Investigation and demonstration of 5G signal transmission over fiber/FSO/wireless links

Abstract

In this paper we experimental demonstrate a photonics-based fiber/free-space/wireless transmission for 5G communication systems. The central office (CO) exploits a frequency comb source (FCS) for wavelength division multiplexing (WDM) generation. The distribution segment includes a hybrid link consists of three segments: fiber, free space optic (FSO) and RF links. A 2 Gbaud quadrature phase shift keying (QPSK) signal is generated in the CO and transmitted over the optical network that consists of 10 km single mode fiber (SMF) and 6.5 m FSO channel. In the base station (BS) unit, the received signal is converted to electrical signal at 28 GHz carrier frequency. Then, the signal is transmitted over the wireless RF link. The received signal is analyzed in terms of the error vector magnitude (EVM) and the bit error rate (BER) measures. The results show that the optical link, that combines the SMF and FSO, introduces low power loss as compared to the wireless RF link. This inferred the advantages of 5G signal transmission over optical channels. Moreover, the BER analysis shows the successful transmission over the three communication mediums with BER below the forward error correction (FEC) limit, for −2 dBm optical received power and 1 meter wireless channel.