Measures of complexity for the radio environment

In this paper we study different methods for characterizing the complexity of the radio environment. Of the various definitions of complexity, we focus on the predictability of received power as a function of the receiver location. Such measures are of interest in estimating the compressibility of radio environment maps as well as for establishing sampling strategies for mobile-centric coverage measurement approaches, such as minimization of drive tests. As a case study, we explore different complexity metrics for DVB-T coverage over Germany using realistic terrain-aware propagation estimates. Based on these we show that the underlying transmitter locations as well as the propagation environment play a major role in the radio environmental complexity. Our results also show that for most cases of interest the radio environmental data is highly compressible, much more so than would be expected from simple spatial models. We also discuss the practical implications of our results for MDT-like approaches, as well as outline directions for future research.