
How much Enterprise Wi-Fi is being upgraded to the latest technology (eg 802.11ac) and is this delivering its full potential?
The Industry is adopting 802.11ac but many sites are simply just replacing their existing access points. A blind “rip and replace” to install the latest technology with new frequencies and protocols won’t deliver its full potential. Enterprises may not realise that the locations used before are not always optimal. Some have not fully considered additional backhaul and the new propagation characteristics of 802.1ac.
Fortunately, we’ve also seen these upgrades being used as an opportunity for a complete RF redesign. By using a design tool, you can predict the results and consider the implications. While there are always trade-offs if you decide you want to add or move access points, a predictive tool allows you to make informed decisions.
It’s quick and easy to do this, where a design already exists and can be revised.
How do you see planning for proposed shared spectrum evolving (e.g. LTE-U/LAA)?
These new technologies provide even more reasons for professional RF planning. It’s still very early days and standards are not yet finalised. We definitely have all the building blocks included in our software solutions and would harness them when such systems become live.
What other aspects differ between Wi-Fi and cellular installations?
Wi-Fi and cellular teams differ in their design philosophies and how they approach a project.
We find that Wi-Fi installers more commonly use a survey and measurement based approach, walking the building, taking measurements, then making adjustments. While cellular installers have evolved from the survey based approach to a more prediction based method, using planning tools to ensure timely delivery of the high volume of projects they are faced with.
We are however starting to see Wi-Fi experts adopting a hybrid design method – testing a few antennas, calibrating the design and then spending some days doing walk tests.
Some of these walk tests use special dongles and equipment. This may not reflect the real-world performance of the typical smartphone/tablet device in use. We’ve developed a method to measure performance directly on those devices and report actual results into our solution, while at the same time also allowing for data capture from external dongles if needed.
In the end, both Wi-Fi and cellular installers have much to learn from each other. There is a demand for faster, more cost effective deployments that deliver high performance. A lot of people underestimate the time and cost to construct a network, but we are seeing the industry taking a more professional view on the longer term lifecycle costs including upgrade cycles.