Optically Upconverted, Spatially Coherent Phased-Array-Antenna Feed Networks for Beam-Space MIMO in 5G Cellular Communications

The densification of cellular networks and their soon-to-increase operational frequency is forcing new topological considerations in 5G networks. In particular, networks that enable extreme spatial discrimination are being considered as a means to significantly increase data capacity by realizing spatial-spectral channels that offer frequency reuse without co-channel or adjacent-channel interference. In this paper, we present a new approach to realizing such a capability based on optically upconverted, spatially coherent phased-array feed networks. The details of our approach, presented herein, include the design and initial demonstration of both transmit (Tx) and receive (Rx) array systems that are used in tandem to form a down-/up-link for the purpose of characterizing both array and link performance. Design parameters and initial link characterization results are presented.