The effectiveness of preselection diversity for indoor wireless systems

This paper presents the experimental results of an investigation into the effectiveness of preselection diversity in an indoor 900 MHz TDMA system. We show that a simple auxiliary antenna, used in conjunction with the standard λ/4 whip on a cellular handset, delivers nearly a 10 dB improvement in signal level in fades that occur 1% of the time, compared to one antenna. Our studies also show that a reasonably designed auxiliary antenna can perform within 2 dB of the primary antenna and, with polarization diversity, deliver a signal that is sufficiently decorrelated from the primary antenna (r<0.2)