Empirical assessment of 1.7 GHz micro-diversity in various buildings

To achieve reliable radio communications inside buildings, microdiversity is required to mitigate the severe multipath and temporal fading. The authors present results of diversity measurements from 100 locations in four university buildings. They computed cumulative distribution functions (CDFs) of the envelope fading statistics for space, frequency, and space/frequency (hybrid) diversity. CDFs from space diversity were best in open areas with an average value of -7.6 dB at 99% time availability and worst in a building with cement interior walls yielding -8.9 dB. These differences were only 1 to 2 dB, suggesting that these results may be useful for similar buildings. Frequency diversity showed similar trends but with 1.5 to 2.0 dB poorer results. In general, the output fading statistics were best in areas with many line-of-sight (LOS) paths, while the diversity gains were larger for buildings with more severe fading due to non-LOS paths. Results from one-minute measurements indicated that higher orders of diversity significantly reduce the fading variations between locations