k-Space tomography for spatial-spectral monitoring in cellular networks

A technique for the spatial-spectral analysis of the cellular environment by performing a near real-time imaging of k-space is presented. The system uses a random spatial-spectral dispersion map from an optically-upconverted RF phased array receiver and tomographic reconstruction techniques to recover the cellular source scene. While spatial dispersion is inherent to phased array antennas, temporal dispersion is introduced by randomizing the fiber length for each up-converted antenna element, which contains the received RF signal as a sideband on an optical carrier. Each fiber is routed into a common fiber bundle where the filtered RF-sidebands are launched into free space, expand and overlap. The resulting complex superposition produces an interference pattern unique to a given RF source location and frequency, which is used to recover the spatial direction and frequency of each source in the cellular environment. We present the theory of operation and experimental results of this approach.