Wireless networks based on 802.11 (802.11b, 802.11g) standards normally transmit their signal in a radio frequency range of 2.4 GHz. Many other electronics devices use the same frequency range, thus they can cause interference to the wireless networks. Some of these electronic devices include microwave ovens, cordless phones, baby monitors and garage door openers. Another possible cause of interference is the wireless networks of the neighbors because they also use the same type of radio signaling. There are a number of ways which can be applied to avoid such interferences. This paper will address the steps to be taken when radio frequency interference impacts an IEEE 802.11 network.
Impacts of RF interference
RF interference refers to the presence of unwanted signal that disrupt the normal operation of the system. Some signals transmitted by electronic devices appears as a 802.11 station transmitting a packet, thus causing the legitimate 802.11 station to wait until the interfering signal goes away before it transmit its signal. The following are the steps which should be taken to when radio frequency interference impacts on the IEEE 802.11.
- Analyze the potential for radio frequency interference
Analysis of the potential for radio frequency interference should always be done before the installation of wireless network. This is done by performing a site survey using specific tools to determine any presence of RF frequencies. Some of the site survey tools which can be used include a pocket PC device such as Casio Cassiopeia and Compaq iPAQ (Geier, Minimizing 802.11 interference issues, 2002). Other tools which can be used to perform the survey are Scorpion and Grasshopper. The one installing the device should also try to find out whether they are RF devices in use in the facility.
- Preventing the interfering sources from operating
When the discovery of potential sources of radio frequency is made, the next step is to put these sources off. Some of the sources can be eliminated by simply turning them off. This is normally the best way to prevent radio frequency interference, although it is not at all times practical. For instance, there is no way one can switch off electronic devices which are used by your neighbors and you cannot tell other wireless network users who are near you to switch off their networks. This type of preventing radio frequency interference can only apply in your place of residence whereby you can disallow the use of micro-ovens and Bluetooth-enabled devices to prevent the interference on 802.11 signals.
- Providing reliable wireless network coverage
One of the best solutions to 802.11 radio frequency interference is the provision of a strong network signal throughout the area of usage. A strong signal is not likely to be affected by other signals. If a wireless network signal gets too weak, the interfering signals can cause a lot of trouble because they might not allow the wireless network signal to transmit its packets. To ensure that your wireless network is strong, you should perform a thorough radio frequency site survey so that you can determine the placement of access point and the most effective number.
- Setting the configuration parameters properly
To avoid radio frequency interference in 802.11 wireless networks you should tune the access points to channels that avoid the frequencies of signals that might cause interference. This set up sometimes does not work but it is recommended to give it a try. In 802.11 frequency hopping systems, you use different hopping patterns to counter the interference. There are some models of 802.11 wireless networks which offer built-in RF interference avoidance. These are the kinds of models which should be installed in areas where RF interference is detected. An example of such a model is the 802.11e MAC layer which has the capability of offering some built-in RF interference avoidance algorithm.
- Using the newer 802.11a wireless LANs
2.4 GHz band is the one which is mostly affected by the radio frequency interference. To counter this you should install 802.11a networks which transmit their signal at a frequency range of 5GHz. At this frequency range radio frequency interference cannot occur because the electronic devices which are known to cause radio frequency interference cannot transmit at this frequency range. Using 802.11a wireless networks has an advantage in that; the user will receive a much higher throughput. The disadvantages associated with 802.11a wireless networks is that, this kind of network require many access points and the cost of installing it is much higher compared to other wireless networks.
Wireless networks signal interference is rampant and something need to be done to avoid the radio frequency interferences. Whenever you are installing a wireless network you should always put into consideration the causes of radio frequency interference. A site survey is recommended before the installation of a wireless network. This will assist in identifying any potential source of radio frequency interference. If radio frequencies are discovered in areas where you are installing a wireless network, you need to find a way of countering the RF interference.
There are a number of ways of curbing up the RF interference as discussed in this paper. There are other ways like adding a wireless repeater which can also help in reducing the radio frequency interference. Thank you to the technology because it has developed new types of wireless networks which are not easily affected by other electronic devices transmitting at the same range. The presence of new wireless networks devices transmitting at a different range other than the common 2.4 GHz has helped a lot in preventing RF interference.