Performance Appraisal of Sigma Delta Modulated Radio over Fiber System

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Muhammad Usman Hadi ◽  
Nelofar Aslam ◽  
Hyun Jung

AbstractRadio over fiber (RoF) is a promising solution for the next-generation wireless networks including fifth-generation Cloud/Centralized Radio Access Network (C-RAN). There exists a possibility to use Sigma Delta Modulated RoF (S-DRoF) that combines the advantages of analog RoF and digital RoF by means of sigma delta modulation (SDM) at the transmitter side subsequently replacing the employment of expensive and high-speed digital-to-analog converters. In this paper, we demonstrate the usage of second-order SDM for LTE 20 MHz signal having 64 QAM modulation on a central carrier frequency of 1.14 GHz for the implementation of S-DRoF for 20 km of standard single mode fiber with baud rate from 25 to 100 Mbaud. Furthermore, a comprehensive analysis of the design of SDM is explained followed by the experimental setup. The performance is reported in terms of error vector magnitude, constellations and adjacent channel power ratio. The results show that the proposed architecture performance is in with accordance to the limitations set by the 3GPP (Third Generation Partnership Project) standards and is a reasonable choice either for upgrading installed systems as well as for the new deployments.

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Muhammad Usman Hadi ◽  
Muhammad Umair Hadi ◽  
Nelofar Aslam ◽  
Rafaqat Ali ◽  
Kiran Khurshid ◽  
...  

AbstractSigma Delta Radio over Fiber (S-DRoF) systems are looked upon as an enabling technology due to their advantages that comes due to combination of analog and digital radio over fiber (RoF) systems. In this paper, we have proposed and experimentally demonstrated a Multi-stAge-noise-SHaping (MASH) based Sigma Delta Modulated RoF system targeting 5G C-RAN (cloud/centralized radio access network) fronthaul applications. The evaluation has been done for LTE 20 MHz signal having 256 quadrature amplitude modulation with a carrier frequency of 3.5 GHz up to 5 Km of Standard Single Mode Fiber (SSMF). Furthermore, a comprehensive analysis of the design is explained followed by the experimental setup. The performance is reported in terms of error vector magnitude (EVM) and adjacent channel leakage ratio. It is concluded that S-DRoF substantiates the desired range of the 5G C-RAN fronthaul networks.


Author(s):  
Muhammad Usman Hadi ◽  
Hyun Jung ◽  
Pier Andrea Traverso ◽  
Giovanni Tartarini

Abstract Sigma-delta radio over fiber (ΣΔ-RoF) is an expedient technology for next-generation networks including 5G cloud/centralized radio access networks (C-RAN). In this article, we demonstrate a realistic experimental scenario for ΣΔ-RoF link targeting C-RAN fronthaul applications, by using baseband second-order 1-bit sigma-delta modulation (ΣΔ-M). The experimental set-up validates the LTE 20 MHz signals having modulation order of 256-quadrature amplitude modulation for a carrier frequency of 3 GHz, up to 10 km of standard single mode fiber. A detailed analysis of the ΣΔ-RoF system performance is reported by adjacent channel leakage ratio and error vector magnitude. Furthermore, an experimental study is evaluated where ΣΔ-RoF is compared with its counterparts. It is deduced that ΣΔ-RoF corroborates the present range of C-RAN fronthaul networks and can be a promising candidate for future mobile haul applications.


2014 ◽  
Vol 988 ◽  
pp. 544-547
Author(s):  
Guang Li

A novel high speed and ultra long-haul radio-over-fiber (ROF) system based on Dual Photoelectric Arms Coherent Modulation (DPACM) and Optical Duo-Binary Coding (ODBC) is proposed, and demonstrated. The signal spectrum bandwidth, generated by ODBC based on the first order DPACM, is half of non-return-to-zero (NRZ ) signal spectrum bandwidth. The secondary order DPACM generates a 40-GHz Millimeter-wave (mm-wave) that is transmitted over fiber (ROF). The simulation results show that, the bit rate can be up to 40 Gbps and the transmission distance is over 1500 Km, based on the ROF system with a 0 dBm continuous-wave laser source, multiple stages Er-Doped Fiber Amplifier (EDFA), a standard single mode fiber (SSMF) with a dispersion of 17 ps/nm/Km and a attenuation of 0.2 dB/Km.


Photonics ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 19
Author(s):  
Muhammad Hadi ◽  
Muhammad Awais ◽  
Mohsin Raza ◽  
Kiran Khurshid ◽  
Hyun Jung

This paper demonstrates an unprecedented novel neural network (NN)-based digital predistortion (DPD) solution to overcome the signal impairments and nonlinearities in Analog Optical fronthauls using radio over fiber (RoF) systems. DPD is realized with Volterra-based procedures that utilize indirect learning architecture (ILA) and direct learning architecture (DLA) that becomes quite complex. The proposed method using NNs evades issues associated with ILA and utilizes an NN to first model the RoF link and then trains an NN-based predistorter by backpropagating through the RoF NN model. Furthermore, the experimental evaluation is carried out for Long Term Evolution 20 MHz 256 quadraturre amplitude modulation (QAM) modulation signal using an 850 nm Single Mode VCSEL and Standard Single Mode Fiber to establish a comparison between the NN-based RoF link and Volterra-based Memory Polynomial and Generalized Memory Polynomial using ILA. The efficacy of the DPD is examined by reporting the Adjacent Channel Power Ratio and Error Vector Magnitude. The experimental findings imply that NN-DPD convincingly learns the RoF nonlinearities which may not suit a Volterra-based model, and hence may offer a favorable trade-off in terms of computational overhead and DPD performance.


Author(s):  
Muhammad Usman Hadi

We propose a 10-Gb/s 64-quadrature amplitude modulation (QAM) signal-based Radio over Fiber (RoF) system for 50 km of standard single mode fiber length which utilizes Reinforcement Learning (RL) SARSA based decision method to indicate an effective decision which mitigates nonlinearity. By utilizing RL-SARSA algorithm, the results demonstrate that significant reduction can be obtained in terms of bit error rate.


2021 ◽  
Author(s):  
Fabio Barros de Sousa ◽  
Fiterlinge M. de Sousa ◽  
Igor R. S. Miranda ◽  
Waldomiro Paschoal ◽  
Marcos B. C. Costa

Abstract In this work, we presented a radio-over-fiber (ROF) access network through two modulation stages for the generation of multiple millimeter wave (mm-wave) signals with frequencies of 20GHz, 40GHz, 60GHz and 80 GHz for the transmission rate of 10 Gbps as a function of the variation of link distance and signal power. The specific purpose of the paper was to design and to investigate a RoF system based on the variation of mm-wave frequencies in order to implement a simple and effective system. In stage 1, there are two modulators in parallel (MZMa and MZMb) called dual-parallel Mach-Zehnder modulator (DP-MZM) and in stage 2 there is only one modulator (MZMc), connected to three pulse generators: Non-Return-to-Zero (NRZ), Return-to-Zero (RZ). A single-mode fiber (SMF) and Gaussian and an erbium-doped fiber amplifier (EDFA) were also used to send signals to base stations (BSs). The numerical analyzes of the results of the eye diagrams showed excellent bit error rate (BER) and quality factor (Q-factor) values, which proved the good performance of the proposed ROF DP-MZM system, for the three encoding formats used, which was able to generate 3-tupling mm-wave for multiple wireless accesses.


Author(s):  
Fakhriy Hario ◽  
Eka Maulana ◽  
Hadi Suyono ◽  
Rini N Hasanah ◽  
Sholeh H Pramono

<p>A well-prepared Radio over Fiber (RoF) is a technology that combines two transmission technologies, radio and optical fiber transmissions. The study focused on the characteristics and problems of the optical fiber medium. One of the problems in the optical fiber is the effect of nonlinear characteristic, which caused by the high light intensity in the optical fiber core with extended interaction area in a single mode fiber (SMF). This characteristic reduces the output width and creates a pulse broadening. The nonlinear characteristics discussed in this study focused on SPM (self-phase modulation) and GVD (Group Velocity Dispersion). To overcome the nonlinear problems, this study presented a method to make the noise-resistant transmitted signal and improve the optical fiber power range. The fundamental of this study was developing similarities of previous studies regarding nonlinearity in the optical fiber. The results show that the use of two modulators combined with the amplification generated the signal with smoother spectrum, which means that the spectrum distribution was more uniform. There was 61.5 % increase of the peak power of the output signal after amplification using an optical amplifier.</p>


2021 ◽  
Vol 11 (9) ◽  
pp. 4015
Author(s):  
Peter Hellwig ◽  
Klaus Schricker ◽  
Jean Pierre Bergmann

High processing speeds enormously enlarge the number of possible fields of application for laser processes. For example, material removal for sheet cutting using multiple passes or precise mass corrections can be achieved by means of spatter formation. For a better understanding of spatter formation at processing speeds of several hundred meters per minute, characterizations of the processing zone are required. For this purpose, a 400 W single-mode fiber laser was used in this study to process stainless steel AISI 304 (1.4301/X5CrNi18-10) with speeds of up to 600 m/min. A setup was developed that enabled a lateral high-speed observation of the processing zone by means of a glass plate flanking. This approach allowed for the measurement of several dimensions, such as the penetration depth, spatter formation, and especially, the inclination angle of the absorption front. It was shown that the loss of mass started to significantly increase when the absorption front was inclined at about 60°. In combination with precise weighings, metallographic examinations, and further external process observations, these findings provided an illustration of four empirical process models for different processing speeds.


2019 ◽  
Vol 0 (0) ◽  
Author(s):  
I. S. Amiri ◽  
P. G. Kuppusamy ◽  
Ahmed Nabih Zaki Rashed ◽  
P. Jayarajan ◽  
M. R. Thiyagupriyadharsan ◽  
...  

AbstractHigh-speed single-mode fiber-optic communication systems have been presented based on various hybrid multiplexing schemes. Refractive index step and silica-doped germanium percentage parameters are also preserved during their technological boundaries of attention. It is noticed that the connect design parameters suffer more nonlinearity with the number of connects. Two different propagation techniques have been used to investigate the transmitted data rates as a criterion to enhance system performance. The first technique is soliton propagation, where the control parameters lead to equilibrium between the pulse spreading due to dispersion and the pulse shrinking because of nonlinearity. The second technique is the MTDM technique where the parameters are adjusted to lead to minimum dispersion. Two cases are investigated: no dispersion cancellation and dispersion cancellation. The investigations are conducted over an enormous range of the set of control parameters. Thermal effects are considered through three basic quantities, namely the transmission data rates, the dispersion characteristics, and the spectral losses.


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