5G RAN architecture based on analog radio-over-fiber fronthaul over UDWDM-PON and phased array fed reflector antennas

Abstract

This manuscript introduces a 5G radio access network architecture concept based on ultra-dense wavelength division multiplexing (UDWDM) and incorporating an optical fronthaul network that uses a novel wireless antenna system for radio frequency transmission and reception. A ring topology is proposed where optical signals travel within the 5G UDWDM passive optical networks and millimeter waves are generated in the optical line terminals by optical heterodyning. The wireless transmission of the millimeter waves is conducted by an innovative phased array fed reflector antenna approach for mobile communications that grants high antenna gain due to highly focused radiation characteristics, as well as multiplexing gain by multiple beam generation. Furthermore, beam steering is provided by a radio frequency analog beamformer network.Finally, implementation options synthesizing the total system are discussed.

Towards a Scaleable 5G Fronthaul: Analog Radio-over-Fiber and Space Division Multiplexing

“…By moving to analog transport, not only does ARoF fronthaul maintain the centralization of the complete baseband processing, it further centralizes the digital to analog converter (DAC) and analog to digital converter (ADC) stages otherwise located at the RU, as shown in Fig. 1(d and -with narrow optical filtering or multiplexing -may even be reduced below that by interleaving optical carriers and modulation sidebands with narrow channel spacings [15], [22]. If combined with optical heterodyning, ARoF becomes especially interesting for mm-wave 5G NR signal generation as the ARoF link can not only transparently transport an IF signal, but also perform its upconversion to mm-wave through optical heterodyning on the photodiode (PD) at the RU -while keeping the required RF oscillator at the CO [14], [27].…”

“…Beyond the introduction of ARoF with PIC-based transceivers, optical space division multiplexing (SDM) can provide a significant capacity upgrade in the RAN and further allows sharing of a common passive optical distribution network (ODN) for both radio access and other fiber-based access networks, such as passive optical networks (PONs) [22]. While initially suggested as a method to push the ultimate capacity of fiber networks using spatial multiplexing in different cores or modes or a combination thereof [23], the use of SDM with multi-core fiber (MCF) in RANs has gained significant interest, especially in connection with ARoF transport and the use of optical beamforming [21], [24], [25].…”

A Review on MIMO Wireless Signals over Fibre for Next Generation Fibre Wireless (FiWi) Broadband Networks

“…Among these methods, the most used and proven to be successful are: PDM [6,40,[50][51][52][53][54][55][56][57][58][59][60], using comb techniques to generate multiple wavelengths [49,[61][62][63][64] and also hybrid method between them as shown in Figure 8c [6]. It takes benefit from the optical frequency comb techniques and high bandwidth optical modulators (up to 100 GHz) as shown in Figure 8b [64][65][66][67], and multiple widely separated wavelengths can be produced from one continuous-wave (CW) laser. Sending MIMO signals with different frequencies (MIMO diversity technique) over fibre as RoF is easy since there is no overlap in the frequency domain.…”

“…It is observed that 5G network technology would enable 20 Gb/s peak rate per cell and 1000 times data traffic compared to the existing 4G LTE [94]. 5G systems can support MIMO technology, enhancing the spectral efficiency and satisfying the high data rate requirements for today's mobile devices [67]. Moreover, the RoF is the qualifying technology for the future 5G cellular networks [95,96], which can be used in combination with the MIMO technology.…”

“…A unique 5G architecture for the backhaul of 5G MIMO signals over an optical network that is based on UDWDM is proposed in [67]. A big number of OLTs is unified through a ring architecture permitting them to communicate, exchange information and deliver access to ultra-dense mm-wave networks, as shown in Figure 15.…”