- 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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[Communications in Computer and Information Science] Futuristic Trends in Network and Communication Technologies Volume 958 (First International Conference, FTNCT 2018, Solan, India, February 9–10, 2018, Revised Selected Papers) || Future Perspectives in Elastic Optical Networks
摘要： The new generation Elastic Optical Networks (EONs) based on Orthogonal Frequency Division Multiplexing (OFDM) can accommodate exponentially increasing heterogeneous data traffic efficiently and economically. In EONs, the optimum channel spacing between various subcarriers is very crucial for its efficient performance. The use of Sub-Carrier Multiplexing (SCM) in EONs is visualized as an evolving field. This paper present the evaluation of SCM based EONs for both mathematical and simulative model. The designed SCM-EON network is analytically evaluated for its performance with different modulation techniques (Direct Modulation and External Modulation). The performance of system is also evaluated for amplification using Semiconductor Optical Amplifier (SOA) and Erbium Doped Fiber Amplifier (EDFA). Simulative results show that Optical Phase Modulation (OPM) along with EDFA offers enhanced performance for the proposed model. It has also been observed that OPM is a better technique for SCM and hence it can be deduced that the combination will boost EONs efficiency in handling network resources.
关键词： SCM,Elastic Optical Networks,OFDM,EDFA,OPM,Bandwidth variable-wavelength cross-connects (BV-WXC),Quadrature Amplitude Modulation (QAM),Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM),Mach-Zehnder modulator (MZM)
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 2018 International Conference on Advanced Science and Engineering (ICOASE) - Duhok (2018.10.9-2018.10.11)] 2018 International Conference on Advanced Science and Engineering (ICOASE) - An ICI Reduction Based on PAPR Clipping in Coherent Optical OFDM System
摘要： The Inter-Carrier Interference (ICI) compensation for Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM) system has been studied in this paper. The purpose behind is to investigate the presence of ICI due to the impact of Laser Phase Noise (LPN) and Fiber Non-Linearity (FNL). Thereby, we propose a simple clipping scheme which represents an effective distortion algorithm to decrease the Peak to Average Power Ratio (PAPR) for 4QAM system. The method exhibits a significant process on ICI cancellation in CO-OFDM system. The OFDM signal is basically transmitted along 550km distance rated at 10Gbps single mode fiber for the coherent optical mode. The new findings show that the receiver sensitivity is highly improved below 10-3 FEC for laser power 5dBm; and archives about 1dBm to 2.4dBm when laser power becomes 8dBm at a typical clipping ratio of 0.6. In particular, the system exhibits a good performance over a 385km transmission distance in comparison to the conventional CO-OFDM. As a result, the proposed clipping shows that the system can enhance its the performance by reducing ICI in the CO-OFDM system; in addition to present a high robustness in BER metric against FNL by a clear reduction in PAPR.
关键词： Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM),Inter-Carrier Interference (ICI),Peak to Average Power Ratio (PAPR),Fiber Nonlinearity (FNL),Bit Error Rate (BER),Laser Phase Noise (LPN)
更新于2025-09-23 15:22:29
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Design of PAM-DMT-based Hybrid Optical OFDM for Visible Light Communications
摘要： In this letter, a pulse-amplitude-modulated based hybrid optical orthogonal frequency division multiplexing (PHO-OFDM) scheme is proposed. We use the high order quadrature-amplitude-modulation to replace the one-dimensional pulse-amplitude-modulated on the even subcarriers for compensating the data capacity weakness of the conventional pulse amplitude modulated discrete multitone (PAM-DMT). The combined time-domain PHO-OFDM signal has a larger amplitude range than the original PAM-DMT but with a reduced peak-to-average power ratio (PAPR). Besides that, a flexible power allocation method is introduced to the proposed PHO-OFDM systems to fully exploit the whole dynamic range of LEDs. The simulation results show that, under the same average bit rate, the proposed PHO-OFDM scheme has a better bit error rate performance compared with the conventional PAM-DMT scheme, thus demonstrating its application potential in visible light communications.
关键词： visible light communications (VLC),pulse-amplitude-modulated discrete multitone (PAM-DMT),optical orthogonal frequency division multiplexing (O-OFDM)
更新于2025-09-23 15:22:29
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Distributed Processing for Multi-Relay Assisted OFDM with Index Modulation
摘要： Orthogonal frequency-division multiplexing with index modulation (OFDM-IM) has become a high-profile modulation scheme for the fifth generation (5G) wireless communications, and thus been extended to multi-hop scenarios in order to improve the network coverage and energy efficiency. However, the extension of OFDM-IM to multi-relay cooperative networks is not trivial, since it is required that a complete OFDM block should be received and decoded as an entity in one node. This requirement prevents the employment of multiple relays to forward fragmented OFDM blocks on individual subcarriers. In this regard, we propose a distributed processing scheme for multi-relay assisted OFDM-IM, by which multiple relays are selected to forward signals in a per-subcarrier manner to provide optimal error performance for two-hop decode-and-forward (DF) OFDM-IM systems. Specifically, a single selected relay only needs to decode partial information carried on certain active subcarriers and forward just as for traditional OFDM systems without IM. After receiving all signals on active subcarriers forwarded by different relays, the destination can reconstruct the complete OFDM block and retrieve the full information. We analyze the average block error rate (BLER) and modulation capacity of the two-hop OFDM-IM system employing the proposed distributed DF protocol and verify the analysis by numerical simulations.
关键词： multi-carrier relay selection,decode-and-forward (DF) relaying,Orthogonal frequency-division multiplexing with index modulation (OFDM-IM),distributed system,distributed processing
更新于2025-09-23 15:22:29
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Dimming Control Systems Based on Low-PAPR SCFDM for Visible Light Communications
摘要： In this paper, the efficient dimming control systems based on single-carrier frequency-division multiplexing (SCFDM) are proposed for visible light communications (VLC). By virtue of the strengths of the low peak-to-average power ratio and the inherent resistance to high-frequency distortion, the proposed SCFDM-based dimming control schemes are adaptive to the bandwidth-limited and linearity-limited VLC system, thus supporting the wide dimming range for different illumination requirements. Two SCFDM-based VLC systems with dimming control including asymmetrical hybrid optical SCFDM (AHO-SCFDM) and DC-biased optical SCFDM (DCO-SCFDM) are proposed. For AHO-SCFDM with spectral efficiency of 1.75 bit/s/Hz and DCO-SCFDM with spectral efficiency of 2 bit/s/Hz, the 20% wider dimming range can be achieved than their orthogonal frequency-division multiplexing (OFDM) based counterparts, respectively. Meanwhile, the two proposed schemes can also achieve 24.8% and 31.3% gains of average spectral efficiency under the same dimming range compared with their counterparts, respectively. For an overall analysis, SCFDM shows the feasibility and superiority for dimming control systems.
关键词： light emitting diode,Visible light communication,single-carrier frequency-division multiplexing,dimming control,orthogonal frequency-division multiplexing
更新于2025-09-23 15:21:21
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Sherman-Morrison Formula Aided Adaptive Channel Estimation for Underwater Visible Light Communication With Fractionally-sampled OFDM
摘要： In this paper, we investigate the channel estimation (CE) problem in an underwater visible light communication (UVLC) system invoking fractionally-sampled optical orthogonal frequency division multiplexing (FS-OOFDM). In practical UVLC scenarios, the communication links inevitably suffer from many stochastic channel effects including multi-path dispersion, scattering, turbulence, etc., and/or from the mobility of the transceiver, therefore resulting in a time-varying, location-dependent non-stationary propagation environment. Naturally, compared with the indoor visible light communication (VLC) scenario with a typical assumption being the time-flat channel models, it becomes a notable challenge for designing a low-complexity adaptive CE in the much more complicated UVLC scenarios. To solve this problem, we derive a class of Bayesian CE algorithms referred to as the Sherman-Morrison formula (SMF) based CE (SMF-CE), by exploiting the property of rank-one structure of the second-order channel statistics in the delay domain. Furthermore, an adaptive version of SMF-CE (ASMF-CE) can be obtained through updating the imperfect a priori knowledge of the channel and the noise’s statistics. Simulation results demonstrate the superior performances of the proposed algorithms in comparison to existing methods, while maintaining a reduced computational complexity in comparison to the conventional linear minimum mean square error (LMMSE) scheme.
关键词： Sherman-Morrison formula (SMF),Channel estimation (CE),underwater visible light communication (UVLC),fractional sampling (FS),optical orthogonal frequency division multiplexing (OOFDM)
更新于2025-09-23 15:21:01
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Performance analysis of colour coded multiple access orthogonal frequency division multiplexing visible light communication system
摘要： Performance analysis of colour coded multiple access (CCMA) orthogonal frequency division multiplexing (OFDM) visible light communication (VLC) System is discussed in this paper. First, characteristics of optical OFDM are studied. Second, CCMA is achieved using three laser diodes (LD): red, green and blue LDs. Finally, OFDM-modulated signals are optically modulated with red, green and blue LDs (RGB LDs). Then these three optical signals are combined together to form white light which illuminates as well as provides high-speed data transmission. The performance of the proposed CCMA OFDM VLC system is studied using constellation diagrams, signals and spectrum comparisons. The system is simulated for the data rate of 10 Gbps.
关键词： red, green blue laser diodes,laser diodes,high data rate,visible light communication,colour coded multiple access,orthogonal frequency division multiplexing
更新于2025-09-23 15:21:01