Analytical derivation of the mean interference power in WLANs & ad-hoc networks

Radio interference from adjacent systems or users is an important limiting quantity for the transmission rate in wireless communications. Interference studies, however, often have the drawback that they are obtained from measurements in a particular environment. A more generally valid characterization for the interference power is highly desirable. In this paper, such an expression is analytically derived for a single link. The derivation is based on a simple, well-accepted pathloss law; furthermore, on a geometrically motivated transformation of the properties of the environment into expressions that depend only on the volume and surface of the domain in which transmitter and receiver are randomly located. This strategy yields a highly flexible and accurate approximation of the mean interference power as an analytical function of the key characteristics of wave propagation and the surroundings. The paper sheds also some light on the question why the stochastic radio channel is geometrically very robust. To the best knowledge of the author, this contribution is the first rigorous, non-empirical derivation of radio interference.