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

Abstract

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 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 4G long term evolution (LTE) signal and 5G candidate waveforms-generalized frequency division multiplexing (GFDM) and universally filtered orthogonal frequency division multiplexing (UF-OFDM), through a directly modulated link. 75 bands of LTE and 10 bands of 5G waveforms are successfully transmitted over 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, we demonstrate the fronthaul network for providing simultaneous 4G & 5G services by propagating LTE signals in coexistence with UF-OFDM.

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

“…In this context, IFoF has emerged as a more appealing A-RoF technique that allows transportation of multiple aggregated IF bands, modulated by cost-effective, low-bandwidth linear EMLs [24]. In IFoF, the signals are transmitted via a fiber in different IFs and the up-conversion at the mm-wave band takes place just before the wireless transmission.…”

“…While D-RoF technology tries to overcome the bandwidth explosion with a network layer approach, analog-radio-over-fiber (A-RoF) fronthaul solutions focusing on the physical-layer have been recently proposed in order to further improve the optical spectrum efficiency by the transmission of native analog waveforms over the fiber [22,23]. Towards bringing A-RoF fronthaul networks into realization, research efforts have been currently directed in the development of some key-enabling technologies comprising the use of: intermediate frequency (IF) channel aggregation [24,25], orthogonal frequency division multiplexing (OFDM) waveforms [26], wavelength division multiplexing (WDM) [27] and photonic integrated circuits (PICs) [28].…”

A Gated Service MAC Protocol for 5G Fiber-Wireless Cloud-Radio Access Networks

“…To that end, Analog-Radio-over-Fiber (A-RoF) technology has received increased attention from the research community mainly by virtue of its capability to meet both the centralization and high fronthaul capacity needs [5][6][7][8]. This is achieved by placing all main hardware, i.e., sampling and digital-to-analog conversion components, within the BBU, hence significantly simplifying the RRHs compared to Digital-Radio-over-Fiber (D-RoF) technology [9].…”

Sistema fibra/rádio com vazão de Gbit/s para aplicações 5G

“…Tal aplicabilidade permite explorar a infraestruturaóptica existente, bem como sua capilaridade, para criar uma rede banda larga de distribuição de RF. O estado da arte inclui a distribuição de ondas milimétricas e formas de onda potenciais para 5G [18][19][20], bem como enlaces analógicos de RoF para C-RAN [21,22], assistidos inclusive por processamento digital de sinais [23]. As arquiteturas correlacionadas vêm sendo implementadas utilizando variadas técnicas e componentes, como por exemplo, modulação direta e externa de laser (LD), moduladores eletroópticos de braçoúnico e de fase e quadratura, fotodetectores do tipo PIN (P-Intrinsic-N) e avalanche.…”

“…O objetivoé usar pré-distorção digital (DPD -digital pre-dirtortion) e equalização como soluções para reduzir o EVM RMS obtido na recepção, especialmente em 26 GHz. A principal contribuição em relação ao estado da arte [18][19][20][21][22][23][24][25] refere-se ao emprego conjunto de processamento digital de sinais (DSP -digital signal processing) e DD-MZM na implementação do sistema fibra/rádio para aplicações 5G. Contribuições adicionais em relação a [24,25] referem-seà investigação de ordens superiores de modulação e diferentes larguras de faixa, bem comoà demonstração de vazão igual a 4 Gbit/s e EVM RMS de 4,6% na femtocélula com 10 m de alcance.…”