- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Subcarrier-Index Modulated Multicarrier Space-Time Shift Keying: Achievable Rate, Performance and Design Guidelines
摘要： Multicarrier (MC) space-time shift keying (STSK) relying on the concept of subcarrier-index modulated orthogonal frequency division multiplexing (SIM-OFDM) is proposed. In conventional MC-STSK system, the performance erosion of STSK in dispersive channels is mitigated by employing OFDM. The SIM-OFDM aided MC-STSK activates a specified limited number of subcarriers for transmitting the STSK codewords. The indices of the activated subcarriers provide additional multiplexing gain. A new receiver architecture, which uses the single-stream maximum-likelihood (ML) detector of STSK and the subcarrier activation principle of SIM-OFDM, is designed. A soft decision logarithmic likelihood ratio (LLR) based detector is also conceived. Helpful design guidelines are provided for the system. The achievable rate, complexity and performance of the system are analytically quantified and verified with the aid of numerical simulations. The system is capable of overcoming the impairments imposed by wideband channels, is benefited from index modulation as well as from STSK. The scheme exhibits an improved error performance compared to the classic OFDM-based STSK as a result of the more reliable detection of the subcarrier index bits.
关键词： Space-time shift keying (STSK),multiple-input multiple-output (MIMO),orthogonal frequency division multiplexing (OFDM),subcarrier index modulation
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Photonics Conference (IPC) - Reston, VA (2018.9.30-2018.10.4)] 2018 IEEE Photonics Conference (IPC) - Assessment of RB Noise in Bidirectional RoF Based on Different O-OFDM SSB Systems
摘要： Novel bidirectional architecture on two optical OFDM SSB modulation techniques to mitigate Rayleigh backscattered and reflections interferences in RoF transmission is proposed. The interference effect is analyzed with mathematical model comparing conventional SSB and the modified SSB based on elimination of higher order RB-RE harmonics.
关键词： Single sideband (SSB) modulation,Orthogonal Frequency Division Multiplexing (OFDM),Bidirectional Radio over Fiber (RoF)
更新于2025-09-23 15:23:52
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[IEEE 2018 21st Saudi Computer Society National Computer Conference (NCC) - Riyadh, Saudi Arabia (2018.4.25-2018.4.26)] 2018 21st Saudi Computer Society National Computer Conference (NCC) - Millimeter Wave Switching in Radio over Fiber Networks using Semiconductor Optical Amplifier (SOA)
摘要： 5G wireless communication systems promise efficient spectrum utilization, advanced modulation and access techniques, and high data rate. To obtain these requirements, millimeter wave (MMW) signals and subsystems are the most suitable to be used. The Modules and devices, proposed for these networks, are intended to use the efficient capabilities of photonic technologies. In this paper, a photonics-based millimeter wave switch, for orthogonal frequency division multiplexing (OFDM) signals, is proposed by exploiting the nonlinear effects in semiconductor optical amplifiers (SOAs). This includes four wave mixing (FWM), self-phase modulation (SPM) and cross-gain modulation (XGM). A 10 Gbps/16QAM-OFDM signal carried over 30 GHz MMW carrier is considered for signal switching. Moreover, we studied the up- and down- wavelength conversion schemes, in terms of probe and pump signal’s power. Furthermore, we investigate the effects of SOA’s injection current and wavelength spacing between the two injected beams that enable optical single sideband (OSSB) generation and switching. Simulation results show possibility of transmitting and switching OFDM signal with 1×10-3 and 13 % rms symbol error rate (SER) and error vector magnitude (EVM), at -22 dBm received power. The simulation is carried out using Virtual Photonic Integrated (VPI) software.
关键词： optical single side band (OSSB),orthogonal frequency division multiplexing (OFDM),millimeter waves (MMW),semiconductor optical amplifier (SOA),wavelength conversion,5G
更新于2025-09-23 15:23:52
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Photomedicine and Its Place in Medicine of the 21th Century
摘要： Digital television signal is a promising signal of opportunity for wireless positioning. This paper studies the time of arrival (TOA) estimation on the European standard DVB-T signals in the context of positioning. Theoretical analysis on the autocorrelation of the pilot signal and multipath error envelop suggests that DVB-T has the appropriate characteristics for positioning. A software defined radio-based DVB-T receiver is developed for field testing, in which the radio frequency DVB-T signals are first sampled by universal software radio peripheral, and then algorithms of the coarse symbol synchronization, the pilot detection, the first path acquisition, and the delay tracking are sequentially performed to obtain the TOA estimation. To quantify the TOA tracking results on real DVB-T signals, field testing campaigns are carried out in five cities in Southern France. Test results showed that, in the high signal-noise ratio condition, the 2-σ error interval is within 1 m. By taking into account all the field tests, the interval of 95% accuracy is within 4 m and the corresponding C/N0 varies from 48 to 62 dB-Hz. In addition, with the developed TOA estimation method, the synchronization of the emitters with global positioning system time is evaluated and the distance difference of the multiple emitters within single frequency networks are also measured during the tests.
关键词： delay locked loop,software defined radio (SDR),wireless positioning,Digital TV,orthogonal frequency division multiplexing (OFDM),time of arrival
更新于2025-09-23 15:19:57
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New binary particle swarm optimization on dummy sequence insertion method for nonlinear reduction in optical direct-detection orthogonal frequency division multiplexing system
摘要： In the paper, a novel new binary particle swarm optimization method based on dummy sequence insertion is proposed and experimentally demonstrated in the IM-DD optical orthogonal frequency division multiplexing (OOFDM) system. This technique can mitigate nonlinearity of OOFDM system without any channel side information. Experimental results demonstrate that compared to the original scheme, the improvement in the receiver sensitivity by the proposed scheme is 1.9 dB and 3.2 dB with launch powers of 2 dBm and 8 dBm, respectively, at the BER of FEC 3.8 × 10^{-3} after transmission over 100-km standard single-mode fiber. At a complementary cumulative distribution function of 10^{-4}, the PAPR of OFDM signal can be reduced about 2.8 dB by using the proposed scheme, while the receiver-side hardware is the same as the origin.
关键词： Optical fiber communication,Particle swarm optimization (PSO),Dummy sequence insertion (DSI),Orthogonal frequency division multiplexing (OFDM)
更新于2025-09-19 17:15:36
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Long Distance IM/DD Transmission with OFDM-QAM based Quantum Noise Stream Cipher
摘要： We propose a QAM-based quantum noise stream cipher (QNSC) scheme for IM/DD transmission employing orthogonal frequency division multiplexing (OFDM) modulation. 2.5Gbit/s IMDD-OFDM signal is demonstrated over 1000 km distance. The experimental results show that Q penalty using IMDD-OFDM based QNSC is only 1.6 dB compared to QPSK without encryption in the cases of back-to-back condition and 1000km transmission.
关键词： orthogonal frequency division multiplexing (OFDM),quantum noise stream cipher (QNSC),intensity modulation/direct detection (IM/DD)
更新于2025-09-16 10:30:52
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Sub-carrier Loading Strategies for DCO-OFDM LED Communication
摘要： LEDs, particularly those used for Visible Light Communications (VLC), have a limited bandwidth, while above their 3 dB bandwidth, the roll-off is relatively gentle. If the modulation bandwidth would be limited to the 3 dB LED bandwidth, the achievable rate would be unacceptably constrained. Hence, effective communication systems need to optimize the use of bandwidth significantly above this 3 dB point. Orthogonal Frequency Division Multiplexing (OFDM) is a popular method to fine-tune the amount of power and constellation as a function of the channel response over different frequencies. Various power and bit loading strategies have been proposed and simulated in literature, but their performance was not captured in expressions. This manuscript derives these for optimal waterfilling, uniform and pre-emphasized power loading for the LED channel, that severely attenuates high frequencies. We also investigate the influence of practical discrete constellations and verify our new results experimentally. Interestingly, simple uniform loading only falls less than 1～2% short of the throughput achieved by waterfilling, but when we restrict OFDM to discrete QAM constellation sizes, the penalty for uniform loading is 1.5 dB. Inspired by the good performance of uniform power loading, we propose an algorithm to find the best discrete bit loading for uniform power within an optimized band. As pre-emphasis is nonetheless attractive because a flattened channel does not need adaptive sub-carrier loading, we quantify its penalty. This can be modest provided that the system can adapt its transmit bandwidth, thereby adaptively switching upper sub-carriers to zero power.
关键词： Orthogonal Frequency Division Multiplexing (OFDM),pre-emphasis,power loading strategies,LED channel,QAM constellation sizes,uniform loading,waterfilling,Visible Light Communications (VLC)
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Machine Learning Scheme for Geometrically-shaped Constellation Classification utilizing Support Vector Machine in Multi-access Internet of Vehicle Lighting
摘要： In this paper, we propose a multi-access Internet of Vehicles (IoV) scheme based on multi-band DFTS-OFDM VLC system. The experimental results show that with the bandwidth of 62.5MHz, the dynamic range was enhanced 1.6 dBm employing SVM in hexagonal constellation Geometrically-shaped (GS) 16QAM and the overall capacity is 250Mbps.
关键词： discrete Fourier transform spread (DFT-S),Geometrically-shaped,optical orthogonal frequency division multiplexing (OFDM),Visible light communication,Internet of Vehicles,Support vector machine
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - A 375Mb/s Real-time Internet of Vehicles System Based on Automotive Headlight Utilizing OFDM-64QAM Modulation Format
摘要： In this paper, we propose a real-time Internet of Vehicles system based on an automotive headlight. The modulation format is OFDM-64QAM and we successfully reach the data rate of 375Mb/s by utilizing a FPGA as the central host. The transmission distance is 2.5m. We also investigated the performance of the system by calculating BER versus bias current, transmission distance and attenuation at both transmitter and receiver. As far as we know, this is the highest data rate of a real-time visible light communication system based on automotive headlight which can be used in the Internet of Vehicles (IoV).
关键词： Internet of Vehicles (IoV),real-time visible light communication (real-time VLC),automotive headlight,Orthogonal Frequency Division Multiplexing (OFDM)
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Electrical Signatures of Contact Degradation for c-Si Solar Cells
摘要： Time synchronization is an important, yet challenging, problem in underwater sensor networks (UWSNs). This challenge can be attributed to: 1) messaging timestamping; 2) node mobility; and 3) Doppler scale effect. To mitigate these problems, we present an acoustic-based time-synchronization algorithm for UWSN, where we compare several message time-stamping algorithms in addition to different Doppler scale estimators. A synchronization system is based on a bidirectional message exchange between a reference node and a slave one, which has to be synchronized. Therefore, we take as reference the DA-Sync-like protocol (Liu et al., 2014), which takes into account node’s movement by using first-order kinematic equations, which refine Doppler scale factor estimation accuracy, and result in better synchronization performance. In our study, we propose to modify both time-stamping and Doppler scale estimation procedures. Besides simulation, we also perform real tests in controlled underwater communication in a water test tank and a shallow-water test in the Mediterranean Sea.
关键词： timestamp,skew,Doppler scale,orthogonal frequency-division multiplexing (OFDM),time synchronization,underwater sensor network (UWSN),Acoustic communication
更新于2025-09-16 10:30:52