Evaluation of novel multi-beam antenna configurations for TDMA (IS-136) systems

For the IS-136 digital PCS standard, downlink performance can be improved via the use of multi-beam arrays to statistically reduce interference at the mobile handsets. Adopting this downlink approach, it is then desirable to use the same antenna configuration for uplink reception for cost and space considerations. However, this presents a potential problem due to the limited diversity gain available from beamforming arrays, and a careful choice of the antenna configuration must be considered. In this paper, we examine this issue of maintaining acceptable uplink performance while implementing multi-beam arrays in the downlink for the IS-136 system. Specifically, different multi-beam array and diversity antenna configurations are compared using bit error-rate (BER) performance which allows an appropriate selection of the antenna configuration