The Impact on Prediction of Modeling Body Loss in High-Density Venues

Forever on a quest to improve the accuracy of network predictions in our software, we recently released a new feature called “Body Loss Modeling.” With Body Loss Modeling, you can now account for the attenuation caused by bodies packed into a tight space together in your design – most useful for high-density venues like stadiums, arenas, or conference centers.

In this blog, I use the design of a basketball arena to examine the impact the body loss modeling feature can have on the prediction results of a network design.

I do that by isolating a small section of the arena seating, placing an Access Point and then looking at the results of both the Signal Strength and SNR heatmaps under two scenarios:

No Body Loss Modeling
With Body Loss Modeling

At the end, I’ll summarize the comparison and discuss the potential impact of the results.

Here is the basketball arena I am using, and the specific seating area looked at in this blog.?

Results: No Body Loss Modeling

Keeping the prediction zone identified as a regular prediction area, I ran the Signal Strength and SNR heatmaps for the 5GHZ band and then used the “Probe” tool to zone in a very specific seating area in the bottom right hand side of the prediction zone (circled).

Here are the results.

Signal Strength Heatmap Results

58.85 dBM {Inclined Surface Area}
58.95 dBM {Horizontal Surface Area}

And zoomed in… ?

SNR Heatmap Results

29.55 dB (Inclined)
29.75 dB (Horizontal)

And zoomed in …?

Results: With Body Loss Modeling

Next, I assigned the same prediction area as a ‘Body Loss Zone’ and then re-ran the Signal Strength and SNR heatmap prediction results. To identify a body loss zone in iBwave Wi-Fi or iBwave Design, you have to first configure the ‘Body Loss Zone’ (unless you just want to use the default), and then assign your prediction area as that particular body loss zone.

Here is the configuration I set up and called ‘Arena Seating’ ?

And here is how I assigned the prediction area as the body loss zone I configured above. ?

With the prediction area now identified as a ‘body loss’ zone, the prediction engine will factor in attenuation caused by tightly packed bodies within that seating area.

Here are the results ?

Signal Strength Heatmap

Incline Surface: 68.20 dBm
Horizontal Surface: 67.88 dBm

SNR Heatmap

Incline Surface: 21.28 dB
Horizontal Surface: 21.44 dB

Comparing Results

To easily compare the prediction results with and without body loss factored in, I put the results into a table.

	No Body Loss	With Body Loss	The Difference
Signal Strength	58.85 dBm	68.20 dBm	-9.35 dB
SNR	29.55 dB	21.28 dB	-8.27 dB

Looking at the table, you can start to see the potential impact that modeling bodies in high-density environments can have on the accuracy of prediction results – and thus on the potential performance of the network post-installation.

In this case, before I modeled body loss into the design, the signal strength is predicted to perform pretty decently with a 58.85 dBM signal strength. With the attenuation due to bodies factored in, the signal strength loses almost 10 dB, which pushes it towards a much less desirable signal strength and could significantly impact the user experience when it comes to critical applications like video streaming or VoWiFi.

Looking at the SNR heatmap, a similar story is supported, even emphasized – before body loss is considered, the SNR sits at a pretty acceptable level of 29.55 dB. After body loss is factored in, the SNR level drops to 21.28 dB – making it even more likely that those critical apps will work as expected for the user.

For the network engineer designing the network, this means she or he needs to factor in that while prediction results without body loss factored in can show acceptable performance results, it could be misleading in high-density venues – which can lead to undesirable and costly consequences later on.

When prediction during the design phase is not accurate, it can lead to more site visits post-install, and possibly re-design work which is all more downtime and cost for the property owner.

How do you factor in body loss into your wireless designs? Let me know in the comments below.

Wirelessly yours,

Kelly

Interested in learning more about iBwave Wi-Fi? Read more about it here, or try out a 15 day free trial.

Wireless Standards References – Poster Series

Designing a high performing wireless network is not easy.

Especially, when the end goal is a network that provides high-performance coverage & capacity, and won’t need much troubleshooting and maintenance. This is even harder when you have limited time and budget to finish your Wi-Fi project within!

As an engineer, how many tables, cheat sheets, and references do you spend time looking up and using when designing your network? Ever find yourself looking up 20, 40, 80, 160 MHz channels, 802.11ac data rates, PoE types and power classes or 5 GHz U-NII bands and channels overview?

Do you ever find yourself spending too much time looking up reference information? The truth is, unless you have a phenomenal photographic memory or have mastered some mathematical conversion tricks, the moment will come when you will need to refer to something to check your data. Even the best wireless gurus or grandmasters of the universe, need a little reference now and then.

So what have we done about it?

Here at iBwave we’ve heard your pains and are continuously searching for ways to make the wireless network design experience faster and easier. Which is why we’ve been gathering your opinions on what cheat sheets, tables, and references you need for your work. Then, together with our R&D team, we have created a series of wireless reference posters to be used during the wireless network planning and design process (you’ve probably seen a few around!).

Which reference posters have we created so far?

We started with a 5 GHz Wireless Standards Reference poster, and after sorting through the requests, released 802.11 Wireless Standards and Power over Ethernet (PoE): Standards & Security.

Finally, our latest poster is about IEEE 802.11 Wireless Standards.

Check the wireless reference posters out if you haven’t already! All of them come in high-resolution, ready-to-print PDFs.

And please leave your comments to let us know what other reference sheets/posters or infographics will interest you or will be helpful in your job!

How Small Modeling Errors Can Lead to Big Costs

Have you ever wondered what could be the impact of selecting a wrong wall material in a wireless design project? How about setting the floor plan scale a tad incorrectly or modeling a flat surface instead of an inclined surface? The answer is, seemingly small modeling errors can have huge impacts on network performances and project costs.

Learn how to avoid small errors that might lead to significant flaws. Join our next webinar with resident Wi-Fi expert, Vladan Jevremovic!

We will discuss how critical correct venue modeling is for wireless network design and the possible impact of even a slight inaccuracy when setting the parameters.

Webinar Agenda:

– Incorrect floor plan scaling

– Missing walls or incorrect wall materials

– Flat surfaces vs. incline surfaces

– Antenna patterns: interpolated vs. measured

– Fading margin

– Choice of survey routes during a site survey

– Q&A

Watch Webinar