Impacts de l'interference dans les reseaux sans fil IEEE 802.11g

The IEEE 802.11 standard is a widespread standard for the wireless networks. It makes it possible for the stations to communicate with each others or with an access point at a distance of a few hundred meters. The bandwidth offered on IEEE 802.11 wireless networks can be significantly affected by the limited number of channels available.; To offer a good coverage, a dense deployment is inevitable. Whereas it is already complex to manage the frequencies allocation inside its network, it is also necessary to take into account the other equipments using unlicensed frequency band. ISM band in the 2.4 GHz is particularly popular, which makes it very vulnerable to interferences.; Modeling as well as the characterization of the interference in the networks without wire IEEE 802.11g are approached in the present research. The interference generated by the IEEE 802.11g equipment is studied by a series of experiments carried out with real wireless network equipment. The theoretical analysis of the channels of IEEE 802.11g protocol indicates that channels 1, 6 and 11 do not overlap and do not interfere each other. The results obtained contradict this theory and indicate that the interference generated by IEEE 802.11g equipment varies according to the manufacturer. Whereas better results are obtained with expensive wireless cards, those obtained with wireless cards integrated in laptop computer are alarming. The latter indicate us that equipment operating at channel 1 can generate interference on all the channels except channels 10 and 11. According to the large deployment of these wireless networks card and networks with access points operating at channels 1, 6 and 11, these results are very interesting.