Wireless Surveys & Spectrum Analysis

Wireless Surveys & Spectrum Analysis


Theory Behind Conducting a Wireless Survey


     Within a wireless system, it’s challenging to predict the radio wave propagation. Building construction materials found in walls, doors, elevator shafts, people, and other obstacles offer varying degrees of attenuation, causing the RF radiation pattern to be irregular and unpredictable. As a result, it’s absolutely necessary to perform a wireless site survey to fully understand the behavior of radio waves within the operating environment before installing access points. It eliminates the guesswork and provides a visual representation of your coverage using heat maps.


Initial Planning


    There are multiple factors to take into consideration before starting your survey. The initial discussions should be circling around the overall functionality of your wireless network and what are you trying to deliver to the end user. Keep in mind, the design of an airport terminal will be quite different than that of a warehouse space.


Spectrum Analysis


     Remember that consumer grade wireless routers, cordless hand held phones, microwave ovens, and video surveillance cameras operate in the same frequency bands as what your wireless access points will. The 2.4GHz and 5GHz bands are unlicensed and unregulated and can be used by everyone.


     By doing a spectrum analysis of your coverage areas you will detect any activity happening within the spectrums and will be able to configure your hardware accordingly. In situations where wireless infrastructure is already in place and in production but the users are experiences problems you will now have visual evidence of any unknown RF activity and have the opportunity to address the problem by something even as simple as a configuration change or even an access point relocation.


     Interference is one of the primary contributors to degraded Wi-Fi performance and reliability causing poor connections. Both the 2.4GHz and 5GHz bands are suffering from interference. To utilize the full benefits of 802.11n and 802.11ac technologies it is strongly recommended to do a spectrum analysis as an initial step.


Performing The Survey


     Once it is time to physically do the survey we then use our custom designed portable survey system to simulate access point placement, orientation, and height. We use our expertise to analyze the coverage area to determine a suitable location. Then we physically walk the area with industry leading software running on our laptop with scaled floor plans uploaded. We now can see in real time how the RF signals propagates and how far the coverage spans. A heat map can be generated upon completion of walking the perimeter and depending on the results the location can be used or rejected and a new location is selected. Once the entire floor space has been surveyed an overall heat map is generated using multiple access point locations. Changes can be made accordingly to meet the specifications of the coverage requirements.


Benefiting From the Results


     The goal of a wireless site survey is to determine placement and density of access points that provides adequate signal coverage throughout a facility or an outdoor area. A wireless site survey can also indicate the presence of any RF interferences present from other sources that could degrade the performance of the wireless LAN.


Final Summary


    In a large facility, such as an office, airport, hospital, or warehouse, or even an outdoor area such as a parking lot it is highly recommended to do a proper wireless site survey. Without the survey, the end result will lead to a poor user experience due to coverage drop outs, roaming issues or worst case scenario “no coverage” at all. Internally within a business it slows down productivity and externally you could be losing customers all of which can be avoided by taking the proper steps.