Realizing future Smart Grid applications highly depend on the communication technologies being used. For this purpose, an ubiquitous communication infrastructure is essential, providing real time communication and reliable connectivity to Smart Grid components. Especially nowadays wireless radio networks offer a cost-efficient, reliable and well-engineered solution. In this paper we present a performance analysis based on a comparison of analytic channel models and Ray Tracing simulations for wireless digital cellular networks with respect to actual Smart Grid deployment scenarios. Both methods are applied especially under consideration of a typical outdoor-to-indoor transition models. Based upon these results a coverage analysis for wireless digital cellular networks (e.g. GSM or UMTS) is shown considering different Smart Metering and energy management application scenarios including position-based radio characteristics, like basement, indoor and outdoor installations. The network topology is described using a simulation environment including various analytic models in order to analyze the capacity of the transmission technology in real-world scenarios. Our analysis shows the impact on the path loss, caused by frequencies, geographical position and indoor deployment, which leads to an additional deviation up to 25 dB.