WIRELESS INFRASTRUCTURE

  • 11/02/2015
    8:00 AM
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How To Improve WiFi Performance: 5 Key Steps

WLANs are under more pressure than ever. Follow these steps to make sure your WLAN performs optimally.

Eighty-nine percent of companies allow their employees to use their own devices for work purposes, according to a study by Cisco. Online statistics company Statista says in the United States the average number of devices per person is three and growing.  Clearly, employee demand for WiFi is surging, which is putting a strain on our WiFi networks.

Previous wireless network designs that were based on coverage are no longer meeting current WiFi requirements. We must optimize our wireless networks to accommodate for both coverage and capacity and take additional steps to improve performance.

Enterprises often quickly deploy access points without performing proper planning. This can result in wasted effort, poor WiFi performance, and increased helpdesk tickets from frustrated users. As Abraham Lincoln said, “Give me six hours to chop down a tree and I will spend the first four sharpening the ax."

Here are five steps an engineer can take to improve WiFi performance from the start:

1. Plan your WiFi deployments. Before stepping on a ladder to hang that access point on a dropped ceiling, ask questions. The process begins with asking the right people -- stakeholders such as directors and managers -- how they expect to use WiFi. 

Find out how many wireless devices are going to be used and what those devices are. In an enterprise network, this may be simple to do, but in environments such as higher education or hospitality, stakeholders may not know what those devices are.

You want to be able to determine how many access points will need to be deployed and what settings will need to be tuned. In addition, you'll need to evaluate the infrastructure in order to determine if the existing hardware can be utilized or upgraded.

2. Conduct a wireless site survey. An engineer must perform pre- and post-deployment site surveys. A pre-deployment site survey can be predictive or "AP-on-a-stick."

Predictive site surveys allow an engineer to use floor plans to decide where access points should be deployed. Planning software uses coverage, capacity, and building materials to make the predictive model. An AP-on-a-stick site survey is a manual on-site process in which an engineer takes readings by placing the access point in different areas of the floor.

Often forgotten in the site survey process is the post-deployment survey. This is the process of validating the predictive survey and the deployment.

3. Perform spectrum analysis. By performing spectrum analysis, an engineer can determine if there are any sources of interference in either 2.4 GHz or 5 GHz. Sources of interference can come from various devices such as microwaves, wireless video cameras, and devices that emit noise from operation.

4. Turn off 2.4 GHz radios. In some scenarios, it may be beneficial to turn off 2.4 GHz radios. This can be due to reasons such as a high number of 2.4 GHz radios in use or a high amount of noise because of the overcrowding of the 2.4 GHz spectrum.

The United States has three non-overlapping channels to use in 2.4 GHz. With a high number of access points deployed, an engineer must plan to reuse these three non-overlapping channels while avoiding co-channel interference.

One thing is certain: Know what devices are going to be using WiFi to make the ultimate decision of turning off 2.4 GHz radios.

5. Avoid co-channel interference. Co-channel interference occurs when two or more access points provide coverage in the same area and are using the same channel. WiFi is a half-duplex shared medium. When multiple access points are serving clients in the same channel, wireless communication is severely degraded. 

Each access point should aim to provide a planned cell size on non-overlapping channels. This plan provides optimal airtime for each client. By having multiple access points on the same channel in the same coverage area, it effectively takes away airtime each device can have.

In a series of articles, I will delve more deeply into each one of these steps for improving WiFi performance. Stay tuned!

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