Performance analysis of Modified 16-Channel WDM-RoF network for Efficient Long-Haul 5G Communication

Haldia Institute of Technology Publishing Int.J.HIT.TRANSC:ECCN.Vol.12: Issue 1 A Available Online at www.hithaldia.in/locate/ECCN *Corresponding Address: [email protected] ORIGINAL CONTRIBUTION Performance analysis of Modified 16 for Efficient LongHaul 5G Communication Suman Singh 1 , Priyanka Dalal 1 , Pravesh Kumari Guru Jambheshwar University of Science and Technology, Dept. of E.E.E., Hisar, India Email Id: priyanka.dalal1[email protected] ABSTRACT This paper presents the design and performance evaluation of a 16 Radio-over-Fibre (WDMRoF) system for long integrates Fiber Bragg Gratings (FBGs) and an Optical Phase Conjugator (OPC) to enhance signal quality. The FBGs provide precise wavelength filtering and dispersion management, while the OPC effectively compensates nonlinear distortions, i mproving spectral efficiency and transmission reach. The system is designed to operate at a carrier frequency of 50 GHz with a data rate of 10 Gbps per channel and a channel spacing of 0.5 nm, achieving reliable transmission over 340 km of standard single the proposed 16-channel WDMRoF model exhibits superior performance compared to conventional configurations, offering enhanced signal integrity, reduced dispersion effects, and improved scalability for high-capacity longhaul communication. KEY WORDS:WDMRoF, Wavelength Division Multiplexing, Fiber Bragg Grating (FBG), Optical Phase Conjugation (OPC), LongHaul Communication, 5g Networks. 1. INTRODUCTION The evergrowing number of wireless communication users, combined with the demand for higher data rates, has led to the migration from conventional frequency bands to higher frequency ranges such as the millimetre-wave (mmwave) spectrum. These high-freque ncy bands are critical for addressing the requirements of nextgeneration communication systems, particularly 5G and beyond, which demand ultrahigh capacity, low latency, and reliable connectivity [1-4]. Optical fiber has established itself as the most ef fective transmission medium for Radio (RoF) systems due to its unique properties, including low attenuation, lightweight nature, high bandwidth, cost efficiency, and immunity to electromagnetic interference [56]. These features make optical fib an efficient medium for transporting radio frequency (RF) signals over long distances while maintaining signal fidelity [79]. Compared with traditional Haldia Institute of Technology Publishing International Journal of HIT Transaction on ECCN A (2025)Page 49-59 ISSN: 0973-6875 Available Online at www.hithaldia.in/locate/ECCN All Rights Reserved [email protected] DOI: 10.5281/zenodo.17499935 Performance analysis of Modified 16 -Channel WDMRoF network Haul 5G Communication , Pravesh Kumari 1 and Sanjeev Kumar Dhull 1 Guru Jambheshwar University of Science and Technology, Dept. of E.E.E., Hisar, India This paper presents the design and performance evaluation of a 16 - channel Wavelength Division Multiplexed RoF) system for long - haul 5G communication networks. The propo integrates Fiber Bragg Gratings (FBGs) and an Optical Phase Conjugator (OPC) to enhance signal quality. The FBGs provide precise wavelength filtering and dispersion management, while the OPC effectively compensates mproving spectral efficiency and transmission reach. The system is designed to operate at a carrier frequency of 50 GHz with a data rate of 10 Gbps per channel and a channel spacing of 0.5 nm, achieving reliable transmission over 340 km of standard single - mode fiber. Simulation results demonstrate that RoF model exhibits superior performance compared to conventional configurations, offering enhanced signal integrity, reduced dispersion effects, and improved scalability for haul communication. RoF, Wavelength Division Multiplexing, Fiber Bragg Grating (FBG), Optical Phase Haul Communication, 5g Networks. growing number of wireless communication users, combined with the demand for higher data rates, has led to the migration from conventional frequency bands to higher frequency ranges such as wave) spectrum. These ncy bands are critical for addressing the generation communication systems, particularly 5G and beyond, which demand high capacity, low latency, and reliable Optical fiber has established itself as the most fective transmission medium for Radio -over-Fiber (RoF) systems due to its unique properties, including low attenuation, lightweight nature, high bandwidth, cost efficiency, and immunity to electromagnetic 6]. These features make optical fib er an efficient medium for transporting radio frequency (RF) signals over long distances while maintaining 9]. Compared with traditional wireless transmission methods, RoF technology leverages the vast bandwidth of optical fibre to suppo rt a significantly larger number of users and higher transmission rates [1012]. To enable longhaul RoF transmission, optical amplification is often required. Erbium Amplifiers (EDFAs) play a key role in boosting signal strength, compensating for transmission losses across fiber spans [13]. In Wavelength Division Radio-over-Fibre (WDMRoF) architectures, additional components such as Mach Modulators (MZMs) are employed for efficient signal modulation, while Optical Phase Con mitigate the effects of nonlinearities [14 effectively compensates for impairments caused by selfphase modulation (SPM), cross modulation (XPM), and fourwave mixing (FWM), thereby improving system performance. Dispersion ma nagement is equally important, with Dispersion Compensating Fiber (DCF) commonly utilized to International Journal of HIT Transaction on ECCN P a g e | 49 RoF network channel Wavelength Division Multiplexed haul 5G communication networks. The propo sed architecture integrates Fiber Bragg Gratings (FBGs) and an Optical Phase Conjugator (OPC) to enhance signal quality. The FBGs provide precise wavelength filtering and dispersion management, while the OPC effectively compensates mproving spectral efficiency and transmission reach. The system is designed to operate at a carrier frequency of 50 GHz with a data rate of 10 Gbps per channel and a channel spacing of 0.5 nm, mode fiber. Simulation results demonstrate that RoF model exhibits superior performance compared to conventional configurations, offering enhanced signal integrity, reduced dispersion effects, and improved scalability for RoF, Wavelength Division Multiplexing, Fiber Bragg Grating (FBG), Optical Phase wireless transmission methods, RoF technology leverages the vast bandwidth of optical fibre to rt a significantly larger number of users and 12]. haul RoF transmission, optical amplification is often required. Erbium -Doped Fiber Amplifiers (EDFAs) play a key role in boosting for transmission losses across fiber spans [13]. In Wavelength Division Multiplexed RoF) architectures, additional components such as Mach –Zehnder Modulators (MZMs) are employed for efficient signal modulation, while Optical Phase Con jugators (OPCs) mitigate the effects of nonlinearities [14 -15]. OPC effectively compensates for impairments caused by phase modulation (SPM), cross -phase wave mixing (FWM), thereby improving system performance. Dispersion nagement is equally important, with Dispersion Compensating Fiber (DCF) commonly utilized to Suman Singh et. al../ Int.J.HIT.TRANSC:ECCN. Vol.12: Issue 1A(2025) ISSN: 0973-6875 DOI: 10.5281/zenodo.17499935 P a g e | 50 counteract chromatic dispersion in WDM transmission [16-18]. Despite these advancements, optical fiber communication still suffers from impairments such as attenuation, dispersion, and nonlinear effects, which degrade overall system performance [5][6]. To address these limitations, Fiber Bragg Gratings (FBGs) have been widely deployed in multi-channel WDM systems to suppress unwanted reflections, filter specific wavelengths, and reduce dispersioninduced distortions. By providing accurate wavelength selectivity and dispersion control, FBGs significantly enhance system efficiency and stability [19-20]. Consequently, WDM-RoF has emerged as a promising solution for robust, high-capacity, and scalable communication networks [21]. Building upon prior research on 4-channel and 8-channel WDM-RoF systems, this work advances the field by developing and analyzing a 16-channel WDM-RoF architecture [22]. The proposed system integrates OPC and FBG components to improve signal integrity, suppress nonlinear impairments, and extend transmission distance, thereby addressing the increasing demands of long-haul 5G communication networks [23-24]. The operation of FBGs is based on the Bragg reflection principle, where the central reflected wavelength is determined by the following relation:   = 2 (1) Where, ηef is the core effective index, and Λ is the grating period. The scalability and performance of the system are validated through simulation, demonstrating its potential as a cost-effective and reliable approach for next-generation communication infrastructures. 2. SYSTEM DESIGN The proposed 16-channel WDM-RoF system is modelled and analysed using OptiSystem simulation software. The setup employs multiple continuous-wave (CW) laser sources, each operating around the standard reference wavelength of 1550 nm, with a uniform channel spacing of 0.5 nm, as illustrated in Fig. 1. This configuration ensures efficient wavelength allocation and supports high-capacity transmission. The overall architecture of the system is divided into two primary subsystems: the transmitter and the receiver, as depicted in Fig. 2, Fig. 3 and Fig. 4, respectively. At the transmitter side, each laser source is externally modulated using a dual-drive Mach–Zehnder Modulator (MZM). This modulation scheme enables efficient conversion of electrical data signals into the optical domain, ensuring broad bandwidth and stable transmission. Table 1: Wavelength utilization in the proposed system corresponding to each channel. Channel No. Wavelength (nm) Channel No. Wavelength (nm) Ch 1 1550 Ch 9 1554 Ch 2 1550.5 Ch 10 1554.5 Ch 3 1551 Ch 11 1555 Ch 4 1551.5 Ch 12 1555.5 Ch 5 1552 Ch 13 1556 Ch 6 1552.5 Ch 14 1556.5 Ch 7 1553 Ch 15 1557 ISSN: 0973-6875 DOI: 10.5281/zenodo.17499935 Ch 8 1553.5 The multiplexed optical signals are then combined to form a 16channel WDM stream, which is transmitted over a 340 km single optical fiber link. To mitigate transmission impairments such as chromatic dispersion and nonlinear distortions, an OPC is strategically placed along the transmission path. The OPC generates a Figure1: Basic Block diagram of the WDM At the receiver side, an APD is utilised optical-toelectrical conversion. The APD is selected for its high sensitivity and low characteristics, which are particularly advantageous for detecting weak signals after long-distance transmission. A lowpass electrical filter is further empl oyed to suppress high frequency noise components, ensuring accurate signal recovery. Finally, WDM analysers and optical spectrum analysers are integrated into the design to Suman Singh et. al../ Int.J.HIT.TRANSC:ECCN. Vol. 12 DOI: 10.5281/zenodo.17499935 1553.5 Ch 16 1557.5 The multiplexed optical signals are then channel WDM stream, transmitted over a 340 km single -mode To mitigate transmission impairments such as chromatic dispersion and nonlinear distortions, an OPC is strategically placed along the transmission path. The OPC generates a conjugated replica of the effectively cancelling phase - and improving system linearity. In addition, FBGs are employed as wavelength filters to manage dispersion, suppress crosstalk, and enhance wavelength stability, thereby improving signal integrity across all channels. Basic Block diagram of the WDM - RoF network At the receiver side, an APD is utilised for electrical conversion. The APD is selected for its high sensitivity and low -noise characteristics, which are particularly advantageous for detecting weak signals after pass electrical oyed to suppress high - frequency noise components, ensuring accurate Finally, WDM analysers and optical spectrum analysers are integrated into the design to evaluate key system performance metrics. These include OSNR and SNR and other trans quality indicators that reflect the efficiency of the proposed 16channel WDM Thestrategic use of OPC and FBG elements, combined with effective detection techniques, ensures improved signal quality, enhanced data rates, and robust perfor mance over long optical communication links. 12 : Issue 1A(2025) P a g e | 51 distorted signal, - related distortions and improving system linearity. In addition, FBGs are employed as wavelength -selective filters to manage dispersion, suppress crosstalk, and enhance wavelength stability, thereby signal integrity across all channels. evaluate key system performance metrics. These include OSNR and SNR and other trans mission quality indicators that reflect the efficiency of channel WDM -RoF model. Thestrategic use of OPC and FBG elements, combined with effective detection techniques, ensures improved signal quality, enhanced data mance over long -haul ISSN: 0973-6875 DOI: 10.5281/zenodo.17499935 Figure 2: Schematic layout of the proposed single Figure 3: SenderFigure 4: Recipient The figure illustrates the overall configuration of the designed RoF system. On the transmitter side, a PseudoRandom Bit Sequence (PRBS) generator produces input data, which is encoded using a Non-Return-toZero (NRZ) encoder and modulated through a Mach– Zehnder Modulator (MZM). A continuouswave laser operating at 1550 nm serves as the optical carrier, while a Suman Singh et. al../ Int.J.HIT.TRANSC:ECCN. Vol. 12 DOI: 10.5281/zenodo.17499935 Schematic layout of the proposed single -channel WDMRoF system. Recipient The figure illustrates the overall configuration of the designed RoF system. On the transmitter Random Bit Sequence (PRBS) generator produces input data, which is encoded Zero (NRZ) encoder and Zehnder Modulator wave laser operating at 1550 nm serves as the optical carrier, while a dual-drive LiNbO  MZM is employed for external modulation, enabling efficient optical signal generation. The modulated signals are transmitted over a singlemode fiber link. Figure 2 illustrates the simulated single WDMRoF system incorporating FBG and OPC [25]. 12 : Issue 1A(2025) P a g e | 52 RoF system. MZM is employed for external modulation, enabling efficient optical signal generation. The modulated signals are mode fiber link. Figure 2 illustrates the simulated single -channel RoF system incorporating FBG and OPC ISSN: 0973-6875 DOI: 10.5281/zenodo.17499935 Figure 5: Schematic layout of the proposed 16 To mitigate impairments accumulated during longhaul transmission, an OPC is placed mid span, in conjunction with an FBG for dispersion and nonlinearity management. At the receiver end, the optical signals are passed through a Gaussian lowpass filter before being det by an APD, ensuring improved sensitivity and reduced noise. The overall configuration enhances transmission performance, providing improved signal quality over extended distances. Figure 5 shows the proposed 16channel WDM RoF network, with transmitt ers and receivers represented as blocks, while their internal architectures are detailed in Figures 3 and 4, respectively. Figure 2 illustrates the simulated single WDMRoF system incorporating FBG and OPC [25]. The transmitter configuration of the proposed 16-channel WDMRoF system integrates several functional components, including a PRBS generator, NRZ pulse encoder, Suman Singh et. al../ Int.J.HIT.TRANSC:ECCN. Vol. 12 DOI: 10.5281/zenodo.17499935 Figure 5: Schematic layout of the proposed 16 -channel WDMRoF system. impairments accumulated during haul transmission, an OPC is placed mid - span, in conjunction with an FBG for dispersion and nonlinearity management. At the receiver end, the optical signals are passed through a pass filter before being det ected by an APD, ensuring improved sensitivity and reduced noise. The overall configuration enhances transmission performance, providing improved signal quality over extended distances. channel WDM - ers and receivers represented as blocks, while their internal architectures are detailed in Figures 3 and 4, Figure 2 illustrates the simulated single -channel RoF system incorporating FBG and OPC [25]. The transmitter configuration of the RoF system integrates several functional components, including a PRBS generator, NRZ pulse encoder, continuouswave laser source, sinusoidal oscillator, DC bias generator, and a dual MZM, as outlined in Fig. 3. The WDM transmitter enhances the transmission capacity by producing multiple optical carriers at distinct wavelengths and subsequently combining them into a single optical fiber using a multiplexer. In this design, 16 unique carrier frequencies are generated. To address nonli near distortions in the fiber link, OPC is employed in conjunction with distributed optical amplifiers and dual fiber spans. OPC, also referred to as wavefront reversal, produces a conjugated optical wave by inverting the phase of the original signal. Repr esenting the input optical field as:    =  ∅ the phaseconjugated signal is mathematically equivalent to taking the complex conjugate of the input, yielding:    = ηAte ∅ ∅!"#$ 12 : Issue 1A(2025) P a g e | 53 RoF system. wave laser source, sinusoidal oscillator, DC bias generator, and a dual MZM, as outlined in Fig. 3. The WDM transmitter enhances the transmission capacity by producing multiple optical carriers at distinct wavelengths and subsequently combining them into a single optical fiber using a multiplexer. In this design, 16 unique carrier frequencies are generated. near distortions in the fiber link, OPC is employed in conjunction with distributed optical amplifiers and dual fiber spans. OPC, also referred to as wavefront reversal, produces a conjugated optical wave by inverting the phase esenting the input (2) conjugated signal is mathematically equivalent to taking the complex conjugate of (3) Suman Singh et. al../ Int.J.HIT.TRANSC:ECCN. Vol.12: Issue 1A(2025) ISSN: 0973-6875 DOI: 10.5281/zenodo.17499935 P a g e | 54 where η represents the device efficiency. The combination of OPC with reversed propagation effectively compensates for nonlinear phase distortions and waveform impairments encountered in optical transmission. FBG operates on the principle of Bragg reflection, which occurs due to a periodic refractive index modulation within the optical fiber. This periodic structure is inscribed along a specific length of the fiber, unlike the uniform refractive index of a standard fiber core that typically allows light to propagate without reflection. However, when a periodic refractive index modulation is introduced, it forms a “grating” structure within the fiber. The refractive index modulation is typically achieved by using an ultraviolet (UV) laser to expose the fiber core to intense UV light through a phase mask or interferometric technique. The UV light causes a photosensitive change in the fibers refractive index, resulting in a periodic fluctuation in the refractive index profile. When light propagates through the fiber and encounters the FBG, a portion of the incident beam is returned due to the periodic refractive index modulation. This reflection occurs at a certain wavelength resolved by the period of the grating. This wavelength is called the Bragg wavelength (%&'(() and is given by the Bragg condition [1][25]. %&'(( = 2 ∗  ∗ * (4) where, Λ = the period of the grating * +,, = the effective refractive index The Bragg condition guarantees that reflected light waves undergo constructive interference, thereby producing a strong reflection precisely at the Bragg wavelength. Conversely, wavelengths outside this range propagate through the grating with negligible reflection. By adjusting the grating period and fabrication parameters, an FBG can be tailored to operate either as a narrowband reflector or as a broadband filter. Moreover, tilted grating structures can be employed to control the reflection angle, offering additional flexibility in design. On the receiver side, the system integrates a wavelength demultiplexer, a Gaussian optical filter, and an APD shown in Fig. 4. The demultiplexer separates the multiplexed optical carriers into their individual channels, after which the Gaussian filter suppresses unwanted noise and out-of-band components. The filtered signal is then converted into an electrical domain by the APD. To restore the original data quality, a signal regenerator is incorporated, while a BER) tester evaluates system performance in terms of OSNR and SNR under varying distances. Table 2 outlines the simulation parameters used in this study along with their assigned values. Table 2. Simulation factors. Parameter Value Modulation Scheme LiNb-MZM Suman Singh et. al../ Int.J.HIT.TRANSC:ECCN. Vol.12: Issue 1A(2025) ISSN: 0973-6875 DOI: 10.5281/zenodo.17499935 P a g e | 55 Bit rate 10 Gbps Radio signal frequency 50 GHz Reference wavelength 1550 nm Wavelength spacing 0.5 nm OSNR & SNR Measurement WDM Analyzer 3. RESULTS AND DISCUSSIONS The system is designed using OptiSystem, and its performance is evaluated in terms of OSNR and SNR with respect to transmission distance, bit rate, and carrier frequency. The simulated performance of the proposed 16channel WDM-RoF system is analyzed in terms of key quality metrics, namely OSNR and SNR. Particular emphasis is placed on evaluating the impact of increasing transmission distance on system efficiency. The assessment is carried out for distances ranging from 50 km to 340 km, thereby enabling an in-depth understanding of the system’s transmission capability over longhaul fiber links. Each of the 16 channels operates within the wavelength range of 1550 nm to 1557.5 nm, with a uniform channel spacing of 0.5 nm. The system is simulated at a data rate of 10 Gbps per channel and a 50 GHz RF carrier frequency, providing a robust basis for performance evaluation. The simulation results are summarised in Tables 3 and 4, corresponding to OSNR and SNR variations across different channels and transmission distances. Table 3 presents the OSNR values (in dB) for the 16-channel system. The results demonstrate a gradual reduction in OSNR with increasing fiber length. For example, Ch 1 records an OSNR of 53.31 dB at 120 km, which decreases to 31.35 dB at 340 km, whereas Ch 15 shows 35.13 dB at 120 km, reducing to 17.08 dB at 340 km. The analysis confirms that the OSNR values across all channels remain above the minimum acceptable threshold of 16 dB within the range of 120 km to 340 km, as illustrated in Fig. 6. This indicates that the proposed system ensures reliable transmission performance over long-haul distances. However, the expected degradation in OSNR with distance is primarily attributed to fiber attenuation and chromatic dispersion. Table 3. Variation of OSNR (dB) for Ch 1 to 16 with transmission distance. Distance (km) Channel (Wavelength (nm)) Ch 1 Ch 3 Ch 5 Ch 7 Ch 9 Ch 11 Ch 13 Ch 15 120 53.31 51.24 49.24 47.76 44.17 42.76 39.45 35.13 Suman Singh et. al../ Int.J.HIT.TRANSC:ECCN. Vol.12: Issue 1A(2025) ISSN: 0973-6875 DOI: 10.5281/zenodo.17499935 P a g e | 56 160 51.85 48.62 46.59 45.70 42.75 39.38 38.19 34.85 200 50.89 47.86 44.82 41.79 38.72 37.32 35.59 33.25 240 47.41 45.92 42.89 39.85 36.81 33.65 30.59 27.79 280 40.79 37.73 34.98 33.97 31.71 29.41 28.40 25.19 320 36.65 33.20 30.65 29.31 27.89 23.81 19.75 18.61 Table 4 provides the SNR results for all 16 channels across the same transmission range. The trend is consistent with the OSNR observations, showing decreasing SNR with distance. Table 4. Variation of SNR (dB) for Ch 1 to 16 with transmission distance. Di stance (km) Channel (Wavelength (nm)) Ch 1 Ch 3 Ch 5 Ch 7 Ch 9 Ch 11 Ch 13 Ch 15 120 53.23 51.78 50.72 47.65 44.8 1 41.89 40.15 35.30 160 52.38 48.54 46.79 44.11 42.8 4 40.19 36.98 35.62 200 50.69 49.77 47.10 44.91 40.9 2 38.16 35.81 33.42 240 47.78 45.67 43.19 41.86 39.7 6 37.65 33.55 31.29 280 42.17 40.82 38.98 35.87 33.9 5 31.22 28.78 25.45 320 38.28 35.23 32.47 30.75 28.6 8 25.82 20.32 18.38 For instance, Ch 1 exhibits an SNR of 53.23 dB at 120 km, reducing to 30.41 dB at 340 km, while Channel 15 decreases from 35.30 dB at 120 km to 16.13 dB at 340 km. Despite this decline, the system maintains SNR values well Suman Singh et. al../ Int.J.HIT.TRANSC:ECCN. Vol.12: Issue 1A(2025) ISSN: 0973-6875 DOI: 10.5281/zenodo.17499935 P a g e | 57 above 18 dB across all channels for distances up to 340 km, as depicted in Fig. 5. This highlights the system’s capability to support high-quality signal transmission, although dispersion and attenuation effects remain significant limiting factors over extended distances. Figure 6: Distance vs OSNR Figure 7: Distance vs SNR Table 5. OSNR Comparison of the 16-Channel WDM-RoF Network: Proposed vs. Existing Work. Existing Work[1] Proposed 16-Channel WDM-RoF System Distance 90 km 110 km 120 km 160 km 200 km 240 km 280 km 320 km 340 km Ch 1 65.08 52.82 53.31 51.85 50.89 47.41 40.79 36.65 31.35 Ch 3 64.48 56.66 51.24 48.62 47.86 45.92 37.73 33.20 26.31 Ch 5 61.93 50.69 49.24 46.59 44.82 42.89 34.98 30.65 25.41 Ch 7 41.27 25.68 47.76 45.70 41.79 39.85 33.97 29.31 23.29 Ch 9 - - 44.17 42.75 38.72 36.81 31.71 27.89 20.66 Ch 11 - - 42.76 39.38 37.32 33.65 29.41 23.81 18.49 Ch 13 - - 39.45 38.19 35.59 30.59 28.40 19.75 17.65 Ch 15 - - 35.13 34.85 33.25 27.19 25.19 18.61 17.08