High-speed millimeter-wave (mm-wave) wireless transmission at 40 Gb/s or higher will be required in the near future. Due to bottleneck in electrical devices, mm-wave wireless signal at such high bit ...rates cannot be generated in an all-electrical method. Photonics-assisted mm-wave generation technology has become an effective solution to handle this problem of bandwidth limitation. Recent efforts with a single modulator to generate optical mm-wave signal largely simplify the architecture of the optical transmitter. Heterodyne detection based on advanced digital signal processing can overcome nonlinear effects in optical and electrical devices, and it also can improve the spectral efficiency and receiver sensitivity. Multidimensional multiplexing techniques can reduce the baud rate of each subchannel, and hence it can realize mm-wave signal long distance transmission. In this tutorial, we will describe these key enabling technologies and principle for the realization of ultrahigh speed, large capacity mm-wave signal transmission. These enabling technologies can effectively improve the transmission capacity and distance, as well as reduce the required bandwidth for optical and electrical devices.
We review and study several single carrier based multi-level and multi-dimensional coding (ML-MDC) technologies recently demonstrated for spectrally-efficient 100-Gb/s transmission. These include ...16-ary PDM-QPSK, 64-ary PDM-8PSK, 64-ary PDM-8QAM as well as 256-ary PDM-16 QAM. 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 a universal receiver front-end and digital coherent detection. We show that the constant modulus algorithm (CMA), which is highly effective for blind polarization recovery of PDM-QPSK and PDM-8PSK signals, is much less effective for PDM-8QAM and PDM-16 QAM. We then present a recently proposed, cascaded multi-modulus algorithm for these cases. In addition to the DSP algorithms used for constellation recovery, we also describe a DSP algorithm to improve the performance of a coherent receiver using single-ended photo-detection. The system impact of ASE noise, laser phase noise, narrowband optical filtering and fiber nonlinear effects has been investigated. For high-level modulation formats using full receiver-side digital compensation, it is shown that the requirement on LO phase noise is more stringent than the signal laser. We also show that RZ pulse shaping significantly improves filter- and fiber-nonlinear tolerance. Finally we present three high-spectral-efficiency and high-speed DWDM transmission experiments implementing these ML-MDC technologies.
The integration of optical and wireless systems is considered to be one of the most promising solutions for increasing the existing capacity and mobility as well as decreasing the costs in ...next-generation optical access networks. In this paper, several key enabling technologies for hybrid optical-wireless access networks are described, including optical millimeter-wave (mm-wave) generation, upconversion, and transmission in a downlink direction, and full-duplex operation based on wavelength reuse by using a centralized light source in an uplink direction. By employing these enabling technologies, we design and experimentally demonstrate an optical-wireless testbed that is simultaneously delivering wired and wireless services in the integrated optical-wireless and wavelength-division-multiplexing passive-optical-network access networks. The actual applications consisting of 270-Mb/s uncompressed standard-definition TV signal and 2.5-Gb/s data channels for downstream are successfully transmitted over a 25-km fiber and a 10.2-m indoor wireless link with less than a 1.5-dB power penalty. The results show that this integrated system is a practical solution to deliver superbroadband information services to both stationary and mobile users.
Recent studies on enzymes and reader proteins for histone crotonylation support a function of histone crotonyla- tion in transcription. However, the enzyme（s） responsible for histone decrotonylation ...（HDCR） remains poorly de- fined. Moreover, it remains to be determined if histone crotonylation is physiologically significant and functionally distinct from or redundant to histone acetylation. Here we present evidence that class I histone deacetylases （HDACs） rather than sirtuin family deacetylases （SIRTs） are the major histone decrotonylases, and that histone erotonylation is as dynamic as bistone acetylation in mammalian cells. Notably, we have generated novel HDAC1 and HDAC3 mutants with impaired HDAC but intact HDCR activity. Using these mutants we demonstrate that selective HDCR in mammalian cells correlates with a broad transcriptional repression and diminished promoter association of cro- tonylation but not acetylation reader proteins. Furthermore, we show that histone erotonylation is enriched in and required for self-renewal of mouse embryonic stem cells.
Aerobic glycolysis (the Warburg effect) is a robust metabolic hallmark of most tumors, including oral squamous cell carcinoma (OSCC). Glucose transporter 1 (GLUT1), a major glucose transporter ...regulating the glucose uptake, is upregulated in OSCC and participated in the cell glycolysis of OSCC. The deregulation and function of noncoding RNAs in cancers have been widely reported. Reportedly, hsa_circular RNA (circRNA)_100290 (circ_SLC30A7) is significantly upregulated (fold change = 6.91, p < 0.0000001) in OSCC. According to online tools prediction (miRWalk, miRanda, and Targetscan), miR‐378a could simultaneously target circRNA_100290 and GLUT1. Herein, the expression of circRNA_100290 and GLUT1 remarkably increased in oral tumor tissue specimens and cells. In OSCC cell lines, cell proliferation and glycolysis could be remarkably downregulated by circRNA_100290 silence, which could be rescued by GLUT1 overexpression. Conversely, miR‐378a expression could be remarkably inhibited in tumor tissue specimens and cells. The effect of miR‐378a overexpression on OSCC cells was similar to those of circRNA_100290 silence. miR‐378a directly bound to circRNA_100290 and GLUT1 3′‐untranslated region, circRNA_100290 could remarkably relieve miR‐378a‐induced inhibition on GLUT1 via acting as a competing endogenous RNA (ceRNA). miR‐378a inhibition remarkably attenuated the effect of circRNA_100290 silence on cell proliferation and glycolysis in OSCC cell lines. In summary, circRNA_100290 serves as a ceRNA to counteract miR‐378a‐mediated GLUT1 suppression, thus promoting glycolysis and cell proliferation in OSCC. We provide a reliable experimental basis for understanding the mechanism of cell growth and glycolysis deregulation in OSCC.
In summary, circRNA_100290 serves as a competing endogenous RNA to counteract miR‐378a‐mediated glucose transporter suppression, thus promoting glycolysis and cell proliferation in oral squamous cell carcinoma (OSCC). We provide a reliable experimental basis for understanding the mechanism of cell growth and glycolysis deregulation in OSCC.
We summarize the enabling technologies for photonics-assisted broadband millimeter-wave (mm-wave) communication, which is a promising candidate for the enhanced mobile broadband (eMBB) ...communications, one of the three main typical application scenarios of 5G wireless networks. These enabling technologies, mainly focusing on the improvement of the system structure, include broadband mm-wave signal generation with simple and cost-effective schemes, multiple-input multiple-output architecture with polarization-multiplexing optical mm-wave signal, advanced multilevel modulation, optical or electrical multicarrier modulation, antenna polarization multiplexing and the employment of the high-gain mm-wave antenna, multi-band multiplexing, and broadband mm-wave signal detection. We also review the advanced digital signal processing (DSP) for heterodyne coherent detection, which can be applied into the photonics-assisted mm-wave communication systems, to further enhance the system performance for a given system structure and certain available devices. Based on these enabling technologies and advanced DSP, we have realized over 1 Tb/s wireless signal transmission at D-band and over 2.5 km wireless transmission with a bit rate up to 54 Gb/s at W-band. Our work verifies the photonics-assisted broadband mm-wave communication can meet the high-data-rate demand of eMBB.
W-band (75-110 GHz) is a potential radio frequency band to provide long-distance wireless links for mobile data transmission. We proposed a high-speed long-distance wireless transmission link at ...W-band based on some enabling technologies and advanced devices, such as antenna polarization multiplexing combined with multiple-input multiple-output, large-gain/high-power W-band electrical amplifiers, high-gain small-beamwidth Cassegrain antennas, and wideband optical/electrical components. We experimentally demonstrated that our proposed wireless transmission link can realize up to 1.7-km wireless delivery of 20-Gb/s@85.5-GHz millimeter-wave signal with a bit-error rate less than <inline-formula><tex-math>3.8 \times 10^{-3}</tex-math></inline-formula>.
We have experimentally demonstrated a full-duplex radio-over-fiber system using a single light source at central station (CS). Optical carrier suppression modulation scheme was employed to generate ...40-GHz optical millimeter wave and up-convert the baseband signal simultaneously at CS for downlink transmission while the same optical carrier was reused at base station for uplink connection. The bidirectional full-duplex 2.5-Gb/s data was successfully transmitted over 40-km standard single-mode fiber (SMF-28) for both upstream and downstream channels with less than 2-dB power penalty. This system shows simple cost-efficient configuration and good performance over long-distance delivery
We have proposed and experimentally demonstrated a novel architecture for orthogonal frequency-division- multiplexing (OFDM) wavelength-division-multiplexing passive optical network with centralized ...lightwave. In this architecture, 16 quadrature amplitude modulation intensity-modulated OFDM signals at 10 Gb/s are utilized for downstream transmission. A wavelength-reuse scheme is employed to carry the upstream data to reduce the cost at optical network unit. By using one intensity modulator, the downstream signal is remodulated for upstream on-off keying (OOK) data at 2.5 Gb/s based on its return-to-zero shape waveform. We have also studied the fading effect caused by double-sideband (DSB) downstream signals. Measurement results show that 2.5-dB power penalty is caused by the fading effect. The fading effect can be removed when the DSB OFDM downstream signals are converted to single sideband (SSB) after vestigial filtering. The power penalty is negligible for both SSB OFDM downstream and the remodulated OOK upstream signals after over 25-km standard single-mode-fiber transmission. Index
High-speed long-haul wireless transmission links are required to meet the demand of mobile backhauling and emergency communications. We experimentally demonstrated ultra-high-speed 432-Gb/s ...polarization-division-multiplexing 16-ary quadrature amplitude modulation modulated W-band millimeter-wave (mm-wave) signal delivery over a 2-m horn antenna-based (HA-based) 4 × 4 multiple-input multiple-output (MIMO) wireless link, enabled by photonic mm-wave generation and optical/antenna polarization multiplexing. We further achieved the field trial demonstration of 80-Gb/s polarization-division-multiplexing quadrature phase shift keying modulated W-band mm-wave signal delivery over a 300-m Cassegrain antenna-based (CA-based) 4 × 4 MIMO wireless link, adopting photonic mm-wave generation, multi-band multiplexing, and optical/antenna polarization multiplexing. To the best of our knowledge, 80 Gb/s or 74.7 Gb/s after removing 7% forward-error-correction overhead is a record for W-band wireless signal delivery over a few hundred meters.
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