DSP enabled Fiber-Wireless IFoF/mmWave link for 5G Analog Mobile Fronthaul

12 Gb/s Multiband Fiber-Wireless Link Using Coherent IFoF and V-band mmWave Radio

“…The robust performance of the SSB scheme against the optical power fading, induced by the interplay of fiber's chromatic dispersion and the chirp of analog RoF transmitters [5], is a prerequisite for transmitting IFoF and RoF signals without imposing limits on the range of the possible fiber link lengths but extending them to longer distances. As presented in [3] the performance of a DSB multi-band IFoF signal is strongly limited by the chromatic dispersion fading for a 25 km link, with the bands close to 8 GHz being the ones exhibiting severe degradation. In the previous section, we proved that an optical IQ modulator facilitated SSB generation of such multiband radio signals.…”

“…In the previous section, we proved that an optical IQ modulator facilitated SSB generation of such multiband radio signals. By modifying the topologies presented in [3] and [12] from IM-DD to IQM-DD, as shown in the testbed of Fig. 2, we implemented an extended-reach Fi Wi link with up to 50 km fiber and 5 m wireless distances.…”

“…To this end, analog Intermediate Frequency and Analog Radio-over-Fiber (IFoF/A-RoF) solutions have been intensively promoted from the research community as a path to overcome the low bandwidth efficiency of the Common Public Radio Interface (CPRI), which lacks scalability in high-capacity interconnections between the Baseband Unit (BBU) and a high number of mmWave Remote Radio Heads (RRHs). The Digital Signal Processing (DSP)-assisted IFoF has been investigated as an option for spectrally efficient FH architectures, employing Intensity Modulation / Direct Detection (IM/DD) schemes over linear low-bandwidth optoelectronics [3]. Moreover, as network operators are focusing on a more demand-driven network planning through centralized architectures and network densification [4], has led to research activities towards unlocking the bandwidth of mmWave bands for Gigabit capacity fiber/wireless fronthaul links to multiple pico/femto cells [5].…”

A 5G C-RAN Optical Fronthaul Architecture for Hotspot Areas Using OFDM-Based Analog IFoF Waveforms

“…In this way the effect of the fiber chromatic dispersion is significantly reduced and the use of cost effective low-speed optical TxRxs is enabled. So far, the IFoF-based fronthaul architectures supporting multiple frequency bands, evaluated only for the fiber part of the network have achieved CPRI equivalent rates up to 1 Tb/s per wavelength [25,36,37]. Moreover, converged FiWi IFoF demonstrations have been shown to reach capacities up to 45 Gb/s per wavelength when using simple quadrature amplitude modulation (QAM) formats and sub-carrier (SC) multiplexing of multiple IF bands [38][39][40][41].…”

“…The 4-λ WDM Tx of the BBU comprised four EMLs modulating the respective CWs at 1536.9 nm, 1537.67 nm, 1538.46 nm and 1539.25 nm with channel spacing of 100 GHz. Each EML was driven by a different electrical multi-IF band OFDM signal resulting in an aggregate data rate of 12 Gb/s per λ, exactly as the one used in the reference link of Figure 3a and equivalent to the experimental demonstration of the EML-based FiWi link [37]. The modulation format of 64-QAM was adopted for all SCs for each of the four OFDM IF up-converted signals.…”