Outage probability in mobile telephony with directive antennas and macrodiversity

Signal-to-interference ratio statistics for mobile telephony systems with hexagonal coverage areas, multiple interferers, and three-corner base stations are investigated. Corner base stations simultaneously reduce total interference (because of antenna directivity) and provide macrodiversity against shadow fading. Our results indicate that for 3 or 7 channel sets, with 2 tiers of interferers and typical system parameters (propagation exponent of 3.7 and lognormal spread of 8 dB), the improvement is on the order of 11 dB over a baseline arrangement which employs centrally located omnibase stations without macrodiversity. Additional considerations of blocking probabilities and average voice activity indicate possible further improvements.