To adapt to the multi-scale and multi-dimensional communication scenarios in 6G wireless communications,photon-assisted terahertz(THz)technology has attracted widespread attention due to its low latency and high direc...To adapt to the multi-scale and multi-dimensional communication scenarios in 6G wireless communications,photon-assisted terahertz(THz)technology has attracted widespread attention due to its low latency and high directivity,which maximizes the broadband and high-frequency response characteristics of optical devices and effectively breaks through the capacity limitation of electronic THz technology[1,2].However,THz wireless communications face the problem of weak THz wave penetration and large path loss caused by strong atmospheric attenuation,which limits the coverage of THz signals[3,4].Therefore,multiple-input multiple-output(MIMO)technology has been introduced in the THz system by using antenna arrays at both the transmitter and the receiver to improve the quality of THz links and increase the capacity of wireless networks[5-7].展开更多
We demonstrate a 200 m outdoor 2×2 multiple-input multiple-output(MIMO)terahertz(THz)communication system operating at 300 GHz with 200 Gb/s polarization-division multiplexed quadrature phase-shift keying(PDM-QPS...We demonstrate a 200 m outdoor 2×2 multiple-input multiple-output(MIMO)terahertz(THz)communication system operating at 300 GHz with 200 Gb/s polarization-division multiplexed quadrature phase-shift keying(PDM-QPSK)transmission.We propose an iteratively pruned two-dimensional convolutional neural network(2D CNN)equalizer that adaptively captures polarization crosstalk and temporal nonlinearities through 2D convolution kernels.The system achieves a bit error rate(BER)below the hard-decision forward error correction(HD-FEC)threshold at a lower power of 6 d Bm,while reducing the computational complexity by 30.2%compared to the iteratively pruned one-dimensional(1D)CNN approach.This enables high-capacity and energy-efficient operation in long-distance THz links.展开更多
In recent years,free space optical communication(FSO)has been a hot topic in satellite-to-ground communications,inter-satellite communications,and wireless access networks[1-4].It has the advantages of rich spectrum r...In recent years,free space optical communication(FSO)has been a hot topic in satellite-to-ground communications,inter-satellite communications,and wireless access networks[1-4].It has the advantages of rich spectrum resources,no need for spectrum authorization,high spectrum efficiency verified by experiments,narrow beam angle,and low space loss under good weather.In point-to-point communications,the beam angle makes the FSO almost immune to multipath effects,and low-complexity Digital Signal Processing(DSP)algorithms can be used for recovery demodulation.展开更多
A pre-coding-assisted power detection scheme for radio over fiber downlink is presented. This scheme can eliminate laser phase noise while avoiding high energy-consuming electrical carrier required in conventional pow...A pre-coding-assisted power detection scheme for radio over fiber downlink is presented. This scheme can eliminate laser phase noise while avoiding high energy-consuming electrical carrier required in conventional power and/or envelope detection schemes. Theoretical analysis and experimental verification are performed.0.625 Gbaud pre-coded quadrature phase-shift keying or 16 quadrature amplitude modulation signals can both be recovered by power detection without electrical carrier assistance at the receiver after 75 km fiber transmission. Not only robust against the laser phase noise, an improvement of about 5 dB in receiver sensitivity can also be achieved, as compared with the conventional power detection scheme.展开更多
We propose and investigate the use of a Kramers–Kronig(KK) receiver in a single sideband orthogonal frequency division multiplexing radio over fiber(SSB-OFDM-RoF) link based on an optical remote heterodyne solution. ...We propose and investigate the use of a Kramers–Kronig(KK) receiver in a single sideband orthogonal frequency division multiplexing radio over fiber(SSB-OFDM-RoF) link based on an optical remote heterodyne solution. This scheme is effective in eliminating the signal-to-signal beating interference introduced by square-law detection of a photo-detector in an SSB-OFDM-RoF link. We extensively study the influences of different carrier-to-signal power ratios(CSPRs), laser linewidths, and transmission distances on our proposed scheme. It is proved that the KK-based receiver can reduce optimal CSPR by more than 5 dB and provide about 1.1 dB gain over the conventional mixer-based receiver scheme with CSPR of 11 dB after 75 km fiber transmission.展开更多
In this Letter,we demonstrate the transmission of fifth-generation new radio(5G NR)signals over a fiber-millimeter-wave(mmWave)-fiber mobile fronthaul system in the 75–110 GHz band for an ultra-dense small cell netwo...In this Letter,we demonstrate the transmission of fifth-generation new radio(5G NR)signals over a fiber-millimeter-wave(mmWave)-fiber mobile fronthaul system in the 75–110 GHz band for an ultra-dense small cell network.The system employs a simple all-optical conversion technology,including mmWave signal generation using an optical heterodyne and a photonicsenabled receiver based on different modulator schemes.As a proof-of-concept demonstration,we successfully transmit400 MHz 64QAM/256QAM at 3.5 and 4.9 GHz.The proposed system can provide a simple solution for facilitating the deployment of ultra-dense small cells in high-frequency bands for 5G mmWave/intermediate-frequency-over-fiber networks.展开更多
基金supported by the National Key R&D Program of China(Grant No.2023YFB2905600)the National Natural Science Foundation of China(Grant Nos.62127802,62331004,62305067,U24B20142,U24B20168,62427815)the Key Project of Jiangsu Province of China(Grant No.BE2023001-4).
文摘To adapt to the multi-scale and multi-dimensional communication scenarios in 6G wireless communications,photon-assisted terahertz(THz)technology has attracted widespread attention due to its low latency and high directivity,which maximizes the broadband and high-frequency response characteristics of optical devices and effectively breaks through the capacity limitation of electronic THz technology[1,2].However,THz wireless communications face the problem of weak THz wave penetration and large path loss caused by strong atmospheric attenuation,which limits the coverage of THz signals[3,4].Therefore,multiple-input multiple-output(MIMO)technology has been introduced in the THz system by using antenna arrays at both the transmitter and the receiver to improve the quality of THz links and increase the capacity of wireless networks[5-7].
基金supported by the National Key R&D Program of China(No.2023YFB2905600)the National Natural Science Foundation of China(Nos.62127802,62331004,62305067,U24B20142,U24B20168,and 62427815)the Key Project of Jiangsu Province of China(No.BE2023001-4)。
文摘We demonstrate a 200 m outdoor 2×2 multiple-input multiple-output(MIMO)terahertz(THz)communication system operating at 300 GHz with 200 Gb/s polarization-division multiplexed quadrature phase-shift keying(PDM-QPSK)transmission.We propose an iteratively pruned two-dimensional convolutional neural network(2D CNN)equalizer that adaptively captures polarization crosstalk and temporal nonlinearities through 2D convolution kernels.The system achieves a bit error rate(BER)below the hard-decision forward error correction(HD-FEC)threshold at a lower power of 6 d Bm,while reducing the computational complexity by 30.2%compared to the iteratively pruned one-dimensional(1D)CNN approach.This enables high-capacity and energy-efficient operation in long-distance THz links.
基金partially supported by the National Key R&D Projects of China(Grant No.2023YFB2905600)the National Natural Science Foundation of China(Grant Nos.61835002,61935005,62305067,62375219,62331004)the Jiangsu Province Key Project(Grant No.BE2023001-4)。
文摘In recent years,free space optical communication(FSO)has been a hot topic in satellite-to-ground communications,inter-satellite communications,and wireless access networks[1-4].It has the advantages of rich spectrum resources,no need for spectrum authorization,high spectrum efficiency verified by experiments,narrow beam angle,and low space loss under good weather.In point-to-point communications,the beam angle makes the FSO almost immune to multipath effects,and low-complexity Digital Signal Processing(DSP)algorithms can be used for recovery demodulation.
基金supported by the National Natural Science Foundation of China(No.61420106011)the Fundamental Research Funds for the Central Universities(No.ZYGX2016J014)
文摘A pre-coding-assisted power detection scheme for radio over fiber downlink is presented. This scheme can eliminate laser phase noise while avoiding high energy-consuming electrical carrier required in conventional power and/or envelope detection schemes. Theoretical analysis and experimental verification are performed.0.625 Gbaud pre-coded quadrature phase-shift keying or 16 quadrature amplitude modulation signals can both be recovered by power detection without electrical carrier assistance at the receiver after 75 km fiber transmission. Not only robust against the laser phase noise, an improvement of about 5 dB in receiver sensitivity can also be achieved, as compared with the conventional power detection scheme.
基金supported by the National Natural Science Foundation of China(Nos.61420106011 and 61471088)the Fundamental Research Funds for the Central Universities(No.ZYGX2016J014)
文摘We propose and investigate the use of a Kramers–Kronig(KK) receiver in a single sideband orthogonal frequency division multiplexing radio over fiber(SSB-OFDM-RoF) link based on an optical remote heterodyne solution. This scheme is effective in eliminating the signal-to-signal beating interference introduced by square-law detection of a photo-detector in an SSB-OFDM-RoF link. We extensively study the influences of different carrier-to-signal power ratios(CSPRs), laser linewidths, and transmission distances on our proposed scheme. It is proved that the KK-based receiver can reduce optimal CSPR by more than 5 dB and provide about 1.1 dB gain over the conventional mixer-based receiver scheme with CSPR of 11 dB after 75 km fiber transmission.
基金supported by the National Natural Science Foundation of China(Nos.62101121,62101126,62201397,62201393,62271135)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX21_0036)。
文摘In this Letter,we demonstrate the transmission of fifth-generation new radio(5G NR)signals over a fiber-millimeter-wave(mmWave)-fiber mobile fronthaul system in the 75–110 GHz band for an ultra-dense small cell network.The system employs a simple all-optical conversion technology,including mmWave signal generation using an optical heterodyne and a photonicsenabled receiver based on different modulator schemes.As a proof-of-concept demonstration,we successfully transmit400 MHz 64QAM/256QAM at 3.5 and 4.9 GHz.The proposed system can provide a simple solution for facilitating the deployment of ultra-dense small cells in high-frequency bands for 5G mmWave/intermediate-frequency-over-fiber networks.
