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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Indoor infrared wireless PPM systems

Chan, Hsun-Hung January 1998 (has links)
No description available.
2

Modeling free space optical communication channels for future generation systems deployment

Alqurashi, Fahad 07 1900 (has links)
The COVID-19 global pandemic forced long lock-downs and physical distancing in different world regions. As a consequence, many jobs, services, and courses switched to online mode. This sudden turn of events created a dramatic increase in internet bandwidth demand, which has reached crisis point—even in developed countries—and widened the gap between those living in cities and far-flung regions. Installing new optical fibers to extend the capacity can be expensive. Radiofrequency (RF) is cur- rently the technology of choice to satisfy the bandwidth demand in under-connected regions, but is bandwidth-limited and strictly regulated. Connecting the unconnected via laser beams propagating in the atmosphere can be an efficient solution to provide fiber-like connectivity, while also being economically profitable. Free-space optics (FSO) is an unlicensed technology that uses infrared links to connect two communi- cating terminals. FSO systems can be running quickly compared to RF ones. FSO is also seen as a potential solution to provide high-speed connectivity between satellites and ground stations, and fly unmanned aerial vehicles (UAVs) and ground terminals. However, FSO is subject to various channel-related challenges, including atmospheric attenuation, turbulence, and pointing errors. In this thesis, we develop an FSO chan- nel simulation tool that considers the various effects that could potentially occur in terrestrial and vertical channels. We extend our study to cover structured light beams, which have been intensively considered in the last decade, as an extra degree of freedom for FSO. Finally, we consider realistic meteorological data from different regions in the Kingdom of Saudi Arabia to identify the best locations to deploy FSO systems.
3

SPECTRUM AND POWER EFFICIENT OPTICAL OFDM FOR VISIBLE LIGHT COMMUNICATION SYSTEMS

Bai, Ruowen Jr January 2021 (has links)
The need for wireless connectivity is ever increasing while conventional radio frequency (RF) communications are limited by the amount of available spectrum. Visible light communications (VLC) are emerging as a promising complementary to the RF wireless, thanks to the enormous available bandwidth in the visible spectrum. Moreover, VLC integrates into the ubiquitous illumination infrastructures to satisfy the need for wireless connectivity indoors. Commercially available light-emitting diodes (LEDs) are low-cost, simple, and have a small modulation bandwidth. For the small modulation bandwidth, VLC systems must enjoy high spectral efficiency to achieve high-rate transmission. Additionally, VLC systems must have high power efficiency to help preserve the critical advantage of LEDs for illumination applications. Furthermore, since LED luminaires are constrained by cost, deployed VLC systems must be low-complexity. Indoor VLC channels are dispersive due to multipath propagation indoors and due to the limited bandwidth of the optoelectronics. However, time-domain equalization on such channels can be prohibitively expensive for long serials. These challenges motivate extensive research on optical orthogonal frequency division multiplexing (OFDM). Given those problems and challenges, this thesis introduces novel spectrum- and power-efficient optical OFDM modulation schemes to implement with low complexity in VLC systems. Firstly, absolute value layered asymmetrically clipped optical OFDM (ALACO-OFDM) is presented to achieve high spectral efficiency and high power efficiency with fewer layers, thus requiring low complexity. Compared to its counterparts, ALACO-OFDM can achieve higher spectral efficiency and information rate even with fewer layers. Antisymmetry-constructed clipped optical OFDM (AC-OFDM) is then introduced as a novel low-complexity modulation scheme. To enhance the spectral efficiency and retain low-complexity, layered AC-OFDM (LAC-OFDM) is introduced, consisting of several layers of AC-OFDM signals. LAC-OFDM is shown to be less complex compared to its state-of-the-art counterparts. Concerning a practical VLC dispersive channel, low-complexity layered ACO-OFDM (L-LACO) is introduced with simple equalization. Mathematically, L-LACO generates identical signals to the existing layered asymmetrically-clipped optical OFDM (LACO-OFDM); however, it requires only half arithmetic operations at both the transmitter and the receiver. For a practical bandlimited VLC dispersive channel, the previous optical OFDM modulation schemes will be no longer non-negative after interpolation with sinc(t) pulse. This thesis presents Kramers-Kronig (KK) optical OFDM (KKO-OFDM) to enhance the spectral efficiency and power efficiency for such bandlimited VLC channels. The KKO-OFDM transmit signal is constructed to be real-valued, non-negative, and strictly bandlimited. Numerical results show that KKO-OFDM outperforms DCO-OFDM and LACO-OFDM in bandlimited VLC channels in terms of optical power efficiency. / Thesis / Doctor of Philosophy (PhD) / Visible light communications (VLC) integrate into the ubiquitous light-emitting diode (LED) luminaires, providing lighting and communication simultaneously. Commercially available LEDs are low-cost, simple, and have a limited modulation bandwidth. These LEDs demand that VLC orthogonal frequency division multiplexing (OFDM) modulation schemes be spectrum- and power-efficient with low complexity. Concerning these challenges, this thesis presents a novel spectrum- and power-efficient VLC OFDM scheme with low complexity. Firstly, absolute value layered asymmetrically clipped optical OFDM (ALACO-OFDM) is presented to achieve high spectral and power efficiency while requiring fewer layers. Then layered antisymmetry-constructed clipped optical OFDM (LAC-OFDM) is introduced, which requires low complexity as compared to existing layered asymmetrically-clipped optical OFDM (LACO-OFDM). Given a VLC dispersive channel, low-complexity LACO-OFDM (L-LACO) is furthermore introduced with simple equalization but generates an identical signal to the existing LACO-OFDM. Finally, for a bandlimited VLC channel, Kramers-Kronig optical OFDM (KKO-OFDM) is presented to achieve high spectral and power efficiency. The ALACO-OFDM and LAC-OFDM work in flat VLC line-of-sight links while L-LACO in VLC dispersive links and KKO-OFDM in bandlimited VLC dispersive links with simple equalizer.
4

Evaluation of spectrally efficient indoor optical wireless transmission techniques

Fath, Thilo Christian Martin January 2014 (has links)
Optical wireless communications (OWC) has the potential to become a remedy for the shortage of the radio frequency (RF) spectrum. Especially in indoor environments, OWC could enable wireless home networking systems which offload data traffic from existing RF systems. In OWC, data is transmitted by modulating the intensity of light sources, typically incoherent light emitting diodes (LEDs). Thus, OWC systems employ intensity modulation (IM) and direct detection (DD) of the optical carrier. Since off-the-shelf LEDs have a limited modulation capability, the transmission bandwidth of practical OWC systems is restricted. Consequently, the available bandwidth has to be used efficiently. In this thesis, spectrally efficient optical wireless transmission techniques are evaluated. Firstly, multiple transmitter-receiver techniques are investigated. These multiple-input-multiple-output (MIMO) techniques provide high spectral efficiency, and therefore high data rates. Specifically, the MIMO techniques repetition coding (RC), spatial multiplexing (SMP) and spatial modulation (SM) are analysed for indoor OWC. The performance of these techniques is evaluated analytically and by means of computer simulations. It is shown that inducing power imbalance between the multiple optical transmitters can substantially improve the performance of optical MIMO techniques as the power imbalance improves the differentiability of the multiple channels. In addition, it is found that link blockage and the utilisation of transmitters having different optical wavelengths enhance channel differentiability as well. These methods enable the utilisation of optical MIMO techniques under conditions which typically disallow the application of MIMO schemes due to little differences between the multiple links. Secondly, a novel optical wireless transmitter concept is developed. This concept uses discrete power level stepping to generate intensity modulated optical signals, such as orthogonal frequency division multiplexing (OFDM) waveforms. The transmitter consists of several on-off-switchable LED groups which are individually controlled to emit scaled optical intensities. As a result, the digital-to-analogue conversion of the signals to be sent is done in the optical domain. This method enables the implementation of low-complex and power-efficient optical transmitter front-ends – the major shortcoming of conventional optical OFDM transmitters. Thirdly, a novel approach for wireless data transmission within an aircraft cabin is presented. The data is transferred by 2-dimensional visual code sequences. These sequences are displayed on the in-flight entertainment (IFE) screen and are captured by the built-in camera of a user device which acts as receiver. Transmission experiments within an aircraft cabin mock-up demonstrate the functionality of the implemented system under realistic conditions, such as ambient illumination and geometric configuration. Altogether, this thesis has analysed the potential of spectrally efficient optical wireless transmission techniques. It is shown that OWC systems can greatly benefit from these techniques.
5

Dynamic Spot Diffusing Channel - A Novel Configuration for Indoor Optical Wireless Communications

Khozeimeh, Farhad 11 1900 (has links)
Some pages are blank, but are kept to satisfy the page count of the thesis. / <p> Indoor optical wireless links can potentially achieve high bitrates because there is a wide and unregulated bandwidth in the optical spectrum. Moreover, optical wireless links can be implemented using simple and inexpensive devices. However, indoor optical wireless links have their own drawbacks such as limited power due to safety issues and incapability of passing thorough opaque objects, which limit their mobility, range and bandwidth and have prevented them from being used widely in commercial systems. Therefore, there has been much effort to find new configurations for indoor optical wireless links which are able to overcome these limitations. In this thesis, a novel configuration for indoor optical wireless communication, termed the dynamic spot diffusing (DSD) channel, is proposed. In the DSD system, the transmitter sends optical signals to a small moving area on the ceiling termed a spot. The receiver receives reflections of optical signal from the spot when spot is in field of view of the receiver. This configuration is shown to achieve high bitrates and provide a good deal of mobility for users inside the room. In this work, a theoretical model for the DSD channel is proposed and the DSD channel capacity is discussed and computed. Furthermore, the DSD system design is explained and design issues are discussed in order to approach capacity. Finally, using computer simulations, achievable rates inside a room are computed and shown to be close to calculated channel capacity.</p> / Thesis / Master of Applied Science (MASc)
6

Optical wireless communications for micro-machines

Yuan, Wei Wen January 2011 (has links)
The main objective of this thesis is to develop a communication system that can minimize the micro-machine size and power consumption and maximize the link range and the number of micro-machines that can communicate simultaneously with the base station. Several possible communication systems are compared, including RF communications and active and passive free space optical communications. A directed, half duplex LOS link using a Ferroelectric liquid crystal (FLC) or multiple quantum well (MQW) modulating retroreflector-base passive uplink is then examined in more detail. Two potential geometries are described. In a broad-beam system, light from a source is broadcast to all micro-machines within the field of view (FOV). However, simulations show that the performance is unacceptable for most applications. In a narrow-beam system, light is holographically steered to active micro-machines within the same FOV. Therefore, the link budget has been improved. For a BER not exceeding 10-9, the 850 nm LC narrowbeam system can support maximum range of 146 m at a data rate of 10kbits/s, and the 1525 nm MQW narrowbeam system can support a maximum range of 34 m at a data rate of 10Mbits/s, when the transmitted power in the diffracted beam of the positive first order is 0.5 mW. Experiments have been carried out to verify the model. These were initially carried out with MQW Modulating RetroReflector (MRR). Results were then be used to modify the characteristics of these components in the model. Available components and discrete electronics have been used to set up a simple retro-reflecting link. Experiments have been performed at a limited data rate of 1 kbits/s over a limited range of 1m due to creating a uniform interrogation beam spot, and the active area of the receiver of 1 mm diameter. An algorithm to find the MQW MRR within the FOV is designed and tested.
7

Performance Analysis of DC-offset STBCs for MIMO Optical Wireless Communications

Sapenov, Yerzhan 04 1900 (has links)
In this report, an optical wireless multiple-input multiple-output communication system employing intensity-modulation direct-detection is considered. The performance of direct current offset space-time block codes (DC-STBC) is studied in terms of pairwise error probability (PEP). It is shown that among the class of DC-STBCs, the worst case PEP corresponding to the minimum distance between two codewords is minimized by repetition coding (RC), under both electrical and optical individual power constraints. It follows that among all DC-STBCs, RC is optimal in terms of worst-case PEP for static channels and also for varying channels under any turbulence statistics. This result agrees with previously published numerical results showing the superiority of RC in such systems. It also agrees with previously published analytic results on this topic under log-normal turbulence and further extends it to arbitrary turbulence statistics. This shows the redundancy of the time-dimension of the DCSTBC in this system. This result is further extended to sum power constraints with static and turbulent channels, where it is also shown that the time dimension is redundant, and the optimal DC-STBC has a spatial beamforming structure. Numerical results are provided to demonstrate the difference in performance for systems with different numbers of receiving apertures and different throughput.
8

Statics and dynamics of electrothermal micromirrors

Morrison, Jessica 07 December 2016 (has links)
Adaptive and smart systems are growing in popularity as we shift toward personalization as a culture. With progressive demands on energy efficiency, it is increasingly important to focus on the utilization of energy in a novel way. This thesis investigates a microelectromechanical system (MEMS) mirror with the express intent to provide flexibility in solid state lighting (SSL). By coupling the micromirror to an optical source, the reflected light may be reshaped and directed so as to optimize the overall illumination profile. In addition, the light may be redirected in order to provide improved signal strength in visible light communications (VLC) with negligible impact on energy demands. With flexibility and full analog control in mind, the design of a fully integrated tip-tilt-piston micromirror with an additional variable focus degree of freedom is outlined. Electrothermal actuators are used to both steer the light and tune the focal length. A detailed discussion of the underlying physics behind composite beams and thermal actuators is addressed. This leads directly into an overview of the two main mirror components, namely the segmented mirror and the deflection actuators. An in-depth characterization of the dynamics of the mirror is discussed including the linearity of the thermal response. Frequency domain analysis of such a system provides insight into tunable mechanical properties such as the resonant frequency and quality factor. The degenerate resonant modes can be separated significantly. It is shown that the frequency response may be tuned by straining specific actuators and that it follows a predictable pattern. As a result, the system can be scanned at increasingly large angles. In other words, coupled mechanical modes allow variable damping and amplification. A means to determine the level of coupling is examined and the mode shape variations are tracked as a function of the tuning parameters. Finally, the applications of such a device are explored and tested. Such applications include reliable signal-to-noise ratio (SNR) enhancements in VLC of 30 dB and color tunable steerable lights using laser diodes. A brief discussion of the implications of dynamic illumination and tunable systems is juxtaposed with an explanation behind the integration of an electrothermal micromirror and an all digital driver.
9

Using angle diverse and modulated optical sources for 3D indoor positioning

Lam, Emily 19 May 2020 (has links)
Indoor positioning is an enabling technology primed to impact the indoor application space as Global Navigation Satellite Systems (GNSS) did for the outdoor space. Amongst the competing positioning technologies are methods of different mediums: light, radio frequency and ultra-wideband, ultrasonic, and imaging; methods of different modalities: received signal strength, angle-of-arrival, time-of-flight; and methods of different mathematics: trilateration, triangulation, machine learning, and signal processing. Light-based positioning compared to other positioning schemes exploits fixed-location directional luminaires placed regularly throughout a space as anchor points -- there is an efficiency argument for multi-purpose lighting and a cost-share argument for infrastructure-based positioning. Similar to the satellite infrastructure with GNSS, with anchor points and models for light propagation and construction, position is estimated based on received signals at active photodiode-equipped target devices. Received signal strength, a common first order attribute, alone is not noise resilient enough for centimeter-level 3D positioning. Methods using angle diversity produce better results particularly in 3D but with more complex hardware. For this dissertation, we exploit angle diversity and modulated optical sources in light-based positioning systems to estimate position to centimeter-level accuracy in 3D. We propose, analyze, and contribute two novel positioning schemes that use these concepts. One of the proposed schemes is a new hybrid 3D indoor positioning technique, Ray-Surface Positioning (RSP), which incorporates a narrow field-of-view (FOV) optical source (Ray) with wide diffuse optical sources (Surfaces) to position active devices in 3D. The second scheme, a Zone-based Positioning Service (ZPS), is a positioning scheme and architecture that incorporates an angle diverse narrow FOV optical source at the positioned device. This unique design decision allows the active device to position itself directly with respect to photovoltaic anchor points but also to position other devices in its FOV called transitive positioning. Along with these contributions, we also investigate several other related topics. Concisely, as part of the dissertation, we contribute (a) review of the state-of-the-art, (b) analysis for steering Lambertian sources, (c) method of creating angle diversity from a narrow FOV optical source, (d) novel positioning approaches in (1) RSP and (2) ZPS, (e) proof of concept prototypes for (1) RSP and (2) ZPS, and (f) architectures for indoor positioning applications.
10

Novel 5G-Modulation Formats and Their Application in Optical Wireless Communications

Bahaaelden, Mohammed S. 27 May 2024 (has links)
[ES] La red de sexta generación (6G) es la solución potencial para satisfacer los requisitos exponencialmente crecientes de los servicios y aplicaciones emergentes. La plataforma 6G espera ofrecer altas velocidades de datos, conectividad ultra alta y baja latencia en función de los indicadores clave de rendimiento (KPI) requeridos. La tecnología de comunicación por luz visible (VLC) representa una tecnología clave para la red 6G, pero requiere una técnica de modulación avanzada eficiente para cumplir con dichos requisitos. En las últimas décadas, las señales ópticas basadas en el esquema de multiplexación por división de frecuencia ortogonal (OFDM) han atraído mucha atención y se han convertido en la modulación más popular entre varios esquemas de acceso multiportadora, gracias a su robustez y simplicidad frente a la cancelación por trayectos múltiples utilizando el prefijo cíclico (CP). Una de las formas de onda más prometedoras para redes de próxima generación es la técnica de modulación Filter Bank MultiCarrier (FBMC). El principal beneficio del esquema FBMC es que no depende de CP y de un gran número de muestras de banda de guarda, por lo tanto, emplea varias funciones de pulso localizadas en el tiempo con una alta relación de supresión de lóbulos laterales, lo que permite mejorar la eficiencia espectral y el rendimiento del sistema como factores clave en las redes ópticas de próxima generación, y proporciona una buena alternativa a la técnica CP-OFDM. Esta Tesis pretende dar un paso adelante en la propuesta de formatos de modulación para ser utilizados en sistemas VLC como tecnología habilitadora en redes 6G. Por lo tanto, se propone el sistema Flip-FBMC con un algoritmo de truncamiento para ofrecer una transmisión de alta velocidad con baja latencia Flip-FBMC mediante el uso del algoritmo de transformación ortogonal isotrópica (IOTA) y la capa PHYsical para DYnamic AccesS y filtros de radio cognitiva (PHYDYAS). En esta Tesis se propone la ecualización multitap con el fin de mitigar la Interferencia imaginaria intrínseca (IMI) en un canal con perfiles de retardos elevado en sistemas VLC de interiores. Además, se ha mejorado rendimiento de error de las señales FBMC no coherentes mediante el análisis de la propiedad de la localización de tiempo-frecuencia con la función gaussiana extendida (EGF), donde el factor de dispersión desempeña un papel crucial en la determinación del equilibrio entre las características espectrales y la reconstrucción óptima de la calidad de la señal. Además, la Tesis proporciona el primer análisis teórico que informa de la degradación en la estimación para varios factores de clipping basada en el impacto del nivel de interferencia imaginario fuera de la zona de primer orden que no puede ser estimada mediante el preámbulo de IAM. Sin embargo, se debe enfatizar en el valor de la técnica Flip-FBMC/IAM para proporcionar el modelo unipolar en comparación con el uso del formato FBMC óptico polarizado con corriente continua (DCO-FBMC) que sufre una reducción en la estimación de la precisión. Por lo tanto, se ha demostrado el descenso del rendimiento con el sistema DCO-FBMC debido al IMI inducido fuera de los símbolos de orden cero, y que es más evidente cuando se requieren niveles bajos de corriente DC. Desde esta perspectiva, la técnica de repetición de tramas con señales Flip-FBMC ha demostrado ser una solución importante para minimizar la interferencia inducida. Por lo tanto, en esta Tesis, la modulación Flip-FBMC con repetición de tramas y perfil de filtro PHYDYAS se propone como un candidato viable para hacer frente al rango dinámico restringido del LED, en comparación con el rendimiento de los sistemas Flip-CP-OFDM y Flip-FBMC/IAM en futuras redes 6G basadas en acceso VLC. / [CA] La xarxa de sexta generació (6G) és la solució potencial per a satisfer els requisits exponencialment creixents dels servicis i aplicacions emergents. La plataforma 6G espera oferir altes velocitats de dades, connectivitat ultra alta i baixa latència en funció dels indicadors clau de rendiment (KPI) requerits. La tecnologia de comunicació per llum visible (VLC) representa una tecnologia clau per a la xarxa 6G, però requerix una tècnica de modulació avançada eficient per a complir amb estos requisits. En les últimes dècades, els senyals òptics basats en l'esquema de multiplexació per divisió de freqüència ortogonal (OFDM) han atret molta atenció i s'han convertit en la modulació més popular entre diversos esquemes d'accés multiportadora, gràcies a la seua robustesa i simplicitat enfront de la cancel·lació per trajectes múltiples utilitzant el prefix cíclic (CP). Una de les formes d'ona més prometedores per a xarxes de pròxima generació és la tècnica de modulació Filter Bank MultiCarrier (FBMC). El principal benefici de l'esquema FBMC és que no depén de CP i d'un gran nombre de mostres de banda de guarda, per tant, empra diverses funcions de pols localitzades en el temps amb una alta relació de supressió de lòbuls laterals, la qual cosa permet millorar l'eficiència espectral i el rendiment del sistema com a factors clau en les xarxes òptiques de pròxima generació, i proporciona una bona alternativa a la tècnica CP-OFDM. Esta Tesi pretén fer un pas avant en la proposta de formats de modulació per a ser utilitzats en sistemes VLC com a tecnologia habilitadora en xarxes 6G. Per tant, es proposa el sistema Flip-FBMC amb un algoritme de truncament per a oferir una transmissió d'alta velocitat amb baixa latència Flip-FBMC mitjançant l'ús de l'algoritme de transformació ortogonal isotròpica (IOTA) i la capa PHYsical per a DYnamic AccesS i filtres de ràdio cognitiva (PHYDYAS). En aquesta Tesi, es proposa l'equalització multitap per als sistemes VLC en interiors per a mitigar la interferència imaginària intrínseca (IMI) en un canal amb perfils de retards elevat. A més, el rendiment d'error dels senyals FBMC no coherents es millora mitjançant l'anàlisi de la propietat de la localització de temps-freqüència amb la funció gaussiana estesa (EGF), on el factor de dispersió exercix un paper crucial en la determinació de l'equilibri entre les característiques espectrals i la reconstrucció òptima de la qualitat del senyal. En tal escenari, a causa del rang dinàmic limitat del díode emissor de llum (LED), la millora de la precisió de l'estimació depén dels nivells de potència dels pseudopilots amb l'ús de l'arquitectura del Mètode d'Aproximació d'Interferència (IAM) i per tant, no és adequada en sistemes VLC d'il·luminació i comunicació. A més, la Tesi proporciona la primera anàlisi teòrica que informa de la degradació en l'estimació per a diversos factors de clipping basada en l'impacte del nivell d'interferència imaginari fora de la zona de primer orde que no pot ser estimada mitjançant el preàmbul de IAM. No obstant això, s'ha d'emfatitzar en el valor de la tècnica Flip-FBMC/IAM per a proporcionar el model unipolar en comparació amb l'ús del format FBMC òptic polaritzat amb corrent continu (DCO-FBMC) que patix una reducció en l'estimació de la precisió. Per tant, s'ha demostrat el descens del rendiment amb el sistema DCO-FBMC a causa del IMI induït fora dels símbols d'orde zero, i que és més evident quan es requerixen nivells baixos de corrent DC. Des d'esta perspectiva, la tècnica de repetició de trames amb senyals Flip-FBMC ha demostrat ser una solució important per a minimitzar la interferència induïda. Per tant, en esta Tesi, la modulació Flip-FBMC amb repetició de trames i perfil de filtre PHYDYAS es proposa com un candidat viable per a fer front al rang dinàmic restringit del LED, en comparació amb el rendiment dels sistemes Flip-CP-OFDM i Flip-FBMC/IAM en futures xarxes 6G basades en accés VLC. / [EN] The sixth generation (6G) network is the potential solution to meet the exponentially increasing requirements of the emerging services and applications. The 6G platform expects to offer high data rates, ultra-high connectivity, and low latency based on the required key performance indicators (KPIs). The visible light communication (VLC) technology represents a key technology for 6G network but requires an efficient advanced modulation technique to support such requirements. In the last decades, optical signals based on Orthogonal Frequency Division Multiplexing (OFDM) scheme has attracted a lot of attention and become the most popular modulation among several multicarrier access schemes, thanks to its robustness and simplicity against multipath fading using the cyclic prefix (CP). One of the most candidate waveforms that is considered as the promising modulation technique for the next generation requirements and applications is Filter Bank MultiCarrier (FBMC) multiplexing. The major benefit of FBMC scheme is non-reliance on CP and high numbers of guard band samples, thereby, it employs several well time-frequency localized pulse functions with high side-lobe suppression ratio instead, which allows enhancing the spectral efficiency and system performance as key factors in next generation optical networks, and provides a good alternative to CP-OFDM technique. This Thesis aims to make a step forward in proposing modulation formats to be used in VLC systems as enabling technology in 6G networks. Hence, Flip-FBMC system with a truncation algorithm is proposed to offer a high-speed transmission with low latency by tackling the doubled-overhead tails at the subframes of Flip-FBMC burst by the use of the isotropic orthogonal transformation algorithm (IOTA) and PHYsical layer for DYnamic AccesS and cognitive radio (PHYDYAS) filters. Multitap equalization is proposed in this Thesis for the sake of mitigating the intrinsic imaginary interference (IMI) over a channel with high delays profile for indoor VLC system. Moreover, the error performance of non-coherent FBMC signals is enhanced by analysing the property of time-frequency localization with Extended Gaussian Function (EGF), where the spreading factor plays a crucial role in determining the trade-off between the spectral features and optimal reconstruction of signal quality. In such scenario, due to the limited dynamic range of light emitting diode (LED), improving in the accuracy of estimation depends on the power-levels of pseudo pilots with the use of Interference Approximation Method (IAM) architecture. Thereby, the analysis reveals that IAM sequence is not suitable for a real transmission scenario due to high power of IAM over the payload data which conflicts with VLC purposes of illumination and communication simultaneously. Additionally, the Thesis provides the first theoretical analysis reporting the degradation of estimation accuracy for several clipping ratios based on the impact of imaginary interference level outside the first order neighbourhood zone that cannot be estimated by IAM preamble. However, the value of Flip-FBMC/IAM technique in providing the unipolar model must be emphasized compared to the use of Direct Current biased Optical FBMC (DCO-FBMC) format that suffers from a reduction in estimating accuracy. Thereby, the downfall performance with DCO-FBMC system has been reported because of the induced IMI that spreads out the first neighbourhood symbols, which is more evident when low levels of the added DC-bias are required. From such perspective, the frame repetition technique with Flip-FBMC signals has been demonstrated as a major solution for minimizing the induced interference. Therefore, in this Thesis, Flip-FBMC/frame repetition with PHYDYAS profile is proposed as a viable candidate to cope with the restricted dynamic range of the LED, compared to the performance for each Flip-CP-OFDM and Flip-FBMC/IAM system in future 6G networks based on VLC access. / Bahaaelden, MS. (2024). Novel 5G-Modulation Formats and Their Application in Optical Wireless Communications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/204634

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