# Investigation of OFDM-Based HS-PON Using Front-End LiFiSystem for 5G Networks  
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1 Department of Electronics and Communication Engineering, UIE, Chandigarh University, Gharuan, Mohali 140413, India; [EMAIL_ADDRESS]  
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2 Electrical Engineering Department, Alexandria University, Alexandria 21544, Egypt; [EMAIL_ADDRESS]  
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3 Department of Electronics and Communications Engineering, FET, Gurunkula Kangri (Deemed to Be University), Haridwar 249404, India; [EMAIL_ADDRESS]  
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4 SRCOM, Centre Technologic de Telecomunicacions de Catalunya, Castelldefels, 08860 Barcelona, Spain 4.0.  
rooms, subways, etc. LiFi technology provides high transmission rates using the unlicensed visible frequency range (400-800 THz), which is ten thousand times wider than the entire RF spectrum. Since it cannot penetrate objects, it provides a secure transmission method [3; 4]. The characteristics of LiFi make it an ideal candidate for 5G technology. However, pure LiFi networks have inherent shortcomings, such as link vulnerability and limited coverage, which negatively affect the quality of service to users [5]. In areas with limited RF wireless and wired communications, LiFi can be integrated to optical fibers for indoor networks. Hybrid LiFi-fiber links offer high transmission rates, wide coverage ranges, and mobility for 5G mobile networks [6]. The passive optical network (PON) has become the primary counterpart of 5G fronthaul and backhaul networks [7]. PON technology has evolved through three generations, 1 Gbps (2000-2005), 10 Gbps (2010-2015), and 25/50 Gbps (2020). By 2030, PONs will provide 100 and 200 Gbps per wavelength due to improved bandwidth efficiency. It is expected that a consensus optical access network in 5G/B5G will be required not only for urbanization, but also for mobile X-haul and business services [8]. There has been a significant increase in vendor interest in time and wavelength division multiplexed (TWDM) PON technology. A shared optical distribution network (ODN) supports multiple optical line terminals (OLTs) with the TWDM-PON [9]. The TWDM-PON is capable of multi-wavelength operation as well as wavelength tunability, enabling enhanced network functionality not possible with prior generations of the PON. Moreover, it offers 'pay-as-you-grow' deployment of OLT transceiver units and a smooth upgrade of the aggregated capacity in the ODN [10]. The TWDM-PON has the advantage of sustaining high transmission rates with simpler and less complex transceivers [11]. There is a need to improve the transmission data rate for the 25 G TDM-PON to meet the bandwidth demand caused by new \"hungry\" applications. International Telecommunication Union-Telecommunication Standardization (ITU-T) and Institute of Electrical and Electronics Engineers (IEEE) continue to work on standardizing the 25 G TDM-PON. In anticipation of the future 50 G-PON or high-speed PON (HSP-PON), they have been seeking optimal modulation formats and technologies [12]. OFDM is considered to be a promising multiplexing technique for HSP-PONs due to its high spectral efficiency, fiber dispersion resistance, and dynamic resource allocation [13]. LiFi is therefore able to enhance the tolerance to fiber nonlinearities, large fluctuations, and noise introduced by LEDs in a hybrid HS-PONs/OFDM system [14]. The work investigates new network architectures in order to satisfy the data traffic demand, which is continuously increasing. It uses visible light for transmission as well as luminance and is high-speed, bidirectional, and fully optically networked [15]. Aside from providing excellent benefits, it offers low costs, increased data security, and many more. LiFi systems can be made flexible, adaptable, and simple by using OFDM multiplexing techniques. Equipment is connected separately to several orthogonal subcarriers in such systems. A key advantage of OFDM is that it effectively mitigates inter-symbol interference caused by light reflection, allowing multiple access and power loading to be adjusted on each subcarrier [16].