Wi-Fi Tips

Reduce Interference

As you learned in the Wireless Network Troubleshooting video other devices within range of a wireless access point (WAP) may interfere in a variety of ways. For example, cordless phones that transmit on 2.4 GHz band my cause interference with 802.11b and 802.11g WAP which also transmit data using the 2.4 GHz band. Well, what if there is another WAP that is in range of your WAP, will it cause interference. Possibly, for example, what if you and your neighbor both use an 802.11b or 802.11g wireless access point and the houses or apartments are close enough to cause interference. What can you do?

Well, wireless access points and wireless network adapters in the US and Canada transmit and receive data by using a 22 MHz-wide set of frequencies. These frequencies are assigned to a specific "channel" and there are eleven channels on which data can be transmitted. For example, channel 1 operates on the 2.412 GHz frequency and channel 2 operates on the 2.417 GHz frequency. Well, that is where things get interesting. Remember I said that a WAP uses a 22 MHz wide channel. Well, when a WAP is configured to transmit and receive on channel 1 or 2.412 GHz it is set to a center frequency which is only 5 MHz apart from the next channel, but 11 MHz is added and subtracted to the center frequency to get a useable 22 MHz wide channel. For example, 2.412 minus 11 is 2.401 and 2.412 plus 11 is 2.423, which gives us a 22 MHz range of 2.401 to 2.423.

Now here is the crucial part to all of this and that is because the center frequencies are only 5 MHz apart and the channels are 22 MHz wide there will be considerable overlap between channels and as a result WAPs that are within range of each other may still interfere with each other even though they are not using the same channel. To ensure that WAPs in close proximity to each other don't have overlapping channels you need to configure each WAP to be at least five channels apart from one another. A simple rule to follow is configure a WAP and wireless network adapters to use either channel 1, 6, or 11 as these are the non-overlapping channels.

In summary

Configure your wireless access point to use either channel 1, 6, or 11 to help reduce interference caused by other wireless access points that are within range of your wireless access point. Also, remember to configure your wireless network adapter to use the same channel that the wireless access point is set to.

How to Boost Signal Strength for Faster and Fore Stable Connections

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