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Behind the WiFi Network @ Mobile World Congress 2014: Site Surveys

In my last blog I discussed setting the stage in preparation for the Wi-Fi network for Mobile World Congress 2014 which supported more than 80k devices over a span of 4 days. Today I’ll talk about one of the many site surveys we conducted at the Fira Gran Via to ensure the success of our high density network.  Full details in the white paper here.

High Density Wi-Fi deployments and site surveys go hand in hand. Pre-installation and post-installation site surveys account for the most effective way to identify the contours of your RF coverage and eliminate potential multipath distortions, hidden nodes, and other coverage issues. Special attention was given to the large keynote auditorium halls in order to keep a check on the additional RF coverage needs to accommodate the high density of users packed in a very close range.

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View of inside the Hall-4 Keynote Auditorium (23000 sq ft) before the Facebook keynote session

Site Survey analysis used to measure the RF coverage in Hall-4 keynote auditorium

Site Survey analysis used to measure the RF coverage in Hall-4 keynote auditorium

The Hall-4 auditorium was one example of such a high density area with the 2000 person capacity area had a peak connection of 1924 concurrently connected Wi-Fi devices distributed across 16 Cisco APs while the Facebook keynote was in progress, with a max load of 530 Mbps of internet traffic. To avoid an RF overlap, the ceiling mounted APs above the auditoriums were converted to monitor mode. Using the final pre-keynote site survey data, the RF profile for the Hall-4 auditorium was tweaked, and RRM automatically optimized the coverage to the desired degree by adjusting the Tx power levels. Read More »

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Behind the WiFi Network @ Mobile World Congress 2014: Setting the Stage

Every year a new attendance record is set at Mobile World Congress by networkers participating from over 200 countries across the globe. This grand attendance of industry-defining vendors, technology enthusiasts and exhibitors triggers an explosive growth in the number of Wi-Fi capable devices being brought to the event. For MWC 2014, Cisco partnered with Fira Gran Via and GSMA to pull off one of the most successful high density Wi-Fi network deployments in the history of global tech events. This blog kicks off a series to provide a glimpse of behind the network, into the design stages, and the course of actions undertaken to implement a robust high density wireless network which served more than 22,000 concurrently connected unique devices and a total of 80,880 devices throughout the event. Full details in whitepaper here.

Setting the Scene

Divided into eight massive exhibition halls, Fira Gran Via covers around 3 million square feet (280,000 square meters) of area which also includes outdoor areas, restaurants, conference rooms, network lounges and a continuous elevated walkway flowing through the entire venue. Higher the environmental complexity, the more fun and challenging it is to achieve the right wireless design for a pervasive network that meets all the needs.

An aerial view of Mobile World Congress 2014 arena at Fira Gran Via, Barcelona

An aerial view of Mobile World Congress 2014 arena at Fira Gran Via, Barcelona

Generally, the physical design of large convention and exhibition halls bear an impish knack of unfavorable conditions for a ubiquitous high density Wi-Fi network, owing mostly to the lofty ceiling heights and construction components. Read More »

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Check your Spectrum!

October 3, 2011 at 10:28 am PST

Lately I had been spending a lot of time in the office rather than on the road.  Which isn’t all bad, as it gives me some semblance of a routine rather than living out of a suitcase.   It has also has given me some spare time to come up with another blog topic, which actually stems from some of the work I have been doing for customers lately.

Typically when a site survey is being done, we will do spectrum analysis work as well, part of my job entails creating and reviewing documents from this work, prior to delivering them to customers, which means I have been watching a lot of  spectrum analysis lately.   Most of the customers I have worked with recently have been with CleanAir APs, so they will be able to monitor their environment in real time, once the WLAN is up and running.  However it’s always a good idea to perform some spectral analysis while you are walking around doing a site survey.  And really why not?  If you are there and you have a few minutes, fire up the old spectrum card and get a capture of whats going on with your RF.   This helps make sure there aren’t any major layer 1 surprises when you go to install the new WLAN.  It doesn’t mean things won’t change, and they often will, due to the dynamic nature of RF.  It’s an ever changing environment, so what wasn’t there on Monday, might show up on Tuesday and be gone again by Wednesday.

Before jumping into particular types of interferes let’s talk about some of the data that Cisco Spectrum Expert can show you.  Two of the things I like to look at when looking at the RF in Cisco Spectrum Expert, are Real Time FFT and Duty Cycle plots, as pictured below.

The Real Time FFT is showing you is the RF energy in real time measured in dBm, so how loud or quiet the device is.  The next is the FFT Duty Cycle, which simply put it’s how utilized the RF is. Let’s say you have a device that is being captured as having a 1% duty cycle.  This means it’s using a very small amount of the available ‘air time’ to transmit its data.  Conversly if there is a device that is showing a 100% duty cycle it is using up all the ‘air time’ and not allowing other devices to use the RF medium to transmit.

Two other views I find helpful are the Spectrogram views.  These display the same info as the plots above, but are plotted out over time.  I use them in a few of the examples below.

Read More »

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