This is a common question that comes up that every Wi-Fi professional needed to address in their time: Why do I have to have someone come on-site, the vendor says I can use an automated tool without anyone coming on-site? Is this true or do we need an on-site assessment? Is there another option? Let’s dig into each and help make the proper decision for your environment.
The first we are going to look at is the onsite assessment. This requires a person to come out to the site that is fully furnished, or at least as close to it, and walk every area of the building. Each person does this slightly differently. Some start with a passive walkthrough collecting background noise, and then bring out the hardware and use temporary mounting to simulate the placement of the APs. Others just start placing the demo AP and measure based on that. After they put the demo AP up where you would expect it to go you then would do a reasonable walk for the expected coverage area, being sure to capture the edges of the coverage cell. When you layer all these APs in whatever program that you are using. The engineer designing the network will then be able to accurately determine the loss each wall or furniture will cause. Some of the best engineers will also take pictures of the IDF closets and make notes of any areas of concern. They will sometimes be able to see firsthand the user density of these areas. While any well-planned survey will consider user and client density, seeing firsthand always makes a difference.
While that is well worth the cost of the engineer traveling to the site, you also are paying for the knowledge of the engineer. Apart from iBwave, I do not know if any program that accurately models reflections[i]. You are relying on the knowledge and experience of the engineer. I’ve worked with some engineers over the years that can almost 100% accurately model the reflections in their heads. One engineer, in particular, has been working with Wi-Fi since its initiation in the 1990s. All that to say, while some engineers can do this, it should not be expected of all as it takes many years to develop this talent. Ultimately, this will give as close as humanly possible, an accurate plan for Wi-Fi deployment. Nothing will be as accurate as an active on-site assessment.
Now, let’s explore what goes into a full remote predictive assessment. This way requires the person requesting the survey to do research and gather significant data to aid the person making the predictive survey. The requestor will need to get information on the wall types, whether they are drywall, plaster, and lathe, brick, elevator shaft, etc. They will also need to provide furniture types and locations. This information all will need to be added to the survey tool. Along with any user and client capacity numbers. Most tools have an auto planner feature, which I have not been impressed by at all in any tool. I personally always manually place the APs. This is because I know generally how waves will pass through and reflect based on the wall materials provided.
Here is the biggest downside to a predictive. It is just a guess. That is right, nothing more than a well-estimated guess based on the information provided and the experience of the engineer doing the survey. Now that’s not to say these are completely useless. Predictive assessments make a great budgetary list for items they will need. It often prompts discussions around infrastructure that while was probably asked about prior, is often overlooked until the end customer sees the report. These predictive reports often help any engineer that plans to go onsite to walk the building for an active assessment, have a general idea of what is expected.
An experimental way of doing a survey is combining the on-site activity that is very expensive and time-consuming, with a predictive. This is called hybrid assessment. What happens is you can send an engineer or a person already on-site gear, such as an Ekahau sidekick with specific instruction on where to walk and how to capture the existing RF signals and background noise. One that is captured, assuming it is completed adequately, a trained Wi-Fi professional then can make some educated assumptions based on the data provided. Since someone did walk the building, you should be able to get a more accurate extrapolation of the walls and other building materials. While this is still a guess, it is based on some measured figures allowing for more accurate assumptions to be made.
If we can train more people to take a little time and at least do a pre-assessment walkthrough, we can tackle two of the main issues with Wi-Fi. We can train newer less skilled people on the best standards, by getting them involved at less critical places of the Wi-Fi planning, in this case, a walkthrough. This will teach them the basics of a walkthrough and then they can see the results from an experienced engineer’s take based on the information they provided, allowing them to grow. It also takes into consideration cost. We can make a decent design at an affordable cost as we do not need to spend the same amount of time, nor ship the equipment we need for an active survey. In my opinion, this will be the way of the future for Wi-Fi planning assessments. It is a fair compromise cost and accuracy, and in my opinion, will be better than a predictive assessment only.
[1] https://store.ibwave.com/buy/products/ibwave-mobile-planner/
Bibliography
“Select Your Plan for Ibwave Mobile Planner.” iBwave Store. Accessed August 16, 2021. https://store.ibwave.com/buy/products/ibwave-mobile-planner/.
