Analogue Coherent-Optical Mobile Fronthaul with Integrated Photonic Beamforming
JSAC, vol. 39, no. 9, pp. 2827-2837, Sep. 2021
Dinka Milovančev, Nemanja Vokić, David Löschenbrand, Thomas Zemen, and Bernhard Schrenk
We present a mobile fronthaul methodology for the analogue optical transmission of native radio signals with integrated photonic true-time delay for the beam steering of phased-array antennas. Laser-based coherent homodyne detectors and the delay dissemination through ultra-dense wavelength division multiplexing ensure a low complexity at the optical layer. We experimentally demonstrate beamsteering for a linear phased-array antenna with a 1×3 configuration at 3.5 GHz carrier frequency and prove native radio signal transmission over the 14.3-km reach coherent optical fronthaul at a low end-to-end error vector magnitude of 3.3%. Experimental results are found to stand in good agreement with theoretical predictions.