In a previous post I explained the first phase of a wireless deployment, gathering requirements. From those requirements, we move into the next section, Part II Performing A Wireless Site Survey. There are different approaches to a wireless site survey.
We’ll talk about these approaches and I’ll mention which one I like to use. In addition to site surveys, spectrum analysis should also be done. This is to find any sources of interference in the 2.4 GHz and 5 GHz channel ranges.
What is a wireless site survey?
A wireless site survey is a process. It’s the process of analyzing coverage and capacity based on the requirements gathered in the first phase. It also includes spectrum analysis.
When we talk about site surveys you’re probably thinking of the AP-on-a-stick approach.
Site survey is a loaded term. I prefer to call it a predictive site survey or predictive modeling.
We are predicting how a wireless network will be implemented based on various pieces of information that we gathered in the first phase.
A predictive survey uses a piece of software to model a deployment for you. An example is using Ekahau Site Survey to import a blueprint of the floor plan. Building materials, such as walls and other objects, would be taken into the design consideration.
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Ekahau and other similar software use hardware profiles and algorithms to create a prediction or model. For the most part, this is how many wireless engineers perform a site survey, or more accurately termed, a predictive site survey.
The software places access points on the floor plan and afterwards, the design can be tweaked and modified to meet the realistic needs of the environment.
The same software can be used to perform what is called an active site survey. Your software and hardware actively associates to an access point to gather more information such as ping statistics, layer 1 radio frequency measurements, and any packet loss.
The AP-on-a-stick is an example of an active site survey.
An engineer physically places an access point in a specific location of an office, and using a piece of software such as Ekahau, a survey is done. The process is repeated until coverage and capacity is accurately documented.
The AP-on-a-stick model takes more time and money to perform. It is performed less often than a predictive site survey.
Most wireless engineers are comfortable with using a predictive design that they can tune because as we will discuss later.. a validation of the wireless deployment will be conducted.