A novel measurement-based approach for modeling and computing interference factors for wireless channels

Wireless communication technologies divide their available spectrum into pre-defined channels. Some wireless technologies, such as the IEEE 802.11b/g, define their channels in such a way that adjacent channels share the spectrum. When two distinct channels share some part of their spectrum, simultaneous transmissions on these channels cause what is known as the adjacent channel interference. For problems that consider adjacent channel interference, such as the channel assignment problem for multi-channel wireless mesh networks, we need a model that quantitatively describes adjacent channel interference. The interference factor is a concept defined to quantify the amount of the overlap, hence the interference, between two wireless channels. Analytical and experimental methods have been proposed in the literature to define the interference factors among channels of a wireless technology. In this article, we propose a physical-layer-measurement-based, technology-independent and generic approach that is capable of determining interference factors between the channels of a wireless technology and also between the channels of two different wireless technologies, such as IEEE 802.11 and IEEE 802.15.4. We also report our measurement results for interference factors among 802.11b DSSS channels and between 802.15.4 and 802.11b channels. Our results show that our approach is practical, accurate and generic enough to compute the interference factors of radio channels belonging to various wireless communication technologies.