Mobility aware of WDM-based CMO OFDM communication system

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Saad M. Hardan ◽  
Ayad A. Abdulkafi ◽  
Saadi Hamad Thalij ◽  
Sherine S. Jumaah
Keyword(s):  
Wavelength Division Multiplexing ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Light Emitting Diode ◽  
Access Point ◽  
Mobile Users ◽  
Visible Light Communications ◽  
Optical Wireless Communications ◽  
High Data ◽  
The Impact

Abstract The continued increase in several mobile applications forces to replace existing limited spectrum indoor radio frequency wireless connections with high-speed ones. Visible light communications (VLC) technology has gained prominence in the development of high data rate transmission for fifth-generation networks. In optical wireless communications, light-emitting diode (LED) transmitters are used in applications that desire mobility as LED divergence enables larger coverage. Since each VLC access point covers a small area, handovers of mobile users are inevitable. Wavelength division multiplexing (WDM) can be used in VLC systems to tackle the above issue and to meet the increasing demand for indoor connectivity with high bit rates. In this paper, a new system architecture for WDM with coded modulated optical in orthogonal frequency division multiplexing (OFDM) VLC system in conjunction with red, green, blue, and yellow (RGBY) LEDs is proposed to reduce the impact of random receiver orientation of indoor mobile users over VLC downlink channels and improves the system’s bit-error-rate (BER) performance. Simulation results show that the proposed method is not affected by the user’s mobility and hence it performs better than other approaches, in terms of BER for all scenarios and at all positions. This study reveals that using WDM-OFDM-VLC with RGBY LEDs to construct a VLC system is very promising.

Lightbeam Configuration Method and Interference Elimination Resource Scheduling for Indoor Multibeam VLC Networks

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Cong-Nam Tran ◽  
Nam-Hoang Nguyen ◽  
Trong-Minh Hoang
Keyword(s):  
Transmission Rate ◽  
Resource Scheduling ◽  
Packet Delay ◽  
Access Point ◽  
Visible Light Communications ◽  
Resource Allocation Algorithm ◽  
Downlink Transmission ◽  
High Data ◽  
Interference Elimination ◽  
Multi Access

AbstractVisible light communications (VLC) is considered as an alternative communications technology for providing indoor wireless services. VLC systems are expected to offer high data transmission rate and seamless coverage. In order to achieve these requirements, VLC systems utilizing multi-lightbeam access points (multibeam VLC-AP) for downlink transmission have been proposed recently. In this paper, we present a lightbeam configuration method and an interference elimination resource scheduling mechanism (IERS) for indoor multibeam multi-access point VLC systems. The proposed lightbeam configuration method ensures seamless connectivity between user equipment and VLC-AP. The proposed IERS mechanism consists of a beam assignment algorithm and a resource allocation algorithm for eliminating co-channel interference as well as improving system performance. Performance results obtained by computer simulation indicate that there are significant improvements in terms of downlink signal to interference plus noise ratio, user throughput and packet delay when the proposed IERS mechanism is deployed.

scholarly journals Experimental Demonstration of Special-Shaped 32-Quadrature Amplitude Modulation Constellations for Visible Light Communications

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Xinyue Guo ◽  
Shuangshuang Li ◽  
Yang Guo
Keyword(s):  
Visible Light ◽  
Amplitude Modulation ◽  
High Speed ◽  
Light Emitting Diode ◽  
Rapid Development ◽  
Average Power ◽  
Visible Light Communication ◽  
Quadrature Amplitude Modulation ◽  
Visible Light Communications ◽  
Transmission Distance

With the rapid development of light-emitting diode, visible light communication (VLC) has become a candidate technology for the next generation of high-speed indoor wireless communication. In this paper, we investigate the performance of the 32-quadrature amplitude modulation (32-QAM) constellation shaping schemes for the first time, where two special circular constellations, named Circular (4, 11, 17) and Circular (1, 5, 11, 15), and a triangular constellation are proposed based on the Shannon’s criterion. Theoretical analysis indicates that the triangular constellation scheme has the largest minimum Euclidian distance while the Circular (4, 11, 17) scheme achieves the lowest peak-to-average power ratio (PAPR). Experimental results show that the bit error rate performance is finally decided by the value of PAPR in the VLC system due to the serious nonlinearity of the LED, where the Circular (4, 11, 17) scheme always performs best under the 7% preforward error correction threshold of 3.8 × 10−3 with 62.5Mb/s transmission data rate and 1-meter transmission distance.

scholarly journals Fuzzy Based Network Assignment and Link-Switching Analysis in Hybrid OCC/LiFi System

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Moh. Khalid Hasan ◽  
Mostafa Zaman Chowdhury ◽  
Md. Shahjalal ◽  
Yeong Min Jang
Keyword(s):  
Hybrid System ◽  
Communication Systems ◽  
High Speed ◽  
Light Emitting Diode ◽  
Flow Analysis ◽  
Optical Wireless Communications ◽  
Light Emitting ◽  
High Speed Data ◽  
Transmission Capability ◽  
Time Division

In recent times, optical wireless communications (OWC) have become attractive research interest in mobile communication for its inexpensiveness and high-speed data transmission capability and it is already recognized as complementary to radio-frequency (RF) based technologies. Light fidelity (LiFi) and optical camera communication (OCC) are two promising OWC technologies that use a photo detector (PD) and a camera, respectively, to receive optical pulses. These communication systems can be implemented in all kinds of environments using existing light-emitting diode (LED) infrastructures to transmit data. However, both networking layers suffer from several limitations. An excellent solution to overcoming these limitations is the integration of OCC and LiFi. In this paper, we propose a hybrid OCC and LiFi architecture to improve the quality-of-service (QoS) of users. A network assignment mechanism is developed for the hybrid system. A dynamic link-switching technique for efficient handover management between networks is proposed afterward which includes switching provisioning based on user mobility and detailed network switching flow analysis. Fuzzy logic (FL) is used to develop the proposed mechanisms. A time-division multiple access (TDMA) based approach, called round-robin scheduling (RRS), is also adopted to ensure fairness in time resource allocation while serving multiple users using the same LED in the hybrid system. Furthermore, simulation results are presented taking different practical application scenarios into consideration. The performance analysis of the network assignment mechanism, which is provided at the end of the paper, demonstrates the importance and feasibility of the proposed scheme.

scholarly journals A 5G C-RAN Optical Fronthaul Architecture for Hotspot Areas Using OFDM-Based Analog IFoF Waveforms

2019 ◽  
Vol 9 (19) ◽  
pp. 4059 ◽  
Author(s):  
Charoula Mitsolidou ◽  
Christos Vagionas ◽  
Agapi Mesodiakaki ◽  
Pavlos Maniotis ◽  
George Kalfas ◽  
...  
Keyword(s):  
Wavelength Division Multiplexing ◽  
Integrated Circuit ◽  
Orthogonal Frequency Division Multiplexing ◽  
Access Network ◽  
Intermediate Frequency ◽  
Error Vector Magnitude ◽  
Photonic Integrated Circuit ◽  
Wavelength Division ◽  
High Data ◽  
Radio Access

Analog fronthauling is currently promoted as a bandwidth and energy-efficient solution that can meet the requirements of the Fifth Generation (5G) vision for low latency, high data rates and energy efficiency. In this paper, we propose an analog optical fronthaul 5G architecture, fully aligned with the emerging Centralized-Radio Access Network (C-RAN) concept. The proposed architecture exploits the wavelength division multiplexing (WDM) technique and multicarrier intermediate-frequency-over-fiber (IFoF) signal generation per wavelength in order to satisfy the demanding needs of hotspot areas. Particularly, the fronthaul link employs photonic integrated circuit (PIC)-based WDM optical transmitters (Txs) at the baseband unit (BBU), while novel reconfigurable optical add-drop multiplexers (ROADMs) cascaded in an optical bus are used at the remote radio head (RRH) site, to facilitate reconfigurable wavelength switching functionalities up to 4 wavelengths. An aggregate capacity of 96 Gb/s has been reported by exploiting two WDM links carrying multi-IF band orthogonal frequency division multiplexing (OFDM) signals at a baud rate of 0.5 Gbd with sub-carrier (SC) modulation of 64-QAM. All signals exhibited error vector magnitude (EVM) values within the acceptable 3rd Generation Partnership Project (3GPP) limits of 8%. The longest reach to place the BBU away from the hotspot was also investigated, revealing acceptable EVM performance for fiber lengths up to 4.8 km.

A Novel Reconfigurable Orthogonal Frequency Division Multiplexing Transceiver

2019 ◽  
Vol 16 (2) ◽  
pp. 430-435
Author(s):  
N. Girinath
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Frequency Division Multiplexing ◽  
Path Delay ◽  
Frequency Division ◽  
Channel Fading ◽  
High Data ◽  
Digital World ◽  
Single Carrier ◽  
Selective Mapping

As the world moves toward 3G/4G there is a need for high data rate and relatively wide bandwidths. OFDM (Orthogonal Frequency Division Multiplexing) a form of multicarrier modulation technique is widely used to achieve high speed efficient data transmission at the rate of several Mbps. It is used in Wi-Fi standards like 802.11a, 802.11n, 802.11ac, broadcast standards like Digital Video Broadcast (DVB) and cellular telecommunications standard LTE. The main advantage of OFDM compared to single carrier modulation is their robustness to channel fading in wireless environment, high baud rates and less inter symbol interference. One major disadvantage is its High PAPR. PTS partial transmit sequences (PTS) and selective mapping are proposed to reduce it. Since FFT is core block of OFDM it must be able to adapt itself to ever changing digital world. A function specific reconfigurable 2k SDF (Single path delay feedback) FFT is proposed. It utilizes less power and can be configured for different FFT sizes ranging from 16-point to 1024-point. The validity and efficiency of the architecture have been verified by simulation in hardware description language VERILOG and targeted on Virtex-6 device. Finally PAPR is estimated by MATLAB simulation.

Modulation and Demodulation Techniques in Indoor Visible Light Communication System

2014 ◽  
Vol 685 ◽  
pp. 306-309
Author(s):  
Hao Wang ◽  
Ze Yu Han
Keyword(s):  
Visible Light ◽  
Communication Technology ◽  
Communication System ◽  
High Speed ◽  
Data Transfer ◽  
Visible Light Communication ◽  
Communication Link ◽  
High Data ◽  
Modulation And Demodulation ◽  
The Impact

Visible light communication technology is a emerging wireless and optical communication technology developed after invention and application of white LED.In this paper, we have a research based on indoor visible light communication system of lighting white LED,discuss of the visible light communication channel characteristics,detailedly analysis of the indoor visible light communication link. This paper focuses on the modulation and demodulation method applied to visible light communication. In the past visible light communication is mainly used off keying modulation,however, the data transfer speed is limited due to the influence of ISI .This paper presents a solution based on OFDM modulation and demodulation, to reduce the impact brought from inter-symbol string under high data transfer speed.Based on data analysis and computer simulation,the program presented in this paper can be used as indoor lighting and high-speed data transmission.Finally, give scheme to achieve visible light communication modulation and demodulation,provide a theoretical basis for further experiments.

scholarly journals ICI Cancellation in OFDM Systems by Frequency Offset Reduction

2014 ◽  
Vol 513-517 ◽  
pp. 3987-3991
Author(s):  
Naveed Ur Rehman ◽  
Lei Zhang ◽  
Muhammad Zahid Hammad ◽  
Emmanuel Anania Mwangosi
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Video Data ◽  
Modulation Scheme ◽  
Ofdm Systems ◽  
Receiver Side ◽  
High Data ◽  
Redundant Data ◽  
Wide Range

The rapid growth within the field of digital communication during the recent years expanded the need for high-speed data transmission to support a wide range of services such as: video, data and voice in wireless communication systems, etc. Orthogonal frequency division multiplexing (OFDM) and a multicarrier modulation scheme are employed to achieve the high data rates. Since OFDM is very much sensitive to carrier frequency offsets, which cause the Inter-carrier Interference (ICI) leads to mitigation of this ICI is necessary. The objectives of this paper are to, proposed an efficient ICI self-cancellation scheme to mitigate the effect of ICI on OFDM systems. For this purpose, a redundant data is transmitted onto adjacent sub-carriers such that the ICI between adjacent sub-carriers cancels out at the receiver side. One data symbol is modulated into a group of adjacent sub carriers with a group of weighting coefficients. At the receiver side, the received signals are linearly combined on these sub carriers with proposed coefficients. The residual ICI contained in the received signals can then be further reduced. This study provides significant carrier-to-interference power ratio (CIR) improvement, which has been studied theoretically and supported by simulations. Since no channel equalization is required to reduce ICI, so the proposed scheme doesnt increase the system complexity.

scholarly journals Performance analysis of symmetrical and bidirectional 40 Gbps TWDM-PON employing m-QAM-OFDM modulation with multi-color LDs based VLC system

2021 ◽  
Author(s):  
Meet Kumari ◽  
Anu Sheetal ◽  
Reecha Sharma
Keyword(s):  
Wavelength Division Multiplexing ◽  
Orthogonal Frequency Division Multiplexing ◽  
Transmission Rate ◽  
Optical Network ◽  
Passive Optical Network ◽  
Input Current ◽  
Full Duplex ◽  
Modulation Formats ◽  
Ofdm Modulation ◽  
The Impact

Abstract In this work, a full-duplex time and wavelength division multiplexing-passive optical network (TWDM-PON) system is analysed. Orthogonal frequency division multiplexing (OFDM) with m-quadrature amplitude modulation (m-QAM) is employed to improve the performance of TWDM-PON for downstream and upstream transmission. Simultaneously, multi-color (390–750 nm) laser diodes (LDs) are employed for visible light communication (VLC) using various VLC links to encourage the information rate of fiber/VLC optical network. A TWDM-PON utilizing 16-, 32- and 64-QAM OFDM with ten LDs based VLC system has been analysed for full-duplex multi-color VLC signals of the system. The impact of the LDs input current and high transmission rate in the proposed PON/VLC link has been investigated for m-QAM OFDM modulation. The results show that the 40/40 Gbps 16-, 32- and 64-QAM signals over ten 8000 m VLC links and a 50 km fiber link are successfully transmitted at the modulation input current of 9 mA under bit error rate (BER) of 3.8×10− 3. Also, the proposed system employing 16-, 32- and 64-QAM signals over a 10 km fiber and ten 10 m VLC links provide the maximum transmission rate of 120, 100 and 80 Gbps respectively. Moreover, the measured error vector magnitudes (EVMs) and calculated BER values for 16-QAM downstream and upstream signals, are well below the required FEC limit than high-order modulation formats. Further, the numerical analysis of the proposed system reveals the superiority of the proposed fiber/VLC links.

scholarly journals Optimization of system’s parameters for wavelength conversion of E-band signals

2022 ◽  
Vol 12 (2) ◽  
pp. 1659
Author(s):  
Yazan Alkhlefat ◽  
Sevia Mahdaliza Idrus Sutan Nameh ◽  
Farabi M. Iqbal
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Wavelength Conversion ◽  
Signal To Noise Ratio ◽  
Optical Amplifier ◽  
Optical Signal ◽  
Error Vector Magnitude ◽  
Wavelength Converter ◽  
High Data

Current and future wireless communication systems are designed to achieve the user’s demands such as high data rate and high speed with low latency and simultaneously to save bandwidth and spectrum. In 5G and 6G networks, a high speed of transmitting and switching is required for internet of things (IoT) applications with higher capacity. To achieve these requirements a semiconductor optical amplifier (SOA) is considered as a wavelength converter to transmit a signal with an orthogonal frequency division multiplexing with subcarrier power modulation (OFDM-SPM). It exploits the subcarrier’s power in conventional OFDM block in order to send additional bits beside the normally transmitted bits. In this paper, we optimized the SOA’s parameters to have efficient wavelength conversion process. These parameters are included the injection current (IC) of SOA, power of pump and probe signals. A 7 Gbps OFDM-SPM signal with a millimeter waves (MMW) carrier of 80 GHz is considered for signal switching. The simulation results investigated and analyzed the performance of the designed system in terms of error vector magnitude (EVM), bit error rate (BER) and optical signal-to-noise ratio (OSNR). The optimum value of IC is 0.6 A while probe power is 9.45 and 8.9 dBm for pump power. The simulation is executed by virtual photonic integrated (VPI) software.

Enhanced Performance Analysis of 10 Gbit/s–10 GHz OFDM-Based Radio over FSO Transmission System Incorporating ODSB and OSSB Modulation Schemes

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Mehtab Singh ◽  
Vigneswaran Dhasarathan
Keyword(s):  
Performance Analysis ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Low Cost ◽  
Weather Conditions ◽  
Space Optics ◽  
Adverse Weather ◽  
Modulation Schemes ◽  
The Impact

AbstractThe exponential rise in the demand for channel bandwidth over the last few years has lead to the problem of spectrum congestion in conventional radio frequency (RF)-based wireless communication systems. Radio over free space optics (RoFSO) provides an effective solution to tackle the problem of spectrum congestion due to its many merits including license-free bandwidth, quick and low-cost installation, cost-effectiveness, and highly secure transmission links. The high-speed data transmission capabilities and immunity to electromagnetic and RF interference makes it a suitable candidate for the development of future 5 G networks. This work focuses on the designing and performance analysis of 10 Gbit/s–10 GHz orthogonal frequency division multiplexing (OFDM) based RoFSO link under the impact of different environmental effects. Also, the performance of the proposed RoFSO link has been compared for different modulation schemes viz. optical dual sideband (ODSB) and optical single sideband (OSSB). Further, we propose an enhanced detection technique deploying Square root module (SRm) at the receiver terminal for link reach enhancement under the impact of adverse weather conditions.

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