Shadow fading cross correlation between basestations
Eldad Perahia, Donald C. Cox, S. Ho · 2002
Macroscopic diversity improves radio link performance by combating shadow fading. Signals from paths between a mobile and different base stations are combined to mitigate log normal shadow fading. Link improvement is a function of cross correlation of shadow fading on paths between mobile and base stations. The lower the positive cross correlation, the higher the gain from macroscopic diversity. Negative cross correlation provides even higher gain. Signal level data were collected from a 1900 MHz GSM system in rural and suburban areas. The shadow fading cross correlation for several different base stations and a mobile traveling in an area ranged from -0.34 to +0. 43. Standard deviations for different paths ranged from 2 dB to 10 dB, and decorrelation lengths ranged from 50 m to 500 m. The angle between paths from the mobile to the base stations was calculated.