Multi-beam antenna combining for 28 GHz cellular link improvement in urban environments

This article demonstrates the performance of multi-beam antenna combining for improving link quality in future millimeter-wave cellular systems. Using experimental data obtained from 28 GHz propagation measurements in New York City [8], we demonstrate how the combination of two, three and four beams, either noncoherently or coherently at the mobile receiver antenna, can improve the propagation link substantially. The results reveal that an average of 28.1 dB improvement in path loss can be achieved via combining the strongest four received signals coherently, when compared to the case of randomly received signals using a single beam at the receiver. This paper is the first to present the potential of multi-beam combining for improving link budget (e.g., extending range) in future mm-wave urban cellular systems.