ANGLE AND SPACE DIVERSITY COMPARISONS IN DIFFERENT MOBILE RADIO ENVIRONMENTS

The angle diversity performances of two types of high-gain multibeam a ntennas-24 vertically polarized 15 degrees beams and 12 vertically pol arized 30 degrees beams-were tested and compared to the space-diversit y performances of traditional sector antenna configurations. The anten nas were tested at 850 MHz in dense urban and rural cellular mobile ra dio environments. A vehicle equipped with a mobile transmitter was dri ven in the coverage area, while the received signal strength (RSS) was recorded on multiple receiver channels attached to multibeam and sect or antennas at the base site. The RSS data recorded included fast (Ray leigh) fading and was averaged into local means based on the mobile's position/speed. The fast fading was extracted from the recorded RSS an d the fading distributions of the two multibeam antennas tested were s tudied in two distinctly different mobile environments. Fading cumulat ive distributions for the angular diverse antennas were compared to th ose of spatially diverse antennas. Diversity gain was calculated and c ompared to traditional space diversity in these mobile environments. R esults in urban environments indicated that angular diversity performa nce was comparable to space diversity (similar to-8 dB improvement). R ural tests typically suggested that both space diversity and angular d iversity provided little or no (<2 dB) fading reduction. A description of the experiment, data reduction and analyses, and calculation of di versity gain are presented. The motivation for this experiment is the application of fixed multiple beam antennas (FMBA) in cellular radio a nd digital personal communication systems.