Blog: WiFi Experts

A Closer Look at RF Interference and Spectrum Analysis - Part 3
Author/Blog Contributor - Jesse Frankel, AirMagnet Product Marketing Manager at Fluke Networks
Date: May 10, 2011

So far, we've taken a deep dive into basic RF interference and spectrum analysis definitions, decision drivers, deployment models and technical comparisons. With this final post in the series we will examine the technical and deployment trends we see in the field.

As the use of all kinds of wireless technology continues to grow in the enterprise, some interesting technical trends have emerged:

More virulent RFI sources – Employees, visitors and IT staff are using more wireless enabled devices (typically using 2.4 GHz band), causing more potential headaches for Wi-Fi users and IT support staff. Many of the troublesome devices use a point-point RF link and many energize the link at or near 100% duty cycle – meaning just one such gadget can have a strong impact on a fairly large physical area. We have come across two noteworthy gadgets in real customer scenarios: audio headsets and wireless backup cameras.

  • Audio Headsets: Audio headsets that connect to laptops via USB dongle receiver are often used by employees in an IT support area. The transmitter for these devices runs at almost 100% duty cycle, even when the headset itself is not turned on. Even if a new source type like this is classified as a generic interferer, understanding the complete spectral landscape is very valuable to making an accurate diagnosis and planning the best course for remediation.
  • Wireless backup cameras: Small video cameras with point-point wireless links are not new to the world of Wi-Fi RFI. However, a new twist is that various types are finding their way into more places. A recent discovery was made of a car bumper-mounted backup-viewing camera with a wireless link to a display device. The wireless link for this device runs at 100% duty cycle and transmits in two bands. The RFI source can completely knock out Wi-Fi communication across the channel, and the high duty cycle and high power in close proximity to WLAN network infrastructure can also cause other side effects, likely due to desensitization and signal processing slow down in the presence of this RFI source.

Slow migration from 2.4 GHz WLAN use – Although 802.11n infrastructure is expanding in the enterprise space, the migration away from the use of b/g/n in the 2.4 GHz space continues to be very slow. While some enterprise IT groups have specific plans in place to migrate business users to a/n on the 5 GHz band, most do not. The reason for this is there are some competing factors at play, as most mobile devices (including smart phones) only support 2.4 GHz, as well as the possible slowing of laptop replacement over the last two years. The increased use of voice-over-WLAN and other high data intensity applications, like video streaming, also means that RFI impact, even from sources with intermittent or fairly low duty cycles, will become even more of a nuisance. This means that the impact of RFI on business uses of WLAN will continue to worsen, and that IT support will find it increasingly difficult to resolve WLAN issues without an SA-capable monitoring solution in place.

Increasing understanding of spectrum management strategy – Many important users and devices now depend on reliable WLAN services. Because of this, many IT groups understand the importance of developing a comprehensive spectrum monitoring and management strategy. Healthcare institutions were the first to recognize the importance of setting official policies for the use and monitoring of relevant spectrum in and around their premises in order to protect the reliability of mission critical applications, as well as minimizing the chances of RFI sources and neighboring devices having a negative impact. Instituting these kinds of policies can impact overall IT cost, often because costs can increase due to the hidden effects of unseen RFI and other unauthorized devices that may be in use. Without spectrum monitoring capabilities, there is no way to understand the risks that may be present.

Although healthcare has provided most of the momentum for SA-enabled deployments, there is significant motion in the enterprise sector, with an increasing interest from traditional “carpeted office” enterprises for SA deployment.

What are the trends for enterprise deployment?

General interest and demand level – The first trend we see is in general interest and demand levels. We see a marked increase in opportunities for full-time, SA-enabled sensor deployments from traditional enterprises such as financial services, insurance and manufacturing companies. As the added cost of the SA capability has decreased and the rate of WLAN problems due to RFI increases, more IT engineering and support groups are recognizing the value. The decision drivers fall about equally into the previous pain and future protection categories.

SA-enabled sensor ration – The second trend is the SA-enabled sensor ratio. In 2010, about 40% of our sensor shipments were SA-enabled. This is a huge jump—over 300% from the year before. Most of the growth was driven by healthcare related applications, but we have some very significant new projects expected soon from the traditional enterprise space that will push the ratio even higher.

That's a wrap on our RF interference and spectrum analysis series. Hopefully these posts have been informative and led to a deeper understanding of the issues and trends surrounding the topic. Sound off below with questions or comments!

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Blog Contributor

Jesse Frankel has extensive experience in delivering critical wireless security solutions for enterprise, clinical and government networks. During his 6+ years at AirMagnet he served as Director, System Engineering and as a member of AirMagnet's Wireless Intrusion Research Team.

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