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Abstract. There are up to fourteen (thirteen in Europe) overlapping IEEE 802.11 channels in the 2.4 GHz band. A well known set of the non-overlapping channels are 1, 6 and 11, meaning that the spectral overlap does not affect the performance of networks which use them. However, as channels 1, 5, 9 and 13 are theoretically also non-overlapping, the first contribution of this paper is visualization of the spectral overlap of different WLAN signals when using channels 1, 6 and 11 vs. channels 1, 5, 9 and 13. The paper also explores and summarizes the related work done on the topic of channel overlap in the 802.11b, 802.11g and 802.11n networks. The paper ends with a discussion incorporating comments on the previous experimental results and proposals for future research. Based on the available experimental results, the possibility of four non-overlapping channels when used in the low- to medium-density 802.11b and 802.11g networks and the possibility of specifying the conditions under which the fourth non-overlapping channel becomes available provides an opportunity for future research. As the results for the 802.11n networks are inconclusive, the experimental work should be continued. However, in the high-density networks, new effects are observed, less non-overlapping channels are available, and at the nodes operating in a close vicinity, only one non-overlapping channel remains available.

Keywords: overlapping channels, out-of-band interference, OOB interference, adjacent-channel interference, ACI, channel orthogonality, 2.4 GHz band, 802.11b, 802.11g, 802.11n, WLAN, Wi-Fi

O stevilu neprekrivajocih kanalov v IEEE 802.11 brezzicnih lokalnih omrezjih, delujocih v 2,4 GHz pasu

IEEE 802.11 omrezja imajo v 2,4 GHz pasu na voljo do stirinajst (trinajst v Evropi) prekrivajocih se kanalov. Znan nabor neprekrivajocih kanalov so kanali 1, 6 in 11, kar pomeni sicer da se se vedno delno prekrivajo, a je vpliv prekrivanja na zmogljivosti omrezja zanemarljiv. Obstaja pa tudi moznost, da je nabor kanalov 1, 5, 9 in 13 tudi neprekrivajocin tako je prvi prispevek tega clanka graficna predstavitev prekrivanja spektrov razlicnih WLAN signalov pri uporabi kanalov 1, 6 in 11 ter pri 1, 5, 9 in 13. Clanek tudi razisce in povzame prejsnja dela okoli tematike prekrivanja kanalov v 802.11b, 802.11g in 802.11n omrezjih. V zadnjem delu clanka pa je razprava na temo prejsnjega eksperimentalnega dela in predlogi za nadaljnje raziskave. Iz...

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