Performance Comparison of PS Star-16QAM and PS Square-Shaped 16QAM (Square-16QAM)
TL;DR: The star-shaped 16-ary quadrature amplitude modulation scheme shows superiority over the PS-Square-16QAM in terms of the BER improvement.
Abstract: We investigate and compare the performance of star-shaped 16-ary quadrature amplitude modulation (Star-16QAM) and square-shaped 16QAM (Square-16QAM) in the probabilistic shaping (PS) and uniform schemes with coherent detection. With the help of PS technology, the bit error ratio (BER) improvement achieved in the PS-Star-16QAM scheme is greater than that of the PS-Square-16QAM when compared with the uniform schemes in our numerical simulation and experiment. Therefore, the PS-Star-16QAM shows superiority over the PS-Square-16QAM in terms of the BER improvement.
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TL;DR: The programmable nature of smart textiles makes them an indispensable part of an emerging new technology field and a timely overview and comprehensive review of progress of this field in the last five years are provided.
Abstract: The programmable nature of smart textiles makes them an indispensable part of an emerging new technology field. Smart textile-integrated microelectronic systems (STIMES), which combine microelectronics and technology such as artificial intelligence and augmented or virtual reality, have been intensively explored. A vast range of research activities have been reported. Many promising applications in healthcare, the internet of things (IoT), smart city management, robotics, etc., have been demonstrated around the world. A timely overview and comprehensive review of progress of this field in the last five years are provided. Several main aspects are covered: functional materials, major fabrication processes of smart textile components, functional devices, system architectures and heterogeneous integration, wearable applications in human and nonhuman-related areas, and the safety and security of STIMES. The major types of textile-integrated nonconventional functional devices are discussed in detail: sensors, actuators, displays, antennas, energy harvesters and their hybrids, batteries and supercapacitors, circuit boards, and memory devices.
384 citations
TL;DR: A review of the recent progress of all three self-emissive technologies for flexible displays is conducted, including the emissive active materials, device structures and approaches to manufacturing, the flexible substrates, and conductive electrodes, as well as the encapsulation techniques.
Abstract: Featuring a combination of ultrathin and lightweight properties, excellent mechanical flexibility, low power-consumption, and widely tunable saturated emission, flexible displays have opened up a new possibility for optoelectronics. The demands for flexible displays are growing on a continual basis due not only to their successful commercialization but, more importantly, their endless possibilities for wearable integrated systems. Up to now, self-emissive technologies for displays, flexible active-matrix organic light-emitting diodes (flex-AMOLED), flexible quantum dot light-emitting diodes (flex-QLEDs), and flexible perovskite light-emitting diodes (flex-PeLEDs) have been widely reported, but despite the significant progress made in these technologies, enormous obstacles and challenges remain for the vision of truly wearable applications, in particular with flex-QLEDs and flex-PeLEDs. Here, a review of the recent progress of all three self-emissive technologies for flexible displays is conducted, including the emissive active materials, device structures and approaches to manufacturing, the flexible substrates, and conductive electrodes, as well as the encapsulation techniques. The fast-paced improvement made to the efficiency of flexible devices in recent years is also summarized. The review concludes by making suggestions on the future development in this area, and is expected to help researchers in gaining a comprehensive understanding about the newly emerging technologies for flexible displays.
122 citations
TL;DR: In this paper, a detailed review of flexible OLEDs is presented, which summarizes the key components, discuss the method of implementation, highlight the recent research progresses, and conclude the challenges and prospects of FOLEDs.
Abstract: DOI: 10.1002/admt.201800371 wearable displays, and conceptual lighting panels. In addition, besides the excellent designs, a flexible OLED (FOLED)[7,20–40] has several other advantages, the displays and lighting panels are thinner, lighter, more cost effective, shatterproof, and durable compared to glass or silicon based OLEDs. They are impact resistance and less prone to break than glass. At present, both flexible displays and lighting panels are being mass produced (Samsung and LG on displays, LG and Konica Minolta on lighting). FOLEDs are becoming most promising and popular next-generation display technology in consumer electronics and lighting panels. In order to develop the FOLEDs and realize their practical application, many great efforts have been conducted. The key components of the FOLEDs are flexible substrate, bottom and top electrode, organic functional layers, encapsulation layer, and optional light extraction layers. Differed from conventional OLEDs on rigid glass or silicon substrate, FOLEDs are fabricated on flexible substrates. Up to now, metal foil, flexible glass, and plastic film have been commonly used as flexible substrates for FOLEDs. On the other hand, actual fabric materials, natural silk fibroin films, bacterial cellulose, and rubbery poly (urethane acrylate) have also been developed to achieve the requirements of wearable and stretchable displays. The electrode is also very important for FOLEDs. Compared with the top electrode, more research has been conducted on the bottom electrode because its surface roughness, conductivity, and transmittance for bottom emitting OLEDs play a key role in the performance of FOLEDs. As conventional indiumtin-oxide (ITO) is not suitable for flexible devices as it is brittle, many great alternatives such as thin metal film, conducting polymer, dielectric–metal–dielectric (DMD) multilayers, metal nanowires, graphene, carbon nanotubes (CNTs), and their compound have been studied. It should be mentioned that the performance of organic layers has almost no difference with rigid OLEDs because of their inherent excellent ductility and identical working mechanism. Moreover, for practical and commercial applications, stability and efficiency are two factors of crucial importance. As a consequence, the encapsulation technique and light extraction of FOLEDs are also two research hotspots in recent years. This review will summarize the key components, discuss the method of implementation, highlight the recent research progresses, and conclude the challenges and prospects of FOLEDs. As the demand for display technology in consumer electronics and lighting panels increases, thin, light, high-quality, and more cost-effective light-emitting devices are required. Organic light-emitting devices (OLEDs), satisfying the criteria exactly, have been considered the most promising next-generation display and lighting technique. In particular, an OLED based on flexible substrate enables the device to be applied to curved displays, electronic newspapers, wearable displays, and conceptual lighting panels, has been always in the spotlight both in science and industry. Great advances on flexible OLEDs (FOLEDs) have been made over the past three decades. The fundamental elements of FOLEDs including substrates, electrodes, fabrication and encapsulation techniques, as well as the strategies of efficiency improvement are discussed herein. Moreover, emerging electrodes such as graphene, carbon nanotubes, metal nanowire network and their composite, flexible perovskite light emitting devices, and stretchable light emitting devices are also considered. Finally, the future challenges and prospects for these devices are put forward.
103 citations
TL;DR: It is demonstrated that an ultra-wideband and high-efficiency reflective cross-polarization convertor can be achieved by breaking the symmetry of the resonator unit of a perfect absorber.
Abstract: Through the manipulation of co-polarized reflection and cross-polarized reflection from a periodic array of metal-dielectric-metal resonators, a plethora of unprecedented metamaterial devices have been successfully demonstrated, such as perfect absorber and polarization converter. Recently, some broadband absorbers based on anisotropic resonators have been reported, which are actually poor absorbers when the cross-polarized reflection is considered. Here, we demonstrate that an ultra-wideband and high-efficiency reflective cross-polarization convertor can be achieved by breaking the symmetry of the resonator unit of a perfect absorber. Simulation results show that the polarization conversion ratio of the proposed metasurface is above 90% in the frequency range from 6.67 to 17.1 GHz and the relative bandwidth reaches 87.7%. The experimental results are in good agreement with the simulation results. The method paves a new way for the design of broadband polarization convertor, which can also be extended to the terahertz band.
102 citations
30 Sep 2020
TL;DR: In this paper, the status, key challenges and opportunities for the field of next-generation flexible devices are elaborated in terms of materials, fabrication and specific applications, where the definition of flexibility differs from application to application.
Abstract: The concept of flexible electronics has been around for several decades. In principle, anything thin or very long can become flexible. While cables and wiring are the prime example for flexibility, it was not until the space race that silicon wafers used for solar cells in satellites were thinned to increase their power per weight ratio, thus allowing a certain degree of warping. This concept permitted the first flexible solar cells in the 1960s (Crabb and Treble, 1967). The development of conductive polymers (Shirakawa et al., 1977), organic semiconductors, and amorphous silicon (Chittick et al., 1969; Okaniwa et al., 1983) in the following decades meant huge strides toward flexibility and processability, and thus these materials became the base for electronic devices in applications that require bending, rolling, folding, and stretching, among other properties that cannot be fulfilled by conventional electronics (Cheng and Wagner, 2009) (Figure 1). Presently there is great interest in new materials and fabrication techniques which allow for highperformance scalable electronic devices to be manufactured directly onto flexible substrates. This interest has also extended to not only flexibility but also properties like stretchability and healability which can be achieved by utilizing elastomeric substrates with strong molecular interactions (Oh et al., 2016; Kang et al., 2018). Likewise, biocompatibility and biodegradability has been achieved through polymers that do not cause adverse effect to the body and can be broken down into smaller constituent pieces after utilization (Bettinger and Bao, 2010; Irimia-Vladu et al., 2010; Liu H. et al., 2019). This new progress is now enabling devices which can conform to complex and dynamic surfaces, such as those found in biological systems and bioinspired soft robotics. These next-generation flexible electronics open up a wide range of exciting new applications such as flexible lighting and display technologies for consumer electronics, architecture, and textiles, wearables with sensors that help monitor our health and habits, implantable electronics for improved medical imaging and diagnostics, as well as extending the functionality of robots and unmanned aircraft through lightweight and conformable energy harvesting devices and sensors. While conventional electronics are very capable of these functions, flexible electronics are intended to expand the mechanical features to adhere to novel form factors through hybrid strategies, or as standalone solutions where the application does not require high computation power, intended to be highly robust to deformation, low cost, thin, or disposable. The definition of flexibility differs from application to application. From bending and rolling for easier handling of large area photovoltaics, to conforming onto irregular shapes, folding, twisting, stretching, and deforming required for devices in electronic skin, all while maintaining device performance and reliability. While early progress and many important innovations have already been achieved, the field of flexible electronics has many challenges before it becomes part of our daily life. This represents a huge opportunity for scientific research and development to rapidly and considerably advance this area (Figure 2). In this article the status, key challenges and opportunities for the field of nextgeneration flexible devices are elaborated in terms of materials, fabrication and specific applications. Edited and Reviewed by: Jhonathan Prieto Rojas, King Fahd University of Petroleum and Minerals, Saudi Arabia
99 citations
Cites background from "Performance Comparison of PS Star-1..."
...…materials like polyurethane, cellulose nanofibers, and parylene to address challenges including surface roughness, biodegradability, and compatibility with aqueous and biological media (Ummartyotin et al., 2012; Jung et al., 2015; Liu et al., 2017; Park et al., 2018; Liu Y.-F. et al., 2019)....
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References
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TL;DR: A new coded modulation scheme is proposed that operates within less than 1.1 dB of the AWGN capacity 1/2 log2(1 + SNR) at any spectral efficiency between 1 and 5 bits/s/Hz by using only 5 modes.
Abstract: A new coded modulation scheme is proposed. At the transmitter, the concatenation of a distribution matcher and a systematic binary encoder performs probabilistic signal shaping and channel coding. At the receiver, the output of a bitwise demapper is fed to a binary decoder. No iterative demapping is performed. Rate adaption is achieved by adjusting the input distribution and the transmission power. The scheme is applied to bipolar amplitude-shift keying (ASK) constellations with equidistant signal points and it is directly applicable to two-dimensional quadrature amplitude modulation (QAM). The scheme is implemented by using the DVB-S2 low-density parity-check (LDPC) codes. At a frame error rate of $10^{-3}$ , the new scheme operates within less than 1.1 dB of the AWGN capacity $\frac{1}{2}\log_2(1+{\mathsf{SNR}})$ at any spectral efficiency between 1 and 5 bits/s/Hz by using only 5 modes, i.e., 4-ASK with code rate 2/3, 8-ASK with 3/4, 16-ASK and 32-ASK with 5/6, and 64-ASK with 9/10.
642 citations
"Performance Comparison of PS Star-1..." refers methods in this paper
...In the PS-Square-16QAM scheme, we employ the input alphabet X = {−3,−1, 1, 3}, and the probability of signal points x ∈ X is expressed as PX (x) = kv e−v|x | 2 , which is called the probability mass function (PMF) of the input [10], [14], [15]....
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TL;DR: A transmission system with adjustable data rate for single-carrier coherent optical transmission is proposed, which enables high-speed transmission close to the Shannon limit, and it is experimentally demonstrated that the optical transmission of probabilistically shaped 64-QAM signals outperforms the transmission reach of regular 16- QAM and regular 64-ZAM signals.
Abstract: A transmission system with adjustable data rate for single-carrier coherent optical transmission is proposed, which enables high-speed transmission close to the Shannon limit. The proposed system is based on probabilistically shaped 64-QAM modulation formats. Adjustable shaping is combined with a fixed-QAM modulation and a fixed forward-error correction code to realize a system with adjustable net data rate that can operate over a large reach range. At the transmitter, an adjustable distribution matcher performs the shaping. At the receiver, an inverse distribution matcher is used. Probabilistic shaping is implemented into a coherent optical transmission system for 64-QAM at 32 Gbaud to realize adjustable operation modes for net data rates ranging from 200 to 300 Gb/s. It is experimentally demonstrated that the optical transmission of probabilistically shaped 64-QAM signals outperforms the transmission reach of regular 16-QAM and regular 64-QAM signals by more than 40% in the transmission reach.
564 citations
"Performance Comparison of PS Star-1..." refers methods in this paper
...The application of PS in optical communication is able to operate the systems more approach to the Shannon limit thus outperforming conventional modulation formats [2]–[4], [11]....
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Posted Content•
TL;DR: In this paper, a DVB-S2 low-density parity-check (LDPC) codes were used for bipolar amplitude shift keying (ASK) constellations with equidistant signal points.
Abstract: A new coded modulation scheme is proposed. At the transmitter, the concatenation of a distribution matcher and a systematic binary encoder performs probabilistic signal shaping and channel coding. At the receiver, the output of a bitwise demapper is fed to a binary decoder. No iterative demapping is performed. Rate adaption is achieved by adjusting the input distribution and the transmission power. The scheme is applied to bipolar amplitude shift keying (ASK) constellations with equidistant signal points and it is directly applicable to two-dimensional quadrature amplitude modulation (QAM). The scheme is implemented by using the DVB-S2 low-density parity-check (LDPC) codes. At a frame error rate of 1e-3, the new scheme operates within less than 1 dB of the AWGN capacity 0.5log2(1+SNR) at any spectral efficiency between 1 and 5 bits/s/Hz by using only 5 modes, i.e., 4-ASK with code rate 2/3, 8-ASK with 3/4, 16-ASK and 32-ASK with 5/6 and 64-ASK with 9/10.
322 citations
TL;DR: In this paper, the effect of using a small number of input probability mass functions (PMFs) for a range of signal-to-noise ratios (SNRs), instead of optimizing the constellation shaping for each SNR, was investigated.
Abstract: Different aspects of probabilistic shaping for a multispan optical communication system are studied. First, a numerical analysis of the additive white Gaussian noise (AWGN) channel investigates the effect of using a small number of input probability mass functions (PMFs) for a range of signal-to-noise ratios (SNRs), instead of optimizing the constellation shaping for each SNR. It is shown that if a small penalty of at most 0.1 dB SNR to the full shaping gain is acceptable, just two shaped PMFs are required per quadrature amplitude modulation (QAM) over a large SNR range. For a multispan wavelength division multiplexing optical fiber system with 64QAM input, it is shown that just one PMF is required to achieve large gains over uniform input for distances from 1400 to 3000 km. Using recently developed theoretical models that extend the Gaussian noise (GN) model and full-field split-step simulations, we illustrate the ramifications of probabilistic shaping on the effective SNR after fiber propagation. Our results show that, for a fixed average optical launch power, a shaping gain is obtained for the noise contributions from fiber amplifiers and modulation-independent nonlinear interference (NLI), whereas shaping simultaneously causes a penalty as it leads to an increased NLI. However, this nonlinear shaping loss is found to have a relatively minor impact, and optimizing the shaped PMF with a modulation-dependent GN model confirms that the PMF found for AWGN is also a good choice for a multi-span fiber system.
278 citations
TL;DR: It is shown that high-speed QPSK, 8PSK.
Abstract: We review and summarize several 100G per channel high-capacity transmission systems enabled by advanced technologies such as multilevel modulation format, new low-loss and large effective area fiber, hybrid EDFA/Raman amplification, and digital coherent detection technologies. We show that high-speed QPSK, 8PSK, 8QAM, and 16QAM can all be generated using commercially available optical modulators using only binary electrical drive signals through novel synthesis methods, and that all of these modulation formats can be detected using digital coherent detection. We also show our latest research results on 400 Gb/s and 1 Tb/s per channel by using orthogonal DWDM transmission technologies.
144 citations
"Performance Comparison of PS Star-1..." refers methods in this paper
...The offline DSP consists of down-conversion [16]–[18], normalization, orthogonalization, chromatic dispersion (CD) compensation [19], constant-modulus-algorithm (CMA) equalization [20]–[22], cascaded multi-modulus algorithm (CMMA) equalization [23]–[25], frequency offset estimation (FOE), carrier phase estimation (CPE), decision-directed least mean square (DD-LMS) algorithm, decision, 16 quadrature amplitude demodulation and BER counting....
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