Five ways to easily address wireless network interference

RF interference can cause catastrophic problems with wireless local area network (WLAN) deployments. However, many companies are still able to make use of their wireless networks, and there is no trouble, but some companies after the installation of wireless network, but found that the network does not run as planned. Interference signals from external RF sources are often the culprit. Therefore, it is necessary to understand the impact of RF interference and avoid interference technology.





do not complain about the network slow, radio frequency interference is the culprit





in order to understand the RF interference-related issues in wireless networks, it's a quick way to see how 802.11 stations (Customer wireless communications devices and access points) access wireless media. Each 802.11 station can transmit packets without transmitting data from other stations. If another station happens to be sending a packet, the other stations will wait until the media is idle. The real 802.11 media access Protocol is more complex, but it makes it easier for us to analyze the problem.





RF interference including unsolicited interference RF signal, it will interrupt the normal wireless operation, due to the characteristics of the 802.11 media access Protocol, to achieve a certain amplitude and frequency of the interference radio frequency signal, it looks like a 802.11 station sent packets, of course, this is a false signal. This false signal will cause the 802.11 station to wait for an indeterminate time before attempting to access the media before the jamming signal disappears.





worse, RF interference does not comply with the 802.11 protocol, so the legitimate 802.11 station in the process of sending packets, interference signals may suddenly start to stir up trouble. If this happens, the destination station receives the wrong packet and cannot respond to the source station with a "confirmation" signal. On the other hand, the source station will attempt to resend the packet, which will further increase the operating costs of the network.





This all leads to network latency, and users are dissatisfied. Sometimes, the 802.11 protocol automatically switches to a lower data rate during the presence of radio frequency interference (which also lowers the use of the wireless application) and tries to continue running. The worst case scenario is that 802.11 stops will wait until the jamming signal disappears, delaying for hours or longer.







What are the
RF interference sources?





For 24. GHz Wireless network, the interference signal sources are as follows: microwave ovens, mobile phones, Bluetooth-enabled devices, frequency hopping spread spectrum wireless network, neighboring wireless network. One of the most destructive is the 24 of people who are widely used in homes and units. GHz cell phones and cordless phones. If someone is in a wireless network (for example, use 24.) In a room where the 802.11b or 802.11g of the GHz band is used, the performance of the wireless network will be greatly compromised.





microwave ovens, which are about 3 meters from the AP, can also cause a decrease in the performance of the wireless network (802.11b/g). Of course, this refers to a working microwave oven. If someone is working close to 802.11 stations to operate Bluetooth-enabled devices such as laptops and PDAs, especially if the 802.11 stops are very far away from the station it communicates with (that is, the signal is weak), it can also cause a significant performance degradation. Although the frequency hopping spread spectrum wireless network is very few, but if exists, it causes the performance to reduce is also extremely serious. Like a wireless network adjacent to your wireless network, if you do not coordinate with the other side of the choice of frequency, will also cause conflict.








take measures to avoid RF interference





unless you are "Superman", you are not able to directly see or exclude radio frequency interference. Of course, in the process of using the network, you may find the problem, such as discovering the speed of the Internet browsing is very slow.





below the author gives some tips, you can consider using these methods to reduce your network's RF interference problem:





1, analyze the possibility of RF interference





you may need to do this before installing a wireless network, you might want to analyze it by using the RF field survey. Also, talk to people in the facility about other RF devices that may be in use. This will give you some information that will help you decide what action you need to take to reduce distractions.





2, to prevent the operation of interference source





after you know the potential source of RF interference, you can turn it off to clear the interference. This is the best way to deal with radio-frequency conflicts. However, this method is not always practical. For example, you can't let the people in the next company who are using the phone stop using their phone. However, in the company's user location, you can turn off Bluetooth-enabled devices and the operation of the microwave oven.





3, the provision of adequate wireless network coverage




One way to reduce the frequency of
is to ensure that the wireless network has a strong signal that it can pass through the location of its users. If the signal weakens, then the interference signal will naturally be more troublesome. It's like you're talking to someone, and then there's a plane flying over and you have to be a little louder to get the other person to hear it. Of course, it also means that you are doing a thorough investigation of the site in order to determine the optimal number and location of Access point AP.





4, the correct configuration parameters





If you are deploying a 802.11g network, you should adjust the AP frequency so that it can avoid the frequency of potential interference signals. But this method is not always effective, but it is worth a try. For example, microwaves typically have a conflict with the upper part of 2.4GHz bandwidth. As a result, you may need to adjust the AP close to the microwave to make it use only 1 or 6 channels instead of 11 channels.





5, deployment of 5GHZ wireless network





today most RF interference is in the 2.4GHz band. If you find that the other techniques we've mentioned earlier do not work too much, you might consider deploying a 802.11a or 802.11n network. Doing so, in addition to allowing you to avoid RF interference, you can also enable the network to have higher throughput.





one of the problems with radio frequency interference is that it will change over time. For example, a neighbour has just bought a cordless phone and used it frequently, or the use of wireless networks in your area has increased significantly. This means that the impact of RF interference will increase over time, and of course it may disappear. As a result, you can also investigate potential RF disturbances in advance.





to make your network smoother, keep a close eye on those wireless devices that can cause wireless network performance to degrade.