RoFSO System Based on BCH and RS Coded BPSK OFDM for 5G Applications in Smart Cities

2021 ◽  
Author(s):  
Abhishek Kumar ◽  
Prabu Krishnan
Keyword(s):  
Atmospheric Turbulence ◽  
Orthogonal Frequency Division Multiplexing ◽  
Smart Cities ◽  
Multiple Input Multiple Output ◽  
Weather Conditions ◽  
Error Correcting Codes ◽  
Free Space Optical ◽  
Pointing Error ◽  
Shift Keying ◽  
Input Multiple Output

Abstract In recent years, the radio over free space optical (RoFSO) communication system has become a popular research topic in the field of 5G communication. Atmospheric turbulence typically degrades the performance of RoFSO system. Multiple input multiple output, aperture averaging, error correcting codes, and robust modulation are common mitigation techniques used to reduce the effects of atmospheric turbulence. In this paper, a Reed Solomon (RS) and Bose-Chaudhuri-Hocquenghem (BCH) coded binary shift keying (BPSK) orthogonal frequency division multiplexing (OFDM) based RoFSO system is proposed for 5G applications in smart cities. The average bit error rate (ABER) of the proposed system is investigated for various turbulence, weather, and pointing error cases. The ABER results for uncoded, BCH, and RS coded cases are compared. The results show that the BCH coded system outperforms the RS coded and uncoded systems in all turbulence regimes, weather conditions, and pointing error scenarios.

scholarly journals Performance Improvement for Mixed RF–FSO Communication System by Adopting Hybrid Subcarrier Intensity Modulation

2019 ◽  
Vol 9 (18) ◽  
pp. 3724 ◽  
Author(s):  
Jiang ◽  
Zhao ◽  
Liu ◽  
Deng ◽  
Luo ◽  
...  
Keyword(s):  
Atmospheric Turbulence ◽  
Channel Capacity ◽  
Communication System ◽  
Rayleigh Distribution ◽  
Intensity Modulation ◽  
Phase Shift Keying ◽  
Free Space Optical ◽  
Pointing Error ◽  
Shift Keying ◽  
Binary Phase Shift Keying

The improvement for hybrid radio frequency–free space optical (RF–FSO) communication system in wireless optical communications has acquired growing interests in recent years, but rarely improvement is based on hybrid modulation. Therefore, we conduct a research on end-to-end mixed RF–FSO system with the hybrid pulse position modulation–binary phase shift keying–subcarrier intensity modulation (PPM–BPSK–SIM) scheme. The RF link obeys Rayleigh distribution and the FSO link experiences Gamma–Gamma distribution. The average bit error rate (BER) for various PPM–BPSK–SIM schemes has been derived with consideration of atmospheric turbulence influence and pointing error condition. The outage probability and the average channel capacity of the system are discussed as well. Simulation results indicate that the pointing error aggravates the influence of atmospheric turbulence on the channel capacity, and the RF–FSO systematic performance is improved obviously while adopting PPM–BPSK–SIM under strong turbulence and severe pointing error conditions, especially, when the system average symbol length is greater than eight.

scholarly journals Performance Investigation of OFDM-FSO System under Diverse Weather Conditions of Bangladesh

2018 ◽  
Vol 8 (5) ◽  
pp. 3722
Author(s):  
Maliha Sultana ◽  
Agnila Barua ◽  
Jobaida Akhtar ◽  
Mohammad Istiaque Reja
Keyword(s):  
Atmospheric Turbulence ◽  
Communication Systems ◽  
Weather Conditions ◽  
Index Structure ◽  
Propagation Path ◽  
Free Space Optical ◽  
Atmospheric Attenuation ◽  
Suitable Alternative ◽  
Pointing Error ◽  
Free Spectrum

Free space optical (FSO) communication systems which are deployed for last mile access, being considered as a suitable alternative technology for optical fiber networks. It is one of the emerging technologies for broadband wireless connectivity which has also been receiving growing attention due to high data rate transmission capability with low installation cost and license free spectrum. However, the widespread use of FSO technology has been hampered by the randomly time varying characteristics of propagation path mainly due to atmospheric turbulence, sensitivity to diverse weather conditions and the nonlinear responsivity of laser diode. This paper presents the performance investigation of an OFDM-FSO system over atmospheric turbulence channels under diverse weather conditions of Bangladesh. The channel is modeled with gamma-gamma distribution using 16-QAM modulation format and 4×4 multiple transceiver FSO system. All possible challenges are imposed on the system performance such as atmospheric attenuation, turbulence, pointing error, geometric loss etc. The refractive index structure parameter and atmospheric attenuation coefficient for different weather conditions are calculated by using the data, collected from Bangladesh Meteorological Department. The acquired results can be fruitful for scheming, forecasting and assessing the OFDM-FSO system’s ability to transmit wireless services over turbulent FSO links under actual conditions of Bangladesh.

scholarly journals Unified Performance Analysis of MIMO Mixed RF/FSO Relaying System

2021 ◽  
Vol 11 (7) ◽  
pp. 3054
Author(s):  
Haodong Liang ◽  
Yiming Li ◽  
Maoke Miao ◽  
Chao Gao ◽  
Xiaofeng Li
Keyword(s):  
Outage Probability ◽  
Multiple Input Multiple Output ◽  
Approximate Expression ◽  
Ergodic Capacity ◽  
Free Space Optical ◽  
Decode And Forward ◽  
Pointing Error ◽  
Input Multiple Output ◽  
Practical Engineering ◽  
Relaying System

This paper investigates the asymmetric dual–hop multiple input multiple output (MIMO) mixed radio frequency (RF)/free space optical (FSO) decode–and–forward (DF) relaying system. This kind of system can utilize two different fading characteristic channels to reduce the possibility of the system falling into deep fading. In addition, each link of the system adopts MIMO technology to mitigate the disadvantages of fading. In this paper, the closed form expressions of the outage probability, bit error rate (BER) and average ergodic capacity are derived. The approximate expression of the system outage probability considering the pointing error is also derived. Additionally, asymptotic performance for diversity order and diversity–multiplexing tradeoff (DMT) of the system is analyzed and discussed, which provides direct theoretical basis for practical engineering design.

scholarly journals Study of 5G-NR-MIMO Links in the Presence of an Interferer

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 732
Author(s):  
Avner Elgam ◽  
Yael Balal ◽  
Yosef Pinhasi
Keyword(s):  
Mobile Networks ◽  
Communication Systems ◽  
Multiple Input Multiple Output ◽  
Local Area ◽  
Maximum Energy ◽  
Base Station ◽  
Small Cells ◽  
Diversity Coding ◽  
Shift Keying ◽  
Input Multiple Output

Many communication systems are based on the Multiple Input, Multiple Output (MIMO) scheme, and Orthogonal Space–time Block Transmit diversity Coding (OSTBC), combined with Maximal Ratio Receive Combining (MRRC), to create an optimal diversity system. A system with optimal diversity fixes and optimizes the channel’s effects under multi-path and Rayleigh fading with maximum energy efficiency; however, the challenge does not end with dealing with the channel destruction of the multi-path impacts. Susceptibility to interference is a significant vulnerability in future wireless mobile networks. The 5th Generation New Radio (5G-NR) technologies bring hundreds of small cells and pieces of User Equipment (UE) per indoor or outdoor local area scenario under a specific Long Term Evolution (LTE)-based station (e-NodeB), or under 5G-NR base-station (g-NodeB). It is necessary to study issues that deal with many interference signals, and smart jammers from advanced communication equipment cause deterioration in the links between the UE, the small cells, and the NodeB. In this paper, we study and present the significant impact and performances of 2×2 Alamouti Phase-Shift Keying (PSK) modulation techniques in the presence of an interferer and a smart jammer. The destructive effects affecting the MIMO array and the advanced diversity technique without closed-loop MIMO are analyzed. The performance is evaluated in terms of Bit Error Rate (BER) vs. Signal to Interference Ratio (SIR). In addition, we proved the impairment of the orthogonal spectrum assumption mathematically.

Performance analysis of WDM free space optics transmission system using MIMO technique under various atmospheric conditions

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Kavitha Thandapani ◽  
Maheswaran Gopalswamy ◽  
Sravani Jagarlamudi ◽  
Naveen Babu Sriram
Keyword(s):  
Wavelength Division Multiplexing ◽  
Free Space ◽  
Multiple Input Multiple Output ◽  
Atmospheric Conditions ◽  
Free Space Optical ◽  
Wavelength Division ◽  
Space Optics ◽  
Space Optical Communication ◽  
Input Multiple Output ◽  
And Performance

Abstract Free Space Optical (FSO) communication has evolved as a feasible technique for wireless implementations which offers higher bandwidth capacities over various wavelengths and refers to the transmission of modulated visible beams through atmosphere in order to communicate. Wavelength Division Multiplexing (WDM) is a technology that multiplexes numerous carrier signals onto single fiber using nonidentical wavelengths and enables the efficiency of bandwidth and expanded data rate. Multiple Input Multiple Output (MIMO) is implemented to improve the quality and performance of free space optical communication in various atmospheric conditions. In this paper, a WDM-based FSO communication system is being implemented that benefits from MIMO which receives multiple copies of the signal at receiver that are independent and analyzed for various streams of data in MIMO i.e. 2 × 2, 4 × 4, 8 × 8. Various factors like BER, Quality Factor are analyzed for the WDM-based FSO communication with MIMO using the OptiSystem for various data streams of MIMO under different atmospheric conditions.

A companding approach for PAPR suppression in OFDM based massive MIMO system

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ajay Kumar Yadav ◽  
Pritam Keshari Sahoo ◽  
Yogendra Kumar Prajapati
Keyword(s):  
Massive Mimo ◽  
Orthogonal Frequency Division Multiplexing ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Base Station ◽  
Convex Optimization Problem ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Mimo Ofdm

Abstract Orthogonal frequency division multiplexing (OFDM) based massive multiuser (MU) multiple input multiple output (MIMO) system is popularly known as high peak-to-average power ratio (PAPR) issue. The OFDM-based massive MIMO system exhibits large number of antennas at Base Station (BS) due to the use of large number of high-power amplifiers (HPA). High PAPR causes HPAs to work in a nonlinear region, and hardware cost of nonlinear HPAs are very high and also power inefficient. Hence, to tackle this problem, this manuscript suggests a novel scheme based on the joint MU precoding and PAPR minimization (PP) expressed as a convex optimization problem solved by steepest gradient descent (GD) with μ-law companding approach. Therefore, we develop a new scheme mentioned to as MU-PP-GDs with μ-law companding to minimize PAPR by compressing and enlarging of massive MIMO OFDM signals simultaneously. At CCDF = 10−3, the proposed scheme (MU-PP-GDs with μ-law companding for Iterations = 100) minimizes the PAPR to 3.70 dB which is better than that of MU-PP-GDs, (iteration = 100) as shown in simulation results.

Effect of adverse weather conditions and pointing error on the performance of 2-D WH/TS OCDMA over FSO link

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Bithi Mitra ◽  
Md. Jahedul Islam
Keyword(s):  
Free Space ◽  
Atmospheric Condition ◽  
Optical Power ◽  
Weather Conditions ◽  
Free Space Optical ◽  
Central Wavelength ◽  
Pointing Error ◽  
Adverse Weather ◽  
Code Division Multiple ◽  
Ber Performance

AbstractIn this paper, the performance of two-dimensional (2-D) wavelength-hopping/time-spreading (WH/TS) optical code division multiple access (OCDMA) system over free space optical (FSO) channel is analyzed in the presence of pointing error and different weather conditions. Prime code scheme is employed for both wavelength-hopping and time-spreading to address user code-matrix. The operating central wavelength of 1550 nm is considered to demonstrate the bit error rate (BER) performance of the proposed system as a function of various system parameters. The required optical power of the proposed system is determined to maintain a BER value of 10−9. The numerical evaluation interprets that the BER performance is highly dependent on transmission length, transmitted power, pointing error angle as well as the number of simultaneous user. It is also observed that the 2-D OCDMA system over free space needs minimum required optical power in case of rainy atmospheric condition, but it is maximum for foggy atmospheric condition.

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