Updated: Jun 5, 2020
When a newly deployed WiFi network is deployed the next step will be to conduct a validation survey. A validation survey ensures that your Wireless LAN (WLAN) is meeting your requirements and is built the way it was designed.
After deploying a new WLAN, the validation results may show something less than optimal. In this case, you can “tune” your WLAN and re-survey.
When tuning a WLAN, you may end up turning off the automatic channel planning and deploy the static power and channel plan from your design. If you used 20 of the 5 GHz channels in your design, be sure to use them in your deployment.
If you designed your higher density WLAN with 20 MHz channels, be sure to use 20 MHz channels in the real world. Changing the AP or controller’s settings to use 40 MHz (or higher) channels may increase co-channel contention (CCI/CCC) and retry packets, lower signal to noise ratio as well as and the average data rate on the client.
When tuning the WLAN, use your validation survey data to help you decide how to change the power and channels that you wish to modify in the real world. Look at the signal strength and channel overlap.
The tuning process can take some time, but it will prove to be well worth the effort.
During the re-surveying (validation surveys) in tuning process, look at the APs and make sure they are installed properly. If the WLAN was designed with APs that were meant to be horizontal/parallel to the floor, check to see if they are mounted that way and free from obstruction like air conditioning vents, lights, metal pipes, false ceilings etc.
Periodic validation surveys will assist in keeping your WLAN healthy. You may start to see patterns with problem areas that are reported by the user community. The views mentioned above will show a visual representation of what the WLAN looks like in the problem areas. The signal strength grey-out slider within Ekahau Pro can be helpful if signal strength is the suspected culprit. Not all WLAN client devices are created equal, and do not “see” the WLAN just like the WLAN client used in your Validation Survey.
In conclusion, we will wrap it up with the following ‘checklist’:
Go on-site and see the facility, measure the walls for RF attenuation, and do a validation survey of the existing infrastructure.
Document the off-limits areas for APs - it will cut down on modifications to the design during construction.
Gather all of the requirements – capacity, data, voice, RTLS, and the applications that will be used.
Observe the users – foot traffic patterns for voice users, where people gather, walk between buildings, etc.
Find out what the WLAN does today, and what it is going to be used for tomorrow – is the existing WLAN meeting the current and future needs?
Design for 5 GHz WLANs. Define your requirements and design for them. Such as secondary coverage @ -67 dBm for voice, or -72 dBm x 3 APs for RTLS.
Do a post deployment validation survey. After the system is built, do a survey to ensure everything is working properly and verify that it is built how it was designed.
Be prepared to defend your design. If rooms require AP’s in them, insist on placing them in those areas.
Use the area tool to define capacity planning for your WLAN design.
Design the access point placement according to the manufacturer’s recommendations.
Do not skip the on-site visit/survey of the facility.
Do not design “Hall-Fi” where APs are lined up in a hallway because they are easier to install. Hall-Fi creates Co-Channel Interference (CCI), which reduces WLAN capacity.
Measure the floor to floor propagation. It could be 20+ dB, or it could be less than 5 dB if the building was built in 1920.
Do not be afraid to be creative with your design. Use directional antennas if needed.
Do not skip the validation design after it is built. You may have to tweak your design when you see the results.
Do not use an AutoPlanner to design your WLAN. It may get you started with access points on the floor, but don’t leave it that way. Move them around as if you were designing it yourself.
Get in contact if you'd like to discuss options for tooling and training your own internal teams or if you'd like to work with a specialist and experienced partner for WiFi design, surveying, troubleshooting and/or analysis.
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