What happens when everyone has a WLAN?

Q: Will interference limit the value of wireless LANs in the future? What happens when every company, resident and such has a wireless LAN? - Chris A.

The Wizards gaze into their crystal ball and respond:

Greg Murphy, Airwave

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Q: Will interference limit the value of wireless LANs in the future? What happens when every company, resident and such has a wireless LAN? - Chris A.

The Wizards gaze into their crystal ball and respond:

Greg Murphy, Airwave

Increasing usage will not limit the value of WLANs in the future, but it will mean that organizations will need to grow more sophisticated in managing the RF environment. For the first time, IT organizations (and even home network users) will have to pay a great deal of attention to what is happening outside their four walls.

When I first installed a wireless network in my home, I didn’t give a moment’s thought to the RF channel setting. It never occurred to me to think about it until my previously blazing fast Wi-Fi connection unexpectedly slowed to a crawl one day. What happened? My neighbor had installed an access point on exactly the same channel and our networks were interfering with each other. I couldn’t get a strong signal, so my throughout dropped precipitously.

Did that limit the value of my WLAN? No. It just meant that I had to become a slightly more sophisticated user. By changing to a non-overlapping channel and fine-tuning the RF transmission power of my access point, I got my blazing speed back.

This same scenario is going to play out over and over again in businesses and homes in the next few years. The answer is not to abandon WLANs but to learn and manage the airspace to achieve optimal performance.

Alan Cohen, Airespace

With wireless, interference is a way of life. There are several forms of interference a WLAN system must account for, including non-802.11 radiation (e.g., microwave oven), 2.4 GHz cordless telephony, and even Bluetooth. There are also several forms of 802.11 interference (including co-channel interference), in which adjacent access points interfere with access points on the same channel. But interference should not inhibit the global rollout of WLANs. The cellular network operates successfully with more than 1 billion users by applying several of the approaches noted below.

To offset the potential challenges of interference, next-generation wireless systems must achieve several key capabilities. The most important is dynamic RF management. An active wireless system must maximize its spectral capacity by adjusting channel assignment, transmit power and load balancing among clients on a WLAN. For example, if your neighbor’s access point is on channel 1, you want your WLAN to move to channel 6 or 11. With the introduction of new “Uniband” frequencies, 802.11a provides a substantially larger amount of spectrum for wireless transmissions (more than 20 vs. the three bands of 802.11 b/g).

Access points must constantly scan all channels, and if a major source of interference is detected, pinpoint where the amount of traffic crosses the predefined threshold. If your WLAN system can increase system performance in the presence of the interference, the system will rearrange the channel assignment. This rearrangement might end up with adjacent access points on the same channel, but logically that would be a better choice (due to utilization) than sitting on a channel that is totally unusable due to an interfering access point.