A Hybrid LDM, TDM/FDM and Hierarchical Modulation Signal Structure for In-band Distribution Link Transmission in SFN

2021 ◽  
Author(s):  
Lidie Liu ◽  
Yin Xu ◽  
Yiyan Wu ◽  
Dazhi He ◽  
Wenjun Zhang
Keyword(s):  
Hierarchical Modulation ◽  
Signal Structure ◽  
Modulation Signal

Dual-Hop Transmission Scheme Based on Hierarchical Modulation in Wireless Networks

2010 ◽  
Vol E93-B (6) ◽  
pp. 1645-1648 ◽  
Author(s):  
Jeong-Chul SHIN ◽  
Jin-Hyuk SONG ◽  
Jee-Hoon KIM ◽  
Hyoung-Kyu SONG
Keyword(s):  
Wireless Networks ◽  
Transmission Scheme ◽  
Hierarchical Modulation

Improvement of Carrier Power to Third-Order Intermodulation Distortion Power Ratio for a Power Amplifier at 5.25 GHz using LINC Method

2018 ◽  
Vol 12 (1) ◽  
pp. 34-40
Author(s):  
Said Elkhaldi ◽  
Naima Amar Touhami ◽  
Mohamed Aghoutane ◽  
Taj-eddin Elhamadi
Keyword(s):  
Power Amplifier ◽  
Artificial Neural Network Model ◽  
Power Ratio ◽  
Linear Amplification ◽  
Third Order ◽  
Gaas Mesfet ◽  
Constant Envelope ◽  
Modulation Signal ◽  
Low Efficiency ◽  
Nonlinear Components

Introduction:This paper focuses on improving the power amplifier linearity for wireless communications. The use of a single branch of a power amplifier can produce high distortion with low efficiency.Method:In this paper, the Linear Amplification with Nonlinear Components (LINC) technique is used to improve the linearity and efficiency of the power amplifier. The LINC technique is based on converting the envelope modulation signal into two constant envelope phase-modulated baseband signals. After amplification and combining the resulting signals, the required linear output signal is obtained. To validate the proposed approach, LINC technique is used for linearizing an amplifier based on a GaAs MESFET (described by an artificial neural network Model).Conclusion:Good results have been achieved, and an improvement of about 40.80 dBc and 47.50 dBc respectively is obtained for the Δlower C/I and Δupper C/I at 5.25 GHz.

scholarly journals Fault detection for planetary gearbox based on an enhanced average filter and modulation signal bispectrum analysis

2020 ◽  
Vol 101 ◽  
pp. 408-420 ◽  
Author(s):  
Junchao Guo ◽  
Dong Zhen ◽  
Haiyang Li ◽  
Zhanqun Shi ◽  
Fengshou Gu ◽  
...  
Keyword(s):  
Fault Detection ◽  
Planetary Gearbox ◽  
Modulation Signal ◽  
Average Filter

Fast speed switching response and high modulation signal processing bandwidth through LiNbO3 electro-optic modulators

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Mahmoud M. A. Eid ◽  
Ahmed Nabih Zaki Rashed ◽  
Iraj S. Amiri
Keyword(s):  
Near Infrared ◽  
Infrared Region ◽  
Modulation Bandwidth ◽  
Fast Speed ◽  
Electrooptic Modulators ◽  
High Modulation ◽  
Data Rates ◽  
Electro Optic ◽  
Modulation Signal ◽  
Speed Response

AbstractThis work outlined the fast speed response and high modulation bandwidth through LiNbO3 electro-optic modulators. The refractive index is analyzed to estimate the switching voltage and modulation bandwidth for these modulators. The modulation voltage and data transmission data rates are analyzed and discussed clearly through LiNbO3 electro-optic modulators. The modulator’s performance efficiency is upgraded with the optimum modulator length of 10 mm and its thickness of 2 mm. The proposed modulators are compared with GaAs electrooptic modulators under various electro-optic modulators dimensions at 1300 nm near-infrared region and room temperature.

scholarly journals Neural Network DPD for Aggrandizing SM-VCSEL-SSMF-Based Radio over Fiber Link Performance

Photonics ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 19
Author(s):  
Muhammad Hadi ◽  
Muhammad Awais ◽  
Mohsin Raza ◽  
Kiran Khurshid ◽  
Hyun Jung
Keyword(s):  
Neural Network ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Radio Over Fiber ◽  
Error Vector Magnitude ◽  
Computational Overhead ◽  
Link Performance ◽  
Modulation Signal ◽  
Experimental Findings ◽  
Memory Polynomial

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.

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