Performance Analysis of Analog IF Over Fiber Fronthaul Link With 4G and 5G Coexistence

Fifth generation (5G) mobile communications will require a dense deployment of small cell antenna sites and higher channel bandwidth, in conjunction with a cloud radio access network (C-RAN) architecture. This necessitates low latency and high-capacity architecture in addition to energy-and cost-efficient fronthaul links. An efficient way of achieving such connectivity is to make use of an optical-fiber-based infrastructure where multiple wireless services may be distributed over the same fiber to remote radio head (RRH) sites. In this work, we demonstrate the spectral containment of fourth generation (4G) Long-Term Evolution (LTE) signals and 5G candidate waveforms-generalized frequency division multiplexing and universally filtered orthogonal frequency division multiplexing (UF-OFDM) through a directly modulated link. Seventy-five bands of LTE and 10 bands of 5G waveforms are successfully transmitted over a 25 km analog intermediate frequency signal over fiber (AIFoF) link through our setup, limited only by the bandwidth of the laser. For the first time, to the best of our knowledge, we demonstrate the fronthaul network for providing simultaneous 4G and 5G services by propagating LTE signals in coexistence with UF-OFDM.