Efficient modelling of channel maps with correlated shadow fading in mobile radio systems

For simulating mobility of both user terminals and base stations in wireless access systems, it is often advantageous to generate environment "maps" of the channel attenuations including path loss and shadow fading. However, the generation of a large number of spatially correlated shadow fading values, using for example the Cholesky decomposition of the corresponding correlation matrix, is computationally complex and requires a large amount of memory. In this paper an efficient low complexity alternative is proposed, where each new fading value is generated based only on the correlation with selected neighbouring values in the map. This results in a significant reduction of the computational complexity and memory requirements. It is shown that taking a small number of neighbouring values into account is sufficient to achieve relatively small correlation errors in the generated shadow fading maps.