Measurements and Models for the Wireless Channel in a Ground-Based Urban Setting in Two Public Safety Frequency Bands

We report on measured peer-to-peer (ground-based) wireless channel characteristics for an urban environment in two public safety frequency bands. Results are based upon measurements taken in Denver in June 2009. The public safety bands we investigated are the 700 MHz and 4.9 GHz bands, both intended for public safety and emergency-response applications. Our study of the urban environment in these bands included an estimation of the distributions of both the number of multipath components and their delays. Our measurements employed a vector network analyzer, from which both path loss and delay dispersion characteristics were obtained for link distances up to approximately 100 m. Log-distance models for path loss are presented, and dispersive channel models are also described. Our dispersive channel models employ a statistical algorithm for the number of multipath components, previously used only in indoor settings. By employing a transmit-antenna positioner, we introduced spatial diversity into the measurement system, which enabled analysis of the dispersion characteristics of the angle of departure, also new for this ground-to-ground channel. The channel models should be useful for public safety communication system design and development.