scholarly journals Performance Enhancement for Visible Light Communication Based ADO-OFDM

2021 ◽  
Author(s):  
Samir M. Hameed ◽  
Sinan M. Abdulsatar ◽  
Atheer A. Sabri
Keyword(s):  
Wireless Communications ◽  
Visible Light ◽  
Channel Coding ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Performance Enhancement ◽  
Visible Light Communication ◽  
Ofdm Systems ◽  
Optical Efficiency ◽  
Optical Ofdm

Abstract The increasing demand for bandwidth through modern applications and multimedia services has led to high-speed wireless communications. Optical Wireless Communications (OWC) encourages solutions that provide a higher data rate due to the large bandwidth available. In this paper, performance enhancement approaches will be studied and simulated for Visible Light Communication (VLC) as a case study. The Orthogonal Frequency Division Multiplexing (OFDM) systems are used to investigate Intensity Modulation/ Direct Detection (IM/DD) to improve the performance of VLC. The IM/DD in OWC requires positive real OFDM symbols, so there are many approaches to satisfy this requirement. This paper proposed a model of Asymmetrically Clipped DC-Biased Optical (ADO-OFDM) to use in OWC/VLC environment. The Proposed system has avoided the use of the noise cancelation technique that is used in traditional ADO-OFDM. The results show that the ADO-OFDM has the best spectral efficiency than DC-biased Optical (DCO-OFDM) and Asymmetrically Clipped Optical (ACO-OFDM). Also, it has better optical efficiency than DCO-OFDM with the equally overall Bit Error Rate (BER) at the same signal-to-noise ratio. Hamming channel coding/decoding with different code lengths is applied in various optical OFDM schemes for BER improvements. Furthermore, we simulate and analyze these optical OFDM systems with many modulation orders.

scholarly journals BER Performance of Stratified ACO-OFDM for Optical Wireless Communications over Multipath Channel

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Zelalem Hailu Gebeyehu ◽  
Philip Kibet Langat ◽  
Ciira Wa Maina
Keyword(s):  
Wireless Communications ◽  
Spectral Efficiency ◽  
High Speed ◽  
Multipath Fading ◽  
Ofdm Systems ◽  
Optical Wireless ◽  
Optical Wireless Communications ◽  
Efficiency Loss ◽  
Optical Ofdm ◽  
Ber Performance

In intensity modulation/direct detection- (IM/DD-) based optical OFDM systems, the requirement of the input signal to be real and positive unipolar imposes a reduction of system performances. Among previously proposed unipolar optical OFDM schemes for optical wireless communications (OWC), asymmetrically clipped optical OFDM (ACO-OFDM) and direct current biased optical OFDM (DCO-OFDM) are the most accepted ones. But those proposed schemes experience either spectral efficiency loss or energy efficiency loss which is a big challenge to realize high speed OWC. To improve the spectral and energy efficiencies, we previously proposed a multistratum-based stratified asymmetrically clipped optical OFDM (STACO-OFDM), and its performance was analyzed for AWGN channel. STACO-OFDM utilizes even subcarriers on the first stratum and odd subcarriers on the rest of strata to transmit multiple ACO-OFDM frames simultaneously. STACO-OFDM provides equal spectral efficiency as DCO-OFDM and better spectral efficiency compared to ACO-OFDM. In this paper, we analyze the BER performance of STACO-OFDM under the effect of multipath fading. The theoretical bit error rate (BER) bound is derived and compared with the simulation results, and good agreement is achieved. Moreover, STACO-OFDM shows better BER performance compared to ACO-OFDM and DCO-OFDM.

scholarly journals Hybrid Adaptive Bias OFDM-Based IM/DD Visible Light Communication System

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 257
Author(s):  
Huandong Hong ◽  
Zhengquan Li
Keyword(s):  
Visible Light ◽  
High Power ◽  
Power Efficiency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Visible Light Communication ◽  
Frequency Division ◽  
Optical Ofdm ◽  
Papr Performance ◽  
High Power Efficiency

Conventional optical orthogonal frequency division multiplexing (OFDM) schemes, such as adaptively biased optical OFDM (ABO-OFDM) and hybrid asymmetrically clipped optical OFDM (HACO-OFDM), are unable to tap all the resources of the subcarriers and only achieve relatively high power efficiency. In this paper, a hybrid adaptive bias optical OFDM (HABO-OFDM) scheme for visible light communication (VLC) is proposed to improve spectral efficiency and power efficiency. In the proposed HABO-OFDM scheme, different optical OFDM components are combined for transmission at the same time, and the adaptive bias is designed to ensure the non-negativity, as well as obtaining significantly high power efficiency. Meanwhile, the implementation complexity of the HABO-OFDM receiver is notably lower than the conventional superimposed optical OFDM schemes. Simulation results show that the proposed HABO-OFDM scheme outperforms ABO-OFDM and HACO-OFDM in terms of both peak-to-average-power ratio (PAPR) and power efficiency. The PAPR performance of HABO-OFDM is about 3.2 dB lower than that of HACO-OFDM and 1.7 dB lower than that of ABO-OFDM. Moreover, we can see that the Eb(elec)/N0 required for HABO-OFDM to reach the BER target is lower than the other two schemes at the Bit rate/Normalized bandwidth range of 3.5 to 8.75, which means that the power efficiency of HABO-OFDM is higher in this range.

scholarly journals EVALUASI KINERJA DIRECT CURRENT-BIASED OPTICAL ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (DCO-OFDM) TERHADAP SKALABILITAS SISTEM VISIBLE LIGHT COMMUNICATION

2019 ◽  
Vol 4 (1) ◽  
pp. 33
Author(s):  
Brian Pamukti ◽  
Vinsensius Sigit Widhi Prabowo
Keyword(s):  
Visible Light ◽  
Direct Current ◽  
Orthogonal Frequency Division Multiplexing ◽  
Visible Light Communication ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Optical Ofdm

Direct Current-biased Optical Orthogonal Frequency Division Multiplexing (DCO-OFDM) dengan penambahantegangan 3 V dilakukan menutupi loss 3 dB pada Asymmetrical Clipping Optical-OFDM (ACO-OFDM). Pengujianterhadap dampak dari perubahan posisi penerima terhadap kinerja dianalisis dengan mengubah sudut antarapengirim dan penerima. DCO-OFDM berbeda dengan sistem OFDM pada komunikasi seluler yang menggunakanfrekuensi radio dan nilai sinyal bipolar. Hasil simulasi komputer menunjukan bahwa jarak paling jauh daripengirim ke penerima yang dihasilkan dari sudut 24 adalah 2,413 m atau sama dengan area seluas 1,05 m2.

scholarly journals Experimental Investigation of Zadoff-Chu Matrix Precoding for Visible Light Communication System with OFDM Modulation

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Xinyue Guo ◽  
Yang Guo ◽  
Shuangshuang Li
Keyword(s):  
Visible Light ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Forward Error Correction ◽  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Average Power ◽  
Visible Light Communication ◽  
Potential Candidate ◽  
Ofdm Modulation

Light-emitting diode- (LED-) based visible light communication (VLC) has become a potential candidate for next generation high-speed indoor wireless communication. Due to the limited modulation bandwidth of the LED, orthogonal frequency division multiplexing (OFDM) modulation is particularly preferred in the VLC system to overcome the ISI, which suffers from the high peak-to-average power ratio (PAPR) and leads to severe performance loss. In this paper, we propose and experimentally demonstrate a novel Zadoff-Chu matrix (ZCM) precoding scheme, which can not only reduce the PAPR, but also provide uniform signal-to-noise ratio (SNR) profile. The theoretical analysis and simulation show that the proposed scheme achieves better PAPR performance compared with the traditional precoding schemes. The experimental demonstration further validates the bit error rate (BER) performance improvement, where the measured BERs are all below the 7% pre-forward error correction (pre-FEC) limit of 3.8 × 10−3 when the transmitted data rate is 50 Mb/s.

scholarly journals Experimental Demonstration of Zadoff–Chu Matrix Transform Precoding for MIMO-OFDM Visible Light Communications

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Xinyue Guo ◽  
Chuxian Wang ◽  
Wei Wang
Keyword(s):  
Visible Light ◽  
Orthogonal Frequency Division Multiplexing ◽  
Forward Error Correction ◽  
Average Power ◽  
Visible Light Communication ◽  
Potential Candidate ◽  
Visible Light Communications ◽  
Ofdm Systems ◽  
Experimental Demonstration ◽  
Mimo Ofdm

Visible light communication (VLC) based on a light-emitting diode (LED) is considered to be a potential candidate for the next-generation communication. In this paper, a novel Zadoff–Chu matrix transform (ZCT) precoding is proposed to improve the performance of the traditional space-time block coding- (STBC-) based multiple-input multiple-output and orthogonal frequency division multiplexing (MIMO-OFDM) system. Compared with the existing orthogonal circulant matrix transform (OCT) precoding scheme, the proposed ZCT precoding achieves a much lower peak-to-average power ratio (PAPR) while maintaining the advantage of the uniform signal-to-noise ratio (SNR), which reduces the performance loss caused by LED nonlinearity. To study the system performance further, we set up an experimental demonstration to verify performance improvement under the condition of different driving peak-to-peak voltages (Vpps) and direct current (DC) offsets. Experimental results show that ZCT precoding gains the best bit error rate (BER) performance compared with the traditional and the OCT precoding MIMO-OFDM systems, whose BER is always below the 7% pre-forward error correction (pre-FEC) threshold of 3.8 × 10−3.

New Hybrid PAPR Reduction Techniques for OFDM-Based Visible Light Communication Systems

2018 ◽  
Vol 39 (4) ◽  
pp. 427-435 ◽  
Author(s):  
Haitham Freag ◽  
Emad S. Hassan ◽  
Sami A. El-Dolil ◽  
Moawad I. Dessouky
Keyword(s):  
Visible Light ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Average Power ◽  
Visible Light Communication ◽  
Cumulative Distribution ◽  
Papr Reduction ◽  
Reduction Techniques ◽  
Ber Performance

Abstract Orthogonal frequency division multiplexing (OFDM) is used with visible light communication (VLC) systems to reduce the effects of inter-symbol interference (ISI) and to achieve communication with high speed of data transmission and huge bandwidth. However, OFDM-based VLC systems suffer from high peak-to-average power ratios (PAPRs). This paper proposes a new hybrid PAPR reduction technique based on signal transformation combined with clipping. The Hadamard transform is used in the proposed technique due to its advantages in reducing the PAPR without affecting the bit error rate (BER) of VLC systems. The optimum clipping threshold at which we can simultaneously reduce the PAPR and improve the BER of VLC systems is also determined. In this paper, we also propose a new OFDM structure based on using discrete cosine transform (DCT) precoding before inverse fast Fourier transform (IFFT) stage to further improve the PAPR reduction capability and BER performance. Several experiments are carried out to test the performance of the proposed technique in terms of complementary cumulative distribution function (CCDF) and the BER. The obtained results show that the proposed technique can simultaneously reduce the PAPR and achieve good BER performance when compared to the original OFDM-based VLC system.

scholarly journals Switching MIMO System with Adaptive OFDM Modulation for Indoor Visible Light Communication

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Xinyue Guo ◽  
Keer Zhang ◽  
Xufa Huang
Keyword(s):  
Visible Light ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Mimo System ◽  
Transmit Diversity ◽  
Visible Light Communication ◽  
Spatial Multiplexing ◽  
Visible Light Communications ◽  
Ofdm Modulation ◽  
Adaptive Ofdm

In this paper, we propose and experimentally demonstrate a switching multiple input and multiple output (MIMO) system combining with adaptive orthogonal frequency division multiplexing (OFDM) modulation for high-speed indoor visible light communications. The adaptive OFDM modulation, which is realized by power and bit allocation on OFDM subchannels, is utilized to achieve the maximum channel capacity under a given target bit error rate (BER). Meanwhile, the MIMO mode switches between spatial multiplexing and transmit diversity adapting to the channel correlation, where the modulation order solved by adaptive OFDM modulation is chosen as the switching criterion. Experimental results validate data rates improvement over the pure spatial multiplexing and the pure transmit diversity system, where BERs are all below the 7% preforward error correction (pre-FEC) threshold of 3.8 × 10−3 in experiments.

scholarly journals Hadamard Coded Modulation for Visible Light Communication

2017 ◽  
Vol 4 (1) ◽  
pp. 96 ◽  
Author(s):  
Surendra Shrestha
Keyword(s):  
Visible Light ◽  
Frequency Spectrum ◽  
Secure Communication ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Microwave Frequency ◽  
Visible Light Communication ◽  
Coded Modulation ◽  
Local Networks ◽  
Very High

<p class="Default">In the recent days, Visible Light Communication (VLC), a novel technology that enables standard Light-Emitting-Diodes (LEDs) to transmit data, is gaining significant attention. However, to date, there is very little research on its deployment. The enormous and growing user demand for wireless data is placing huge pressure on existing Wi-Fi technology, which uses the radio and microwave frequency spectrum. Also the radio and microwave frequency spectrum is heavily used and overcrowded. On the other hand, visible light spectrum has huge, unused and unregulated capacity for communications (about 10,000 times greater bandwidth compared to radio spectrum). Li-Fi, the wireless technology based on VLC, is successfully tested with very high speed in lab and also implemented commercially. In the near future, this technology could enable devices containing LEDs, such as car lights, city lights, screens and home appliances, to form their own networks for high speed, secure communication. In this paper the performance analysis of Hadamard Coded Modulation (HCM) for Visible Light Communication (VLC) is carried out. Its performance is compared with that of Orthogonal Frequency Division Multiplexing (OFDM). Also wide overview of need of VLC, applications of VLC and design challenges for VLC are observed. The potential application areas of VLC that are identified include smart lighting of buildings, vehicular communication, defense &amp; security, indoor positioning, road safety, hospitals &amp; healthcare, aviation etc. Aside from the high bandwidth availability of VLC, it has the advantages of very high speed, enhanced security of local networks, less susceptible to interference, less expensive due to co-existence with illumination devices and obviously no fear of health hazards due to radiation.</p><p><strong>Journal of Nepal Physical Society</strong><em><br /></em>Volume 4, Issue 1, February 2017, Page: 93-96</p>

scholarly journals Research on Secure Debugging Interaction of Sensor Nodes Based on Visible Light Communication

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 953 ◽  
Author(s):  
Yuanchu Yin ◽  
Jiefan Qiu ◽  
Zhiqiang Li ◽  
Mingsheng Cao
Keyword(s):  
Visible Light ◽  
Channel Coding ◽  
Sensor Node ◽  
Source Coding ◽  
Visible Light Communication ◽  
Propagation Characteristic ◽  
Transmission Efficiency ◽  
Sensor Nodes ◽  
Pulse Interval ◽  
Inaccessible Area

When a wireless sensor node’s wireless communication fails after being deployed in an inaccessible area, the lost node cannot be repaired through a debugging interaction that relies on that communication. Visible light communication (VLC) as a supplement of radio wave communication can improve the transmission security at the physical layer due to its unidirectional propagation characteristic. Therefore, we implemented a VLC-based hybrid communication debugging system (HCDS) based on VLC using smartphone and sensor node. For the system’s downlink, the smartphone is taken as the VLC gateway and sends the debugging codes to the sensor node by the flashlight. To improve the transmission efficiency of the downlink, we also propose a new coding method for source coding and channel coding, respectively. For the source coding, we analyze the binary instructions and compress the operands using bitmask techniques. The average compression rate of the binary structure reaches 84.11%. For the channel coding, we optimize dual-header pulse interval (DH-PIM) and propose overlapped DH-PIM (ODH-PIM) by introducing a flashlight half-on state. The flashlight half-on state can improve the representation capability of individual symbols. For the uplink of HCDS, we use the onboard LED of the sensor node to transmit feedback debugging information to the smartphone. At the same time, we design a novel encoding format of DH-PIM to optimize uplink transmission. Experimental results show that the optimized uplink transmission time and BER are reduced by 10.71% and 22%, compared with the original DH-PIM.

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