- 标题
- 摘要
- 关键词
- 实验方案
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ACO–OFDM with Improved Bandwidth Efficiency over Long Haul and MIMO Optical Fiber Communication Systems
摘要： Authors propose an improved orthogonal frequency division multiplexing (OFDM) scheme in which the information samples are transmitted in otherwise discarded negative frame of asymmetrically clipped OFDM (ACO–OFDM). ACO–OFDM has two similar positive and negative OFDM envelopes so that clipping does not result in loss of signal information. The flipped polarity negative samples are inserted at the zeros of positive frame or back to back with positive frame, in time-compressed frame such that composite signal has the same frame duration as ACO–OFDM but improved transmission power, bandwidth efficiency. Simulation results for bit error rate with respect to number of subcarriers and optical launch power show that the proposed time-compressed OFDM frames perform better in high-dispersion condition over long distance, high data rate, and high transmission power over single-mode fiber. It has been demonstrated that the proposed time-compressed frame structure also performs well with the 2*2 MIMO setup for multimode fiber link.
关键词： ACO–OFDM,Efficiency,Dispersion,Nonlinearity,MIMO,Bandwidth
更新于2025-09-11 14:15:04
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Comparison of Optical OFDM and M-PAM for LED-Based Communication Systems
摘要： Light-emitting diode (LED)-based communications, such as visible light communications (VLC) and infrared (IR) communications, are candidate techniques to provide short-range and high-speed data transmission. In this paper, M-ary pulse amplitude modulation (M-PAM), used as a high bandwidth efficiency scheme, is compared with three well-known optical orthogonal frequency division multiplexing (OFDM) schemes. Considering the bandwidth limit and constrained peak transmitted power characteristics of LEDs, a bit loading algorithm and single-tap equalizer with an optimized modulation index are used for the optical OFDM schemes tested. To reduce the inter-symbol interference caused by the bandlimited channel, an optimized pulse shape and a minimum mean squared error (MMSE) equalizer are applied to the M-PAM system. From numerical results, M-PAM can provide a substantially higher data rate than OFDM for bandlimited channels. When the channel bandwidth is ample compared with the symbol rate, optical OFDM outperforms M-PAM.
关键词： pulse shaping,infrared communications,M-PAM,OFDM,bit loading,visible light communications,MMSE equalizer,optical wireless communications
更新于2025-09-11 14:15:04
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[IEEE 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Fukuoka, Japan (2019.7.7-2019.7.11)] 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Flexible Management of WDM-PON Using AMCC for 5G Radio Access Networks
摘要： This paper overviews flexible management functions of WDM-PON using an auxiliary management and control channel and introduces wavelength allocation, adjustment as use-cases.
关键词： Optical access networks for post 5G mobile service,Future high capacity and long-reach access networks including WDM-PON, OFDM-PON, TWDM-PON,Access Network and Subsystem,Optical access network architecture, design, protection, and management
更新于2025-09-11 14:15:04
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Compressed Sensing-Aided Index Modulation Improves Space-Time Shift Keying Assisted Millimeter-Wave Communications
摘要： In this treatise, we present the concept of Compressed-Sensing (CS)-aided Space-Time Shift Keying Index Modulation (STSK-IM), where a virtual domain Orthogonal Frequency Division Multiplexing (OFDM) symbol is divided into Na-sized blocks, which carry K STSK codewords over a specific combination of virtual-domain sub-carriers and then converted to the frequency domain with the aid of a CS matrix. We design the system for operation in the Milli-meter Wave (mmWave) frequency band. Furthermore, we amalgamate our soft-decision-aided scheme both with the concept of Coordinate-Interleaving (CI) as well as a Discrete Fourier Transform (DFT)-aided codebook design conceived for analogue beamforming, which is vitally important for mmWave systems. In the proposed system, the number of implicit bits conveyed by the activated sub-carrier Frequency Index (FI) is determined by the number of the available K to Na sub-carrier permutations. Hence, we propose two FI allocation techniques, namely the Distinct FI (DFI) and the Shared FI (SFI) based schemes, which strike a trade-off between the attainable sparsity level and the achievable capacity limit. We then introduce a reduced-complexity detection technique in order to mitigate the detection complexity to order of the optimum detector from O(Nc · (Q · L)K) to O(?Nc · (Q · L)K), where ?Nc ≤ Nc. We also formulate the Discrete-Input Continuous-Output Memoryless Channel (DCMC) capacity and invoke EXtrinsic Information Transfer (EXIT) charts for characterizing the achievable performance limit of the reduced-complexity aided detector. Finally, we analyze the BER performance of both the uncoded and of our coded CS-aided STSK-IM systems associated with both the optimum and the reduced-complexity detectors.
关键词： Spatial Modulation,Compressed Sensing,mmWave,Reduced Complexity detection,Millimeter-wave communications,Space-Time Shift Keying,channel coding,PSK,QAM,MIMO,Coordinate Interleave,Spatial modulation,5G,OFDM,Index modulation,wideband channel
更新于2025-09-11 14:15:04
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Performance Analysis of Radio-over-Fiber Based on Phase-Modulation and Direct-Detection for the Future 5G Network
摘要： Access transport network plays a vital role in actual mobile networks to support the need of high data rates, real time services and spectrum efficiency. The future 5G requires an access network with high performances especially in the mm-wave bands. In this work, we propose a radio-over-fiber architecture based on intensity modulation for the downlink and phase modulation for the uplink. This solution permits to cancel optical sources and reduces electrical consumption in the multiple base stations. We focus our study on the phase modulation and direct detection link by evaluation of the quality of the wireless transmitted signal.
关键词： radio-over-fiber,5G network,optical phase modulation,filtered-OFDM
更新于2025-09-11 14:15:04
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Comparison of DCO-OFDM, ADO-OFDM, HDC-OFDM and HNC-OFDM for Optical Wireless Communications
摘要： This paper presents a new form of orthogonal frequency division multiplexing (OFDM) termed as hybrid noise cancelled asymmetrically clipped optical OFDM (HNC-OFDM) for optical wireless communication. This HNC-OFDM is formed by combining the concepts of noise cancelled asymmetrically clipped optical OFDM and DC biased optical OFDM (DCO-OFDM). HNC-OFDM has the same bit error rate (BER) performance and dimming flexibility but less complexity compared to the recently developed hybrid diversity combined OFDM. The optimum DC bias level for HNC-OFDM, DCO-OFDM and asymmetrically clipped DC biased optical OFDM is shown to depend on the target BER, the constellation size, the received signal to noise power ratio, the proportion of DCO-OFDM element, the link type, equalization, etc. Simulations results show that with an optimum bias, HNC-OFDM can outperform others in an average power limited channel, while DCO-OFDM is a better choice for a peak power limited channel.
关键词： optical wireless communication,Dimming,LiFi,visible light communication,OFDM
更新于2025-09-11 14:15:04
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[IEEE 2018 41st International Conference on Telecommunications and Signal Processing (TSP) - Athens, Greece (2018.7.4-2018.7.6)] 2018 41st International Conference on Telecommunications and Signal Processing (TSP) - A Novel Discrete Wavelet Transform based Coherent Optical OFDM System
摘要： In optical communication, which is an important part of the Radio over Fiber (RoF) systems, coherent optical OFDM (CO-OFDM) systems allow the use of amplitude and phase belong to the light at the same time for data transmission. However, the data transmission speed and distance of the CO-OFDM system are limited by optical channel impairment effects. One of the major disadvantages of CO-OFDM systems is its sensitivity to fiber nonlinearity effects. For this reason, in order to be used the new signal processing techniques efficiently in the receiver, the optical channel information must be estimated and the received signal must be equalized. In this work, different equalizer constructions are investigated and a frequency domain channel equalizer used in the novel DWT-based CO-OFDM system has been proposed. With the simulation studies made, the equalizers were compared and the results were given with different changes. From the obtained simulation results, it is seen that the proposed method provides about 5.5 OSNR gain for 1E-4 BER value.
关键词： fiber nonlinearity impairment,discrete wavelet transform,Radio over Fiber,CO-OFDM systems,frequency domain equalizer
更新于2025-09-10 09:29:36
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Symbol Error Probability Analysis of DFrFT-based OFDM Systems with CFO and STO in Frequency Selective Rayleigh Fading Channels
摘要： In this article we derive exact symbol error probability (SEP) expressions for orthogonal frequency-division multiplexing (OFDM) based on discrete fractional Fourier transform (DFrFT) when symbol timing offset (STO) and carrier frequency offset (CFO) are present together. Closed form expressions are derived for binary phase shift keying, quadrature phase shift keying, and 16-ary quadrature amplitude modulation in the case of transmission over a frequency selective Rayleigh fading channel. As is well known, in OFDM the presence of CFO destroys the orthogonality between the sub-carriers, generating inter-carrier interference (ICI), while the presence of STO introduces intersymbol interference, between successive symbols, and phase rotations in frequency domain, within the same symbol. It is well recognized that an OFDM system based on DFrFT is more robust to ICI introduced by CFO than that based on discrete Fourier transform (DFT). Motivated by this, the combined effect of CFO and STO on the SEP of a DFrFT-based OFDM system is analyzed. Our results show that the DFrFT-based OFDM system outperforms that based on the DFT for different values of the DFrFT ‘angle parameter’. Monte Carlo simulations are used to demonstrate the correctness of the derived analytical expressions.
关键词： sampling-type FrFT,frequency selective fading,carrier frequency offset.,orthogonal frequency-division multiplexing (OFDM),Error rate analysis,symbol timing offset
更新于2025-09-10 09:29:36
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[IEEE 2017 IEEE International Conference on Computational Intelligence and Computing Research (ICCIC) - Coimbatore, India (2017.12.14-2017.12.16)] 2017 IEEE International Conference on Computational Intelligence and Computing Research (ICCIC) - Multiuser Visible Light Communication System For Reliable Wireless Communication
摘要： Visible Light Communication (VLC) is evolving likewise a guaranteeing act on give pervasive remote association. In this paper, we study an indoor multiuser Visible Light Communication framework can substantially increase the achievable bit rate of Adaptively Modulated Optical Orthogonal Frequency-Division Multiplexing (AMO-OFDM) system and has the ability to maximise data throughput by adjusting the number of bits per subcarrier based on the set of subcarrier's channel Gain to Noise Ratio (GNR). For each subcarrier resolved alongside OFDM, those comparing precoding grids will be in the recurrence area to eradicate multiuser viewed as obstruction. VLC is one of the promising candidates because of its features of non-licensed channels, high bandwidth and low power consumption. As a visible light source can be used both for illumination and communication, therefore, it saves the extra power that is required in RF communication. The revolution in the field of solid state lighting leads to the replacement of florescent lamps by Light Emitting Diodes (LEDs) which further motivates the usage of VLC.The modulation bandwidth of white emanation is about ～2MHz.
关键词： VLC (Visible Light Communication),Multiple transmitter and receiver links,MIMO (Multiple Input Multiple Output),OFDM (Orthogonal Frequency Division Multiplexing),MMSE (Minimum Mean-Squared Error),Precoding
更新于2025-09-10 09:29:36
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Convolution neural network-based time-domain equalizer for DFT-Spread OFDM VLC system
摘要： This paper presents a novel time-domain equalizer for visible light communication (VLC) system using machine learning (ML) method. In this work, we employ discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) as modem scheme and convolution neural network (CNN) as kernel processing unit of equalizer. After estimating channel state information (CSI) from training sequence, the proposed equalizer recovers transmitted symbols according to the estimated CSI. Numerical simulations indicate that the equalizer can significantly enhance bit error rate (BER) performance. For example, when signal-to-noise ratio (SNR) is 20dB and 16/32/64-quadrature amplitude modulation (QAM) is exploited, original BER is about 0.5 while the BER after recovery achieves 10?5, which is much lower than forward error correction (FEC) limit 3.8×10?3. This work promotes the application of ML in VLC domain. To the best of our knowledge, this is the first time a CNN-based equalizer has been explored.
关键词： Machine learning (ML),Discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM),Visible light communication (VLC),Convolution neural network (CNN)
更新于2025-09-10 09:29:36