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White Paper: RX-SOP 101

Just released yesterday: Cisco Wireless Release 8.0 includes a feature called Receiver Start of Packet (RX-SOP), which you can think of as putting earmuffs on the access point.  It’s not a new feature, as it has been used in stadiums and other high density deployments to great success for several years.  WLC 8.0 adds GUI configuration support with a low, medium, and high setting.

RX-SOP is meant for dense deployments, where channel reuse is a concern.  It’s a way to shrink cell sizes, but be careful: too much SOP and you can shrink your cells to the point where clients are no long able to connect.

Check out this whitepaper from the guys at the No Strings Attached Show.  It provides detailed configuration guidance as well real-world data--even the actual config.

For those of you interested in the nitty-gritty of how RX-SOP works, we had one of our RF Technical Leaders, John Blosco, go in-depth at Wireless Field Day 7.  If you missed it, here’s the video:


For more on WLC 8.0, read the product bulletin here.

 

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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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Not All 802.11ac AP’s are Created Equal: Demand the Full Story

It’s always interesting and often entertaining to observe how competitors promote their products and what they choose to focus on—and more importantly, what they choose not to focus on and what they hope people won’t ask questions about.

Consider yet again how a competitor chooses to position their “purpose built” AP vs. the Cisco Aironet 3700 802.11ac Access Point Series.

This competitor frequently (and somewhat obsessively) points out that its 802.11ac AP has dual “active” 800 MHz cores while the Cisco AP3700 has only one “active” 800 MHz core. This is not completely true since it completely overlooks the fact that the Cisco AP3700 also has a dedicated CPU core and DSP for each radio subsystem.

Furthermore, it also overlooks that the dual “active” cores in the competitor’s AP share 512 MB of DRAM. The single “active” core of the AP3700 has dedicated 512 MB of DRAM. Also each radio subsystem has a dedicated 128 MB DRAM (for 768 MB total DRAM in the AP3700).

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Why is all of this important? Read More »

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Winning Back the Weather Radio Channels Adds Capacity to 5GHz Wi-Fi Spectrum

In my last blog on 5 GHz spectrum, I discussed the recent FCC ruling that permitted outdoor access points to use the U-NII 1 band (5150-5250 MHz).

But the story doesn’t  stop there. As mentioned last time, there are significant technical challenges to using the 5 GHz band. It is not cleared spectrum. It contains incumbent uses that are important for national security and public safety. Therefore, it is imperative that Wi-Fi not create harmful interference to these incumbent systems. Cisco will not settle for less.

On the topic of interference, a particularly interesting component of the same  FCC ruling that opened the U-NII1 band for outdoor AP’s is that it also re-opened the Terminal Doppler Weather Radar (TDWR) band (channels 120, 124, 128) with new test requirements for DFS protection. Hold on, let’s backtrack a bit before diving into what this means:

What is TDWR?

In brief, Terminal Doppler Weather Radar (TDWR) “is a Doppler weather radar system used primarily for the detection of hazardous wind shear conditions, precipitation, and winds aloft on and near major airports situated in climates with great exposure to thunderstorms in the United States.” TDWR uses the frequency band from 5600-5650 MHz which is why wireless network equipment needs to be proven to “do no harm” to TDWR. If you’re curious for more information on TDWR, then please click here and/or here.

A Brief History

Many of you reading this will recall that the FCC closed the use of the TDWR band several years ago as the result of numerous reports of wireless equipment creating interference with TDWR. Read More »

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