Test procedures and performance assessment of mobile fading channel simulators

This paper is devoted to the test and the performance assessment of both hardware- and software-implemented simulation models for mobile fading channels. Test procedures are proposed for narrowband as well as for wideband simulators. In the case of narrowband fading, the simulation model's level-crossing rate (LCR) is identified as a proper performance criteria. This quantity gives insight into the distribution of the emulated signal envelope as well as its rate of change. It is shown how the LCR can be measured efficiently and precisely, especially when the signal envelope level is low. It is also shown how this concept can be extended to assess the performance of wideband fading channel simulators based on the tapped-delay-line structure. In this case, the overall LCR and the power delay profile (PDP) are proper quantities which are proposed for the performance assessment. To determine these quantities from the emulated fading signal, various operation modes of the channel simulator are introduced. Several examples illustrate the usefulness of the proposed procedures. They also give insight into the precision of state of the art channel simulators.