In this work, millimeter wave generation of sixtuple frequency scheme using dual parallel Mach–Zehnder modulator configuration has been investigated. The proposed scheme is mathematically analyzed and its performance is evaluated using software optisystem v.18. The vital parameters of both Mach–Zehnder modulator and phase of radio frequency local oscillator are properly adjusted for upconversion of 10 GHz radio frequency drive signal into 60 GHz mm wave. The impact of Mach–Zehnder modulator extinction ratio on radio frequency sideband suppression ratio, optical sideband suppression ratio and third sideband to carrier suppression ratio, is evaluated. An improved 63 dB third sideband to carrier suppression ratio is achieved at increased extinction ratio of Mach–Zehnder modulator. Impact of bias point drift and electrical phase shift on sideband suppression ratios are evaluated. Further, millimeter wave signal of 6–60 GHz tunability is realized by applying radio frequency local oscillator signal from 1 to 10 GHz.
{"title":"Design and investigation of filterless sixtuple RoF upconversion system with improved sideband to carrier suppression ratio using MZM extinction ratio variance","authors":"Ajay Kumar, Shelly Singla, Deepak Kedia","doi":"10.1515/joc-2023-0384","DOIUrl":"https://doi.org/10.1515/joc-2023-0384","url":null,"abstract":"\u0000 In this work, millimeter wave generation of sixtuple frequency scheme using dual parallel Mach–Zehnder modulator configuration has been investigated. The proposed scheme is mathematically analyzed and its performance is evaluated using software optisystem v.18. The vital parameters of both Mach–Zehnder modulator and phase of radio frequency local oscillator are properly adjusted for upconversion of 10 GHz radio frequency drive signal into 60 GHz mm wave. The impact of Mach–Zehnder modulator extinction ratio on radio frequency sideband suppression ratio, optical sideband suppression ratio and third sideband to carrier suppression ratio, is evaluated. An improved 63 dB third sideband to carrier suppression ratio is achieved at increased extinction ratio of Mach–Zehnder modulator. Impact of bias point drift and electrical phase shift on sideband suppression ratios are evaluated. Further, millimeter wave signal of 6–60 GHz tunability is realized by applying radio frequency local oscillator signal from 1 to 10 GHz.","PeriodicalId":509395,"journal":{"name":"Journal of Optical Communications","volume":"83 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139810859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the current era of everything online, home-users are demanding high speed internet access at their figure tip. The giga-bit (XGPON) fiber based network has proven its capacity to provide higher speed internet at a light-speed. However in such network effectiveness is directly relies on the bandwidth allocation to the each of the user in timely manner. In this paper, modified bandwidth allocation algorithm is proposed to prove its capacity to support larger user with effective bandwidth allocation. The throughput result of this proposed DBA is carried out in network simulator-3 (NS-3), which is improved by 3 % over the existing DBA like Giant, Proportional DBA etc., at little increase in the delay performance of the TCONT-4 based traffic.
{"title":"A modified bandwidth allocation algorithm for XGPON network","authors":"Mehul C. Patel, A. Mandloi","doi":"10.1515/joc-2023-0379","DOIUrl":"https://doi.org/10.1515/joc-2023-0379","url":null,"abstract":"\u0000 In the current era of everything online, home-users are demanding high speed internet access at their figure tip. The giga-bit (XGPON) fiber based network has proven its capacity to provide higher speed internet at a light-speed. However in such network effectiveness is directly relies on the bandwidth allocation to the each of the user in timely manner. In this paper, modified bandwidth allocation algorithm is proposed to prove its capacity to support larger user with effective bandwidth allocation. The throughput result of this proposed DBA is carried out in network simulator-3 (NS-3), which is improved by 3 % over the existing DBA like Giant, Proportional DBA etc., at little increase in the delay performance of the TCONT-4 based traffic.","PeriodicalId":509395,"journal":{"name":"Journal of Optical Communications","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140478858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study proposes a deep neural network (DNN) and long-short-term memory (LSTM) nonlinear compensators method for direct current (DC)-biased optical orthogonal frequency division multiplexing (DCO-OFDM) in indoor visible light communication (VLC) conventional to handle the nonlinearity and retrieve the high-fidelity signals, and compared in terms of performance and complexity. Unlike the data training after fast Fourier transform in existing deep neural network schemes, this study proposes a scheme that uses the time domain waveform data output by photodiodes for direct equalization. The OFDM signal at the receiving end is equalized, which can mitigate hybrid linear and nonlinear impairments and save spectrum resources without requiring the pilots’ assistance. Compared with conventional receivers based on different guide frequencies and existing DL-based reception methods, the proposed adaptive receiver approach yields better bit error rate performance at different signal-to-noise ratios. This research reveals the extreme sensitivity of the LSTM’s performance to system SNR. LSTM outperforms DNN in high signal-to-noise ratio (SNR) situations, but at low SNR, even with high complexity, LSTM falls short of DNN’s performance.
{"title":"Evaluating DNN and LSTM nonlinear compensators for enhanced performance in DCO-OFDM system","authors":"Gerges M. Salama, Amira A. Mohamed, H. Abdalla","doi":"10.1515/joc-2023-0392","DOIUrl":"https://doi.org/10.1515/joc-2023-0392","url":null,"abstract":"\u0000 This study proposes a deep neural network (DNN) and long-short-term memory (LSTM) nonlinear compensators method for direct current (DC)-biased optical orthogonal frequency division multiplexing (DCO-OFDM) in indoor visible light communication (VLC) conventional to handle the nonlinearity and retrieve the high-fidelity signals, and compared in terms of performance and complexity. Unlike the data training after fast Fourier transform in existing deep neural network schemes, this study proposes a scheme that uses the time domain waveform data output by photodiodes for direct equalization. The OFDM signal at the receiving end is equalized, which can mitigate hybrid linear and nonlinear impairments and save spectrum resources without requiring the pilots’ assistance. Compared with conventional receivers based on different guide frequencies and existing DL-based reception methods, the proposed adaptive receiver approach yields better bit error rate performance at different signal-to-noise ratios. This research reveals the extreme sensitivity of the LSTM’s performance to system SNR. LSTM outperforms DNN in high signal-to-noise ratio (SNR) situations, but at low SNR, even with high complexity, LSTM falls short of DNN’s performance.","PeriodicalId":509395,"journal":{"name":"Journal of Optical Communications","volume":"11 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140478536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sidra Ejaz, Sawaiba Shafqat, Kainat Qureshi, Farhan Qamar, Romana Shahzadi, Mudassar Ali
FSO, known as free-space optics, is a competent technology in wireless communication for providing license free spectrum, bandwidth, and high efficiency in next-generation networks. In this paper, an experimental approach is used to deploy FSO channel communication using different intensity modulation schemes such as CSRZ, chirped NRZ, duobinary and AMI. The performance of FSO link is adversely affected by weather conditions like haze, rain, and fog. By using different techniques, it is possible to overcome the effect of atmospheric turbulences. Therefore, four different modulation formats are compared and analyzed by testing different parameters like laser power, range, attenuation, and data rates. Quality of received signal is judged by taking Q-factor, bit error rate (BER), and eye-diagrams. An operating wavelength of 850 nm has been used to simulate the system designs. This paper aims to conclude the best intensity modulation scheme for its use in next generation networks such as 5G where direct deployment of optical fiber is not possible or feasible.
{"title":"Performance comparison of Duobinary, AMI, CNRZ and CSRZ for next generation FSO communication system","authors":"Sidra Ejaz, Sawaiba Shafqat, Kainat Qureshi, Farhan Qamar, Romana Shahzadi, Mudassar Ali","doi":"10.1515/joc-2023-0367","DOIUrl":"https://doi.org/10.1515/joc-2023-0367","url":null,"abstract":"\u0000 FSO, known as free-space optics, is a competent technology in wireless communication for providing license free spectrum, bandwidth, and high efficiency in next-generation networks. In this paper, an experimental approach is used to deploy FSO channel communication using different intensity modulation schemes such as CSRZ, chirped NRZ, duobinary and AMI. The performance of FSO link is adversely affected by weather conditions like haze, rain, and fog. By using different techniques, it is possible to overcome the effect of atmospheric turbulences. Therefore, four different modulation formats are compared and analyzed by testing different parameters like laser power, range, attenuation, and data rates. Quality of received signal is judged by taking Q-factor, bit error rate (BER), and eye-diagrams. An operating wavelength of 850 nm has been used to simulate the system designs. This paper aims to conclude the best intensity modulation scheme for its use in next generation networks such as 5G where direct deployment of optical fiber is not possible or feasible.","PeriodicalId":509395,"journal":{"name":"Journal of Optical Communications","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140478297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The article presents an investigation into Peak-to-Average Power Ratio (PAPR) reduction techniques in Optical Orthogonal Time Frequency Space (O-OTFS) modulation. Focusing on clipping and filtering as well as companding methods, the study explores their efficacy in mitigating PAPR challenges inherent in O-OTFS waveforms. The research evaluates the impact of these techniques on signal quality, particularly in the context of a Rician channel. Clipping and filtering (C&F) are examined for their ability to control amplitude peaks, while companding is analyzed for its role in optimizing dynamic range. The study conducts a comprehensive analysis of Bit Error Rate (BER) and power spectrum density (PSD) under varying conditions, shedding light on how these methods influence the reliability and robustness of OTFS communication. The investigation considers the interplay of these PAPR reduction methods with the unique characteristics of the Rician and Rayleigh channel, which includes a dominant line-of-sight component. The findings contribute valuable insights into designing efficient OTFS modulation systems for real-world scenarios. Ultimately, this research aims to provide a deeper understanding of PAPR reduction strategies in OTFS, offering guidance for optimizing signal processing techniques in communication systems where mitigating PAPR is crucial for achieving high performance and reliable data transmission. It is noted that the proposed C&F and companding algorithms outperform the conventional methods and achieved a PAPR gain of 1–3 dB and BER gain of 10.6–2 dB.
{"title":"Analysis of PAPR reduction of optical-OTFS for 256-QAM using companding and clipping–filtering algorithms","authors":"Arun Kumar, S. Chakravarty, Aziz Nanthaamornphong","doi":"10.1515/joc-2023-0369","DOIUrl":"https://doi.org/10.1515/joc-2023-0369","url":null,"abstract":"Abstract The article presents an investigation into Peak-to-Average Power Ratio (PAPR) reduction techniques in Optical Orthogonal Time Frequency Space (O-OTFS) modulation. Focusing on clipping and filtering as well as companding methods, the study explores their efficacy in mitigating PAPR challenges inherent in O-OTFS waveforms. The research evaluates the impact of these techniques on signal quality, particularly in the context of a Rician channel. Clipping and filtering (C&F) are examined for their ability to control amplitude peaks, while companding is analyzed for its role in optimizing dynamic range. The study conducts a comprehensive analysis of Bit Error Rate (BER) and power spectrum density (PSD) under varying conditions, shedding light on how these methods influence the reliability and robustness of OTFS communication. The investigation considers the interplay of these PAPR reduction methods with the unique characteristics of the Rician and Rayleigh channel, which includes a dominant line-of-sight component. The findings contribute valuable insights into designing efficient OTFS modulation systems for real-world scenarios. Ultimately, this research aims to provide a deeper understanding of PAPR reduction strategies in OTFS, offering guidance for optimizing signal processing techniques in communication systems where mitigating PAPR is crucial for achieving high performance and reliable data transmission. It is noted that the proposed C&F and companding algorithms outperform the conventional methods and achieved a PAPR gain of 1–3 dB and BER gain of 10.6–2 dB.","PeriodicalId":509395,"journal":{"name":"Journal of Optical Communications","volume":"39 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139379962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Free space optical (FSO) communication has gained considerable interest for various applications because of its high speed, security, and low power consumption, which seem like promising advantages for the future. FSO systems are severely constrained by turbulence produced by air temperature and density fluctuations, resulting in scattered and distorted light beams. The capacity and bit error rate (BER) of an FSO link can be influenced by fading brought on by turbulence. Turbulence raises the BER, especially under conditions of moderate and high turbulence. The proposed model suggests using a turbo encoder with an intensity modulator at the FSO transmitter and combining maximum likelihood estimation (MLE), zero-forcing equalization (ZFE), and a turbo decoder for the direct detection receiver. However, MLE does an accurate channel estimate, which minimizes fading and turbulence. ZFE improves the quality of the link even further, while turbo coding lowers the bit error rate by increasing redundancy and greatly enhancing error-correcting capability. The Gamma–Gamma turbulence model simulation showed the proposed system’s superiority over other techniques, which achieved a BER of 10−5 with a signal-to-noise ratio (SNR) of 16 dB for moderate and strong turbulence, respectively. Consequently, even though turbo coding adds redundancy to the signal, it can achieve substantial coding gains that increase FSO capacity.
{"title":"Turbulence mitigation in FSO based on turbo coding and equalization","authors":"Samir M. Hameed","doi":"10.1515/joc-2023-0307","DOIUrl":"https://doi.org/10.1515/joc-2023-0307","url":null,"abstract":"\u0000 Free space optical (FSO) communication has gained considerable interest for various applications because of its high speed, security, and low power consumption, which seem like promising advantages for the future. FSO systems are severely constrained by turbulence produced by air temperature and density fluctuations, resulting in scattered and distorted light beams. The capacity and bit error rate (BER) of an FSO link can be influenced by fading brought on by turbulence. Turbulence raises the BER, especially under conditions of moderate and high turbulence. The proposed model suggests using a turbo encoder with an intensity modulator at the FSO transmitter and combining maximum likelihood estimation (MLE), zero-forcing equalization (ZFE), and a turbo decoder for the direct detection receiver. However, MLE does an accurate channel estimate, which minimizes fading and turbulence. ZFE improves the quality of the link even further, while turbo coding lowers the bit error rate by increasing redundancy and greatly enhancing error-correcting capability. The Gamma–Gamma turbulence model simulation showed the proposed system’s superiority over other techniques, which achieved a BER of 10−5 with a signal-to-noise ratio (SNR) of 16 dB for moderate and strong turbulence, respectively. Consequently, even though turbo coding adds redundancy to the signal, it can achieve substantial coding gains that increase FSO capacity.","PeriodicalId":509395,"journal":{"name":"Journal of Optical Communications","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140514054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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