Simulating radio channel statistics for different buildingenvironments

摘要

The design of advanced radio systems requires knowledge of highernorder channel statistics, such as the time delay spread and the angle ofnarrival spread. Time delay has been measured in a number of cities,nwhile angle of arrival has been measured in only a few. Since the linkngeometry is not the same for all measurements, it is not clear how toncompare the measured values, or if they are applicable to other buildingnenvironments, antenna height, etc. To clarify these issues, we have usedna three-dimensional ray tracing code, called the vertical plane launchn(VPL) method, to simulate time delay spread and angle of arrival spreadnin different building environments. Results for elevated base stationnantennas show that the distribution of root mean square (RMS) delaynspreads is not sensitive to the statistical properties of the buildingsnbut increases with distance to the mobiles and increases as the basenantenna is lowered below the rooftops. In contrast, the distribution ofnRMS angle spread is sensitive to the distribution of building heightsnand to the height of the base station antenna but not to the distance tonthe mobile. The influence of street geometry on delay and angle spreadnfor low base station antennas is also discussed