A5029906478- Optical Wireless Communication Technologies
- Advanced Photonic Communication Systems
- Optical Network Technologies
- Semiconductor Lasers and Optical Devices
- Underwater Vehicles and Communication Systems
- Advanced Wireless Communication Technologies
- PAPR reduction in OFDM
- Radio Wave Propagation Studies
- Satellite Communication Systems
- Image Enhancement Techniques
- Indoor and Outdoor Localization Technologies
- Advanced Optical Network Technologies
- Water Quality Monitoring Technologies
- Photonic and Optical Devices
- Advanced MIMO Systems Optimization
- Energy Efficient Wireless Sensor Networks
- Power Line Communications and Noise
- Orbital Angular Momentum in Optics
- Advanced Fiber Optic Sensors
- Energy Harvesting in Wireless Networks
- Adaptive optics and wavefront sensing
- Neural Networks and Reservoir Computing
- Radio Frequency Integrated Circuit Design
- Millimeter-Wave Propagation and Modeling
- IoT-based Smart Home Systems
University of Edinburgh
2015-2024
University of Aveiro
2022
Defence Science and Technology Laboratory
2021
Coventry University
2017
National Institute of Ocean Technology
2016
The University of Western Australia
2016
Glasgow Caledonian University
2013-2014
Northumbria University
2005-2012
Free-space optical communications (FSO) propagated over a clear atmosphere suffers from irradiance fluctuation caused by small but random atmospheric temperature fluctuations. This results in decreased signal-to-noise ratio (SNR) and consequently impaired performance. In this paper, the error performance of FSO using subcarrier intensity modulation (SIM) based on binary phase shift keying (BPSK) scheme turbulent is presented. To evaluate system turbulence regimes weak to strong, probability...
In this paper, the performance of non-orthogonal multiple access (NOMA) is characterized in a downlink visible light communication system for two separate cases. case guaranteed quality service (QoS) provisioning, we derive an analytical expression coverage probability and show existence optimal power allocation coefficients on two-user paired NOMA. opportunistic best-effort formulate closed-form ergodic sum rate, which applicable arbitrary strategies. The that NOMA achieves higher...
An expression for the bit error rate of a multiple subcarrier intensity-modulated atmospheric optical communication system employing spatial diversity is derived. Spatial used to mitigate scintillation caused by turbulence, which assumed obey log-normal distribution. Optimal but complex maximum ratio, equal gain combining (EGC) and relatively simple selection techniques in clear atmosphere are considered. Each modulated using binary phase shift keying. Laser irradiance subsequently signal,...
This paper investigates the use of a pilot signal in reducing electrical peak-to-average power ratio (PAPR) an orthogonal frequency division multiplexing (OFDM) intensity-modulated optical wireless communication system. The phase is chosen based on selected mapping (SLM) algorithm while maximum likelihood criterion used to estimate at receiver. Bit error rate (BER) performance pilot-assisted OFDM system identical that basic (with no and PAPR reduction technique implemented) desired BER less...
In this paper, we experimentally demonstrate for the first time an on off keying modulated visible light communications system achieving 170 Mb/s using artificial neural network (ANN) based equalizer. Adaptive decision feedback (DF) and linear equalizers are also implemented performances measured both real (TI TMS320C6713 digital signal processing board) offline (MATLAB) implementation of equalizers. The performance each equalizer is analyzed in paper a low bandwidth (4.5 MHz) emitting diode...
In this paper the error performance analysis of a low complexity, multiple transmitter generalised space shift keying (GSSK) signalling technique for short range indoor visible light communications is presented. an N_t system, capable achieving spectral efficiency bits/s/Hz. The GSSK system has higher than conventional on-off (OOK) and pulse position modulation (PPM) techniques. much simpler that equivalent regular amplitude (PAM) with similar efficiency. An analytical expression symbol rate...
In this paper, we experimentally demonstrate a multiband carrierless amplitude and phase modulation format for the first time in VLC. We split conventional modulated signal into m subcarriers order to protect from attenuation experienced at high frequencies low-pass VLC systems. investigate relationship between throughput/spectral efficiency m, where = {10, 8, 6, 4, 2, 1} over fixed total bandwidth of 6.5 MHz. show that transmission speeds (spectral efficiencies) 31.53 (4.85), 30.88 (4.75),...
Novel solutions are required to connect billions of devices the network as envisioned by IoT. In this article we propose use LiFi, which is based on off-the-shelf LEDs, an enabler for IoT in indoor environments. We present LiFi4IoT, a system which, addition communication, provides three main services that radio frequency (RF) networks struggle offer: precise device positioning; possibility delivering power, since energy can be harvested from light; and inherent security due propagation...
This paper proposes a low complexity spatial modulation (SM) scheme that combines shift keying (SSK) with pulse position (PPM) for optical wireless communication systems. SM is multi-transmitter technique achieving increased data rate over the traditional on-off (OOK) and PPM signalling methods. Analysis of error performance system in presence noise presented validated via simulations. There perfect agreement between simulation theoretical analysis case <i...
Visible light communications is a technology with enormous potential for wide range of applications within next generation transmission and broadcasting technologies. VLC offers simultaneous illumination data by intensity modulating the optical power emitted LEDs operating in visible electromagnetic spectrum (~370-780 nm). The major challenge systems to date has been improving speeds, considering low bandwidths available commercial LED devices. Thus, improve spectral usage, research...
The performance of underwater visible light communication (UVLC) system is severely affected by absorption, scattering and turbulence. In this article, we study the spectral efficient DC-biased optical orthogonal frequency division multiplexing (DCO-OFDM) in combination with transceiver spatial diversity turbulence channel. Based on approximation weighted sum lognormal random variables (RVs), derived a theoretical exact bit error rate (BER) for DCO-OFDM systems diversity. simulation results...
This paper proposes a coherent multilevel polarization shift keying (MPOLSK) modulation scheme using the spatial diversity detection in free-space optical (FSO) turbulence channel. The symbol error probability (SEP) analysis for proposed MPOLSK system under various regimes has been carried out. power penalty caused by phase tracking investigated. For instance, floors of 1.3×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-5</sup> and 3.4×10...
We present recent progress on visible light communication systems using polymer light-emitting diodes as the transmitters and a commercial silicon photodetector receiver. In this paper, we use at red, green, blue wavelengths to investigate maximum on-off keying link performance of each device type first steps toward wavelength-division multiplexed link. show that total transmission speed 13 Mb/s is achievable when considering raw bandwidth RGB PLEDs. Such rate represents 30% gain over...
This paper reports the effect of data modulation on emitted light quality phosphor converted white LEDs. The results showed that provided expected average current driving LEDs remains unchanged then will stay same. For a dc-balanced modulating signal, with nonvarying value, any fluctuations in instantaneous due to do not have significant impact measured metrics. visible communication applications therefore, signalling becomes prerequisite if by is be preserved. findings are premised adequate...
In this work, we study probabilistic shaping (PS) for optical wireless communications and apply the technique to wavelength division multiplexing (WDM) based visible light communication (VLC). The performance of proposed scheme is validated with an experimental demonstration. set up uses lenses collimate beam triple LEDs. system parameters WDM VLC are then optimised, channel response measured, PS symbols allocated individual orthogonal frequency (OFDM) subcarriers. For conditions under...
This paper presents a simulation framework for modelling optical underwater turbulence in conjunction with absorption and scattering. Using this technique, the channel is evaluated two ways: turbulent statistics different conditions; stationary characteristics. The observed from show that relative impact of on received signal lower highly scattering channel, showing an in-built resilience these channels. Received intensity distributions are presented, commonly used Log-Normal fading model...
Free-space optical communications (FSO) propagated over a clear atmosphere suffers from irradiance fluctuation caused by small but random atmospheric temperature fluctuations. This results in decreased signal- to-noise ratio and consequently impaired error performance. In this paper, the performance of FSO using subcarrier intensity modulation (SIM) based on binary phase shift keying scheme turbulent is presented. To evaluate system turbulence regimes weak to strong, probability density...
Free-Space Optical (FSO) communication is reputed for its ability to proffer solution the access network bottle-neck but when used over long range links, it suffers from scintillation caused by atmospheric turbulence. The modelled using negative exponential distribution. Hereby, we present outage probability and bit error equations of digital sub-carrier intensity modulated FSO system in
This paper demonstrates the merit and de-merit of a low complexity, multiple transmitter generalised space shift keying (GSSK) signalling technique for short range indoor visible light communications. To illustrate high spectral efficiency credential GSSK, an array Nt white emitting diodes (LEDs) is used to demonstrate bits/symbol transmission by exploiting natural differences in channel gains spatially separated LED array. With two power LEDs each having 3 dB modulation bandwidth 8 MHz,...