scholarly journals Analysis of the Performance of Coded and Uncoded Mixed RF and Multihop Coherent OFDM-FSO Systems for 5G-CRAN Applications

2021 ◽  
Author(s):  
Anbarasi K ◽  
Sangeetha R.G. ◽  
Hemanth C
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Access Network ◽  
Distribution Channel ◽  
Symbol Error Rate ◽  
Coherent Detection ◽  
Bch Codes ◽  
Decode And Forward ◽  
Detection Scheme ◽  
Pointing Error ◽  
Rs Codes

Abstract The performance of coded and uncoded mixed single-hop RF links and multihop FSO link systems for the 5G centralized radio access network (C-RAN) is investigated in this paper using a coherent detection technique. A generalized Nakagami-m fading channel is chosen for the RF link, and the Gamma-Gamma distribution channel is chosen for the FSO link. The RF and FSO links use M-Quadrature Amplitude Modulated Orthogonal Frequency Division Multiplexing (M-QAM OFDM) modulation for the coherent detection scheme. The Meijer-G function is used to calculate outage probability (OP) and average symbol error rate (ASER) for analyzing the performance of coded and uncoded systems. Reed Solomon (RS) and Bose-Chaudhuri-Hocquenghem (BCH) codes are used in the coded system. In relays, the decode and forward (DF) method is used. For analysis, the effects of atmospheric turbulence, atmospheric loss, and pointing error are considered. The results show that the coding technique improves the system's performance. When compared to BCH codes, RS codes improve system performance more. A Monte-Carlo simulation is used to validate the analytical results.

Performance Analysis of Digital Modulation for Coherent Detection of OFDM Scheme on Radio over Fiber System

2016 ◽  
Vol 6 (3) ◽  
pp. 1086 ◽  
Author(s):  
Fauza Khair ◽  
Fakhriy Hario P ◽  
I Wayan Mustika ◽  
Budi Setiyanto
Keyword(s):  
Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Fiber Length ◽  
Direct Detection ◽  
Symbol Error Rate ◽  
Radio Over Fiber ◽  
Coherent Detection ◽  
Fiber System ◽  
Digital Modulation ◽  
Modulation Formats

Radio over fiber (RoF) system with the coherent detection offers high linearity for the transparent transport of high-frequency microwave signals, and better receiver sensitivity compared with intensity-modulated direct detection systems. The purpose of this paper is to analyze the performance of digital modulation for coherent detection of orthogonal frequency division multiplexing (OFDM) scheme on RoF system at 10 Gbps up to 100 km fiber length. The results show that coherent detection of OFDM-RoF system with 16 quadrature amplitude modulation (16-QAM) has the value of  bit error rate (BER) and the symbol error rate (SER) is very low and its constellation is better compared with other modulation formats (4-QAM, quadrature phase shift keying (QPSK), 8-PSK and 16-PSK), which BER 16-QAM is 0.053 and SER is 15.7%. The results also show that BER value of 4-QAM and QPSK relatively similar to fiber length variations. In general, an increasing value of the BER and SER for each modulation format are almost equal to the fiber length of 60-70 km (Region I and II). However, there is a significant increase in the value of BER in fiber length of 80-100 km (Region III. A and III. B) for the modulation of 4-QAM, QPSK, 8-PSK, and 16-PSK.

scholarly journals Performance Analysis of Digital Modulation for Coherent Detection of OFDM Scheme on Radio over Fiber System

2016 ◽  
Vol 6 (3) ◽  
pp. 1086
Author(s):  
Fauza Khair ◽  
Fakhriy Hario P ◽  
I Wayan Mustika ◽  
Budi Setiyanto
Keyword(s):  
Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Fiber Length ◽  
Direct Detection ◽  
Symbol Error Rate ◽  
Radio Over Fiber ◽  
Coherent Detection ◽  
Fiber System ◽  
Digital Modulation ◽  
Modulation Formats

Radio over fiber (RoF) system with the coherent detection offers high linearity for the transparent transport of high-frequency microwave signals, and better receiver sensitivity compared with intensity-modulated direct detection systems. The purpose of this paper is to analyze the performance of digital modulation for coherent detection of orthogonal frequency division multiplexing (OFDM) scheme on RoF system at 10 Gbps up to 100 km fiber length. The results show that coherent detection of OFDM-RoF system with 16 quadrature amplitude modulation (16-QAM) has the value of  bit error rate (BER) and the symbol error rate (SER) is very low and its constellation is better compared with other modulation formats (4-QAM, quadrature phase shift keying (QPSK), 8-PSK and 16-PSK), which BER 16-QAM is 0.053 and SER is 15.7%. The results also show that BER value of 4-QAM and QPSK relatively similar to fiber length variations. In general, an increasing value of the BER and SER for each modulation format are almost equal to the fiber length of 60-70 km (Region I and II). However, there is a significant increase in the value of BER in fiber length of 80-100 km (Region III. A and III. B) for the modulation of 4-QAM, QPSK, 8-PSK, and 16-PSK.

Performance Analysis of Laser Phase Noise Compensated COOFDM System

2020 ◽  
Vol 41 (4) ◽  
pp. 445-451
Author(s):  
Divya Dhawan ◽  
Neena Gupta
Keyword(s):  
Phase Noise ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Extinction Ratio ◽  
Symbol Error Rate ◽  
Coherent Detection ◽  
Error Vector Magnitude ◽  
Modulation Formats ◽  
Promising Solution

AbstractOrthogonal Frequency Division Multiplexing along with the coherent detection and spectrally efficient modulation formats is a promising solution for long haul and high speed communication systems. Although they offer significant advantages which make them suitable for high speed and long haul communication systems they all are susceptible to phase noise. In this paper a combination of RF-pilot-based approach followed by pilot-based equalization approach is used for laser phase noise compensation. The various parameters such as drive voltage, bias voltage and extinction ratio are optimized to get the optimum performance from the proposed scheme. The designed system is then analyzed in terms of Symbol Error Rate (SER), constellation diagrams and error vector magnitude using various types of Quadrature Amplitude Modulation (QAM) formats.

On the End-to-End Performance of a Mixed RF-FSO link with a Decode-and-Forward Relay

2019 ◽  
Vol 40 (3) ◽  
pp. 323-332 ◽  
Author(s):  
Himanshu Khanna ◽  
Mona Aggarwal ◽  
Swaran Ahuja
Keyword(s):  
Atmospheric Turbulence ◽  
Error Rate ◽  
Path Loss ◽  
Symbol Error Rate ◽  
Free Space Optical ◽  
Short Term ◽  
Decode And Forward ◽  
Pointing Error ◽  
The Impact

Abstract In this paper, we investigate the performance of a decode-and-forward relayed mixed radio frequency-free space optical (RF-FSO) dual-hop link. The transmitter to receiver link’s first-hop is a RF channel and the second-hop is a FSO channel. The RF link experiences long-term shadowing and short-term multi-path fading effects, while the FSO channel suffers atmospheric turbulence fading, path loss, and pointing error-induced misalignment fading. The performance of the system is analyzed considering the impact of these parameters. We model the RF link by generalized-K fading distribution and the atmospheric turbulence over the FSO link by the gamma–gamma fading. The expressions in closed form for the outage probability, symbol error rate for the system employing $q$-ary PSK modulation schemes, and the channel capacity of the system are derived. The obtained numerical results are also depicted by numerical plots.

Improving Space-Time-Frequency MIMO-OFDM with ICI Self-Cancellation Scheme using Least Square Error Estimator

2015 ◽  
Vol 12 (1) ◽  
pp. 25
Author(s):  
Nur Farahiah Ibrahim ◽  
Zahari Abu Bakar ◽  
Azlina Idris
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Symbol Error Rate ◽  
Space Time ◽  
Least Square ◽  
Error Estimator ◽  
Frequency Diversity ◽  
Time Frequency ◽  
Mimo Ofdm ◽  
Subcarrier Mapping

Channel estimation techniques for Multiple-input Multiple-output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) based on comb type pilot arrangement with least-square error (LSE) estimator was investigated with space-time-frequency (STF) diversity implementation. The frequency offset in OFDM effected its performance. This was mitigated with the implementation of the presented inter-carrier interference self-cancellation (ICI-SC) techniques and different space-time subcarrier mapping. STF block coding in the system exploits the spatial, temporal and frequency diversity to improve performance. Estimated channel was fed into a decoder which combined the STF decoding together with the estimated channel coefficients using LSE estimator for equalization. The performance of the system was compared by measuring the symbol error rate with a PSK-16 and PSK-32. The results show that subcarrier mapping together with ICI-SC were able to increase the system performance. Introduction of channel estimation was also able to estimate the channel coefficient at only 5dB difference with a perfectly known channel.

Performance analysis of RF-FSO communication systems over the Málaga distribution channel with pointing error

Optik ◽  
2021 ◽  
Vol 247 ◽  
pp. 167891
Author(s):  
Vineeth Palliyembil ◽  
Jagadeesh Vellakudiyan ◽  
Palanivel Muthuchidambaranathan
Keyword(s):  
Performance Analysis ◽  
Communication Systems ◽  
Distribution Channel ◽  
Pointing Error

scholarly journals Evaluation of PLC Channel Capacity and ABER Performances for OFDM-Based Two-Hop Relaying Transmission

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Sana Ezzine ◽  
Fatma Abdelkefi ◽  
Jean Pierre Cances ◽  
Vahid Meghdadi ◽  
Ammar Bouallégue
Keyword(s):  
Channel Capacity ◽  
Orthogonal Frequency Division Multiplexing ◽  
Low Cost ◽  
Relay Node ◽  
Destination Node ◽  
Direct Link ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Maximum Ratio Combining ◽  
The Impact

Powerline network is recognized as a favorable infrastructure for Smart Grid to transmit information in the network thanks to its broad coverage and low cost deployment. The existing works are trying to improve and adapt transmission techniques to reduce Powerline Communication (PLC) channel attenuation and exploit the limited bandwidth to support high data rate over long distances. Two-hop relaying BroadBand PLC (BB-PLC) system, in which Orthogonal Frequency Division Multiplexing (OFDM) is used, is considered in this paper. We derive and compare the PLC channel capacity and the end-to-end Average BER (ABER) for OFDM-based direct link (DL) BB-PLC system and for OFDM-based two-hop relaying BB-PLC system for Amplify and Forward (AF) and Decode and Forward (DF) protocols. We analyze the improvements when we consider the direct link in a cooperative communication when the relay node only transmits the correctly decoded signal. Maximum ratio combining is employed at the destination node to detect the transmitted signal. In addition, in this paper, we highlight the impact of the relay location on the channel capacity and ABER for AF and DF transmission protocols. Moreover, an efficient use of the direct link was also investigated in this paper.

scholarly journals Mobile Fog Computing-Assisted Resource Allocation for Two-Hop SWIPT OFDM Networks

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Xiaofei Di ◽  
Yu Zhang ◽  
Tong Liu ◽  
Shaoli Kang ◽  
Yue Zhao
Keyword(s):  
Resource Allocation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Fog Computing ◽  
Achievable Rate ◽  
Fast Time ◽  
Power Splitting ◽  
Frequency Division ◽  
Decode And Forward ◽  
Subcarrier Pairing ◽  
Receiver Architecture

The mobile fog computing-assisted resource allocation (RA) is studied for simultaneous wireless information and power transfer (SWIPT) two-hop orthogonal frequency division multiplexing (OFDM) networks, where a decode-and-forward (DF) relay first harvests energy from signals emitted by a source and then helps the source to forward information to its destination by using the harvested energy. Power splitting (PS) strategy is adopted at the relay and a different PS (DPS) receiver architecture is proposed, where the PS factors of all subcarriers are different. A RA problem is formulated to maximize the system’s achievable rate by jointly optimizing subcarrier pairing, power allocation, and PS factors. Since the RA problem is a nonconvex problem and is difficult to solve, an efficient RA algorithm is designed. As the wireless channels are fast time-varying, the computation is performed in mobile fog node close to end nodes, instead of remote clouds. Results demonstrate that the achievable rate is significantly increased by using the proposed RA algorithm. It is also found that the computation complexity of RA algorithm of DPS receiver architecture is much lower than the existing identical PS (IPS) receiver architecture, and thus the proposed DPS architecture is more suitable for computation-constrained fog system.

scholarly journals Realization of multiplierless coherent detection scheme in digital domain

1988 ◽  
Vol 76 (10) ◽  
pp. 1394-1395
Author(s):  
Kang Cheol-Ho ◽  
Ryu Heunggyoon ◽  
C.H. Lee
Keyword(s):  
Coherent Detection ◽  
Detection Scheme
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